Yesterday, researchers presented results from two of the STAMPEDE trial's original questions at the American Society of Clinical Oncology's Genitourinary Cancers Symposium in San Francisco. They looked at whether adding the drug celecoxib, or a combination of celecoxib plus zoledronic acid, to standard long-term hormone therapy improved survival for men with prostate cancer.
In 2012, a pre-planned intermediate analysis showed that adding celecoxib, a Cox-2 inhibitor, to hormone therapy did not delay treatment failure enough to justify continuing to recruit more patients to these comparisons. The researchers continued to follow-up these men to monitor the long-term effects. These results (with an average of five years of follow-up) were presented yesterday.
All the men in the trial received the standard treatment which was hormone therapy, with radiotherapy encouraged for men whose disease had not spread to distant parts of their body. Just over 300 men were randomised to receive celecoxib tablets twice a day for up to a year in addition. The researchers then compared the results for these men with those of more than 600 men who had the standard treatment. Adding celecoxib made no difference to how long men lived for. Men who received celecoxib were no more likely to have severe side-effects than men treated with just the standard treatment.
Another 300 men were randomised to have a combination of celecoxib and zoledronic acid, in addition to the standard treatment. These were compared to the same men who had the standard treatment. Overall, this combination did not significantly improve how long men lived for. In a large subgroup of men whose disease had already spread to distant parts of their body, there was some evidence to suggest this combination may help these men live longer.
This is the first trial to suggest that a combination of celecoxib and zoledronic acid may improve survival. There is not enough evidence to impact on the standard treatment for prostate cancer, but it does raise some interesting questions. There may be a role for adding celecoxib to zoledronic acid where zoledronic acid is already used for other types of cancer (eg. later stages of prostate cancer, breast cancer, multiple myeloma). Further research is needed to investigate this.