Page 27 – Practical Gastro

Prior research has demonstrated that children from low- and middle-income countries have a specific microbiome taxa that change in the setting of malnutrition, and such changes may contribute to malnutrition. This study from Bangladesh recruited children between 12 and 18 months of age with moderate acute malnutrition. Such children were randomized to consume either a newly developed microbiota-directed complementary food (MDCF) or a standard ready-to-use supplementary food (RUSF) for three months. The MDCF used in this study was MDCF-2 which is a new formulation that previously has been shown to change the microbiome to beneficial taxa. Anthropometric data was measured every 15 days, and fecal samples were obtained one month after the intervention. Besides anthropometric data, all patients underwent plasma proteomic profiling and gut microbiota determination.

A total of 123 subjects were enrolled (61 received MDCF-2 and 62 received RUSF). No was present regarding anthropometrics and social demographics between the two treatment groups. Both weight-for-length z scores and weight-for-age z scores significantly improved in the MDCF-2 group compared to the RUSF group. Plasma protein analysis showed that 714 proteins significantly increased or decreased in patients receiving MDCF-2 versus 82 proteins which significantly increased or decreased in patients receiving RUSF. Specific proteins that increased significantly in the MDCF-2 group included intermediate layer protein 2 (which improves articular cartilage formation), thrombospondin-4 (which helps develop bone and skeletal muscle), and SFRP4 (which is an osteoclast inhibitor). Fecal analysis demonstrated that 23 bacterial taxa (identified by amplicon sequence variants) were significantly associated with weight-forlength z scores (21 positively associated; 2 negatively associated). Interestingly, 5 of these taxa promoting growth had been identified previously in gnotobiotic mouse studies. Finally, these specific 21 bacterial taxa associated with increased weightfor- length z scores were significantly increased in children receiving MDCF-2 compared to children receiving RUSF and had a positive correlation with 70 plasma proteins associated with improving weight-for-length z scores.

This study demonstrates that changing the fecal microbiome via dietary manipulation may reverse the effects of malnutrition. This finding is intriguing as such effects also could occur in the setting of various types of intestinal inflammation. It is interesting to note that the significant improvements in malnutrition in children receiving MDCF-2 occurred despite this formulation having less caloric density compared to RUSF.

^{Chen R, Mostafa I, Hibberd M, Das S, Mahfuz M, Naila N, Islam M, Huq S, Alam A, Zaman M, Raman A, Webber D, Zhou C, Sundaresan V, Ahsan K, Meier M, Barratt M, Ahmed T, Gordon J. A microbiotadirected food intervention for undernourished children. N Engl J Med 2021; 384: 1517-1528.}

Safety of Biopsy Techniques for Hirschsprung Disease

Hirschsprung Disease (HD) is due to aganglionosis of the colon that presents in the distal colon and then proximally. HD typically presents in the first few days of life, and early diagnosis is imperative to provide corrective surgery and to prevent complications such as enterocolitis. Several colonic biopsy techniques exist which help determine the presence of HD, and the authors of this study performed a meta-analysis using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement (PRISMA) for patients younger than 18 years of age with potential HD. All included studies had to include at least 5 patients or at least 5 rectal biopsy specimens. Biopsy types included suction, open surgical, endoscopic, or punch biopsy. Various staining techniques to diagnose HD included hematoxylin and eosin staining, acetylcholinesterase staining, and calretinin staining.

Although an initial analysis by text and abstract screening produced 469 articles, only 159 articles met inclusion criteria after full-text review. A total of 300 patients in the meta-analysis underwent endoscopic biopsy while 3369 patients underwent open biopsy, 1507 underwent punch biopsy, and 20,775 patients underwent suction biopsy. The mean age of patients ranged from 27.84 months (suction biopsy group) to 50.40 months old (punch biopsy group). Interestingly, although no significant difference was present between the conclusive rate result of the various biopsy techniques, the heterogeneity between meta-analysis of biopsy types (using the I2 statistic) was significant (P<0.001). Funnel plot analysis for suction biopsy and open biopsy suggested a possible publication bias.

There was no difference in age (defined as less than 36 months of age and greater than 36 months of age) for conclusive results for patients undergoing suction rectal biopsy, and not enough evidence was available to determine effectiveness of results using the other rectal biopsy techniques. No difference was seen between the various staining techniques in determining conclusive results for HD; however, there was significant study heterogeneity between staining types (P<0.001). Various staining techniques were not significantly different for patients undergoing open surgical biopsy for HD although significant heterogeneity existed between the study groups (P<0.001) while no significant heterogeneity existed for patients undergoing suction rectal biopsy. Finally, the pooled complication rate for the various biopsy techniques was 2% with a significant rate of complications noted for patients receiving punch biopsy versus those receiving suction biopsy.

This study demonstrates that all biopsy techniques for the diagnosis of HD likely are equal in their capacity to generate conclusive results. The authors state that the safety of suction rectal biopsy (including the potential lack of need of sedation) makes it a first-line method for diagnosing HD in children.

^{Comes G, Ortolan E, Moreira M, de Oliveira Junior W, Angelini M, El Dib R, Lourencao P. Rectal biopsy technique for the diagnosis of Hirschsprung disease in children: a systematic review and meta-analysis. Journal of Pediatric Gastroenterologists and Nutrition 2021; 72: 494-500.}

DISPATCHES FROM THE GUILD CONFERENCE, SERIES #38

Therapeutic Drug Monitoring of Biologics in Inflammatory Bowel Disease: What, When and Why?

Divya Ashat,

Millie D. Long

Therapeutic drug monitoring (TDM) of biologics in inflammatory bowel disease (IBD) is useful in various arenas of clinical practice. It involves the measurement of drug concentrations and anti-drug antibody levels to help optimize therapy. The most popular strategy now considered to be standard of care is ‘reactive drug monitoring’ which is done when the patient is symptomatic from their disease. Reactive TDM is both efficacious and cost effective when compared to empiric therapy changes. ‘Proactive drug monitoring’ is an emerging strategy that utilizes a target drug level, often early during an induction period, with adjustments in dosing prior to any development of symptoms. Additional uses of TDM include during de-escalation from combination therapy to biologic monotherapy and re-initiation of biologic therapy after a drug holiday. Prudent use of these assays is essential to reduce costs and avoid unnecessary testing.

Inflammatory bowel disease (IBD) is characterized by chronic inflammation of the gastrointestinal tract and has two subtypes, namely Crohn’s disease (CD) and ulcerative colitis (UC). Immunosuppressive agents used in the treatment of IBD include corticosteroids, immunomodulators [thiopurines or methotrexate], biologic agents [anti-tumor necrosis factor alpha (anti-TNFs), anti-integrin therapies, anti-IL-12/23 inhibitors] and janus kinase inhibitors.

Biologic therapies in IBD are genetically engineered monoclonal antibodies targeted against inflammatory antigens. They have revolutionized IBD treatment and are considered as first-line therapy in moderate-severe IBD patients.^1,2 Despite their proven efficacy, almost 50% of biologics require discontinuation due to failure to respond to induction therapy (primary non-response), loss of response over time (secondary non-response) or serious adverse events.³ The concept of therapeutic drug monitoring (TDM) refers to the practice of measuring drug concentrations and anti-drug antibodies to help guide treatment changes and optimize the use of biologics. This article will review recommendations from current guidelines and recent evidence on therapeutic drug monitoring of biologics in IBD.

Drug Assays in Practice

At present, therapeutic classes of biologics we can monitor in IBD include anti-TNFs biologics (infliximab, adalimumab, certolizumab pegol and golimumab) and other biologics (vedolizumab, ustekinumab). Drug assays measure drug concentrations and anti-drug antibody levels for individual biologics.⁴ Drug concentrations show good correlation amongst assays when measured as trough levels, that is, as close to the next dose as possible within 24 hours.⁵ Multiple factors both drug-related (route of administration, dose, inherent immunogenicity, presence of anti-drug antibodies, use of concomitant immunomodulators) and patientrelated (such as sex, body mass index, albumin levels, CRP levels) affect the drug concentrations of biologics.⁶ Low drug concentrations are associated with antibody development, loss of response and overall poor outcomes.⁵ Higher drug concentrations have been associated with better outcomes and do not necessarily increase the risk of side effects. Anti-drug antibody levels are produced as an immune response to the biologic protein and is one of the major causes for loss of response to biologic therapy. Anti-TNFs are considered to be more immunogenic than other biologics.⁷ Unlike drug trough levels, there is low agreement across assays on the levels of anti-drug antibody levels.⁵ It is, therefore, important to check the reference ranges for the assay being used. There are a variety of commercially available assays for measurement of biologics. The choice of assay typically depends on what is available in the area of practice and insurance coverage. Trying to use of the same assay in practice allows one to become familiar with the reference ranges. Costs vary across various commercial assays and should be taken into consideration when these assays are being ordered.

