Drug Has ‘Potential to Redefine the Standard of Care’ for Ovarian Cancer Subset

Mirvetuximab soravtansine had promising response rates and tolerability in patients with pretreated folate receptor alpha-high platinum-resistant ovarian cancer.

Top-line findings from the SORAYA clinical trial showed that mirvetuximab soravtansine is a promising treatment option for patients with folate receptor alpha (FRα) -high platinum-resistant ovarian cancer who have been treated with Avastin (bevacizumab).

"Despite advances in the platinum-sensitive setting, most patients with ovarian cancer eventually develop platinum-resistant disease, for which there are limited treatment options, especially for those patients who have previously received bevacizumab," said Dr. Robert Coleman, Chief Scientific Officer of US Oncology Research and SORAYA Co-Principal Investigator, in a statement.

SORAYA included 106 patients, all of whom received one to four prior treatments, with at least one of them being Avastin. The main goal of the study was to see the objective response rate (ORR) – meaning the percentage of patients whose disease shrunk as a result of treatment – with the secondary goal being duration of response (DOR).

At an average follow-up of 8.1 months, the ORR as determined by the investigators was 32.4%, which included five complete responses (meaning that there was no detectable trace of cancer). ORR determined by blinded independent central review was 31.6%, also with five complete responses.

The average DOR for patients receiving mirvetuximab soravtansine was 5.9 months, though since nearly half of patients who responded are still being treated with the drug, the DOR is expected to change.

"Data from SORAYA have the potential to redefine the standard of care for patients with FRα-high platinum-resistant ovarian cancer, as this trial has demonstrated that mirvetuximab delivers clinically meaningful benefit in this setting, with significant and durable responses and a favorable tolerability profile,” Coleman said.

Overall, mirvetuximab soravtansine was well-tolerated, with side effects being consistent with other patients who were treated with the drug. Nineteen percent of patients had to have their dose reduced due to side effects; 32% had dose delays; and 7% stopped treatment altogether. The most common side effects were blurred vision (41% all-grade and 6% grade 3 or higher), keratopathy (disease of the eye; 35% all-grade and 9% grade 3 or higher) and nausea (29% all grade, with no grade 3 or higher events).

"These data have the potential to be transformative for ovarian cancer patients and their physicians," said Dr. Ursula Matulonis, Chief of the Division of Gynecologic Oncology at the Dana-Farber Cancer Institute, Professor of Medicine at the Harvard Medical School, and SORAYA Co-Principal Investigator, in a statement. "In the platinum-resistant setting and particularly in later-line treated patients, response rates with available therapy are in the single digits with significant toxicities. With an ORR above 30%, a duration of response of around six months, and a treatment-related discontinuation rate below 10%, mirvetuximab shows impressive activity and tolerability for patients with platinum-resistant ovarian cancer. If approved, mirvetuximab will become a critical therapeutic option for patients with FRα-high ovarian cancer."

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