SWOG Cancer Research Network researchers have dramatically increased the median survival time for individuals with hormone-sensitive metastatic prostate cancer. This finding comes from a large, randomised clinical study that was designed to evaluate a novel medication for these individuals.
The study’s findings were published in the “Journal of Clinical Oncology.” It investigated the efficacy of the medication orteronel in these individuals by combining it with androgen deprivation treatment on the exploratory arm and comparing that combination to androgen deprivation therapy with bicalutamide on the control arm.
Although the research fell short of its primary aim of a 33% increase in overall survival (OS), it did demonstrate an extraordinary median OS of 70 months in the control arm, the longest ever recorded for these patients in a non-intensified androgen deprivation treatment arm.
This OS represents a 24-month improvement over the outcomes of the SWOG-9346 study, which enrolled a roughly equal number of patients with severe illness in 2013.
The researchers believe that the life-prolonging extra therapies patients got after completing the S1216 study are the key explanation for this increased survival compared to earlier trials.
After concluding the trial therapy, 77% of patients in the control arm who had advanced cancer received further life-prolonging treatment, compared to 61% in the orteronel arm.
“We are seeing the benefit of advancements in advanced prostate cancer therapy over the last decade, resulting in unprecedented improvements in the survival of men with advanced prostate cancer in general, which is great news for our patients,” said study lead author Neeraj Agarwal, MD, a SWOG investigator at the University of Utah’s Huntsman Cancer Institute.
Setting the trial’s success as an improvement in OS of at least 33%, the S1216 research team assumed that the median control arm OS would be 54 months, a figure that was based on the SWOG-9346 results and additional time to account for the anticipated impact of new medications then being assessed for approval.
The results did not satisfy the criterion for S1216 to be declared a positive trial since the actual median control arm OS surpassed this assumption by 16 months.
Men on the orteronel arm also had significantly better median progression-free survival (47.6 months versus 23.0 months) and prostate-specific antigen (PSA) response rates measured seven months after treatment initiation (complete-, partial-, and no-response rates of 58, 22, and 19% versus 44, 31, and 25%); these were secondary endpoints in the trial.