Strategies for TDM in biologics

Over the years, the indications for TDM in biologics have evolved. Its two main uses are in reactive drug monitoring and proactive drug monitoring. Other indications for TDM are in de-escalation and reinitiation of therapy.

Reactive Drug Monitoring

Reactive TDM with biologic use in IBD is now well-established and is considered standard of care.^3,5,8,9 It refers to drug monitoring in a patient who is symptomatic from their IBD. This is done by checking drug level and anti-drug antibodies in a patient who is losing response to therapy, as defined by clinical symptoms or by an increase in biomarkers, and allows appropriate therapeutic intervention by either salvaging or switching of therapies.

If drug trough levels are undetectable or low with no antibodies, intensification of therapy by increasing the dose or decreasing the interval would be appropriate. Adding an immunomodulator would also be beneficial in reducing immunogenicity and increasing drug levels. Low drug levels are often in the setting of a high inflammatory burden resulting in rapid drug clearance.
If drug trough levels are adequate with or without presence of antibodies, it suggests a mechanistic failure of the drug. In other words, the biologic in use is not targeting the appropriate inflammatory pathway for this particular patient. Switching to another drug class of drug with a different mechanism would be the next step.
If drug levels are undetectable or low with presence of antibodies, treatment options would be based on whether the antibody levels are low or high. Low antibody titers can be a transient phenomenon, and response may be recaptured with dose escalation or addition of an immunomodulator. If antibody titers are high, then either switching to another biologic within the same class or switching class altogether would be appropriate.

An algorithmic approach helps us to understand the role of reactive TDM and shift gears appropriately based on drug concentration and antibody levels (Figure 1).10 Target trough concentrations of at least 5 mcg/mL for infliximab and 7.5 mcg/mL for adalimumab have been historically considered to be adequate to achieve mucosal healing.^5,11 More recent prospective data has suggested slightly higher levels are predictive of response (7.5 mcg/mL for infliximab and 12 mcg/mL for adalimumab). For other biologics, such as ustekinumab and vedolizumab, the data is not as robust and the overall drug exposure and efficacy relationship are less clear.¹² Target trough levels of biologics for reactive TDM based on currently available data are summarized in Table ^1.3,5,12 Above these levels, there is a low chance of further improvement with dose titration.

Proactive Drug Monitoring

Proactive TDM refers to drug monitoring in a patient who is clinically doing well on a biologic therapy. Dose adjustments are made preemptively based on drug concentration and antibody levels. The goal is to adjust therapy early on and thereby prevent primary or secondary loss of response. Proactive TDM could be done at specific timepoints such as during induction, post induction or during maintenance therapy, though current evidence is most supportive for post induction (post loading) TDM.

Consensus guidelines recommendations on TDM state that proactive drug monitoring could be a consideration during the first year of therapy, though its role was uncertain.^3,5,9 Since then, we have more data looking at proactive TDM. An important study is a large prospective cohort study (PANTS study) of nearly 1500 Crohn’s disease patients on infliximab or adalimumab looking at predictors for anti-TNF treatment failure.¹³In multivariable analysis, the only factor independently associated with non-response was low drug concentration at week 14. Optimal week 14 (post loading) drug concentrations associated with remission were 7 mcg/mL for infliximab and 12 mcg/mL for adalimumab. Another randomized control trial (PAILOT trial) in pediatric Crohn’s disease patients started on adalimumab showed significantly higher rates of steroid-free clinical remission than reactive monitoring with adalimumab trough concentrations adjusted to achieve trough concentrations of at least 5 mcg/mL.¹⁴With newly emerging data from the aforementioned studies, there seems to be a role of checking a one time early drug concentration (post loading) as a part of active monitoring and dose intensification if needed, which is associated with improved long-term outcomes. Target drug concentrations used for post loading doses should be at least those suggested for reactive TDM monitoring (Table 1) or higher (7 mcg/mL for infliximab and 12 mcg/mL for adalimumab based on the PANTS study). These can be checked at week 12-14 for infliximab and week 6-8 for adalimumab. At present, there is no role for an ultra-proactive approach, that is, measuring drug at every interval and adjusting medications accordingly.

De-Escalation from Combination Therapy

De-escalation from long-term use of combination therapy (biologic with immunomodulator therapy) is often considered in clinical practice because of safety concerns. Discontinuation of infliximab and continuing immunomodulatory monotherapy (azathioprine or methotrexate) has resulted in nearly 50% relapse rates and lack of maintenance of remission.¹⁵Therefore, once biologic therapy has been initiated, it is important to continue therapy with the biologic unless there is loss of response or an adverse event. On the other hand, de-escalation from combination therapy (biologic with immunomodulator therapy) to biologic monotherapy can be attempted in carefully selected patients.^16,17 It is important to assess risk factors associated with poor prognosis and confirm deep (clinical, endoscopic and histological) remission. TDM of biologics to determine if biologic levels are appropriate can help in decision making prior to de-escalation. Drug trough levels similar to those suggested in Table 1 for reactive TDM are considered appropriate prior to withdrawal of an immunosuppressive agent. It is important to note that withdrawal of immunomodulator therapy can drop in biologic drug levels and increase immunogenicity, especially with anti-TNF therapies and increases the risk of relapse. De-escalation should be a shared decision making process. It is important to have a risk-benefit discussion with the patient. It is also important to have a monitoring and rescue strategy in case of a relapse. Post deescalation, drug concentrations and antibody levels can be checked at some point, usually in 6-12 months once the effect of discontinuation of the immunomodulator has worn off, to ensure adequate drug levels persist without development of immunogenicity.

Re-Initiation of Therapy after a Drug Holiday

Reasons for drug holiday or discontinuation of biologic therapy in IBD patients can include elective discontinuation due to infection or surgery, loss of insurance coverage, de-escalation from combination therapy or self-discontinuation by patients. In these situations, the same therapy may need to be restarted. The main concern is of an immunologic reaction to the biologic once it has been withdrawn, especially with the anti- TNF class of drugs that are considered to be highly immunogenic. Studies looking at restarting anti- TNF therapy after a drug holiday (providing no prior significant reaction to the anti-TNF) are promising. Approximately two-thirds of patients are able to recapture response even after a one-year gap.^15,18 TDM has a role in determining efficacy and safety of reintroducing anti-TNFs, and if there is a need to switch therapies based on an immunogenic reaction. Institution specific protocols have been described with strategies to re-capture response after a drug holiday.¹⁹These include initiation of a concomitant immunomodulator, premedication with steroids, slow infusion rates for the first few doses and checking antibody levels 7-14 days after the first infusion. It is not useful to check drug antibody levels prior to therapy re-initiation as antibody levels will be negative due to lack of drug exposure and will not be informative.

Conclusion

The field of therapeutic drug monitoring for biologic therapies in IBD is evolving. It is useful in various arenas of clinical practice. Gastroenterology providers taking care of IBD patients should familiarize themselves with its appropriate application. The most common form of TDM used is reactive TDM: checking serum drug levels and anti-biologic antibodies to modify therapy in the setting of active IBD symptoms or a change in biomarkers. Reactive TDM is considered standard of care and should be implemented in one’s practice. This strategy helps avoid empiric therapy changes and decision making is more evidence-based. Trough drug levels (levels checked just before the next dose) are the most interpretable and are consistent amongst different assays. Proactive TDM is emerging as a new therapeutic strategy. Newer prospective data shows the benefit of checking drug levels after completion of induction regimens (post loading) for early adjustment of therapy and improvement in long-term outcomes. Other uses of TDM include in de-escalation from combination to monotherapy and in re-initiation of biologic therapy after a drug holiday. Judicious use of drug assays in the right clinical setting is imperative to improve outcomes, prevent unnecessary testing and to avoid significant out-of-pocket costs to the patient.

