Preliminary Results of the OPERA I and OPERA II Open-Label Extension Study
Objectives: To preliminarily assess annualized relapse rate (ARR) at 144 weeks among patients with RMS who received ocrelizumab or interferon beta-1a (IFN β-1a) in the OPERA I and II trials, followed by ocrelizumab in an OLE.
Methods: During the controlled treatment period, patients received intravenous ocrelizumab 600 mg every 24 weeks or subcutaneous IFN β-1a 44 μg three times weekly for 96 weeks. During the OLE, patients from the IFN β-1a group were switched to ocrelizumab.
Results: Patients from OPERA I (ocrelizumab, 352/410; IFN β-1a, 326/411) and OPERA II (ocrelizumab, 350/417; IFN β-1a, 297/418) were enrolled in the OLE. At the time of analysis, 317 and 322 patients on continuous ocrelizumab and 307 and 268 patients switching from IFN β-1a in OPERA I and II, respectively, had ≥48 weeks of follow-up in the OLE (144 weeks total). Across groups, patients received a median of two doses of ocrelizumab in the OLE. Among patients switching from IFN β-1a to ocrelizumab, the unadjusted ARR improved from 0.245 and 0.254 over the 96-week double-blind controlled treatment period in OPERA I and II, respectively, to 0.092 and 0.115 in the OLE. Among patients on continuous ocrelizumab, the unadjusted ARR was 0.136 and 0.138 during the double-blind controlled treatment period of OPERA I and II, respectively; during the OLE, the ARR in this group was 0.118 and 0.100, respectively. Imaging metrics will be presented.
Conclusions: Patients who originally received ocrelizumab in the OPERA studies continued to have favorable ARR outcomes in the OLE. Patients who switched from IFN β-1a to ocrelizumab in the OLE rapidly experienced ARR outcomes consistent with those of patients who received continuous ocrelizumab.