The earlier-than-expected U.S. Food and Drug Administration approval of Medivation’s once-daily prostate cancer pill, Xtandi introduces significant new competition for companies trying to gain a foothold in a potential multi-billion dollar market.

Xtandi joins Zytiga, made by Johnson & Johnson subsidiary Janssen Biotech, at the front of the pack for easy dosing and becomes a top-three performer in terms of median survival benefit.

Following chemotherapy, Xtandi has been demonstrated to offer median overall survival of 18.4 months, as compared to a median overall survival of 14.8 months for patients receiving Zytiga and prednisone in combination. Only Dendreon’s Provenge offers a greater median survival benefit, at 25.8 months, but it has struggled to gain sales traction. Jevtana, sold by Sanofi and also delivered as an injectable, offers a median overall survival benefit of 15.1 months.

Leerink Swann analyst Howard Liang told Bloomberg that Medivation’s “cancer drug to me looks to be the best drug so far for prostate cancer, which is a big category, a big market,” while other analysts have begun to focus less on the competition oral therapies pose for injectables and more on the race to approval for a pre-chemotherapy indication, something that both Medivation and Janssen are pursuing.

Credit Suisse estimates the metastatic prostate cancer more could grow from approximately $1 billion to $8 billion by 2020.

In the United States, prostate cancer is the most common non-skin cancer among men, with over one million men currently diagnosed with the disease. It is the second leading cause of cancer deaths in men in the United States.

“The need for additional treatment options for advanced prostate cancer continues to be important for patients,” says Richard Pazdur director of the Office of Hematology and Oncology Products in FDA’s Center for Drug Evaluation and Research.