ImmunoGen presents full data from Phase 3 FORWARD I study
ImmunoGen announced full data and additional exploratory analyses from the Phase 3 FORWARD I study evaluating mirvetuximab soravtansine compared to chemotherapy in women with folate receptor alpha-positive, platinum-resistant ovarian cancer during an oral presentation at the European Society for Medical Oncology 2019 Congress in Barcelona, Spain. "While it is disappointing that FORWARD I did not meet the primary endpoint of progression-free survival, mirvetuximab demonstrated consistent and meaningful efficacy signals in patients with high levels of FRalpha expression and was well tolerated with a differentiated safety profile in both the ITT and FRalpha high populations," said Kathleen Moore, Associate Director of Clinical Research at the Stephenson Cancer Center at the University of Oklahoma. The FORWARD I Phase 3 trial randomized 366 patients 2:1 to receive either mirvetuximab or the physician's choice of single-agent chemotherapy. Eligibility criteria included patients with platinum-resistant ovarian cancer that expressed medium or high levels of FRalpha, who had been treated with up to three prior regimens. The primary endpoint of this study was progression-free survival, which was assessed using the Hochberg procedure in the entire study population and in the subset of patients with high FRalpha expression. The Hochberg procedure enables the simultaneous testing of two overlapping populations. Under this statistical analysis plan, if the p-value of the primary endpoint in either population is greater than 0.05, the p-value in the other population needs to be less than or equal to 0.025 to achieve statistical significance. In the entire study population, the confirmed overall response rate was higher for mirvetuximab than for chemotherapy, without a significant difference in the primary endpoint of PFS or overall survival. In the pre-specified FRalpha high subgroup: Median PFS was longer in patients who received mirvetuximab compared with chemotherapy. Given that the p-value in the entire study population exceeded 0.05, the statistical analysis plan for the study required the p-value in the high subset to be less than or equal to 0.025 to achieve statistical significance. Confirmed ORR was higher for mirvetuximab than for chemotherapy.