FDA Grants Accelerated Approval to Mirvetuximab Soravtansine for Subset of Platinum-Resistant Ovarian Cancer

Mirvetuximab soravtansine-gynx (Elahere) was given accelerated approval by the FDA for the treatment of patients with folate receptor-α (FR-α)-positive platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer cancer who have been treated with 1 to 3 lines of prior therapy, according to a press release from ImmunoGen, the manufacturer of the drug.¹

The FDA based its approval off findings from the phase 3 SORAYA trial (NCT04296890), which demonstrated that treatment with mirvetuximab soravtansine elicited an overall response rate as determined by the investigators of 31.7% (95% CI; 22.9%-41.6%) with 5 complete responses.² Moreover, as assessed by the investigators, the median duration of response to mirvetuximab soravtansine was 6.9 months (95% CI; 5.6-9.7).

The FDA based its approval of mirvetuximab soravtansine-gynx (Elahere) off findings from the phase 3 SORAYA trial (NCT04296890), which demonstrated that treatment with mirvetuximab soravtansine elicited an overall response rate as determined by the investigators of 31.7% (95% CI; 22.9%-41.6%) with 5 complete responses.

"The approval of (mirvetuximab soravtansine) is significant for patients with FRα-positive platinum-resistant ovarian cancer, which is characterized by limited treatment options and poor outcomes," Ursula Matulonis, MD, chief of the Division of Gynecologic Oncology at Dana-Farber Cancer Institute, professor of medicine at Harvard Medical School, and SORAYA co-principal investigator, said in the company-issued press release. “[Mirvetuximab soravtansine’s] impressive anti-tumor activity, durability of response, and overall tolerability observed in SORAYA demonstrate the benefit of this new therapeutic option, and I look forward to treating patients with [mirvetuximab soravtansine]."

In May, the FDA accepted the biologics license application of mirvetuximab Soravtansine under priority review.

A total of 106 patients were enrolled at baseline, of whom 105 had measurable disease and were included in the efficacy population. The safety population included 106 patients which had 1 or more doses of mirvetuximab.

The median age was 62 years and primary cancer diagnoses included epithelial ovarian cancer (80%), fallopian tube cancer (8%), and primary peritoneal cancer (11%). Most patients had an ECOG performance status of 0 (57%) and negative or unknown BRCA mutation status (80%). Nine percent of patients received 1 line of prior systemic therapy, 39% received 2 lines, or 52% received 3 lines. All patients were previously exposed to bevacizumab (Avastin), and 48% were exposed to PARP inhibitors. Fifty-nine percent of patients had a primary platinum-free interval of 3 to 12 months and 41% had an interval of 12 months or more. Additionally, 37% of patients had a platinum-free interval of 0 to 3 months and 63% had an interval of 3 to 6 months.

The overall response rate (ORR) was 32.4% in the overall population. The complete response (CR) rate was 4.8%, with a partial response (PR) rate of 27.6% and 45.7% had stable disease. The median duration of response (DOR) was 6.9 months, and the disease control rate (DCR) was 51.4%. Investigators also reported a 71.4% reduction in tumor size.

In patients who were PARP inhibitor naïve (n = 51) the ORR was 27.5%, with a CR rate of 3.9%, a PR of 23.5%, and stable disease in 58.8%. The median DOR was 6.4 months and the DCR was 51.0%. Additionally, 70.6% of patients experienced a reduction in tumor size. In patients who had a prior PARP inhibitor (n = 50), the ORR was 38.0%, the CR rate was 4.0%, the PR rate was 34.0%, and the stable disease was 34.0%. Moreover, median DOR for this group was 5.7 months, DCR was 54.0%, and tumor reduction rate was 74.0%.

Patients who received 1 to 2 lines of prior therapy (n = 51) had an ORR of 35.3%, a CR rate of 3.9%, a PR rate of 31.4%, and stable disease rate of 47.1%. The median DOR was 5.9 months, with a DCR of 58.8% and tumor reduction rate of 76.5%. In patients who had 3 prior lines of therapy (n = 53), the ORR was 30.2% including a CR rate of 5.7%, a PR rate of 24.5%, and a stable disease rate of 45.3%. The median DOR was 7.4 months. Moreover, the DCR was 45.3%, and 67.9% of patients experienced tumor reduction.

Overall, treatment-related adverse effects (TRAEs) were relatively low-grade. Grade 3 or higher serious TRAEs occurred in 9% of patients. The most common grade 3 TRAEs were keratopathy (8%) and blurred vision (6%). There was 1 event of grade 4 keratopathy.

References

1. ImmunoGen announces FDA accelerated approval of ELAHERE™ (mirvetuximab soravtansine-gynx) for the treatment of platinum-resistant ovarian cancer. News release. ImmunoGen. November 14, 2022. Accessed November 14, 2022. https://bwnews.pr/3AayMyH
2. Coleman RL, Lorusso D, Oaknin A, et al. Clinical benefit of mirvetuximab soravtansine in ovarian cancer patients with high folate receptor alpha expression: results from the SORAYA study. Presented at: 2022 Annual Global Meeting of the International Gynecologic Cancer Society; New York, NY; September 29-October 1, 2022. Abstract O028.