ASCO: AZ, Merck's Lynparza levels up in ovarian cancer, extending lives by 13 months

AstraZeneca and Merck's Lynparza competes against PARP rivals Zejula from GSK and Rubraca from Clovis in the ovarian cancer field. (AstraZeneca)

With competitor Zejula threatening to steal share after a key new approval, AstraZeneca and Merck’s Lynparza is taking things to the next level in BRCA-mutated ovarian cancer with evidence it can extend patients’ lives.

Among women with platinum-sensitive relapsed ovarian cancer receiving Lynparza as a maintenance treatment, the drug reduced the risk of death by 26%, the partners showed ahead of the American Society of Clinical Oncology (ASCO) virtual annual meeting. 

RELATED: AstraZeneca's Lynparza, armed with new FDA nod, aims to regain share from Tesaro's Zejula

Patients taking Lynparza (olaparib) saw their lives extended by 12.9 months compared with those taking placebo. At the five-year mark, 42.1% of those in the Lynparza group were still alive, versus 33.2% of the placebo group.

Improvements in overall survival can be tricky to demonstrate in ovarian cancer trials, in part because of high levels of patient crossover to the treatment group, investigator Andrés Poveda said during a pre-recorded press briefing aired Tuesday. And “limited progress has been made in improving overall survival in the last two decades,” he added.

But Lynparza’s showing, from the phase 3 Solo-2 study, “confirms that the PARP inhibitor olaparib should be the standard maintenance therapy for patients with BRCA-related relapsed ovarian cancer responding to platinum-based chemotherapy,” ASCO Chief Medical Officer and Executive Vice President Richard Schilsky, M.D., said in a statement.

That’s music to the ears of AZ and Merck, who are battling fellow PARP drugmakers GlaxoSmithKline—which fields Zejula—and Clovis Oncology in the ovarian cancer field. Zejula, in particular, could put a thorn in Lynparza’s side thanks to a recent FDA nod in women who haven’t yet relapsed.

RELATED: AstraZeneca, Merck's Lynparza wins bid to challenge GSK's Zejula in wider ovarian cancer pool

In late April, the drug won FDA clearance to ward off ovarian cancer recurrence in any woman who has responded to one round of platinum chemo. As of last week, Lynparza bears an OK in only some of those women—those who have a homologous recombination deficiency—and only in combination with Roche’s Avastin, an infusion.

GSK’s plan? Convince doctors to offer patients Zejula, a single pill, and forego the need for genetic testing. “You don’t need to undergo testing to find out if you are eligible for this based on mutation. Everyone can benefit,” Axel Hoos, SVP and oncology head at GSK, said in a recent interview.

But Leerink Partners analyst Andrew Berens expects Lynparza to hang onto its current lead in BRCA mutation-positive patients, for whom it’s approved without Avastin. “We continue to believe that Lynparza will remain the dominant PARP in patients testing positive for BRCA by blood test,” he wrote to clients last week.