References

Feuerstein JD, Isaacs KL, Schneider Y, et al. AGA Clinical Practice Guidelines on the Management of Moderate to Severe Ulcerative Colitis. Gastroenterology. 2020;158(5):1450-1461.
Lichtenstein GR, Loftus EV, Isaacs KL, Regueiro MD, Gerson LB, Sands BE. ACG Clinical Guideline: Management of Crohn’s Disease in Adults. Am J Gastroenterol. 2018;113(4):481-517.
Papamichael K, Cheifetz AS, Melmed GY, et al. Appropriate Therapeutic Drug Monitoring of Biologic Agents for Patients With Inflammatory Bowel Diseases. Clin Gastroenterol Hepatol. 2019;17(9):1655-1668 e1653.
Vande Casteele N. Assays for measurement of TNF antagonists in practice. Frontline Gastroenterol. 2017;8(4):236- 242.
Feuerstein JD, Nguyen GC, Kupfer SS, Falck-Ytter Y, Singh S, American Gastroenterological Association Institute Clinical Guidelines C. American Gastroenterological Association Institute Guideline on Therapeutic Drug Monitoring in Inflammatory Bowel Disease. Gastroenterology. 2017;153(3):827-834.
Ordas I, Mould DR, Feagan BG, Sandborn WJ. Anti- TNF monoclonal antibodies in inflammatory bowel disease: pharmacokinetics-based dosing paradigms. Clin Pharmacol Ther. 2012;91(4):635-646.
Vermeire S, Gils A, Accossato P, Lula S, Marren A. Immunogenicity of biologics in inflammatory bowel disease. Therap Adv Gastroenterol. 2018;11:1756283X17750355.
Mitrev N, Vande Casteele N, Seow CH, et al. Review article: consensus statements on therapeutic drug monitoring of anti-tumour necrosis factor therapy in inflammatory bowel diseases. Aliment Pharmacol Ther. 2017;46(11- 12):1037-1053.
Melmed GY, Irving PM, Jones J, et al. Appropriateness of Testing for Anti-Tumor Necrosis Factor Agent and Antibody Concentrations, and Interpretation of Results. Clin Gastroenterol Hepatol. 2016;14(9):1302-1309.
Sofia MA, Rubin DT. Current approaches for optimizing the benefit of biologic therapy in ulcerative colitis. Therap Adv Gastroenterol. 2016;9(4):548-559.
Ungar B, Levy I, Yavne Y, et al. Optimizing Anti- TNF-alpha Therapy: Serum Levels of Infliximab and Adalimumab Are Associated With Mucosal Healing in Patients With Inflammatory Bowel Diseases. Clin Gastroenterol Hepatol. 2016;14(4):550-557 e552.
Restellini S, Khanna R, Afif W. Therapeutic Drug Monitoring With Ustekinumab and Vedolizumab in Inflammatory Bowel Disease. Inflamm Bowel Dis. 2018;24(10):2165-2172.
Kennedy NA, Heap GA, Green HD, et al. Predictors of anti- TNF treatment failure in anti-TNF-naive patients with active luminal Crohn’s disease: a prospective, multicentre, cohort study. Lancet Gastroenterol Hepatol. 2019;4(5):341-353.
Assa A, Matar M, Turner D, et al. Proactive Monitoring of Adalimumab Trough Concentration Associated With Increased Clinical Remission in Children With Crohn’s Disease Compared With Reactive Monitoring. Gastroenterology. 2019;157(4):985-996 e982.
Louis E, Mary JY, Vernier-Massouille G, et al. Maintenance of remission among patients with Crohn’s disease on antimetabolite therapy after infliximab therapy is stopped. Gastroenterology. 2012;142(1):63-70 e65; quiz e31.
Van Assche G, Magdelaine-Beuzelin C, D’Haens G, et al. Withdrawal of immunosuppression in Crohn’s disease treated with scheduled infliximab maintenance: a randomized trial. Gastroenterology. 2008;134(7):1861-1868.
Fiorino G, Cortes PN, Ellul P, et al. Discontinuation of Infliximab in Patients With Ulcerative Colitis Is Associated With Increased Risk of Relapse: A Multinational Retrospective Cohort Study. Clin Gastroenterol Hepatol. 2016;14(10):1426-1432 e1421.
Baert F, Drobne D, Gils A, et al. Early trough levels and antibodies to infliximab predict safety and success of reinitiation of infliximab therapy. Clin Gastroenterol Hepatol. 2014;12(9):1474-1481 e1472; quiz e1491.
Hughes JT, Herfarth HH, Isaacs KL, et al. Infliximab Re-treatment in Inflammatory Bowel Disease: A Single- Center Routine Clinical Experience. Clin Gastroenterol Hepatol. 2015;13(9):1704-1705.

MEDICAL BULLETIN BOARD

Arrowhead Presents Additional Clinical Data on Investigational Aro-aat Treatment In Patients with Alpha-1 Liver Disease at Easl International Liver Congress

PASADENA, CA– Arrowhead Pharmaceuticals Inc. (NASDAQ: ARWR) presented additional positive interim 48-week liver biopsy results from the ongoing AROAAT2002 study, an openlabel Phase 2 clinical study of ARO-AAT, the company’s second generation investigational RNA interference (RNAi) therapeutic being codeveloped with Takeda Pharmaceutical Company Limited (“Takeda”) as a treatment for the rare genetic liver disease associated with alpha-1 antitrypsin deficiency (AATD), at The International Liver Congress – The Annual Meeting of the European Association for the Study of the Liver (EASL).

The results demonstrate that, in the AROAAT2002 study, investigational AROAAT treatment led to improvements in multiple measures of liver health, including fibrosis, with substantial and sustained reductions in the level of mutant AAT protein (Z-AAT). In addition, AROAAT treatment was generally well tolerated after up to 1 year of treatment.

Javier San Martin , M.D., chief medical officer at Arrowhead, said: “We believe the interim results that were presented today at EASL represent an important breakthrough for the field and are encouraging for patients with alpha-1 liver disease, who currently have no available treatment options other than liver transplant. The data indicate that treatment with investigational ARO-AAT, being developed in collaboration with Takeda as TAK-999, resulted in substantial, sustained, and consistent reductions in the production of the toxic mutant Z-AAT protein, which has been identified as the cause of progressive liver disease in patients with alpha-1 antitrypsin deficiency. This reduction over 6 and 12 months led to multiple important signals associated with healing of patients’ liver disease. Importantly, we believe ARO-AAT is the first investigational therapy to show this type of benefit in patients with alpha-1 liver disease. We want to thank all the investigators and patients for their participation in the study, and we look forward to the availability of additional results from this study and from our ongoing SEQUOIA study of ARO-AAT, which we anticipate will reach full enrollment during the third quarter of 2021.”

Pharmacodynamics and Efficacy

After 24 weeks (cohort 1, n=4) and 48 weeks (cohort 2, n=5) of treatment with investigational ARO-AAT in the AROAAT2002 study, the following results were observed:

Serum Z-AAT levels decreased in all patients
Median decrease in intra-hepatic Z-AAT levels were:
- Total Z-AAT -80.1% (range -72 to -97%)
- Monomer -90% (range -79 to -97%)
- Polymer -81% (range* -42 to -97%)
- ■ *Excluding 1 subject in cohort 1 that had very low Z-AAT polymer levels at baseline that increased at week 24
- Histological globule burden was reduced in all nine patients, with two achieving full resolution (total aggregate globule burden score=0)
Six of the nine patients (2/4 after 24 weeks and 4/5 after 48 weeks) achieved a 1 or greater stage improvement in Metavir fibrosis stage, with no worsening of fibrosis in the other three patients
- Two patients had baseline F4 fibrosis (cirrhosis), with one patient achieving a twostage improvement to F2 and the other patient achieving a one-stage improvement to F3
Multiple biomarkers of liver health improved, including liver stiffness (FibroScan), liver enzymes alanine aminotransferase (ALT) and gamma-glutamyl transferase (GGT), and PRO-C3, a marker of collagen formation

Safety and Tolerability

In AROAAT2002, investigational ARO-AAT demonstrated an acceptable safety profile and was generally well tolerated after up to 1 year of treatment. There were no treatment-emergent adverse events leading to drug discontinuation, dose interruptions, or study withdrawal. Lung function was assessed throughout the study and there were no clinically meaningful changes in percent predicted forced expiratory volume in 1 second (ppFEV1). Three serious adverse events (SAEs) were reported, but none were considered related to the study drug. All SAEs were moderate in severity and all resolved.

AROAAT2002 (NCT03946449) is a pilot open-label, multi-dose, Phase 2 study to assess the response to investigational ARO-AAT in 16 patients with AATD associated liver disease and baseline liver fibrosis. All eligible participants receive a predose biopsy and an end of study biopsy. Treated participants will also be offered the opportunity to continue treatment in an open-label extension (OLE). Including the OLE, interim assessments will be made after 6 months, 12 months, 18 months, and 24 months of treatment with ARO-AAT.

Presentation Details

Title: ARO-AAT an investigational RNAi therapeutic demonstrates improvement in liver fibrosis with reduction in intra-hepatic Z-AAT burden

Authors: Pavel Strnad , et al.

