Sales of Clovis Oncology's (NASDAQ:CLVS) Rubraca could get a big lift just in time for summer. Today, the company told investors a supplemental application that could expand the addressable patient population of its lead drug will get a speedy review.

In November, Clovis submitted an application to expand Rubraca's drug label to include prostate cancer patients with tumors driven by BRCA1/2 mutations. The U.S. Food and Drug Administration (FDA) has officially started reviewing the application and an approval decision is expected in May.

Hand holding cubes that spell FDA.

Image source: Getty Images.

Finding room to grow

Rubraca's an easy-to-swallow tablet that makes it hard for tumor cells to repair their DNA. It's not the only member of the PARP-inhibitor class approved to treat ovarian cancer patients. For example, Lynparza from partners AstraZeneca (NYSE:AZN) and Merck (NYSE:MRK) works the same way and had been gaining popularity among ovarian cancer patients for years before Clovis Oncology entered the space.

More recently, Zejula from Tesaro earned approval to treat the same group of ovarian cancer patients as Rubraca. Following Tesaro's acquisition by GlaxoSmithKline (NYSE:GSK) Zejula has a lot more marketing muscle than a smaller biotech like Clovis Oncology can squeeze together.

In 2020, an estimated 43,000 men will be diagnosed with advanced-stage prostate cancer that doesn't respond to standard hormone therapy. Around 12% of these patients will have aggressive tumors that harbor gene mutations that Rubraca could earn approval this spring.