Here’s Why Therapeutic Drug Monitoring Should Work

RC Ungaro et al. Inflamm Bowel Dis 2022; 28: 649-651. Impact of Thiopurine Exposure on Immunogenicity to Infliximab Is Negligible in the Setting of Elevated Infliximab Concentrations

Background: Whether proactive therapeutic drug monitoring (pTDM) is superior to reactive TDM (rTDM) is not entirely clear, though some studies have shown better outcomes with pTDM. Additionally, Colombel et al (Clin Gastroenterol Hepatol 2019; 17: 1525-32) showed that antidrug antibodies during combination therapy were detected only in those with the lowest quartile of infliximab trough levels; this suggests that optimized monotherapy should be similarly effective to combination therapy.

Methods: The authors retrospectively analyzed a commercial laboratory database (Prometheus) with 3970 patients and paired 6-thioguanine (6-TGN) levels with infliximab (IFX) and antibodies to infliximab (ATIs)

Key findings:

  • “Those with higher levels of IFX had negligible benefit from concomitant thiopurine treatment in preventing ATIs.”
  • ATIs were detected in 9.9% of all patients. IFX level of >5 mcg/mL were associated with a very low risk of ATI (OR 0.05). “Immunogenicity was negligible (<3%) in the presence of IFX concentrations greater than 5 mcg/mL.”
  • 6-TGN levels (>125) were associated with lower risk of ATI, OR 0.42; though, this effect had a significant impact, only for those with with IFX <5 mcg/mL.
  • The authors note the prospective OPTIMIZE study (NCT04835506) should help determine the effectiveness of pTDM.

My take: In patients with IFX levels >5 mcg/mL, there does not appear to be much benefit for most patients from the addition of a thiopurine; this may not be true for those who are switching to a 2nd anti-TNF agent due to antidrug antibodies. This study supports pTDM to assure adequate IFX levels.

Related blog posts:

Disclaimer: This blog, gutsandgrowth, assumes no responsibility for any use or operation of any method, product, instruction, concept or idea contained in the material herein or for any injury or damage to persons or property (whether products liability, negligence or otherwise) resulting from such use or operation. These blog posts are for educational purposes only. Specific dosing of medications (along with potential adverse effects) should be confirmed by prescribing physician.  Because of rapid advances in the medical sciences, the gutsandgrowth blog cautions that independent verification should be made of diagnosis and drug dosages. The reader is solely responsible for the conduct of any suggested test or procedure.  This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition

White Sands National Park, New Mexico

IBD Shorts: Ustekinumab in Kids, Subcutaenous Infliximab, Nutrition Highlights

MT Dolinger et al. J Crohns Colitis 2022.  doi: 10.1093/ecco-jcc/jjac055. Online ahead of print. Outcomes of Children With Inflammatory Bowel Disease Who Develop Anti-Tumor Necrosis Factor Induced Skin Reactions

In this retrospective study, among those who developed skin reactions to anti-TNF agents, 71 (64%) continued anti-TNF and 40 (36%) switched to ustekinumab (UST). Key findings:

  • Switching to UST had a higher rate and odds of resolution of skin findings (29/40 (73%) vs. 24/71 (34%); p <0.0001) and combined remission (21 (52%) vs. 22 (31%); p=0.03) vs. continuing anti-TNF at 6 months

PJ Smith et al. J Crohns Colitis, jjac053, https://doi.org/10.1093/ecco-jcc/jjac053 Open Access: Efficacy and Safety of Elective Switching From Intravenous to Subcutaneous Infliximab (Ct-P13): A Multi-Centre Cohort Study

Patients (n=181) on established maintenance IV infliximab who switched to SC CT-P13 were included in this retrospective multi-centre cohort study. Key findings:

  • Treatment persistence rate was high (N=167, 92.3%) and only 14 patients (7.7%) stopped treatment during the follow-up period. There were low rates of immunogenicity with no change in clinical disease activity indices or biomarkers

Link: Crohn’s and Colitis Congress 2022 Nutritional Highlights (Nutritional Therapy for IBD Website). This website has a summaries, and links to extensive information (videos/posters) from recent IBD meeting.

