Mirvetuximab sBLA Receives FDA Priority Review in Ovarian Cancer

• Priority review status has been given to the supplemental biologics license application (sBLA) for mirvetuximab soravtansine-gynx (Elahere) in the treatment of patients with folate receptor alpha (FRα)-positive, platinum-resistant ovarian, fallopian tube, or primary peritoneal cancer who have received 1 to 3 prior lines of systemic treatment.
• The priority review designation indicates that the FDA plans to act on an application within 6 months.
• The Prescription Drug User Fee Act (PDUFA) target action date is April 5, 2024.

The sBLA for mirvetuximab soravtansine in FRα-positive, platinum-resistant ovarian cancer has been granted priority review by the FDA.1 The review is supported by findings from the phase 3 MIRASOL trial (NCT04209855), and the FDA has set a PDUFA target action date of April 5, 2024.¹

"With the FDA’s filing of our sBLA, we are one step closer to securing full approval of [mirvetuximab soravtansine] in the [United States] and establishing this novel [antibody drug conjugate (ADC)] as the standard of care in FRα-positive platinum-resistant ovarian cancer," said Michael Vasconcelles, MD, executive vice president of Research, evelopment, and Medical Affairs, ImmunoGen, in a press release. "This regulatory milestone, achieved just over 1 year after [mirvetuximab soravtansine’s] accelerated approval, underscores the significance of the confirmatory MIRASOL data and the broader data set seen to date with [mirvetuximab soravtansine], as well as the urgency with which our teams worked to bring this potentially practice-changing therapy to eligible patients in need.”

Mirvetuximab soravtansine is a first-in-class ADC that is composed of an FRα-binding antibody, cleavable linker, and a tubulin inhibitor. In November 2022, the agent was granted accelerated approval from the FDA for FRα-high platinum-resistant ovarian cancer.

Data from the MIRASOL trial showed improvements in progression-free survival (PFS), overall survival (OS), and objective response rate (ORR) in this patient population. In patients who previously received a poly ADP ribose polymerase inhibitor (PARPi), the PFS hazard ratio (HR) was 0.58 (95% CI, 0.43, 0.78; P =.0002). ORR in those who received mirvetuximab soravtansine was 45% (95% CI, 36%-54%), including 7 complete responses (CR), compared with 17% in patients who received investigator’s choice chemotherapy (95% CI, 11%-25%). The HR for OS was 0.48 (95% CI, 0.33-0.71; P =.0002).^1,2

In patients who were not previously administered a PARPi (n = 191), the HR for PFS was 0.74 (95% CI, 0.54-1.03, P =.0685). The ORR among patients who were administered mirvetuximab soravtansine was 45% (95% CI, 36%-54%), including 7 CRs, compared with 17% (95% CI, 11%-25%). The HR for OS was 0.90 (95% CI, 0.590-1.38; P =.6319).

Among patients who received 1 or 2 previous lines of therapy (n = 245), the PFS HR was 0.61 (95% CI, 0.45-0.81; P =.0007). The ORR in patients who received mirvetuximab soravtansine was 46% (95% CI, 37%-55%), including 10 CRs, compared with 15% (95% CI, 9%-22%) with no CRs in patients who received chemotherapy (P <.0001). The OS HR was 0.66 (95% CI, 0.45-0.98; P =.0375).

Further, in patients who received 3 previous lines of therapy, the PFS HR was 0.71 (95% CI, 0.52-0.98; P =.0362), and the ORR in patients who received mirvetuximab soravtansine was 38% (95% CI, 29%-48%), including 2 CRs, compared with 18% (95% CI, 11%-26%). There were no CRs in patients who received chemotherapy (P =.0009). The OS HR was 0.65 (95% CI, 0.43-0.96; P =.0308).

The MIRASOL trial has an enrollment of 453 patients and an estimated study completion date of April 2024.³

REFERENCES:

1. FDA grants priority review of ImmunoGen’s supplemental biologics license application for Elahere (mirvetuximab soravtansine-gynx) in platinum-resistant ovarian cancer. News release. ImmunoGen. December 5, 2023. Accessed December 5, 2023. https://tinyurl.com/5n89ky8k

2. Elahere® shows overall and progression-free survival benefit regardless of prior PARPi exposure or prior lines of therapy in FRα-positive platinum-resistant ovarian cancer. News release. ImmunoGen, Inc. September 28, 2023. Accessed December 5, 2023. https://tinyurl.com/mf36ryvt

3. A study of mirvetuximab soravtansine vs. investigator’s choice of chemotherapy in platinum-resistant, advanced high-grade epithelial ovarian, primary peritoneal, or fallopian tube cancers with high folate receptor-alpha expression (MIRASOL). ClinicalTrials.gov. Updated March 6, 2023. Accessed December 5, 2023. https://clinicaltrials.gov/study/NCT04209855