Pfizer Inc announced on Monday that it had agreed to purchase Medivation Inc a biotech firm for a per share price of $81.50 that values the company at close to $14 billion. The acquisition will add to the portfolio of Pfizer one of the top sellers in the cancer drugs market.

News of this impending deal had been first reported on Sunday. It ends a number of months of bidding for the company, based in San Francisco. Medivation is one of the most sought after biotechs that are still independent because it is a seller of a leading drug for prostate cancer.

The deal represents a premium of 21% to the closing price of Medivation shares as of last Friday. Shares at Medivation were up 20% as Pfizer shares were down 0.1% in early premarket trading on Monday.

Xtandi, one of Medivaton’s drugs, already is generating close to $2 billion in annual sales and has been given the potential to double, according to reports by analysts.

Pfizer said this deal would add a full 5 cents to its earnings in the first full year following the closing and is not expected to have an impact on financial guidance for 2016.

Pfizer has sought to expand its portfolio of oncology treatments. The addition of Xtandi would give Pfizer, based in New York, a leader in prostate cancer treatments that complements Ibrance its treatment for breast cancer, which is expected to be another blockbuster.

Drugs in the development stage at Medivation could also be complementary to the efforts of Pfizer to make combinations of cancer agents with the new immunotherapies that deploy the body’s immune system to fight the cancer.

This acquisition, would further the efforts of Ian Read the Pfizer CEO, to bolster the innovative side of the business.

Read said that Pfizer would make a decision by the end of 2016 whether it would split into two parts, with one part selling brand name fast growing drugs such as Ibrance and the other selling drugs that no longer have protection from patents.

This new deal should close before the end of 2016 and will be subject to the usual closing conditions as well as antitrust clearance in the U.S.

Cancer has become one of the biggest markets in the pharmaceutical industry with sales worldwide reaching close to $80 billion annually and growing over 10% each year, indicated a report from EvaluatePharma.

Get Analysts' Upgrades and Downgrades Daily - Enter your email address below to receive a concise daily summary of analysts' upgrades, downgrades and new coverage with MarketBeat.com's FREE daily email newsletter.