Type: Late-Breaking Oral Presentation

Date and Time: June 26, 2021 at 12:15 CEST A copy of the presentation materials may be accessed on the Events and Presentations page under the Investors section of the Arrowhead website.

About Arrowhead and Takeda Collaboration

In October 2020, Arrowhead and Takeda announced a collaboration and licensing agreement to develop investigational ARO-AAT. Under the terms of the agreement, Arrowhead and Takeda will codevelop ARO-AAT which, if approved, will be cocommercialized in the United States under a 50/50 profit-sharing structure. Outside the U.S., Takeda will lead the global commercialization strategy and receive an exclusive license to commercialize ARO-AAT with Arrowhead eligible to receive tiered royalties of 20-25% on net sales. Arrowhead received an upfront payment of $300 million and is eligible to receive potential development, regulatory and commercial milestones of up to $740 million.

About Alpha-1 Antitrypsin-Associated Liver Disease

Alpha-1 Antitrypsin-Associated Deficiency (AATD) is a rare genetic disorder associated with liver disease in children and adults and pulmonary disease in adults. AATD is estimated to affect 1 per 3,000-5,000 people in the United States and 1 per 2,500 in Europe. The protein AAT is primarily synthesized and secreted by hepatocytes. Its function is to inhibit enzymes that can break down normal connective tissue. The most common disease variant, the Z mutant, has a single amino acid substitution that results in improper folding of the protein. The mutant protein cannot be effectively secreted and accumulates in globules inside the hepatocytes. This triggers continuous hepatocyte injury, leading to fibrosis, cirrhosis, and increased risk of hepatocellular carcinoma.

Individuals with the homozygous PiZZ genotype have severe deficiency of functional AAT leading to pulmonary disease and liver disease. Lung disease is frequently treated with AAT augmentation therapy. However, augmentation therapy does nothing to treat liver disease, and there is no specific therapy for hepatic manifestations. There is a significant unmet need as liver transplant, with its attendant morbidity and mortality, is currently the only available cure.

About Arrowhead Pharmaceuticals

Arrowhead Pharmaceuticals develops medicines that treat intractable diseases by silencing the genes that cause them. Using a broad portfolio of RNA chemistries and efficient modes of delivery, Arrowhead therapies trigger the RNA interference mechanism to induce rapid, deep, and durable knockdown of target genes. RNA interference, or RNAi, is a mechanism present in living cells that inhibits the expression of a specific gene, thereby affecting the production of a specific protein. Arrowhead’s RNAi-based therapeutics leverage this natural pathway of gene silencing.

For more information, please visit: www.arrowheadpharma.com or follow us on Twitter: @ArrowheadPharma

To be added to the Company’s email list and receive news directly, please visit: http://ir.arrowheadpharma.com/email-alerts

NUTRITION ISSUES IN GASTROENTEROLOGY, SERIES #212

Auto-Brewery Syndrome: A Schematic for Diagnosis and Appropriate Treatment

Fahad Malik,

Prasanna Wickremesinghe,

Atif Saleem

Auto-Brewery Syndrome (ABS), also called Gut Fermentation Syndrome, is a rare, underdiagnosed medical condition. This is caused by fermentation of ingested carbohydrate by gut fungi resulting in endogenous production of ethanol. Though this syndrome has been described in the medical literature for over 50 years, it still remains misunderstood with limited information regarding diagnosis and treatment. The presenting symptoms and signs of ABS can be protean and mimic other clinical entities. This can make diagnosing this condition challenging. We propose the following schematic for diagnosing and treating this unusual entity based on our ongoing study of ABS patients. The initial step in confirming this diagnosis is a standardized carbohydrate challenge test which we have devised and studied in our ongoing cohort of ABS patients.

Introduction

Auto-Brewery Syndrome (ABS), which has also been described as Gut Fermentation Syndrome, is a rare, underdiagnosed medical condition. In this condition, fermentation of ingested carbohydrate results in endogenous production of ethanol. This syndrome was originally described in 1946 in a 5-year-old South African child undergoing emergency laparotomy, during which a 3-inch posterior stomach wall tear was detected and alcohol noted in the stomach.1 Multiple cases of ABS were subsequently described in Japan during the 1970s. In these cases, identified yeast forms were mostly Candida species as the causative agent.2 ABS is more common in patients with chronic medical conditions such as diabetes, inflammatory bowel disease (Crohn’s disease patients with strictures), short bowel syndrome or immunosuppressed subjects. Since then, there have been sporadic case reports of ABS worldwide.3-7 ABS can also occur in healthy individuals. In our cohort of ABS patients prior exposure to antibiotics was universal. Antibotics can alter the gut microbiome allowing fungal elements to proliferate.8,9 Nonetheless, this condition has continued to be regarded as a myth due to limited knowledge on the subject. Initially, only fungi were implicated in the conversion of carbohydrate to alcohol, but a recent large Chinese study also identified certain species of high alcoholproducing bacteria (e.g., Klebsiella species).10

Pathophysiology

Although the initiating or triggering factors resulting in ABS remain uncertain, we propose the following in its causation:
1. Alteration of the gut microbiome: The disruption of gut homeostasis resulting in overgrowth of fungi, and in rare cases, high alcohol-producing bacteria (e.g., Klebsiella species).1,10 All of our patients had prior exposure to antibiotics before developing ABS symptoms.

2. Fungal fermentation: Commercially, Saccharomyces cerevisiae (i.e., brewer’s yeast) has been used for manufacturing beer for centuries.11

Risk Factors

In our ABS cohort of patients, the most common risk factor for its causation has been prior use of antibiotics. Antibiotics may have disrupted the fine homeostatic balance and symbiotic relationship between the different types of gut microbiota causing yeast overgrowth. Several patients with diabetes, short bowel syndrome, intestinal bacterial overgrowth, and inflammatory bowel disease (Crohn’s disease with strictures), have also been described with ABS. Healthy patients may also suffer from ABS if exposed to a precipitating cause.1,4,5-7,12 It is uncertain if any genetic components could have predisposed these patients to ABS.

Symptoms

Patients with ABS are known to present with signs and symptoms of inebriation. Some with psychiatric symptoms (i.e. altered mood, anxiety, dysphoria, changes in affect and depression) or neurological symptoms (i.e. changes in mental status, drowsiness, brain fog, seizures, and ataxia). The patients can also have the smell of alcohol on their breath. The effects of alcohol are the same regardless of whether it is endogenously or exogenously derived, and can increase the risk of fatty liver, cirrhosis of the liver and acute or chronic pancreatitis.10 The legal limit for driving while intoxicated (DWI) is 0.08% in New York and many other states. We have encountered many patients with ABS with 3-4 times this level. These symptoms could also overlap with those of chronic fatigue syndrome, depression, and alcoholism itself.

Diagnosis

Usually, these patients are either identified by a concerned family member or had been arrested for alleged “DWI”. Identifying these patients is difficult as ABS symptoms could masquerade as other entities. The medico-legal implications of DWI are self-evident. When investigating a patient with possible ABS, a complete medical history and a physical examination should be augmented with interrogation of family and friends as they may provide additional vital information. The patient can develop “memory fog” and therefore might have poor recall of past events. Particular attention should be paid to the onset of the condition, inciting factors, prior antibiotic use, mold exposure, and any other useful information available from their previous evaluations. Needless to say, the present or past detailed history of alcohol intake is mandatory, including asking when the patient last drank alcohol, if at all.

Basic laboratory tests, i.e. complete blood count, comprehensive metabolic panel, and stool testing should be performed to rule out other medical conditions (e.g. diabetes, immunosuppression, leukopenia). It is also important to ascertain that the patient is not surreptitiously drinking. Therefore, ideally the validity of the patient’s denial of alcohol consumption has to be corroborated by a family member or a friend. The diagnosis of ABS can only be considered after other conditions which may present with similar symptoms have been ruled out. These patients are advised to purchase a breathalyzer and keep a log of their breathalyzermeasured breath alcohol content (BAC) morning and evening, and at any time when they are symptomatic. Any positive level of breathalyzer BAC measurement needs to be confirmed with a concomitant blood alcohol level and the patient’s physician should also be immediately informed.

Just prior to the carbohydrate challenge test, we initially perform upper and lower endoscopy to obtain gastric, upper small bowel, terminal ileal, and colon secretions. These samples are then tested for pH, gram strain, culture, and antibiotic and antifungal sensitivity in a commercial laboratory. Once a particular fungal species is identified, further antifungal sensitivity testing is conducted to determine the appropriate choice of subsequent therapy. The stepwise process for ABS diagnosis is summarized in Figure 1.

