One very targeted clue to treatment failure: An observational study from Israel identifies Sephardic Jews as more likely than Ashkenazim to form antibodies against the biologic drug infliximab.
Ungar, HO, Kopylov U, et al. Ashkenazi Jewish Origin Protects Against Formation of Antibodies to Infliximab and Therapy Failure Medicine. May 2015 94(18):e673. doi: 10.1097/MD.0000000000000673
Sephardic Jews were more likely to develop antibodies to infliximab, and treatment failure, than Ashkenazi Jews.
An observational study at Sheba Medical Center, Israel, reviewed the charts of 159 patients with inflammatory bowel disease. About half were identified as Ashkenazi, and half as Sephardic, the two main Jewish ethnic groups. Ashkenazi Jews are from central and Eastern Europe; Sephardic Jews are from the Mediterranean, North Africa, and Asia.
In the multivariate analysis, the odds ratio for formation of anti-infliximab antibodies, and treatment failure, was about 0.35 for Ashkenazi compared to Sephardic ethnicity. This differential was maintained for a 54-week followup.
Other factors that prevented antibody formation were episodic therapy and concomitant immunomodulator therapy.
Overall, 45% of patients treated with infliximab develop antibodies and treatment failure.