Johnson & Johnson’s Zytiga, approved last year to treat metastatic prostate cancer, helped eliminate tumors in high-risk patients whose malignancy hadn’t yet spread, a small study found.
The pill was given as an initial therapy before surgery to 58 patients with aggressive tumors that were confined to the prostate gland, a group typically treated with radiation. These patients are rarely cured by surgery and previous studies using older drugs failed to improve survival, said Mary-Ellen Taplin, an associate professor at Harvard Medical School in Boston.
One-third of those on Zytiga for six months showed no cancer or only trace levels when the prostate gland was removed, said Taplin, who is the lead researcher. Fifteen percent of men on it for three months had a similar benefit. The drug, with $200 million in worldwide sales in 2011, may eventually generate $1 billion annually, said Larry Biegelsen, an analyst at Wells Fargo Securities in New York, in a May 1 note to investors.
“What we’ve shown is that the concept is valid, that in some patients you can eliminate the cancer completely,” Taplin said in a telephone interview. “To really prove what the overall benefit is to a patient with this type of approach, you would have to do a very large trial.”
J&J fell less than 1 percent to $63.55 at the close of New York trading. Dendreon Corp., which makes a rival medicine to Zytiga, dropped 11 percent to $7.65.
J&J’s once-a-day drug, which costs about $5,000 a month, targets a protein to block production of the androgen hormone that fuels prostate cancer growth. While other medications can stop androgen production in the testes and adrenal glands, Zytiga also shuts it down inside the tumor itself.
Participants in the study were also given the generic hormone therapy leuprolide and steroids.
Prostate cancer is the most-common tumor in men, according to the American Cancer Society. Fifteen percent of the 218,000 Americans diagnosed with it each year have it spread beyond the walnut-sized gland that lies between the bladder and urethra, according to the National Cancer Institute.
J&J, which helped fund the initial study, isn’t planning any additional research on the use of Zytiga as an initial therapy in men with high-risk, local disease that hasn’t spread, said Kellie McLaughlin, a spokeswoman for the New Brunswick, New Jersey-based company.
The Prostate Cancer Foundation also helped fund the study, which was conducted by the Department of Defense-supported Prostate Cancer Clinical Trial Consortium.
Taplin, an oncologist at the Dana-Farber Cancer Institute in Boston, said she is working on a trial that adds the experimental medication ARN-509 from closely held Aragon Pharmaceuticals Inc., based in San Diego, to the mixture of Zytiga and the steroid prednisone used in the current study. She is also exploring the use of Medivation Inc.’s prostate cancer drug MDV3100, which also blocks androgen production, before surgery in high-risk patients.
The findings released yesterday will be presented at the American Society of Clinical Oncology meeting in Chicago on June 2. The results were released ahead of the event by the organizers to coincide with the publication of the study’s abstract.
Among the 29 men who received Zytiga for the entire six months, three had no signs of cancer once the prostate was eliminated, while seven had very low levels, Taplin said. One of the 27 men treated for three months had no cancer, and three had only a smattering of cancer cells, she said.
Results from a pivotal trial examining the use of Zytiga before chemotherapy in patients with prostate cancer that has spread will also be presented at the meeting. The studies may boost use of the drug in patients who aren’t formally approved to receive it, making it one of several medicines to accelerate J&J’s sales growth, Biegelsen, of Wells Fargo, wrote.