Rubraca is part of a new class of cancer therapies known as “PARP inhibitors.” It’s already been granted an accelerated approval by the Food and Drug Administration (FDA); but, as drug makers often do, Clovis has been trying to expand the drug’s label so that it can be taken by more patients for a longer period of time.

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The new late-stage study data could set the company up for just such an expansion. In a 564-person trial, patients whose ovarian cancer recurred (and who had already started treatment with chemotherapy) given Rubraca lived, on median, for double the amount of time without their disease getting even worse compared with those given a placebo (10.8 months versus 5.4 months, respectively). Furthermore, the results were evident in patients with a variety of genetic mutations. Rubraca is currently approved for people with certain kinds of BRCA gene variations.

Now, Clovis believes that the drug can win FDA approval for use as a “maintenance treatment” to stymie cancer’s recurrence.

The news made rival Tesaro’s, which is also working on PARP inhibitors, stock fall about 2%. British drug giant AstraZeneca, which has a similar treatment in the space called Lynparza (a product that’s produced its own impressive results of late), was fairly flat in Monday trading.

Clovis’ success could make things a bit more difficult for Tesaro in particular. Buyout rumors have been swirling around the latter firm, but the study data could push down its sell price—and maybe even encourage bidders to pursue Clovis.