Changes in the Use of IBD Biologic Therapy

A recent study (W-J Lee et al. Inflamm Bowel Dis 2016; 22: 2410-17) offers a great deal of insight into changes in the use anti-Tumor Necrosis Factor Alpha (ant-TNF) therapy from 2009-2013 in patients ≤24 years.  The authors utilized databases with about 180 million people and identified 11,962 patients with inflammatory bowel disease (IBD).

Key findings:

  • 3300 of the 11,962 (27.6%) patients were treated with anti-TNF therapy.
  • Top-down treatment: 1298 of 3300 (39.3%) were treated with top-down therapy which was defined as usage of anti-TNF therapy within 30 days of first IBD medication prescription.  Interestingly, over the course of the study, there was a trend towards more top-down (versus step-up) therapy and shorter time to initiation of anti-TNF therapy. In 2009, 31.4% used a top-down approach compared with 49.8% in 2013.
  • Top-down therapy is associated with lower rates of corticosteroid use.
  • Infliximab dominant anti-TNF: infliximab was the anti-TNF in 89.2% of patients less than 12, 82.3% of patients 12-17, and 55.1% of patients 18-24.  Adalimumab accounted for the vast majority of the other TNF users. Though, the authors note a trend towards increasing use of adalimumab in both adult and pediatric patients in a separate study (Park KT et al. Inflamm Bowel Dis 2014; 20: 1242-49)
  • Cotherapy: thiopurines and methotrexate were used as cotherapy in 13.5% and 7.2% of top-down group compared with 54.8% and 14.6% respectively in step-up strategy.
  • Drug therapy among non-TNF users: 25.4% (2199) received a thiopurine, 79.3% (6871) received a 5-aminosalicylate, and 2.3% (201) received methotrexate.
  • Anti-TNF therapy discontinuation: Using top-down strategy 69.2% persisted on infliximab at 12 months and 56.8% persisted at 24 months.  In comparison, using step-up approach with infliximab, it was 72.7% at 12 months and 64.0% at 24 months.  The numbers were quite similar with all the anti-TNF agents indicating that step-up approach had significantly lower rate of anti-TNF discontinuation. The authors speculate that one factor could be use of cotherapy or possibly other adverse reactions.

The authors explain some of the limitations of their study in its reliance on databases, particularly with regard to misclassification.  However, in my opinion, these limitations do not affect any of the trends that the authors are able to document.

My take: For most of my patients, I have preferred to continue to utilize cotherapy  and/or step-up therapy because I think there is likely to be a more durable anti-TNF response.  The fairly small differences in anti-TNF durability have huge implications for those  who lose anti-TNF responsiveness given the limited treatment options.

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Hidden Lake and Bear Mountain, Glacier National Park

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Reporting Bias: Infections with TNF Inhibitors

A recent article (Clin Infect Dis 2013; 57: 1318-30 -thanks to Jeff Lewis for this reference) summarized the pediatric literature on infectious complications associated with tumor necrosis factor-α (TNF) inhibitors for both Juvenile Idiopathic Arthritis (JIA) and Inflammatory Bowel Disease (IBD).

In total 33 studies for JIA were included and 39 studies for IBD.  Many others were excluded due to overlapping cohorts or lack of sufficient data.

For JIA, the authors identified 296 infliximab (IFX) patients, 2465 etanercept patients, and 242 adalimumab patients.  Most infectious were mild and mainly viral etiology.  For example, 1016 upper respiratory illnesses with etanercept were reported.  However there were a significant number of more serious infections which included lower respiratory infections (n=37), cellulitis/abscess (n=15), histoplasmosis (n=2), and meningitis (n=4). Four patients had infectious fatalities.

Similarly, for IBD, most patients had mild infections.  Among 1407 IFX patients and 241 adalimumab (ADA) patients, there were 105 URIs noted.  Again, more serious infectious were noted in many.  Four fatalities were reported; 1 was due to disseminated CMV, 1 due to bacterial sepsis, and 2 were due to central line infections.

When examining this report, the question of reporting bias cannot be avoided. The various reports that were summarized included 30 prospective studies, 23 retrospective studies, and 19 various reports (case reports, case series, and FDA reports).  The composite, in my view, likely overestimates the risk of serious infections.  In addition, many of the infections may have been due to concurrent immunosuppressive therapy, but the details for this are lacking.

With regard to microbiology:

  • 5 JIA patients had tuberculosis; there were no tuberculosis cases reported in the IBD cohort
  • Varicella/zoster was the most frequent viral infection and was frequently severe.  In JIA cohort, there were 39 VZV cases (11 severe); among IBD cohort, there were 16 VZV cases (3 severe).

Bottomline: Given the frequent use of anti-TNF agents, better prospective pediatric data are needed.  In addition, careful analysis of the data is needed for better attribution; the risk for many of these infections is likely due to concurrent medications like corticosteroids.

Also Noted:

Clin Gastroenterol Hepatol 2013; 11: 826-31.  In a prospective cohort of 200 anti-TNF-naive adult patients (100 treated with IFX and 100 with ADA), the effectiveness was similar for IFX and ADA at both 1 and 2 year followup.  Improved efficacy was noted when these agents were combined with immunomodulators, though this was statistically significant for IFX. The total patient response was 63.5% at 1 year and 45% at 2 years.

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