Clovis' Rubraca joins the 'three-horse' PARP race in recurrent ovarian cancer

It's go time for Rubraca. Clovis Oncology picked up a crucial new use for the ovarian cancer drug, putting it on par with rivals AstraZeneca and Tesaro in recurrent disease. In short, it's now a "three-horse race," as one analyst put it, and a race in which Clovis needs to speed up from behind.

The approval will boost Rubraca sales in the field, but because of its competitors' head start, it's likely to remain a third-place player, Evercore ISI's Steve Breazzano said in a note after the Friday approval.

On Friday, the FDA approved the PARP inhibitor as a maintenance therapy for women whose cancer has returned after responding to chemotherapy, with or without BRCA mutations.

The U.S. regulator signed off on the drug based on phase 3 results of the Ariel3 trial, in which Rubraca topped placebo at staving off disease progression. Because of the BRCA mutation-agnostic approval, patients won't need to undergo biomarker testing before treatment.

The nod should help Clovis grow Rubraca sales in the U.S. to $133 million this year, Breazzano said in a note to investors. The new "label reads fine," and the company has been working to grow its sales force to 155 staffers, he said. 

"With a preference for physicians to use PARP inhibitors early and broadly, we expect [Clovis] sales to increase, though retain a minority market position," he wrote. 

Mid-Monday morning, Clovis' share prices were up about 10% since the Friday nod. 

RELATED: ESMO: Clovis CEO deems new Rubraca data 'better' than its PARP rivals. Is it enough? 

Clovis presented its Ariel3 data at last year's European Society for Medical Oncology conference in Madrid, showing that the medication boosted progression-free survival in women with BRCA-positive tumors, in patients with homologous recombination deficiencies and in an overall intent-to-treat group. At the time, Clovis CEO Patrick Mahaffey told FiercePharma the data were “better than anybody has seen” in the field.

The FDA granted Clovis' drug a priority review for the use in December. With the nod, Clovis is entering a field already occupied by Tesaro's Zejula and AstraZeneca and Merck's Lynparza, which won their maintenance uses in March and August, respectively. 

RELATED: Clovis' Rubraca takes aim at Lynparza, Zejula with priority review for new use 

While working to grow sales, Clovis' management has backed Rubraca's efficacy and said the PARP class will only expand. At ESMO, Mahaffey told FiercePharma that Rubraca's data “speak for themselves" and that the drug can stand "alone and above" competitors.  

At the same time, Mahaffey said "I also know there’s room for more than one" drug in the PARP class, pointing to the crowded PD-1/PD-L1 field.