December 15, 2016 (Last Updated: 11:11am PT)
By Mark Terry, BioSpace.com Breaking News Staff
Pfizer and Astellas Pharma announced today that its drug Xtandi (enzalutamide) did not meet its top-line results in a Phase IV clinical trial.
Pfizer acquired Medivation , which developed Xtandi, in a $14 billion deal in August. Xtandi was approved in 2012 for late-stage prostate cancer. In 2015, U.S. sales exceeded $1 billion. In this year’s second quarter alone, sales in the U.S. were $330.3 million.
The Phase IV PLATO study was evaluating the efficacy and safety of Xtandi, plus abiraterone acetate and prednisone in comparison to abiraterone acetate and prednisonen alone. Abiraterone acetate is marketed by Johnson & Johnson as Zytiga. Prednisone is a steroid. The trial failed to show progression-free survival (PFS) in patients with chemotherapy-naive metastatic castration-resistant prostate cancer (CRPC) whose prostate-specific antigen (PSA) had previously progressed while on Xtandi.
“While the PLATO trial did not meet its primary endpoint, it is critical that we continue to focus on addressing the unmet needs of men with metastatic CRPC, who have a poor prognosis despite treatment advances,” said Mohammad Hirmand, interim chief medical officer at Medivation, in a statement. “We will continue to analyze these data to better understand the results with the goal of further helping these patients.”
CRPC is a type of prostate cancer that has metastasized outside the prostate and continues to spread despite treatment. According to studies, up to 40 percent of men with prostate cancer who undergo treatment develop metastatic, or advanced, prostate cancer. The five-year relative survival rate in the U.S. for men with prostate cancer with metastatic disease is 28 percent, compared to 100 percent in prostate cancer patients with non-metastatic disease.
The Phase IV PLATO trial enrolled 509 patients with CRPC who received open label Xtandi during the first period of the study, until PSA progression was confirmed. They were randomized into one of the two arms of the trial, Xtandi plus Zytiga and prednisone, and just Zytiga and prednisone.
“Xtandi continues to remain an important treatment option for men with metastastic CRPC and their physicians,” said Steven Benner, senior vice president, therapeutic area head for oncology development at Astellas, in a statement. “We are committed to continuing to explore the clinical potential of Xtandi across the disease continuum.”
The news didn’t make much of an impact, if any, on Pfizer . Shares are currently trading for $32.74. On Dec. 7, shares traded for $31.19.
Shares popped on Monday after the company indicated it was raising its quarterly dividend by 6.7 percent, which will be payable on March 1, 2017 to shareholders. Tomi Kilgore, writing for MarketWatch, said, “At the current stock price of $32.51, the new annual dividend rate implies a dividend yield of 3.94 percent, compared with the aggregate yield for the Dow components of 2.33 percent, according to FactSet.”
“The dividend increase demonstrates our continued commitment to deliver value to our shareholders and our confidence in the business,” Ian Read, Pfizer’s chief executive officer, said in a statement at the time.
