Shares of Myovant Sciences /zigman2/quotes/201447012/composite MYOV -9.91% soared 20% in premarket trade Monday, after its parent Sumitovant Biopharma said Myovant will work with Pfizer Inc. /zigman2/quotes/202877789/composite PFE +2.54% to jointly develop a treatment for prostate cancer and women's health in a deal worth up to $4.2 billion in upfront and potential milestone payments. Myovant will receive an upfront payment of $650 million to develop relugolix, a once-daily, oral gonadotropin-releasing hormone receptor antagonist for use in oncology and women's health in the U.S. and Canada. Pfizer will have the exclusive right to commercialize relugolix in oncology outside the U.S. and Canada, excluding some Asian countries. Myovant is one of five companies under the Sumitovant umbrella. "Myovant and Pfizer will jointly develop and commercialize ORGOVYX(TM) (relugolix) in advanced prostate cancer and, if approved, relugolix combination tablet (relugolix 40 mg, estradiol 1.0 mg, and norethindrone acetate 0.5 mg) in women's health in the U.S. and Canada," the companies said in a joint statement. The U.S. Food and Drug Administration approved Orgovyx on Dec. 18 as a treatment for advanced prostate cancer. Pfizer shares were slightly higher premarket and have gained 0.4% in the year to date, while the S&P 500 /zigman2/quotes/210599714/realtime SPX -1.90% has gained 15%.