Ursula A. Matulonis, MD, Reviews Efficacy of Mirvetuximab Soravtansine Monotherapy in Ovarian Cancer With High FR- α Expression

Ursula A. Matulonis, MD, chief of the Division of Gynecologic Oncology, Brock-Wilson Family Chair, and institute physician at Dana-Farber Cancer Institute as well as professor of medicine at Harvard Medical School in Boston, Massachusetts, spoke with CancerNetwork^® at the 2022 Annual Global Meeting of the International Gynecologic Cancer Society about results of the phase 3 SORAYA trial (NCT04296890) which looked at mirvetuximab soravtansine monotherapy in patients with folate receptor α–high platinum-resistant ovarian cancer.

The overall response rate in the entire cohort was 32.4%, with 4.8% of patients having a complete response (CR) and 27.6% having a partial response (PR). The median duration of response was 6.9 months, the disease control rate was 51.4%, and 71.4% of patients had tumor reduction.

Transcript:

There are 105 patients who had measurable disease as designated by the investigator and the safety population [comprised] 106 patients who had received at least 1 dose of mirvetuximab soravtansine. The median age of the patients was 62 years. Their ECOG performance status was either 0 or 1, but most of the patients had 0 ECOG performance status. About 20% of the patients had an underlying BRCA mutation and 52% of patients had 3 prior lines of treatment. This represents a heavily pretreated patient population; 100% of patients had received prior bevacizumab [Avastin] because that was a requirement and about half the patients had received prior PARP inhibitors. The primary platinum-free interval was 3 to 12 months for about 60% of patients. For the rest, it was more than 12 months. The platinum-free interval that got them into the trial was 0 to 3 months in 37% of the patients, and the rest of the patients, 63%, had up to 6 months of a platinum-free interval. Again, this was a heavily pretreated population with about 40% of patients having a 0- to 3-month platinum-free interval.

I presented the results at a number of different meetings, most recently at IGCS. The overall response rate [ORR]—the primary end point of the study is looking at the investigator-assessed ORR, and these are all confirmed responses—was 32.4%. The 2 predefined subset analyses were the number of prior lines, so 1 to 2 or 3 prior lines. The other predefined subset was an analysis around the receipt of prior PARP inhibitors. When looking at the ORR, the number of [prior] lines the patient had received did not impact the ORR, it was still very good. In addition, there were 5 CRs. The responses were quite impressive, especially in this patient population where you would expect response rates of single-agent drugs to be closer to 10% or lower. The median duration of response was 6.9 months. It did not matter if the patients had received 1 to 2 vs 3 prior lines [of therapy] or whether they had received a prior PARP inhibitor.

What’s new [at this meeting is that] the disease control rate is now 51.4%. That’s the CR plus PR plus stable disease lasting 12 weeks or more. That also did not seem to be influenced at all by the number of prior lines of therapy or prior PARP inhibitors. The tumor reduction percentage was 71.4%, so 71% of patients in SORAYA had some tumor reduction.

Reference

Coleman RL, Matulonis U, Lorusso D, 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.