The carbohydrate challenge test should be performed when the patient’s breath and blood alcohol levels are zero. If elevated, the patient will have to wait until it becomes zero prior to testing. Patients have to be under complete observation with no access to alcohol along with zero initial blood alcohol level in order for this test to be performed. A diagnostic standardized carbohydrate challenge test was performed after upper and lower endoscopic evaluation. This test consisted of administering 200g of glucose orally in a supervised setting in an isolation room and testing both breath and blood alcohol levels at baseline (0) and at 0.5, 1, 2, 4, 8 hours after glucose administration. Patient were allowed to eat any meal of their choice after the ingestion of 200g of oral glucose. If alcohol levels are elevated at any time during this evaluation, the test is aborted and considered to be positive. Patients who are still negative at 8 hours are given the option to return for a collection of a 16- and 24-hour sample as some fungi can take longer than 8 hours to ferment carbohydrate. Therefore, a negative 8 hour test cannot exclude this diagnosis due to some fermentation occurring even after 24 hours.

Testing a stool sample can assist in the screening process, but the lower gastrointestinal tract can contain small amounts of fungal colonization which would be considered normal and fermentation here would have little clinical significance. Upper gastrointestinal tract fungal colonization is significant, as the presence of fungi is considered pathological in this location. All of the patients who are currently under treatment for ABS had a positive carbohydrate challenge test and positive stool mycological studies on gut secretions.

Until now there had been no known standardized screening test for ABS. Therefore sensitivity and/ or specificity of this test is unstudied. We are the first to propose a carbohydrate challenge test to identity ABS patients. If BAC or blood alcohol is negative, it is unlikely to see a positive carbohydrate challenge test, even if there is a strong suspicion for ABS. When this carbohydrate challenge test is accepted and used more widely, we would have a better idea of the sensitivity, specificity and validity of this test. In our literature review, we have found less than 100 cases since 1952. We are now studying these patients and might be able provide more statistical information in the future.

Treatment

The same initial treatment protocol used for exogenous alcohol intoxication should be used to treat ABS patients as well. This would include administering appropriate intravenous fluids for hydration, maintaining a clear airway, and correcting calorie and nutritional deficiencies (folate and thiamine). Alcohol withdrawal symptoms if present should also be managed with benzodiazepines. After the resolution of the patient’s acute symptoms and stabilization of the patient’s condition, targeted treatment for the patient’s ABS can be initiated. An interdisciplinary approach is strongly recommended in these situations with the assistance of a Gastroenterologist, Psychiatrist and Nutritionist for optimal care. The mainstay of our dietary treatment should be to keep the patient initially on a carbohydrate free diet for 6 weeks as carbohydrate is the only substrate that is converted to alcohol by fungi. Otherwise, these patients are at liberty to ingest any non-carbohydrate meal. A total elimination of carbohydrate is difficult to to practice. We allowed small amounts of carbohydrate found in fruits or vegetables to be acceptable. Antifungal sensitivity testing should be done on any fungal strains isolated from the gastrointestinal secretions to determine the appropriate choice of antifungal treatment. We used nystatin as a firstline treatment when appropriate, as it has the least amount of side effects and an established safety record. Oral azole compounds (e.g., fluconazole and itraconazole) are our next drugs of choice if the patient is still symptomatic with elevated breath and blood alcohol levels while on nystatin therapy. Finally, intravenous micafungin is used for treatment failure.

In addition to antifungal therapy, these patients are started on a single strain probiotic (Lactobacillus acidophilus). Patients should continue to check their BAC twice a day during, and after the 6 weeks of antifungal treatment, and inform their physicians of any positive results. After successfully completing the 6-week therapy if the patient is asymptomatic with negative BAC, the antifungal therapy is gradually tapered during the next 6 weeks and then discontinued. We continued treatment with the probiotic long-term. It would be ideal to have the patient repeat the carbohydrate challenge test prior to reintroducing carbohydrate in their diet if feasible. If this test is positive then the patient would require further antifungal therapy.

Additionally, the role of probiotic use in ABS needs to be fully investigated. Probiotic strains of Lactobacillus have been studied and found to have inhibitory effects on biofilm formation and filamentation in Candida albicans species. This probiotic has also previously been shown to competitively inhibit gut fungal growth in patients.8,13-15 We had previously postulated that fecal microbiome transplant might be valuable in ABS patients. There has only been a single successful report of using fecal microbiome transplant for the treatment of ABS in Belgium. We await further studies on this treatment modality.17 See Figure 2 for proposed treatment algorithm.

Conclusion

ABS is a rare and underdiagnosed medical condition where ingested carbohydrate is converted to alcohol by fermentation in the gut. This condition should be considered in any patient who has signs and symptoms of inebriation despite denying alcohol intake. This syndrome has been described in the medical literature for over 50 years, but it still remains a condition with limited information regarding diagnosis and treatment. If a physician suspects that a patient has ABS, breathalyzer analysis during the symptomatic episodes could help the clinician determine if this condition might be present. We propose a standardized carbohydrate challenge test to screen patients with suspected diagnosis of ABS. While a positive test is very useful in detecting patients with ABS, a negative test does not definitively rule out ABS, as fungi could take longer than 24 hours to convert carbohydrate to alcohol. The seminal NIH microbiome study from 2007 using genetic methodology has found many fungi are undetected by our usual commercial laboratory culture techniques.15,17 As more research emerges on the gut microbiome, it is hoped that a better understanding of this medical condition will ensue.

References

Ladkin RG, Davies JNP. Rupture of the stomach in an African child. Br Med J. Br Med J. 1948 Apr 3;1(4552):644.
Iwata K. A review of the literature on drunken syndromes due to yeasts in the gastrointestinal tract. Tokyo, Japan: University of Tokyo Press; 1972.
Hafez EM, Hamad MA, Fouad M, et al. Auto-brewery syndrome: ethanol pseudo-toxicity in diabetic and hepatic patients. Hum Exp Toxicol. 2017;36:445–50.
Welch BT, Coelho Prabhu N, Walkoff L, et al. Auto-brewery syndrome in the setting of long-standing Crohn’s disease: a case report and review of the literature. J Crohns Colitis. 2016;10:1448–50.
Spinucci G, Guidetti M, Lanzoni E, et al. Endogenous ethanol production in a patient with chronic intestinal pseudoobstruction and small intestinal bacterial overgrowth. Eur J Gastroenterol Hepatol. 2006;18:799–802.
Green AD, Antonson DL, Simonsen KA. Twelve-year-old female with short bowel syndrome presents with dizziness and confusion. Pediatr Infect Dis J. 2012;31(4):425.
Jansson-Nettelbladt E, Meurling S, Petrini B, et al. Endogenous ethanol fermentation in a child with short bowel syndrome. Acta Paediatr. 2006;95:502–4.
Malik F, Wickremesinghe P, Saverimuttu J. Case report and literature review of auto-brewery syndrome: probably an underdiagnosed medical condition. BMJ Open Gastroenterol. 2019;6:e000325.
Painter K, Cordell BJ, Sticco KL. Auto-brewery syndrome (Gut fermentation) [updated 2020 Jun 26]. In: StatPearls [Internet]. Treasure Island, FL: StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/ NBK513346/
Yuan J, Chen C, Cui J et al. Fatty liver disease caused by high-alcohol-producing Klebsiella pneumoniae. Cell Metabolism. 2019;30:675–88.e7.
Walker GM, Stewart GG. Saccharomyces cerevisiae in the production of fermented beverages. Beverages. 2016;2:30.
Tameez Ud Din A, Alam F, Tameez-Ud-Din A, et al. Auto-brewery syndrome: a clinical dilemma. Cureus. 2020;12:e10983.
Cordell B, McCarthy J. A case study of gut fermentation syndrome (auto-brewery) with Saccharomyces cerevisiae as the causative organism. Int J Clin Med. 2013;04:309–12.
Suez J, Zmora N, Zilberman-Schapira G, et al. Postantibiotic gut mucosal microbiome reconstitution is impaired by probiotics and improved by autologous FMT. Cell. 2018;174(6):1406-1423.e16.
Vilela SFG, Barbosa J, Rossoni R, et al. Lactobacillus acidophilus ATCC 4356 inhibits biofilm formation by C. albicans and attenuates the experimental candidiasis in Galleria mellonella. Virulence. 2016;6:29–39.
Vandekerckhove E, Janssens F, Tate D, et al. Treatment of gut fermentation syndrome with fecal microbiota transplantation. Ann Intern Med. 2020;173(10):855.
Sam QH, Chang M, Chai L, et al. The fungal mycobiome and its interaction with gut bacteria in the host. Int J Mol Sci. 2017;18(2):330.

