Pivotal SORAYA trial of IMGN 853 shows efficacy in ovarian cancer.

SORAYA is a single-arm study of mirvetuximab in patients with platinum-resistant ovarian cancer whose tumors express high levels of FRalpha and who have been treated with up to three prior regimens – at least one of which included bevacizumab.

The primary endpoint for the study is confirmed objective response rate (ORR) as assessed by investigator, including complete and partial responses, and the key secondary endpoint is duration of response (DOR). ORR was also assessed by blinded independent central review (BICR). The study is designed to rule out a 12% ORR, based on expected outcomes with available single agent chemotherapy from the AURELIA study in patients with platinum-resistant ovarian cancer and one to two prior lines of therapy. SORAYA enrolled 106 patients with a median of three prior lines of therapy (range one to four); 51% had three prior lines of therapy and 48% had one to two prior lines of therapy. All patients received prior bevacizumab; 48% of patients received a prior PARP inhibitor.

As of the data cutoff on November 16, 2021, the median follow-up time was 8.1 months. ORR by investigator was 32.4% (95% confidence interval [CI]: 23.6%, 42.2%), including five complete responses (CRs). ORR by BICR was 31.6% (95% CI: 22.4%, 41.9%), including five CRs. Responses were observed regardless of prior PARP inhibitor or number of prior lines of therapy. The median DOR is currently 5.9 months (95% CI: 5.6, 7.7). With nearly half of responders continuing on therapy, the duration of response continues to evolve and, with longer follow-up, median DOR could range from 5.7 to just above 7 months.

Mirvetuximab was well-tolerated, consistent with the known safety profile seen in more than 700 patients treated in the broader mirvetuximab program. Treatment-related adverse events led to dose reductions in 19% of patients, dose delays in 32% of patients, and discontinuations in 7% of patients. The most common treatment-related adverse events included blurred vision (41% all grade; 6% grade 3+), keratopathy (35% all grade; 9% grade 3+), and nausea (29% all grade; 0% grade 3+).