Results from a recent international randomized phase II trial for the drug tasquinimod (TASQ), shows that TASQ is a potential therapy for men with advanced prostate cancer. The men who received TASQ on average went twice as long without disease progression as those who received only a placebo.

The subject men who participated in the study had castrate resistant recurrent metastatic prostate cancer, cancer that has spread beyond the prostate and whose disease had progressed even after receiving standard hormonal therapy. Recently released data from the study showed that TASQ significantly slowed the rate of disease progression, particularly in the bone and lymph nodes, and improved progression-free survival time in patients.

Sixty-nine percent of the men who took TASQ had not progressed at six months while only 34% of those taking the placebo had not progressed in that same time period.

TASQ seems to block new blood vessel growth in tumors as well as boosts the impaired immune response that is present. Combining both of these strategies seem to slow the rate of growth of prostate cancer cells. The reported side effects from TASQ for the most part have been mild.

Duke oncologist Andrew Armstrong, MD, ScM, the principal investigator of the trial and one of the lead authors on the upcoming publication, has presented these findings at several scientific meetings, including most recently in February at the American Society for Clinical Oncology’s Genitourinary Cancers Symposium.

“TASQ appears to be a promising new drug for the treatment of men with advanced prostate cancer,” says Armstrong. “We hope that this builds upon the other recent successes for the treatment of prostate cancer such as Provenge as well as recent successes with newer chemotherapy agents (cabazitaxel), hormonal agents (abiraterone) and bone-targeted agents (denosumab). This has been an exciting past year in prostate cancer.”

There is a newly opened, worldwide phase III trial of TASQ. This trial is designed to confirm the results of the previous studies. The trial will enroll 1200 men worldwide and is expected to last five years. More information about the trial can be found at: A Study of Tasquinimod in Men With Metastatic Castrate Resistant Prostate Cancer.

As promising as this trial seems to be we need to remember that there is no evidence that the rate of disease progression has any effect upon overall survival. There are many drugs, like Provenge that does extend life but does not effect disease progression or PSA. This phase III trial has as its primary end point disease progression and does not include overall survival as an endpoint!

Joel T. Nowak, M.A., M.S.W.