A Pilot Study of Omalizumab to Treat Oxaliplatin-Induced Hypersensitivity Reaction.

Abstract

Oxaliplatin hypersensitivity reactions (HSRs) are immunoglobulin E (IgE)-mediated and prevent maximum benefit from this drug. This study was designed to determine whether oxaliplatin HSRs could be prevented or reduced with omalizumab (Xolair), an anti-IgE antibody. This was a single-arm prospective pilot study. Patients receiving oxaliplatin-based chemotherapy for gastrointestinal cancers who were experiencing grade 1/2 HSRs were eligible. Patients received omalizumab 300 mg subcutaneously every 2 weeks, alternating with oxaliplatin-based chemotherapy. Nine patients enrolled. The primary end point was reduction of repeat HSR over the next 2 cycles. The sample size of 12 patients would achieve 79% power to detect a decrease from HSR rate of 70% (the null hypothesis) to 35% using a 1-sided binomial test. The study would be considered positive if fewer than 6 HSR events over 2 cycles occurred on omalizumab. Nine patients received 58 cycles of omalizumab. The mean number of treatments was 6 (range, 1-12). Eight of 9 patients (88%) completed 2 or more cycles and 7 (78%) completed 4 or more cycles; the overall rate of HSR was 12%. Five of 7 evaluable patients had stable disease, including 1 with near partial response. Omalizumab reduces or abrogates oxaliplatin HSRs and allows months of additional therapy with apparent clinical benefit.