Omalizumab and the risk of malignancy: results from a pooled analysis

Since initial registration, the omalizumab clinical trial database has expanded considerably, with a doubling of patients exposed in the clinical trial environment. Previous pooled data (2003) from phase I to III studies of omalizumab showed a numeric imbalance in malignancies arising in omalizumab recipients (0.5%) compared with control subjects (0.2%). The previous analysis was based on limited available data, warranting further investigation.

We sought to examine the incidence of malignancy using comprehensive pooled data from clinical trials of omalizumab-treated patients.

This pooled analysis included data from 67 phase I to IV clinical trials. The prespecified primary analysis assessed the incidence of primary malignancy in 32 randomized, double-blind, placebo-controlled (RDBPC) trials.

There were 11,459 unique patients in all clinical trials (7,789 received omalizumab). The primary analysis identified malignancies in 25 patients (RDBPC trials): 14 in 4,254 omalizumab-treated patients and 11 in 3,178 placebo-treated patients. Incidence rates per 1,000 patient-years of observation time for omalizumab- and placebo-treated patients were 4.14 (95% CI, 2.26-6.94) and 4.45 (95% CI, 2.22-7.94), respectively; the corresponding rate ratio was 0.93 (95% CI, 0.39-2.27). Primary malignancies were of varying histologic type and occurred in a number of different organ systems; no cluster of histologies was identified.

In this pooled analysis no association was observed between omalizumab treatment and risk of malignancy in RDBPC trials; the rate ratio was below unity. The data suggest that a causal relationship between omalizumab therapy and malignancy is unlikely.