Medical Bulletin Board

Mirikizumab Up-regulates Genes Associated with Mucosal Healing in Ulcerative Colitis for up to One Year in Phase 2 Study

INDIANAPOLIS, July 9, 2021 /PRNewswire / – Eli Lilly and Company (NYSE: LLY) announced new Phase 2 data showing that gene expression changes induced by mirikizumab in patients with ulcerative colitis (UC) over a 12-week induction treatment were maintained for up to one year. These gene transcript changes, which were unique among those who responded to mirikizumab compared to placebo, were associated with mucosal healing, indicating that mirikizumab affects a distinct molecular healing pathway, compared to the spontaneous healing that occurred among those who responded to placebo.

Mirikizumab is being studied in Phase 3 trials for UC and Crohn’s disease (CD), two forms of inflammatory bowel disease that can cause serious and debilitating symptoms, and disruptions in daily life.

A separate analysis of patients with moderate to severe UC evaluated meaningful improvement of bowel urgency, a common symptom of UC that is associated with higher levels of disease activity, decreased work productivity and worse quality of life. These results were presented virtually at the Congress of the European Crohn’s and Colitis Organisation (ECCO), July 8-10, 2021.

Mirikizumab Showed Early and Sustained Gene Expression Changes Associated with Mucosal Healing in UC for Up to One Year

In a previously-published Phase 2 study evaluating patients with UC, mirikizumab down-regulated several gene transcripts associated with inflamed mucosa and up-regulated gene transcripts correlated with healthy mucosa and markers of functional healing after 12 weeks, as defined by clinical disease indices of endoscopy and histology.

In this analysis, a set of differentially-expressed gene transcripts were identified in patients who responded to mirikizumab that were not found in those who responded to placebo at 12 weeks. Of the modulated genes, 71% (n=63) were present only in patients who responded to mirikizumab, 5.6% (n=5) were present only in those who responded to placebo, and 23.6% (n=21) were present in both groups. Effect size estimates were also examined to account for differences in sample size and associated power between treatment groups. The set of gene transcripts regulated by mirikizumab correlated with UC disease activity indices, demonstrating consistency of these molecular changes across symptomatic, clinical, endoscopic and histologic indices of UC disease activity.

The results observed at 12 weeks were maintained for up to one year in patients receiving mirikizumab. For methodology, see the “About the Studies” section below.

“In the first clinical study of an anti-IL- 23p19 therapy in ulcerative colitis to evaluate gene expression on this large scale, mirikizumab demonstrated an ability to down-regulate the gene transcripts associated with inflammation and upregulate transcripts associated with mucosal healing in ulcerative colitis, with changes maintained for up to one year,” said Walter Reinisch, Director of the Clinical IBD Study Group, Department of Gastroenterology and Hepatology, Medical University of Vienna. “These results support the continued development of mirikizumab as a potential treatment option for ulcerative colitis, given the importance of mucosal healing and functional healing as key treatment goals for this difficult-to-treat disease.”

Patients with UC Reported on Definition of Meaningful Change in Bowel Urgency

Bowel urgency, the sudden or immediate need for a bowel movement, is one of the most distressing symptoms experienced by patients with UC. In this qualitative study of patients with moderate to severe UC, patients defined both bowel urgency severity and what would be a meaningful improvement in bowel urgency based on an 11-point numeric rating scale (NRS).

In this study, half of patients with UC (50%, n=10) reported that a 1-point change on the urgency NRS would be a meaningful change, indicating improved emotional well-being and greater confidence to leave the home or do their work.

A quarter of respondents (25%, n=5) indicated that a 2-point improvement in the urgency NRS was required to be considered meaningful, and another 25% of respondents (n=5) noted that a 3-point change or more was needed to achieve improvements in quality of life.

Importantly, among the 75% of patients who endorsed a 1 to 2-point change in urgency NRS, initial scores on the urgency NRS ranged from 2 to 9, indicating that this amount of change was meaningful regardless of the severity of an individual’s bowel urgency. For methodology, see the “About the Studies” section below.

“We are very excited to present these findings at ECCO, which provide one of the first analyses from the patient perspective on the impact of bowel urgency and what would constitute a meaningful change,” said Prentice Stovall, Jr., Global Development Leader, Immunology at Lilly. “Given the impact that bowel urgency has on an individual’s ability to work and overall quality of life, this analysis will help us further understand the experience of people with UC and the potential impact of our treatments on this burdensome and debilitating symptom.”

About the Studies

Mirikizumab-Induced Transcriptome Changes in Patient Biopsies at Week 12 are Maintained Through Week 52 in Patients with Ulcerative Colitis

Patients who achieved clinical response at 12 weeks, as measured by a decrease in 9-point Mayo subscore (rectal bleeding, stool frequency, endoscopy) of ≥2 points and ≥35% from baseline, with either a decrease of rectal bleeding subscore of ≥1 or an RB subscore of 0 or 1 continued onto maintenance mirikizumab treatment. Patients given placebo in induction who achieved clinical response continued on placebo in the maintenance period. In this study, colonic biopsies from 52 patients were obtained at Weeks 0, 12 and 52 from the most affected area ≥30 cm from the anal verge (mirikizumab, n=31, placebo, n=7). Of those patients, 31 were 200 mg mirikizumab responders and seven responded to placebo. Transcript changes at Week 12 from baseline in the placebo and mirikizumab arms were clustered into differentially expressed genes using the Bayesian Limma R-package. Differentially expressed genes which maintained their Week 12 expression level through Week 52 in both the placebo and mirikizumab arms were identified and designated as similarly expressed genes. Overall, the safety profile at 52 weeks was consistent with that of mirikizumab in studies of UC and with the class.

A Qualitative Study Exploring Meaningful Improvement in Bowel Urgency among Adults with Moderate to Severe Ulcerative Colitis

In this qualitative study assessing meaningful improvement in bowel urgency based on a NRS, in-depth interviews were conducted in the United States with 20 adults with clinician-confirmed moderate to severe UC. Using an 11-point NRS developed specifically to assess bowel urgency severity, participants were asked to define levels of bowel urgency (where 0=no urgency and 10=worst possible urgency). Participants were also asked to describe what would be a meaningful improvement based on how this change would impact their daily life.

About Mirikizumab

Mirikizumab is a humanized IgG4 monoclonal antibody that binds to the p19 subunit of interleukin 23. Mirikizumab is being studied for the treatment of immune diseases, including ulcerative colitis and Crohn’s disease.

About Ulcerative Colitis

Ulcerative colitis is a chronic inflammatory bowel disease that affects the colon. UC occurs when the immune system sends white blood cells into the lining of the intestines, where they produce chronic inflammation and ulcerations. There is an unmet need for additional treatment options for UC that provide meaningful symptom relief, including bowel urgency, and deliver sustained clinical remission.

About Eli Lilly and Company

Lilly is a global health care leader that unites caring with discovery to create medicines that make life better for people around the world. We were founded more than a century ago by a man committed to creating high-quality medicines that meet real needs, and today we remain true to that mission in all our work. Across the globe, Lilly employees work to discover and bring life-changing medicines to those who need them, improve the understanding and management of disease, and give back to communities through philanthropy and volunteerism.

To learn more about Lilly, please visit us at: lilly.com and lilly.com/newsroom

Lilly Forward-Looking Statement

This press release contains forward-looking statements (as that term is defined in the Private Securities Litigation Reform Act of 1995) about mirikizumab as a potential treatment for patients with ulcerative colitis and/or Crohn’s disease and reflects Lilly’s current beliefs and expectations. However, as with any pharmaceutical product, there are substantial risks and uncertainties in the process of drug research, development, and commercialization. Among other things, there can be no guarantee that future study results will be consistent with study results to date, that mirikizumab will prove to be a safe and effective treatment or that mirikizumab will receive regulatory approvals or be commercially successful. For further discussion of these and other risks and uncertainties, see Lilly’s most recent Form 10-K and Form 10-Q filings with the United States Securities and Exchange Commission. Except as required by law, Lilly undertakes no duty to update forward-looking statements to reflect events after the date of this release.

DISPATCHES FROM THE GUILD CONFERENCE, SERIES #39

Management of Intestinal Metaplasia and Gastric Cancer

Shradha Gupta,

Aasma Shaukat

Epidemiology of Gastric Cancer

Gastric cancer is the fifth most common and fourth most deadly cancers worldwide.¹ The World Health Organization estimates that in 2018, gastric cancer accounted for 783,000 deaths globally.² Gastric cancer incidence and mortality varies geographically.

