Pfizer (PFE) will offer Medivation (MDVN) shareholders $81.50 per share in cash, a substantial premium to Sanofi SA’s first offer of $52.50 made in April that forced Medivation to put itself up for sale.

Shares of Medivation, best known for its prostate cancer drug Xtandi, were up 19% at $80.01 in premarket trade, just shy of the offer price.

Sanofi later raised its offer to $58 per share in cash and $3 per share in the form of a contingent value right relating to the sales performance of Talazoparib, a breast cancer drug under development.

However, Medivation said in July it had agreed to share confidential information with potential buyers after Sanofi agreed to drop a campaign to oust Medivation’s board of directors.

Reuters had reported that Pfizer, Merck (MRK), Celgene (CELG), and Gilead Sciences (GILD) had submitted expressions of interest to acquire Medivation.

Pfizer said it expects to complete the acquisition, which was approved by boards of both companies, in the third or the fourth quarter.

Pfizer’s financial advisers were Guggenheim Securities and Centerview Partners, with Ropes & Gray LLP providing legal counsel .

J.P. Morgan Securities and Evercore were Medivation’s financial advisers, while Cooley LLP and Wachtell, Lipton, Rosen & Katz served as its legal advisers.