Sunrise in Sandy Springs (4/9/22) -no filter

Dietary Therapy for Adults with Crohn’s Disease

H Yanai et al. The Lancet 2021; The Crohn’s disease exclusion diet for induction and maintenance of remission in adults with mild-to-moderate Crohn’s disease (CDED-AD): an open-label, pilot, randomised trial https://doi.org/10.1016/S2468-1253(21)00299-5

In this open-label trial of adults with mild-to-moderate biologic naive Crohn’s disease, key findings:

  • At week 6, 13 (68%) of 19 patients in the CDED plus partial enteral nutrition group and 12 (57%) of 21 patients in the CDED group had achieved clinical remission (p=0·4618)
  • Among the 25 patients in remission at week 6, 20 (80%) were in sustained remission at week 24 (12 patients in the CDED plus partial enteral nutrition group and eight in the CDED alone group)
  • 14 (35%) of 40 patients were in endoscopic remission at week 24 (eight patients in the CDED plus partial enteral nutrition group and six in the CDED alone group)

My take: Dietary therapy may be effective option for motivated adult patients with Crohn’s disease.

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Expert Consensus: New Recommendations for Therapeutic Drug Monitoring

AS Cheifetz et al. Am J Gastroenterol 2021;116: 2014-2025. A Comprehensive Literature Review and Expert Consensus Statement on Therapeutic Drug Monitoring of Biologics in Inflammatory Bowel Disease (published online August 13, 2021)

Key recommendations:

  • The panel agreed that reactive TDM should be used for all biologics for both primary nonresponse and secondary loss of response
  • It was recommended that treatment discontinuation should not be considered for infliximab or adalimumab until a drug concentration of at least 10–15 mg/mL was achieved
  • Consensus was also achieved regarding the utility of proactive TDM for anti–tumor necrosis factor therapy. It was recommended to perform proactive TDM after induction and at least once during maintenance.
  • More data are needed with regard to proactive TDM for biologics other than anti-TNF agents
  • There are no differences in interpreting TDM between originator biologics and biosimilars
  • When considering switching within drug class in case of secondary loss of response to a first anti-TNF drug because of the development of antidrug antibodies, an immunomodulator should be added to a subsequent anti-TNF therapy
  • Low-titer antidrug antibodies can be overcome by treatment optimization (dose escalation, dose interval shortening, and/or addition of an immunomodulator)

My take: This article should help support the practice of proactive TDM and discourage stopping anti-TNF agents until an adequate therapeutic level is achieved.

Related blog posts:

Disclaimer: This blog, gutsandgrowth, assumes no responsibility for any use or operation of any method, product, instruction, concept or idea contained in the material herein or for any injury or damage to persons or property (whether products liability, negligence or otherwise) resulting from such use or operation. These blog posts are for educational purposes only. Specific dosing of medications (along with potential adverse effects) should be confirmed by prescribing physician.  Because of rapid advances in the medical sciences, the gutsandgrowth blog cautions that independent verification should be made of diagnosis and drug dosages. The reader is solely responsible for the conduct of any suggested test or procedure.  This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition.

Can Antibiotics Increase the Risk of Antidrug Antibodies to Infliximab?

A lot of research is looking at how alterations in the microbiome affect a plethora of medical outcomes. Recently, there was a study linking sugar consumption in adolescence with an increased risk of adenomas (full text link: Simple Sugar and Sugar-Sweetened Beverage Intake During Adolescence and Risk of Colorectal Cancer Precursors; Gastroenterol 2021; 161: 128-142).

Now, a study indicates that taking oral antibiotics can influence the risk of developing antibodies to infliximab.

Full text (open access): Antibiotic use differentially affects the risk of anti-drug antibody formation during anti-TNFα therapy in inflammatory bowel disease patients: a report from the epi-IIRN (thanks to John Pohl for this reference)

Citation: Gorelik Y, Freilich S, Gerassy-Vainberg S, et al Antibiotic use differentially affects the risk of anti-drug antibody formation during anti-TNFα therapy in inflammatory bowel disease patients: a report from the epi-IIRNGut Published Online First: 03 August 2021. doi: 10.1136/gutjnl-2021-325185

This study reviewed data from 1946 patients with 363 who developed anti-drug antibodies (ADA). Then, specific pathogen and germ-free C57BL mice were treated with respective antibiotics and challenged with infliximab. ADA were assessed after 14 days.

