A biologics license application for mirvetuximab soravtansine, which demonstrated a clinically meaningful objective response rate, was submitted to the FDA for folate receptor α-high platinum-resistant ovarian cancer that has previously been treated with 1 to 3 lines of systemic treatments.
A biologics license application for mirvetuximab soravtansine was submitted to the FDA for patients with folate receptor α–high platinum-resistant ovarian cancer who have previously been treated with 1 to 3 lines of systemic treatments, according to a press release from ImmunoGen Inc.1
The application is based off results from the phase 3 SORAYA trial (NCT04296890)which was previously presented at The Society of Gynecologic Oncology 2022 Annual Meeting.2 Investigators observed an objective response rate (ORR) of 32.4% (95% CI, 23.6%-42.2%) in the overall population. ImmunoGen also filed for priority review, and if the application is accepted, it will be reviewed within 6 months.
"The [biologics license application] submission for mirvetuximab soravtansine is a key inflection point on our journey to delivering a safe and effective treatment option to patients with platinum-resistant ovarian cancer and moves us one step closer to transforming ImmunoGen into a fully-integrated oncology company," Mark Enyedy, president and chief executive officer of ImmunoGen, said in a press release.
The single-arm trial assessed mirvetuximab in patients with platinum-resistant high-grade serous epithelial ovarian cancer, primary peritoneal cancer, or fallopian tube cancer. Patients received mirvetuximab at 6 mg/kg intravenously with adjusted body weight once every 3 weeks. The primary end point was confirmed ORR and the secondary end point was duration of response (DOR).
In total, 106 patients with a median age of 62 years were enrolled. The majority of patients had epithelial ovarian cancer (80%), followed by primary peritoneal cancer (11%), and fallopian tube cancer (8%). Additionally, most patients had stage IV disease at initial diagnosis (38%). Most patients had no BRCA mutation or an unknown mutational status (80%). Fifty-one percent of patients had 3 lines of prior therapy.
Prior exposure to therapy included bevacizumab (Avastin; 100%) and PARP inhibitors (48%). A primary platinum-free interval of 3 to 12 months was reported in 60% of patients and 40% had an interval of 12 months or more.
Among responders in the overall efficacy population, 5 had complete responses and 29 had partial responses.
In the subgroup analysis, patients who had 1 to 2 lines of prior therapy (n = 51) had an ORR of 35.3% (95% CI, 22.4%-49.9%) and those with 3 prior lines of therapy (n = 53) had an ORR of 30.2% (95% CI, 18.3%-44.3%). Those with prior exposure to PARP inhibitors (n = 50) had an ORR of 38.0% (95% CI, 24.7%-52.8%) and those who had not been treated with PARP (n = 51) had an ORR of 27.5% (95% CI, 15.9%-41.7%).
Additionally, the investigator-assessed median DOR was 6.9 months (95% CI, 5.6-8.1). This remained unchanged for patients who had complete and partial responses, as well.
The subgroup analysis for median DOR found that those with 1 to 2 lines of prior therapy (n = 18) had a DOR of 5.9 months (95% CI, 4.2-8.1) and those with 3 lines of prior therapy (n = 16) had a DOR of 7.0 months (95% CI, 3.5–not reached [NR]). Those with prior exposure to PARP inhibitors (n = 19) had a DOR of 5.7 months (95% CI, 3.5-8.1) and those who had not (n = 14) had a DOR of 5.9 months (95% CI, 3.0-NR).
Grade 3 treatment-related adverse effects (TRAEs) occurred in 27% of patients, and grade 4 TRAEs were reported in 1%. The most common grade 3 TRAEs were keratopathy (8%), blurred vision (6%), and dry eye (2%). TRAEs delayed treated in 32% of patients, and 19% had a dose reduction, with 7% discontinuing treatment entirely. Additionally, 1 patient died potentially due to treatment.
Unique events related to treatment included blurred vision and keratopathy, with 31 patients experiencing both. Patients typically experienced these TRAEs at a median of 2.0 months from onset of treatment, and 22% of patients had related dose delays or reductions. At the time of data cutoff, over 80% of patients had grade 2 or 3 TRAEs that resolved to grade 0 or 1, and 9 patients were still be monitored in follow-up for resolution.
Less than 1% of patients had discontinued treatment because of ocular events, which resolved within 15 days.