Shares of Medivation jumped 12 percent Wednesday after the company reported more details from a late-stage clinical trial of its prostate cancer pill.

Medivation and its partner Astellas Pharma said Tuesday that men who took the drug Xtandi had larger declines in PSA levels, a protein produced by the prostate, than patients who took a placebo. The higher the PSA level, the greater the chance of prostate cancer in many cases.

The patients who took Xtandi also started chemotherapy later than patients in the placebo group. The companies said in October that patients in the Xtandi group lived longer and that the drug slowed the progression of the disease. They say the drug reduced the risk of death by 29 percent and the risk of disease progression or death by 81 percent compared to placebo.

Xtandi was approved in 2012 for men whose cancer has returned or spread despite major medical intervention. The company wants to market the drug for men whose cancer is progressing despite androgen deprivation therapy, a broader approval that could boost sales.

Medivation shares rose $9.13 to $84.91 in early trading. Shares hit an all-time high of $87.45 at the open.

The study compared Xtandi to a placebo in men with advanced prostate cancer who had not received chemotherapy.

Jefferies & Co. analyst Biren Amin said Xtandi looked better than Johnson & Johnson's drug Zytiga "on every metric," including survival, time to the start of chemotherapy, and PSA responses. He said patients who took Xtandi remained in treatment almost four times longer than patients who were given a placebo, and the Xtandi patients were less likely to have additional treatment after disease progression.

He now expects sales of Xtandi to reach $866 million in 2014, up from his previous estimate of $645 million. Amin rates Medivation shares at "Buy" with a price target of $89.

Credit Suisse analyst Lee Kalowski said the long duration of treatment for the Xtandi patients means Medivation can charge a higher price and get more revenue from the drug. He rates the stock "Outperform" and raised his price target to $95 per share from $80.