"This is actually quite reassuring and I think important data that, at least in this scenario, patients tend to stay off treatment for a much longer period of time," he said at the symposium, co-sponsored by the American Society for Clinical Oncology, American Society for Radiation Oncology, and the Society of Urologic Oncology.
Dr. Oliver Sartor, medical director of the Tulane Cancer Center in New Orleans, said the question of survival with intermittent therapy has now been answered, and that it is very reasonable for intermittent therapy to be considered the standard of care in these patients.
"The only caveat is that you do have to monitor this; you just can’t send them out the door and say, ‘I’ll see you in a year,’ " said Dr. Sartor, who has been using intermittent therapy for the past decade in his patients to reduce adverse events. "I will be monitoring, typically, every 2 months."
In an interview, Dr. Klotz described the results as a win-win for patients and may also save them money. Although significantly less costly than many of the newer targeted therapies, a monthly injection costs about $350. He speculated that in treatment-naïve patients, the investigational agent MDV3100 and intermittent androgen deprivation may be a good partnership, but did not recommend this approach with abiraterone acetate should it gain approval this year, as is anticipated.
Of the 1,368 men evaluated, 11% had undergone a prior prostatectomy, and for 78%, it had been at least 3 years since radiation therapy. They had a median age of 74 years, 81% had a performance status of 0, and 23% had a PSA of more than 15 ng/ml when entering the trial, which was sponsored by several research groups including the National Cancer Institute Clinical Trials Group and Southwest Oncology Group.
Dr. Klotz and his co-authors disclosed no conflicts. Dr. Logothetis disclosed consulting for and honoraria and research funding from several drug companies. Dr. Sartor disclosed honoraria from Sanofi-Aventis as well as consulting for and receiving research funding from multiple drug companies.