Key findings:

  • Cox proportional hazard model demonstrated an increased risk of ADA development in patients who used cephalosporins (HR=1.97, 95% CI 1.58 to 2.44), or penicillins with β-lactamase inhibitors (penicillin-BLI, HR=1.4, 95% CI 1.13 to 1.74), whereas a reduced risk was noted in patients treated with macrolides (HR=0.38, 95% CI 0.16 to 0.86) or fluoroquinolones (HR=0.20, 95% CI 0.12 to 0.35).
  • In mice exposed to infliximab, significantly increased ADA production was observed in cephalosporin as compared with macrolide pretreated mice. Germ-free mice produced no ADA.

My take: The combination of retrospective data and mouse studies suggests that taking some antibiotics (mainly penicillins and cephalosporins) could increase the risk of immunogenicity to infliximab and increase the risk of anti-drug antibodies.

2021 AGA Guidelines For Crohn’s Disease

A series of articles details the 2021 AGA Guidelines for Crohn’s disease (CD) including a clinical practice guideline (pg 2496-2508), a clinical decision support tool (2509-2510), a spotlight summary (pg 2511), a technical review (2512-2557), and a review of the recommendations (pg 2557-2262). I will highlight the first article.

JD Feuerstein et al. Gastroenterol 2021; 160: 2496-2508. Full text: AGA Clinical Practice Guidelines on the Medical Management of Moderate to Severe Luminal and Perianal Fistulizing Crohn’s Disease

Full text: Spotlight

For me the most important of their recommendations was #7:

  • In adult outpatients with moderate to severe CD, the AGA suggests early introduction with a biologic with or without an immunomodulator rather than delaying their use until after failure of 5-aminosalicylates and/or corticosteroids.

Other points:

From Spotlight:

What Happens With Double Switches of Infliximab Products

N Trystram et al. Alimentary Pharmacology & Therapeutics, 01 Mar 2021, 53(8):887-899 Outcomes after double switching from originator Infliximab to biosimilar CT-P13 and biosimilar SB2 in patients with inflammatory bowel disease: a 12-month prospective cohort study.

Key findings:

  • Drug persistence was high (94.9%) after 54 weeks in cohort of 158 patients
  • Double switching from the originator Infliximab to CT-P13 and then to SB2 was associated with continued effectiveness; this study did not identify issues related to immunogenicity or safety of anti-TNF therapy after 54 weeks of follow-up.

My take: There is very limited data on repeated infliximab product changes; this small study did not identify any problems. Due to mandates from insurance, more frequent switching is likely to be more widespread and more definitive outcome data will emerge.

Abstract:

Related blog posts:

How Much Infliximab Can You Give to Young Children?

A recent case series (A Assa et al. JPGN 2020; 71: 516-520. Therapeutic Drug Monitoring-guided High-dose Infliximab for Infantile-onset Inflammatory Bowel Disease: A Case Series) describes four infants (2 mo-12 mo) with infantile-onset IBD who received high doses of infliximab.

Treatments regimens utilized infliximab dosing of 10-22 mg/kg/dose with initial three doses over 2-4 weeks. Other prior treatments in these patients included antibiotics (eg. vancomycin/gentamicin) and corticosteroids. Sulfasalazine was administered in two of the patients.

Other Key Points:

  • The authors noted that patients gradually transitioned to every 4 week therapy whild seeking to maintain trough concentrations >10 mcg/mL.
  • Infants have several risk factors for inadequate serum infliximab levels. Infliximab clearance is not linearly weight-related and infants are “most susceptible for under-dosing.”
  • Infliximab distribution in infants & children differs from adults with more peripheral compartment distribution, leading to lower trough levels.
  • Severity of disease impacts infliximab levels and can cause a ‘sink’ effect

The authors note that higher doses may increase adverse events, including infections

My take: This study shows that highly-selected patients may need both accelerated and higher doses of infliximab to enable response. It adds to the literature that children, in general, are at high risk of under-dosing with ‘standard’ infliximab dosing.

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Published IBD-COVID-19 Data from SECURE-IBD & Others

When I received an email in EARLY MARCH of this year regarding SECURE-IBD, I thought the researchers were insightful and proactive.  Recently, the authors published their early findings: EJ Brenner, RC Ungaro et al. Gastroenterol 2020; 159: 481-491. Full Text PDF: Corticosteroids, But Not TNF Antagonists, Are Associated With Adverse COVID-19 Outcomes in Patients With Inflammatory Bowel Diseases: Results From an International Registry

“Surveillance Epidemiology of Coronavirus Under Research Exclusion for Inflammatory Bowel Disease (SECURE-IBD) is a large, international registry created to monitor outcomes of patients with IBD with confirmed COVID-19.”

