NEW YORK (Reuters Health) – Apalutamide markedly extends overall survival in patients with nonmetastatic castration-resistant prostate cancer (nmCRPC), according to a final analysis of data from the phase-3 SPARTAN study.
“With data presented herein, all primary and secondary study end points of SPARTAN were met; findings demonstrate the value of apalutamide as a treatment option for nonmetastatic castration-resistant prostate cancer,” Dr. Matthew R. Smith of Massachusetts General Hospital Cancer Center and Harvard Medical School in Boston and colleagues conclude in European Urology.
Patients with nmCPRC have increasing prostate-specific antigen (PSA) levels despite being on androgen-deprivation therapy (ADT), without metastases, Dr. Smith and his team explain in their report. They will “invariably progress to metastatic disease” without additional treatment, they add.
In the SPARTAN study 1,207 nmCPRC patients with PSA doubling times of 10 months or less on continuing ADT were randomized 2:1 to apalutamide, an androgen-signaling inhibitor developed by Janssen, or placebo. The U.S. Food and Drug Administration approved apalutamide in September 2019, based on interim findings showing a two-year metastasis-free survival advantage for the drug.
The current study is a final analysis of SPARTAN, which was funded by Janssen. At follow-up of a median 52 months, 428 patients had died. Patients on apalutamide were treated for a median of 32.9 months, placebo patients for 11.5 months.
Median overall survival was 73.9 months for apalutamide versus 59.9 months with placebo (hazard ratio, 0.78). Patients on apalutamide were less likely to initiate cytotoxic chemotherapy than those on placebo (HR, 0.63).
The rate of adverse events was similar for both groups, at 97% with apalutamide, 94% with placebo, and 90% in the crossover group.
“After crossover from placebo to apalutamide, the median treatment duration with apalutamide exceeded 2 yr (26.1m), which is approximately double the median time on treatment reported for crossover patients in other studies in nmCRPC, (ie, 14.5 mo in PROSPER and 11.0 mo in ARAMIS)” Dr. Smith and colleagues note.
Dr. Smith was not available for an interview by press time. He and other study authors report financial relationships with Janssen.
SOURCE: https://bit.ly/3klJVlI European Urology, online September 6, 2020.