FDA Approves Mirvetuximab Soravtansine-gynx for FRα+ Platinum-resistant Ovarian Cancer

The FDA has granted accelerated approval to mirvetuximab soravtansine-gynx (Elahere) for the treatment of adult patients with folate receptor α (Frα)–positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer, who have received 1 to 3 prior systemic treatment regimens.^1-3

The regulatory agency also gave the green light to the VENTANA FOLR1 (FOLR-2.1) RxDx Assay for use as a companion diagnostic device to identify patients who are eligible to receive the agent. Testing can be done on fresh or archived tissue. Newly diagnosed patients can be tested at diagnosis to determine whether this agent will be an option for them at the time of progression to platinum resistance.

The decision was supported by findings from the phase 3 SORAYA trial (NCT04296890), in which mirvetuximab soravtansine elicited a confirmed investigator-assessed objective response rate (ORR) of 31.7% (95% CI, 22.9%-41.6%); this included a complete response rate of 4.8% and a partial response rate of 26.9%. Moreover, the median duration of response (DOR) was 6.9 months (95% CI, 5.6-9.7) per investigator assessment.

"The approval of Elahere 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 the Dana-Farber Cancer Institute, professor of medicine at the Harvard Medical School, and SORAYA co-principal investigator, stated in a press release. “Elahere 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 Elahere."

The global, single-arm SORAYA trial enrolled a total of 106 patients with platinum-resistant ovarian cancer whose tumors expressed high levels of FRα. Patients were allowed to have received up to 3 prior lines of systemic treatment, and all were required to have received bevacizumab (Avastin).

If patients had corneal disorders, ocular conditions in need of ongoing treatment, peripheral neuropathy that was greater than grade 1 in severity, or noninfectious interstitial lung disease, they were excluded.

Study participants received intravenous mirvetuximab soravtansine at 6 mg/kg once every 3 weeks until progressive disease or unacceptable toxicity. Investigators conducted tumor response assessments every 6 weeks for the first 36 weeks, and every 12 weeks thereafter.

Confirmed investigator-assessed ORR served as the primary end point for the research, and the key secondary end point was DOR by RECIST v1.1 criteria.

In the efficacy-evaluable population (n = 104), the median age was 62 years (range, 35-85). Ninety-six percent of patients were White, 2% were Asian, and 2% did not have their race information reported; 2% of patients were Hispanic or Latino. Regarding ECOG performance status, 57% of patients had a status of 0 and the remaining 43% had a status of 1.

Ten percent of patients received 1 prior line of systemic treatment, 39% received 2 prior lines, and 50% received 3 or more prior lines. All patients previously received bevacizumab, as required, and 47% previously received a PARP inhibitor.

The safety of mirvetuximab soravtansine was evaluated in all 106 patients. The median duration of treatment with the agent was 4.2 months (range, 0.7-13.3).

The all-grade toxicities most commonly experienced with mirvetuximab soravtansine included vision impairment (50%), fatigue (49%), increased aspartate aminotransferase (50%), nausea (40%), increased alanine aminotransferase (39%), keratopathy (37%), abdominal pain (36%), decreased lymphocytes (35%), peripheral neuropathy (33%), diarrhea (31%), decreased albumin (31%), constipation (30%), increased alkaline phosphatase (30%), dry eye (27%), decreased magnesium (27%), decreased leukocytes (26%), decreased neutrophils (26%), and decreased hemoglobin (25%).

Thirty-one percent of patients experienced serious adverse reactions with the agent, which included intestinal obstruction (8%), ascites (4%), infection (3%), and pleural effusion (3%). Toxicities proved to be fatalfor 2% of patients, and these included small intestinal obstruction (1%) and pneumonitis (1%).

Twenty percent of patients required dose reductions due to toxicities. Eleven percent of patients discontinued treatment with mirvetuximab soravtansine because of adverse reactions. Toxicities that resulted in more than 2% of patients discontinuing treatment included intestinal obstruction (2%) and thrombocytopenia (2%). One patient discontinued because of visual impairment.

References

1. ImmunoGen announces FDA accelered approval of Elahere (mirvetuximab soravtansine-gynx) for the treatment of platinum-resistant ovarian cancer. News release. ImmunoGen Inc. November 14, 2022. Accessed November 14, 2022. http://bit.ly/3GgrCwL
2. FDA grants accelerated approval to mirvetuximab soravtansine-gynx for FRα positive, platinum-resistant epithelial ovarian, fallopian tube, or peritoneal cancer. News release. FDA. November 14, 2022. Accessed November 14, 2022. http://bit.ly/3UP742w
3. Elahere (mirvetuximab soravtansine-gynx). Prescribing information; ImmunoGen Inc; 2022. Accessed November 14, 2022. https://www.accessdata.fda.gov/drugsatfda_docs/label/2022/761310s000lbl.pdf