ESMO: AZ, Merck's Lynparza brings precision medicine to prostate cancer with 'game-changer' results

BARCELONA—AstraZeneca and Merck are working hard to bring their PARP inhibitor Lynparza into the prostate cancer arena, and they laid out a second case with new data Monday.

The partners presented results at the European Society for Medical Oncology annual meeting showing that among previously treated metastatic, castration-resistant prostate cancer patients with one of three genetic mutations, Lynparza could cut the risk of disease progression or death by a whopping 66%.

Men with BRCA1, BRCA2 or ATM mutated cancers went a median 7.4 months without their cancer worsening, versus just 3.6 months for those treated with next-gen therapies such as Johnson & Johnson’s Zytiga or Pfizer and Astellas’ Xtandi. And among men with any of those mutations or one of 12 other mutations in their homologous recombination repair (HRR) genes, Lynparza cut the risk of disease progression or death by 51%.

“This is, I think, a game-changer,” Roy Baynes, M.D., Merck SVP and head of global clinical development, said, adding that Lynparza “could easily become a new standard of care” in HRR mutated patients. HRR mutations affect approximately 25% to 30% of all metastatic, castration-resistant prostate cancer patients, according to AZ.

RELATED: Merck and AZ pile on more positive Lynparza data in bid to break into prostate cancer

While early prostate cancer has seen a number of advances in recent years—thanks in large part to Xtandi and Zytiga, as well as J&J’s Zytiga follow-up Erleada—“it’s important to remember … that we do not have adequate therapies for metastatic, castration-resistant prostate cancer. Once hormones cease to be effective, the five-year survival rates really plummet,” Dave Fredrickson, EVP and global head of AstraZeneca’s oncology business unit, said.

Historically, treatment for the population has been somewhat of a “one-size fits all approach—not targeted, not precision at all,” he noted. But this latest Lynparza study, called Profound, could change that.

“To be able to now have, for the first time, a precision medicine—a targeted therapy in prostate cancer—should be practice-changing,” Fredrickson said.

RELATED: ASCO: AstraZeneca pioneer Lynparza scores with Zytiga combo in prostate cancer

The results follow those from another positive prostate cancer study the partners unveiled at the ASCO annual meeting last year. There, they made the case that adding Lynparza to Zytiga treatment could stave off disease progression by an additional five-plus months.

The data also help set Lynparza apart from PARP peers Zejula from GlaxoSmithKline’s Tesaro and Rubraca from Clovis Oncology, both of which are chasing Lynparza across cancers including prostate and ovarian. Over the weekend at ESMO, both the AZ-Merck team and GSK put up results for their respective PARP drugs showing that they could keep ovarian cancer from returning in chemo-treated women regardless of whether they had a BRCA mutation.