IBD Update Feb 2019

Briefly noted:

B Feagan et al. Systematic review: efficacy and safety of switching patients between reference and biosimilar infliximab. Alim Pharm Ther 2019 Jan;49(1):31-40. “While available data have not identified significant risks associated with a single switch between reference and biosimilar infliximab, the studies available currently report on only single switches and were mostly observational studies lacking control arms. Additional data are needed to explore potential switching risks in various populations and scenarios.”

MP Pauly et al. Incidence of Hepatitis B Virus Reactivation and Hepatotoxicity in Patients Receiving Long-term Treatment with Tumor Necrosis Factor Antagonists. Clin Gastroenterol Hepatol 2018; 16: 1964-73. Using data from 8887 adults, this retrospective review found  “HBV reactivation iin 39% of patients who were HBsAg+ before therapy, but not in any patients who were HBsAg-negative and anti-HBc+ before therapy.”

D Lauritzen et al. Pediatric Inflammatory Bowel Diseases: Should We Be Looking for Kidney Abnormalities? Inflamm Bowel Dis 2018; 24: 2599-2605. In a cross-sectional cohort of 56 children with IBD, the authors found 25% “had either previously reported kidney disease or ultrasonographic signs of chronic kidney disease.” The authors note that plasma cystatin C is a useful biomarker for glomerular filtration as it less dependent on nutritional status; it is increased in the setteing of a decline in GFR.

L Pouillon et al. Mucosal Healing and Long-term Outcomes of Patients with Inflammatory Bowel Diseases Receiving Clinic-Based vs Trouhg Concentration-Based Dosing of Infliximab. Clin Gastroenterol Hepatol 2018; 16: 1276-83.  This retrospective study with patients who completed TAXIT maintenance phase found that patients who received trough-based infliximab dosing had a lower discontinuation rate of infliximab compared with clinic-based dosing (2 of 21 [10%]  vs. 10 of 27 [37%]).  However, both groups had >75% of patients able to continue infliximab for more than 3 years after the trial.

N Ouldali et al. Early Arthritis Is Associated With Failure of Immunosuppressive Drugs and Severe Pediatric Crohn’s Disease Evolution. Inflamm Bowel Dis 2018; 24: 2423-30. In this retrospective study with 272 patients with Crohn’s disease, 23.9% (n=65) developed arthritis and this was associated with failure of immunosuppressive drugs with OR of 6.9 after 2 years. In this study, immunosuppressive drugs refers to thiopurines and methotrexate.  By the completion of study, a much greater proportion of those with arthritis required biologic treatment (76% vs 32%, OR 4.3)

CCFA Conference Notes (Part 1): Preemptive Therapeutic Drug Monitoring Not That Helpful

This blog entry has abbreviated/summarized this terrific presentation; most of the material has been covered in this blog in prior entries but still this was a useful review. Though not intentional, some important material is likely to have been omitted; in addition, transcription errors are possible as well.

Optimizing Therapeutic Drug Monitoring –Dr. Hans Herfarth

  • Trough levels have been recognized to correlate with remission rates. Good data from SONIC (2010) for infliximab. Ultra2 trial (2013) showed similar data for adalimumab.

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  • Low albumin predicts higher rates of failure, possibly due to loss of infliximab in stool.

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  • Reviewed algorithm for loss of response to infliximab based on trough levels. If low infliximab and no antibodies, increase dosing of infliximab has high likelihood of clinical response.
  • If high infliximab and not responding, evaluate for other reasons including irritable bowel, and strictures.

Scenarios that create confusion with therapeutic drug monitoring:

  • If clinically-well patient has antibodies and adequate drug level, could observe or possibly add immunosuppressive agent. ~3% of patients have simultaneous ATI and IFX detection.
  • If clinically-well with low infliximab level, could increase dose or observe.

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  • In TAXIT study, however, lowering dose (panel B above) to get in target range was associated with a lower rate of response. No clear difference between clinically-based changes compared with proactive monitoring. Proactive adaption of trough levels may help prevent relapse in ~10% but not shown to alter long-term outcomes

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  • TAILORIX study looked at tailoring dose at week 14. ‘Week 14 adaption did not make a significant difference at 1 year.’  Limitation: 122 patients.

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Hard to see Group C (clinically-based group) in this slide

Hard to see Group C (clinically-based group) in this slide

Drug monitoring has become popular but its importance as a preemptive measure is unclear.  Dr. Herfarth’s practice is to monitor when loss of response but not to monitor if doing well. His view: if someone is doing well, therapeutic drug monitoring can be confusing. It is not proven that optimizing drug levels will improve long-term outcomes. (In children, especially due to growth, drug monitoring may be more important.)

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One other recommendation from Dr. Herfarth: he recommends combination therapy in his patients are started on a 2nd anti-TNFs.