A recent study (A Assa et al. Inflamm Bowel Dis 2017; 23: 791-97) indicates that after surgery, anti-TNFα treatment is worth another try.
In this retrospective study with 53 children, 18 had “pharmacodynamic failure” with anti-TNFα medications (PK group) and 35 were controls. “Phamacocynamic failure is characterized by either a lack of improvement of CD symptoms or loss of response after initial improvement in the setting of adequate serum drug levels without ADAs” [antidrug antibodies].
- Mean age at time of intestinal resection was 14.8 years
- Median time from resection to anti-TNF initiation was 8 months
- Compared to the control group, the PK group had similar response to anti-TNF therapy. “Similar proportions of patients from both groups were in clinical remission on anti-TNF treatment after 12 months and at the end of follow-up (1.8 years)”
- At 12 months, remission rates were 89% (PK) versus 88.5% (control)
The authors propose an explanation: “A plausible explanation for this finding is that in severely inflamed tissue with high inflammatory burden, local high levels of TNFα serves as a sink for anti-TNFα antibodies and that tissue injury and local hypoxia might further limit drug penetrance to its target.”
My take: This information is useful. Many patients who have surgery may respond to anti-TNFα therapy subsequently. The unanswered question: Could more frequent dosing of anti-TNFα therapy have averted surgery in some patients by overcoming areas of intense disease?