SPARTAN Trial: Apalutamide in Nonmetastatic Prostate Cancer
Posted: Thursday, June 28, 2018
In men with nonmetastatic castration-resistant prostate cancer, the addition of apalutamide to androgen-deprivation therapy significantly increased metastasis-free survival and the time to symptomatic disease progression. These were the findings of the phase III SPARTAN trial, an international study conducted by Matthew R. Smith, MD, PhD, of the Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, and colleagues. The results were published in The New England of Medicine.
“The risk of metastasis or death was more than 70% lower with apalutamide than with placebo, and the median metastasis-free survival was more than 2 years longer,” stated the investigators. “These findings support the clinical benefit of apalutamide.”
The double-blind, placebo-controlled study included men with nonmetastatic, castration-resistant prostate cancer and a prostate-specific antigen (PSA) doubling time of up to 10 months. The researchers randomized 1,207 men in a 2:1 ratio to receive apalutamide, a competitive androgen receptor inhibitor, at 240 mg daily (n = 806) or placebo (n = 401).
The planned primary analysis revealed a median metastasis-free survival of 40.5 months in the apalutamide group versus 16.2 months in the placebo group (P < .001). Secondary and exploratory endpoints consistently showed significant improvement as well, including a median time to symptomatic disease progression (P < .001) and a median time to PSA progression.
The rate of adverse events leading to discontinuation of treatment was 10.6% in the apalutamide group compared with 7.0% with placebo. Rash (23.8% vs. 5.5%), hypothyroidism (8.1% vs. 2.0%), and fracture (11.7% vs. 6.5%) occurred at a higher rate with apalutamide.