CHICAGO ( TheStreet) -- Johnson & Johnson's (JNJ - Get Report) Zytiga improved survival in "pre-chemo" prostate cancer patients by 33% and more than doubled the time before cancer worsened compared to control, according to results from a phase III study to be presented today at the American Society of Clinical Oncology (ASCO) annual meeting.
Zytiga, a pill, was first approved in 2011 as a treatment for prostate cancer patients who have previously been treated with chemotherapy. The new data released for the first time Saturday open a much larger commercial opportunity for J&J because if approved, Zytiga will become a treatment option for men with less advanced prostate cancer.
J&J reported Zytiga sales of $200 million, half of those in the U.S., in the first quarter.
The strong Zytiga results are expected to have positive spillover effects for Medivation (MDVN - Get Report), which is developing its own prostate cancer pill MDV3100 that is similar -- and perhaps superior to -- Zytiga.Both Zytiga and MDV3100 work similarly by interfering with the way prostate cancer cells feed from testosterone produced in the body. Dendreon (DNDN), however, may emerge from this year's ASCO meeting with a limp. Based on today's Zytiga results, the pill could steal prostate cancer patients away from its Provenge immunotherapy. In the J&J study, 1,088 patients with prostate cancer who had not yet received chemotherapy were treated with Zytiga plus the steroid prednisone or a placebo plus prednisone. The study was stopped early after an interim analysis found that treatment with Zytiga reduced the risk of prostate cancer worsening or death (also known as progression-free survival) by 57% compared to placebo. The result was highly statistically significant, with a p value of 0.0001, meaning there was less than a one-hundredth of 1% chance that the outcome was derived by chance. Prostate cancer patients treated with placebo reported a median progression-free survival (PFS) of 8.3 months, while the median PFS for Zytiga-treated patients has not yet been reached. "