Gastric cancers can be divided based on anatomic location into cardia and non-cardia gastric cancers. The non-cardia gastric cancers, arising from the antrum, incisura, body, and/or fundus are associated with Helicobacter pylori (H.pylori) infection.

Adenocarcinoma is the most common type (90- 95%) of gastric cancer followed by some other types including gastrointestinal stromal tumors (GIST), neuroendocrine tumors like carcinoids, lymphoma, leiomyosarcoma and lipomas. Adenocarcinoma are further divided into intestinal and diffuse type.

Asian countries like Japan, Mongolia and Korea have high incidence whereas lower incidence is observed in United States and Northern Europe. In men of South-Central Asian countries, including Iran, Afghanistan, Turkmenistan, and Kyrgyzstan it is the most commonly diagnosed cancer and leading cause of death. According to Global cancer statistics 2020 (GLOBACON), one million new cases were added in 2020.¹ Incidence in males is twice as compared to females. Its incidence is decreasing worldwide but it is still associated with high mortality making it a significant public health concern.

In the United States, gastric cancer ranks 15th in incidence among the major types of cancer.³ The majority of gastric cancers in the United States are non-cardia gastric cancers. In the United States only 10% to 20% of all cases diagnosed are early-stage diagnosis. The remaining patients present with metastatic disease. The median age of diagnosis is 68 years. Over the past 50 years the incidence of gastric cancer has decreased from 33 to 10 cases in males and 30 to 5 cases in female per 100,000. In the United States, 1 in 103 men and women will be diagnosed with gastric cancer in their lifetime.

Overall, 5-year survival rate of gastric cancer is estimated to be 32% (including all stages of cancer). For localized disease this survival rate is 70% whereas for distant metastatic disease the rate is 6%.3 In early limited cancer the 5-year survival rate is more than 95% in Japan. In Japan, endoscopic resection techniques have been refined and is probably related to reduced mortality despite overall high incidence.

Risk Factors for Gastric Cancer

The incidence and mortality of gastric cancer are highly variable geographically. Certain risk factors have been identified which contribute to increase in the incidence of gastric cancer. These are summarized in table.1

Diet is a modifiable risk factor for gastric cancer. Multiple studies including case-control and cohort studies have suggested high risk associated with salt rich diet including pickle, decreased intake of high fiber diet, particularly fruits.⁴ Low Vitamin C consumption might play a role in prevalence of gastric cancer. Consumption of processed meat, dairy foods and N-nitroso compounds are associated with higher rates of gastric cancer. Ingestion of green tea is associated with lower risk. Due to modernization and availability of refrigeration the cooked food is safer for longer duration thereby reducing the risk.

Obesity and lack of physical activity has been recognized as a risk factor in gastric cancer. Cigarette smoking is also related to increase incidence. Moderate amount of physical activity is protective.

The risk of gastric cancer in immigrants is similar to the population of their original country. The birth-place is a stronger risk predictor than the current residential location. Thus, showing the importance of childhood exposure in the etiology of gastric cancer. Migrants do not lose their risk in the first-generation migrants or their young children. Generally, after two generations the risk in immigrant population becomes similar to adopted country. Positive family is a strong predictor of gastric cancer.

Approximately one to three percent of gastric cancer is hereditary in nature. Hereditary diffuse gastric cancer is less than one percent of total gastric cancer cases. It is associated with increased incidence of gastric and breast cancer. Other familial syndromes associated are familial adenomatous polyposis (FAP) and Peutz–Jeghers syndrome (PJS).⁵ In both the above-mentioned disease polyp and dysplasia lead to development of cancer.

Atrophic gastritis and intestinal metaplasia are precancerous lesions for gastric cancer. Certain studies have linked Helicobacter pylori infection with the above. Eradication of Helicbacter pylori leads to reduce incidence of gastric cancer.⁶ Pernicious anemia due to vitamin B12 deficiency secondary to autoimmune gastritis, affects 2%– 5% of the elderly population. Studies have shown that patients with pernicious anemia could have an increased risk of cancer. Vitamin B12 will improve the anemia but have no effect on autoimmune gastritis.

H.pylori infection has been linked to non cardia gastric cancer which is the most prevalent gastric cancer in the United States. Multiple studies have shown that testing and eradication of H. pylori worldwide has resulted in reduced incidence of gastric cancer.

Its prevalence is higher in older males. As the prevalence also increases with safe drinking water and food, logically it is more rampant in lower socio-economic groups. Foundry workers are at risk for developing gastric cancer with dust iron being an important cause. It has also noted to be present in Hiroshima and Nagasaki survivors.

H.PYLORI: DISCOVERY TO CARCINOGEN STATUS

H. pylori was discovered first in 1982 by Australian physicians Drs. Barry Marshall and Robin Warren. It is a gram negative, spiral shaped bacterium living in the stomach. It is transmitted through the feco-oral routes. Studies have shown that this accounts for 50-70 % of gastric ulcers. It is also associated with gastric adenocarcinoma. In 1975 Correa et al. outlined a cascade leading to development of gastric adenocarcinoma.⁷ They suggested the following sequence of events normal gastric mucosa / nonatrophic gastritis / multifocal atrophic gastritis without intestinal metaplasia / intestinal metaplasia of the complete (small intestine) type / intestinal metaplasia of the incomplete (colonic) type / low-grade dysplasia / high-grade dysplasia / invasive adenocarcinoma. H. pylori infection causes gastritis and then in some patients follows the above cascade to eventually gastric adenocarcinoma. (Figure 1)

Patients with peptic ulcer disease (PUD), a past history of PUD (with no documented treatment), low-grade gastric mucosa-associated lymphoid tissue (MALT) lymphoma, or a history of endoscopic resection of early gastric cancer (EGC) should be tested for H. pylori infection. Strong consideration is made for people younger than 60 years with dyspepsia with no alarming can be tested and if positive treated to postpone the EGD. In patients undergoing EGD for dyspepsia biopsies should be taken and tested for H. pylori. Antimicrobial treatment of chronically infected people might trigger antimicrobial resistance as almost half of the world population is infected with H. pylori infection.⁸ Vaccination against has been shown effective in experimental animal models, but so far, such efficacy has not been studied in humans. Studies have shown that among patients with H. pylori infection with or without intestinal metaplasia, H. pylori treatment was associated with a lower risk of incident gastric cancer compared to placebo.

Proton pump inhibitor (PPI) use is associated with worsening of gastric atrophy, particularly in H. pylori–infected individuals. One study analyzed 63,397 patients who had been treated for H. pylori and who had appeared to be cleared of the infection.⁹ The results suggested that people who used PPI after treatment of H. pylori were twice at risk of gastric cancer as compared to people who did not use PPI.

First-line treatment of H. pylori is bismuth quadruple therapy or concomitant therapy consisting of a PPI, clarithromycin, amoxicillin, and metronidazole. Certain factors like previous antibiotic exposure and previous treatments should be put in perspective. If first line therapy fails, a salvage regimen avoids antibiotics previously used and can use other drugs like levofloxacin.

Intestinal Metaplasia and Proposed Progression to Gastric Cancer

Gastric intestinal metaplasia (GIM), defined as the replacement of normal healthy gastric mucosa by epithelium resembling intestinal cells. It is associated with an increased risk for intestinal-type gastric adenocarcinoma. There is increased discussion about further endoscopic testing or surveillance for the same reason. In 1975, Correa et al. described the cascade of steps leading to the development of intestinaltype gastric adenocarcinoma. Less than 0.25% of patients with GIM every year progress to gastric cancer. It has been recognized as a pre malignant condition, when exposed to environmental stimuli like H. pylori, smoking and high salt intake may result to advancement of gastric cancer.

Certain indicators like location, extent and severity of GIM will influence the transformation of GIM to gastric cancer. Lesions found in gastric body are more likely to advance into gastric cancer. One-fourth of the patients diagnosed with high grade dysplasia (HGD) will advance to adenocarcinoma. Once H.pylori infection is diagnosed it should be treated in these patients.

There is no common guideline for surveillance of GIM. In high-grade dysplasia with no endoscopically defined lesions, surveillance at six months or one year is recommended. In low-grade dysplasia with no endoscopically defined lesion, patients should receive follow up within a year after diagnosis.10 In the presence of an endoscopically defined lesion, resection should be considered to obtain a more accurate diagnosis.

A standard surveillance protocol is needed which should focus on the patients at greatest risk. In countries with lower incidence, high risk individuals should be identified. Multiple factors such as genetic risk, epidemiological factors and status of H. pylori infection should be considered. After the initial screening, high-risk patients with intestinal metaplasia should enter surveillance protocols for uniformity of care and future trends.