Key findings:

  • 525 cases from 33 countries were reported (median age 43 years, 53% men)
  • Risk factors for severe COVID-19 among patients with IBD included increasing age (adjusted odds ratio [aOR], 1.04; 95% CI, 1.01–1.02), ≥2 comorbidities (aOR, 2.9; 95% CI, 1.1–7.8), systemic corticosteroids (aOR, 6.9; 95% CI, 2.3–20.5), and sulfasalazine or 5-aminosalicylate use (aOR, 3.1; 95% CI, 1.3–7.7).
  • Tumor necrosis factor antagonist treatment was not associated with severe COVID-19 (aOR, 0.9; 95% CI, 0.4–2.2)

Other COVID-19 articles from same journal:

My take: There is a tremendous amount of information regarding SARS-CoV-2 & COVID-19 with regard to the GI tract and liver disease.  For the most part, the data indicate that individuals need to continue to treat their underlying disease and that most therapies do not increase the risk of worsening infection; the biggest risk factors remain increasing age and common comorbidities (eg. obesity, hypertension, and diabetes).  The published studies also provide insight and recommendations for preventing SARS-CoV-2 for health care providers.

Related blog posts:

“Positioning Biologic Therapies in the Management of Pediatric Inflammatory Bowel Disease” & 14% of U.S. Infected with COVID-19

J Breton et al. Gastroenterology & Hepatology 2020; 16: 400-14. Full text: Positioning Biologic Therapies in the Management of Pediatric Inflammatory Bowel Disease

This is a terrific summary of biologic therapies for pediatric inflammatory bowel disease. Compared to adults, the pediatric data is much more limited.  This may affect recommendations.  For example, recent AGA guidelines for moderate to severe ulcerative colitis in adults suggests that either ustekinumab or tofacitinib is generally preferable as a 2nd line agent rather than vedolizumab in patients with primary infliximab failure (Blog post: AGA Guidelines: Moderate to Severe Ulcerative Colitis).  In the chart below, vedolizumab is recognized as a preferred 2nd line agent.

In the section on vedolizumab:

The favorable risk-benefit profile makes vedolizumab an ideal therapeutic choice for pediatric IBD. However, an important limitation is its delayed onset of action, for which corticosteroid use as bridge therapy is often necessary in this population that is already at increased risk of growth failure and bone loss. Recently, Hamel and colleagues published their small, single-center experience of using concomitant tacrolimus between anti-TNFα withdrawal to vedolizumab maintenance as a corticosteroid-sparing bridge therapy in moderate to severe IBD (Ref: Hamel B, Wu M, Hamel EO, Bass DM, Park KT. Outcome of tacrolimus and vedolizumab after corticosteroid and anti-TNF failure in paediatric severe colitis. BMJ Open Gastroenterol. 2018;5(1):e000195).

This article addresses therapeutic drug monitoring:

TDM is a key component of managing IBD patients on anti-TNFα therapy. While  reactive TDM of antiTNFα agents has been adopted by societal guidelines, there is an increasing body of literature to support the benefit of proactive TDM, particularly in pediatric populations

Conclusions from authors: Anti-TNFα agents have revolutionized the management of IBD, positively modifying the natural disease history in children. Importantly, inception cohort studies of pediatric CD and UC (RISK and PROTECT, respectively) have highlighted the variable course of disease and necessity of adopting an individualized approach with early use of biologic therapy in patients at risk of severe disease progression. 

Biologics Used in Pediatric Inflammatory Bowel Disease

Related blog posts:

Disclaimer: This blog, gutsandgrowth, assumes no responsibility for any use or operation of any method, product, instruction, concept or idea contained in the material herein or for any injury or damage to persons or property (whether products liability, negligence or otherwise) resulting from such use or operation. These blog posts are for educational purposes only. Specific dosing of medications (along with potential adverse effects) should be confirmed by prescribing physician.  Because of rapid advances in the medical sciences, the gutsandgrowth blog cautions that independent verification should be made of diagnosis and drug dosages. The reader is solely responsible for the conduct of any suggested test or procedure.  This content is not a substitute for medical advice, diagnosis or treatment provided by a qualified healthcare provider. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a condition