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Ovarian Cancer Drug Rubraca Linked to High Mortality Rates

The FDA has asked the drugmaker Clovis to limit the use of its ovarian cancer drug Rubraca. This request comes after new evidence that Rubraca’s side effects increase the risk of death in patients with genetic abnormalities. Post-market findings have led the FDA to order Clovis to revise the Rubraca label. The revised label would restrict Rubraca to only patients with BRCA tumor mutations. Further restrictions for Rubraca pose serious concerns for the company’s future since Clovis may already be on the edge of bankruptcy. 

What Is Rubraca?

Rubraca is a prescription tablet used to treat recurrent ovarian cancer, fallopian tube cancer, or primary peritoneal cancer in adults who responded to chemotherapy. Also, adults with castration-resistant prostate cancer take Rubraca if medical or surgical treatments are no longer working. Rubraca contains the active ingredient rucaparib, a poly (ADP-ribose) polymerase (PARP) inhibitor. PARP inhibitors block the PARP enzyme, which helps cells repair themselves. Therefore, Rubraca prevents the repair work of cancer cells so that the cell dies and does not multiply. 

Biotechnology company Clovis Oncology first received FDA approval for Rubraca in 2018 to treat certain forms of ovarian cancer. The agency based its approval on a clinical study that showed significant improvement in patients given Rubraca compared to placebo patients. Then, in 2020, the FDA granted Rubraca accelerated approval for prostate cancer. Although drugs typically go through clinical studies, the FDA sometimes provides fast-track approval for conditions with limited treatment options. 

Completed Clinical Study Raises Concerns for Rubraca

The initial findings from the ARIEL3 clinical trial gained Rubraca its FDA approval in 2018. Earlier phases of the trial displayed promising results in tumor progression over placebo. However, recent data warns of increased death rates associated with Rubraca. The completed and finalized data from ARIEL3 was submitted in September and presented at this year’s International Gynecologic Cancer Society congress. 

Rubraca presented a 28% higher death risk than placebo in patients without BRCA mutations and with a high level of a genetic abnormality called loss of heterozygosity. Even patients with BRCA mutations and low levels of heterozygosity are 15% more likely to die than placebo patients. After reviewing these findings, the FDA met with Clovis on November 14, 2022. Given the overall survival data of the test group in ARIEL3, the FDA asked Clovis to revise the Rubraca label. The FDA wants Clovis to limit Rubraca in this second-line maintenance treatment to tumor BRCA patients only.

Clovis Could Crumble Under New Rubraca Restrictions

Earlier this year, Clovis pulled Rubraca as a third-line treatment from the European and U.S. markets because recent results indicated it did not improve overall survival. Furthermore, with competition from similar cancer drugs and a 10% decline in sales, Clovis has been on the ropes. The second-line maintenance indication is responsible for substantial revenue for Clovis. Therefore, this label revision could lead to the demise of Clovis. 

If Clovis and the FDA cannot agree on a revision, the FDA will convene a committee to evaluate Rubraca and whether it should remain on the market.