There are three PARP inhibitors battling for FDA approval in prostate cancer, and Lynparza from AstraZeneca and Merck is widely believed to have a comfortable lead. But Johnson & Johnson’s Janssen unit isn’t far behind with its entry, Zejula, and it just got a much-needed boost.
The FDA has granted its breakthrough therapy designation for Zejula in metastatic prostate cancer patients who previously received hormone treatments and chemotherapy and who have mutations in the BRCA1 or BRCA2 genes. The agency handed J&J the designation based on data from a phase 2 trial presented at the European Society for Medical Oncology (ESMO) annual meeting in Barcelona earlier this week, J&J said.
According to data released at ESMO, 41% of prostate cancer patients in the trial who had BRCA mutations responded to Zejula.
The breakthrough tag should speed up the FDA’s review of Zejula, which is currently marketed by GlaxoSmithKline’s Tesaro unit to treat ovarian, fallopian tube or primary peritoneal cancer. J&J licensed the exclusive rights to develop and market the drug in prostate cancer in 2016.
Still, when it comes to clinical trial results in prostate cancer, Zejula has often been overshadowed by Lynparza—and this year’s ESMO was no exception. During the conference, AZ and Merck presented data from a phase 3 trial showing that Lynparza cut the risk of disease progression or death by 66% in patients with BRCA1, BRCA2 or ATM mutations.
Roy Baynes, M.D., Merck’s SVP and head of global clinical development, called the Lynparza results “a game-changer” in an interview with FiercePharma, adding that the drug “could easily become a new standard of care” in prostate cancer patients with the mutations.
The Lynparza trial compared men treated with the drug to those who received Johnson & Johnson’s Zytiga or Pfizer and Astellas’ Xtandi. Patients taking Lynparza did not see their disease worsen for a median time of 7.4 months vs. 3.6 months for the other drugs.
J&J is already marketing a follow-up to Zytiga in prostate cancer, Erleada, but that drug is also in a tough spot competition-wise. In 2018, Erleada became the first drug approved to treat nonmetastatic castration-resistant prostate cancer (CRPC). And the drug got another boost this May when the FDA agreed to assess the drug to treat metastatic, castration-sensitive prostate cancer under its Real Time Oncology Review program. Nevertheless, Xtandi, which was also approved in CRPC in 2018, now holds double the market share of Erleada, Pfizer biopharma President Angela Hwang told investors in April.
J&J rolled out new data on Erleada at ESMO in a bid to boost prescriptions, but it may not be enough to wow physicians. The company said that in an interim analysis of a phase 3 trial, Erleada administered along with androgen deprivation therapy (ADT) cut the risk of death by 25% compared with ADT plus placebo—but that the results were not statistically significant. The company’s executives hope the final analysis will hit the statistical-significance bar.
As for PARP inhibitors in prostate cancer, that’s a story that will be closely watched by investors in the coming months. J&J is facing competition not just from Lynparza but also from Clovis Oncology’s Rubraca. Clovis came through with data of its own in prostate cancer at ESMO, announcing a 44% response rate to Rubraca in a phase 2 trial in men with metastatic CRPC.