Pfizer and Astellas’ Xtandi has been locked in a heated prostate cancer tussle with a challenger from Johnson & Johnson and, more recently, one from Bayer. One area where the pair was looking for a win? Showing Xtandi prolonged patients’ lives––and new data has done just that.
Xtandi significantly extended patients’ lives over standard-of-care hormone therapy in nonmetastatic castration-resistant prostate cancer, according to an overall survival analysis from the phase 3 Prosper trial released Tuesday.
The newest survival data met the secondary endpoint for the Prosper trial, which helped Xtandi nab an FDA approval as an add-on to androgen deprivation therapy (ADT) in that hard-to-treat prostate cancer population back in July 2018.
With its overall survival data in hand—considered the gold standard when it comes to cancer trials—Pfizer and Astellas can help build Xtandi’s case as the market leader in castration-resistant prostate cancer as the drug fends off challengers from Johnson & Johnson and Bayer.
Last month, Bayer and Orion’s Nubeqa actually beat Xtandi to the punch with trial data showing it extended patients’ lives over ADT alone in the nonmetastatic setting. Despite being last to the party with a July 2019 approval from the FDA, those results left Xtandi and J&J’s Erleada scrambling to catch up.
Erleada, for its part, has made a run at matching OS data but has so far fallen short.
At the European Society for Medical Oncology annual meeting in September, J&J unveiled that its Erleada-ADT pairing cut patients’ risk of death by 25% compared with a combo of ADT plus placebo. However, at that second interim analysis, the benefit wasn’t enough to cross the statistical significance bar.
While Nubeqa has so far been limited to the nonmetastatic setting, Xtandi and Erleada have been battling it out in metastatic castration-sensitive prostate cancer.
In December, the FDA approved Xtandi to treat castration-sensitive patients, opening the drug to a patient population that includes about 40,000 U.S. males each year, Pfizer said. That influx of patients is a good thing for Pfizer because the drugmaker was well suited to capitalize on its established network of oncologists, the company said.
“There is significant physician and comfort with Xtandi so we hope that this approval will build upon that,” Chris Boshoff, Pfizer Oncology’s chief development officer, said ahead of the approval.
The FDA based its approval on data from the phase 3 Arches trial that showed a combination of Xtandi and ADT reduced the risk of cancer worsening or death by 61% versus ADT alone. In a second investigator-sponsored study, dubbed Enzamet, Xtandi pared down the risk of death by 33% compared with other non-steroidal androgen-fighting drugs.
Xtandi’s approval came three months after Erleada earned an approval in the metastatic, castration-sensitive setting, following the FDA’s real-time review of the drug’s phase 3 Titan trial. Data from that study showed Erleada plus ADT cut the risk of death over placebo plus ADT by 33%. After nearly two years, 84% of patients on Erleada-ADT were still alive, compared with 78% of the placebo-ADT group.