Recommendations For Screening for Gastric Cancer

As evident from the discussion above, there is a high-risk population which is known for gastric cancer. Guidelines to identify precursor lesions and then appropriate screening and surveillance will help in early detection and prevention of gastric cancer. In countries like Japan which are considered high-risk, high false positive results have been identified as a consequence of screening. In the United States, screening high risk populations like older males with pernicious anemia, atrophic gastritis and familial syndromes like FAP, could be a clinically justified method of screening.

ASGE guidelines suggests that patients with GIM at high-risk of gastric cancer due to ethnic background or family history should undergo surveillance endoscopy. Future surveillance endoscopies can be discontinued if two consecutive endoscopies have been negative for dysplasia and eradication of H. pylori has been achieved.

AGA guideline by Gupta S et al. and Gawron AJ et al. are recommended reading for recommendations for surveillance endoscopy in patients with GIM and high-risk individuals.^10,12

Future Research Areas

Despite decreasing incidence of gastric cancer, its mortality is still very high and diagnosis is made at a later stage of the disease. Screening methods available for even high-risk populations do not yield good positive predictive value. Multiple studies aim to identify non-invasive biomarkers from other bodily fluid like urine, saliva, gastric juice or blood.

On routine endoscopy we can miss almost ten percent of the lesions. High-definition endoscopy with virtual chromoendoscopy is superior to white light endoscopy alone. The endoscopist can identify high-risk lesions better with these enhanced imaging modalities. Biopsy of these targeted lesions increases the positive predictive value.

References

Ferlay J, Ervik M, Lam F, et al, eds. Global Cancer Observatory: Cancer Today. International Agency for Research on Cancer; 2020. Accessed November 25, 2020. gco.iarc.fr/today
World Health Organization. Cancer. WHO. Available at http://www.who.int/mediacentre/factsheets/fs297/en/. 12 September 2018; Accessed: February 5, 2020.
Surveillance, Epidemiology, and End Results Program. SEER Stat Fact Sheets: Stomach Cancer. National Cancer Institute. Available at http://seer.cancer.gov/statfacts/html/ stomach.html. Accessed: February 5, 2020.
Karimi P, Islami F, Anandasabapathy S, Freedman ND, Kamangar F. Gastric cancer: descriptive epidemiology, risk factors, screening, and prevention. Cancer Epidemiol Biomarkers Prev. 2014 May;23(5):700-13. doi: 10.1158/1055-9965.EPI-13-1057. Epub 2014 Mar 11. PMID: 24618998; PMCID: PMC4019373.
Liu KS, Wong IO, Leung WK. Helicobacter pylori associated gastric intestinal metaplasia: Treatment and surveillance. World J Gastroenterol. 2016 Jan 21;22(3):1311-20. doi: 10.3748/wjg.v22.i3.1311. PMID: 26811668; PMCID: PMC4716041.
Lee YC, Chiang TH, Chou CK, Tu YK, Liao WC, Wu MS, Graham DY. Association Between Helicobacter pylori Eradication and Gastric Cancer Incidence: A Systematic Review and Meta-analysis. Gastroenterology. 2016 May;150(5):1113-1124.e5. doi: 10.1053/j.gastro. 2016.01.028. Epub 2016 Feb 2. PMID: 26836587.
Kinoshita H, Hayakawa Y, Koike K. Metaplasia in the Stomach-Precursor of Gastric Cancer? Int J Mol Sci. 2017 Sep 27;18(10):2063. doi: 10.3390/ijms18102063. PMID: 28953255; PMCID: PMC5666745.
Altayar O, Davitkov P, Shah SC, Gawron AJ, Morgan DR, Turner K, Mustafa RA. AGA Technical Review on Gastric Intestinal Metaplasia-Epidemiology and Risk Factors. Gastroenterology. 2020 Feb;158(3):732-744.e16. doi: 10.1053/j.gastro.2019.12.002. Epub 2019 Dec 6. PMID: 31816301; PMCID: PMC7425600.
Cheung KS, Chan EW, Wong AYS, et al.: Long-term proton pump inhibitors and risk of gastric cancer development after treatment for Helicobacter pylori: a population-based study. Gut 67 (1): 28-35, 2018.
Gupta S, Li D, El Serag HB, Davitkov P, Altayar O, Sultan S, Falck-Ytter Y, Mustafa RA. AGA Clinical Practice Guidelines on Management of Gastric Intestinal Metaplasia. Gastroenterology. 2020 Feb;158(3):693-702. doi: 10.1053/j.gastro.2019.12.003. Epub 2019 Dec 6. PMID: 31816298; PMCID: PMC7340330.

CASE REPORT GUIDELINES FOR AUTHORS

Practical Gastroenterology Case Report Guidelines for Authors

June 2021 • Volume XLV, Issue 6

• The aim of Case Reports is to provide challenging yet clinically relevant and informative cases to primary care physicians.

• The Case should center around one (1) to three (3) high quality images that are completely described in the report. Images should be endoscopic, pathologic, and/or radiographic (without any patient identifiers) with clear labeling as appropriate.

• The Case must be a concise report submitted as a Word document consisting of no more than 1250 words.

• The images must be submitted as .jpg files separate from the Word document.

• There should be a brief introduction/abstract, relevant presentation of the case, relevant case discussion and conclusion.

• The conclusion should include one or two clinical pearls that the reader may apply to their practice or add to their knowledge set.

• References should be limited to 8. References should follow AMA style and journal names should be abbreviated according to Index Medicus practice. Inclusive page ranges should be indicated.

• Authors should be limited to 3 on each submission. No author photographs are necessary. All authors must provide their names, addresses, phone numbers, complete titles and affiliations.

• Case Reports must not have been published previously. Each Case Report is subject to review by members of our Editorial Board. Case Reports are subject to final editing. Upon publication, Case Reports will be copyrighted by Practical Gastroenterology Publishing, Inc.

• Please submit your Case Report to: Adrien Mahl, Editor Practical Gastroenterology practicalgastro@aol.com

FROM THE LITERATURE

EGD Observation Time and Neoplasm Detection

June 2021 • Volume XLV, Issue 6

To evaluate an institutional policy of EGD observation time and the detection rate of upper gastrointestinal neoplasm (UGI), all endoscopists from July 2010 to March 2019 were requested to follow institutional policy extending more than 3 minutes of observation time in every screening EGD. Observation time was defined as the time from when the endoscope reached the duodenum to when it was withdrawn and neoplasm detection rate (NDR) was obtained during this period and was compared with a baseline period from 2009 to 2015.

During the study period, 30,506 EGDs were performed. The mean subject age was 49.9 and 56.5% were men. All endoscopists achieved an average EGD observation time of more than 3 minutes during the period. Mean observation time was 3.35 and was significantly longer than the baseline at was 2.38. NDR was 33%, which was higher than the baseline (23%). Even after adjusting for subjects’ age and gender, smoking history and endoscopists’ biopsy sampling rate, prolonged EGD observation time of more than 3 minutes increased the NDR of UGI neoplasms (odds ratio 1.51).

It was concluded there was evidence that implementing a period of prolonged observation time could increase NDR and that should be an important quality indicator of the EGD examination.

FROM THE LITERATURE

Gastrointestinal Infection and the Risk of Microscopic Colitis

June 2021 • Volume XLV, Issue 6

To examine the relationship between gastroenteritis and the risk of microscopic colitis (MC), a casecontrolled study was carried out of 5 adult patients with MC diagnosed between 1990 and 2016 in Sweden, matched up to 5 general population controls according to age, sex, calendar year and county. Cases of MC were identified using systematized nomenclature of medicine codes from the ESPRESSO study, a cohort of gastrointestinal pathology reports from all 28 pathology centers in Sweden. Logistic regression modeling that was used to estimate adjusted odds ratio (aORs), and 95% confidence intervals (CIs).

Through December 2016, 13,466 MC cases were matched to 64,479 controls. The prevalence of previous diagnosed gastrointestinal infection was 7.5% among patients with MC, which was significantly higher than controls (3%). After adjustment, gastroenteritis was associated with an increased risk of MC (aOR 2.63). Among specific pathogens, Clostridioides difficile (aOR 4.39), Norovirus (aOR 2.87), and Escherichia species (aOR 3.82), but not Salmonella species, were associated with an increased risk of MC.

The association between gastrointestinal infections and risk of MC was stronger for the collagenous subtype (aOR 3.23), as compared with lymphocytic colitis (aOR 2.51). The associations remain significant after adjustment for immunemediated conditions and polypharmacy than when compared with unaffected siblings.

It was concluded in a nationwide study that gastrointestinal infection, particularly C. difficile, is associated with an increased risk of subsequent MC.