Late-stage study results released ahead of presentation later this week at the ASCO Genitourinary Cancer symposium show that Johnson & Johnson's apalutamide significantly improved median metastasis-free survival (MFS) by 2 years versus placebo in men with non-metastatic castration-resistant prostate cancer (nmCRPC).
The SPARTAN trial randomised 1207 patients with nmCRPC to receive either apalutamide, which is an orally administered next-generation androgen receptor inhibitor, or placebo. The study's primary endpoint was MFS, while secondary goals included time to metastasis, progression-free survival (PFS), time to symptomatic progression and overall survival (OS).
Results showed that apalutamide decreased the risk of distant metastasis or death by 72 percent versus placebo, with a median MFS of 40.5 months and 16.2 months in the two groups, respectively. Data also indicated that apalutamide significantly improved time to metastasis, PFS and time to symptomatic progression versus placebo, while in an interim analysis for OS, there was a trend favouring Johnson & Johnson's drug.
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The findings come as Pfizer and Astellas also unveiled late-stage study data illustrating that Xtandi (enzalutamide), in combination with androgen deprivation therapy (ADT), cut the risk of metastasis or death by a significant 71 percent in patients with nmCRPC, versus ADT alone. Results showed that median MFS was 36.6 months for the Xtandi arm, compared with 14.7 months for ADT alone.
In the SPARTAN trial, rates of discontinuation due to adverse events were low in both groups, at 10.7 percent for apalutamide and 6.3 percent for placebo. In addition, mean baseline health-related quality of life scores were maintained with treatment, with no difference between the two groups over time.
In October last year, Johnson & Johnson submitted an application to the FDA seeking approval of apalutamide for men with nmCRPC based on data from the SPARTAN study. The regulator subsequently granted the filing priority review designation with a target date of April 2018. For related analysis, see ViewPoints: Johnson & Johnson says more about apalutamide while still staying mum.
Johnson & Johnson gained apalutamide, formerly known as ARN-509, after agreeing to buy Aragon Pharmaceuticals for up to $1 billion in 2013.
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