J&J's Zytiga gets early challenge from Medivation's new pill

Astellas Pharma and Medivation ($MDVN) won FDA approval for their prostate cancer treatment Xtandi three months ahead of schedule. That's welcome news for them--but perhaps not so welcome for competitors, especially Johnson & Johnson ($JNJ), whose Zytiga pill will be Xtandi's closest rival.

There's been an arms race in the prostate cancer field over the past couple of years, with four new drugs now approved for sale. Dendreon's ($DNDN) vaccine treatment, Provenge, and Sanofi's ($SNY) Jevtana are both injectables, while Zytiga and Xtandi are both pills. The first three have already been jostling for position as oncologists rejig their treatment protocols for men with prostate cancer--and now, the Medivation drug will be elbowing its way in, too.

Xtandi--previously known as MDV3100--has been hotly anticipated by analysts, who've pegged peak sales at $1 billion to $2 billion. In the near term, Citi Investment Research's Yaron Werber figures the drug will manage $172 million next year and $390 million the next.

Doctors have also been keeping an eye on the Medivation drug. It and Zytiga both aim to disrupt cancer growth by interfering with testosterone, but in different ways. Some brand-new survival data on Xtandi showed the drug extended patients' lives by 5 months longer than the control group. As the NYT points out, J&J recently updated its overall survival advantage to 4.6 months.

Xtandi will be priced at $7,450 per month, higher than some analysts had anticipated. Zytiga costs about $5,500 a month. J&J offers co-pay assistance for patients in the U.S., and it recently won approval from U.K. cost-effectiveness watchdogs after offering an unspecified discount. No doubt Astellas and Medivation will have their own schedule of rebates, discounts and assistance as well.

Key for Xtandi, and for Zytiga for that matter, is expanding the potential market beyond the current approval for patients with metastatic, castration-resistant prostate cancer who've already been treated with the standard chemo drug, docetaxel. FDA put Zytiga on the fast track for that new indication, after J&J unveiled data in patients earlier in the disease course.

- see the release from Medivation
- read the NYT story