By Michael Flaherty and Greg Roumeliotis

(Reuters) - U.S. cancer drug company Medivation Inc <MDVN.O> said on Tuesday it had agreed to provide confidential information to French pharmaceutical company Sanofi SA <SASY.PA> as part of exploring a sale that would be open to other bidders.

San Francisco-based Medivation shares jumped as much as 4.2 percent after Reuters first reported that Medivation and Sanofi were in talks over a confidentiality pact, adding to similar agreements Medivation has with Pfizer Inc <PFE.N> and Celgene Corp <CELG.O>, which have also expressed interest in an acquisition.

The move comes after Medivation rejected Sanofi's $9.3 billion offer in April, prompting Sanofi to embark on a campaign to convince Medivation shareholders to oust Medivation's board of directors and replace them with its nominees in a so-called written consent process.

Medivation said on Tuesday it expected to provide each party interested in an acquisition the opportunity to review non-public information and meet with Medivation's management. Sanofi also agreed to withdraw its consent solicitation challenging Medivation's board and to enter into a six-month conditional standstill.

Sanofi said it was confident that its due diligence can be completed and that it could close a deal with Medivation quickly given that it had received U.S. regulatory clearance and there was no financing condition.

Pfizer and Celgene did not immediately respond to requests for comment.

Sanofi also said it had increased its offer from $52.50 per share to $58 per share in cash and $3 per share in the form of a contingent value right relating to Talazoparib sales performance. Talazoparib is a Medivation drug under development for the treatment of breast cancer. Medivation said it had turned down that new offer as well.

Last month, shareholder advisory firm Glass Lewis & Co recommended that Medivation's shareholders should not support Sanofi's efforts to replace the company's board members.

Sanofi wants Medivation - which sells a successful prostate cancer drug called Xtandi - so Sanofi can expand in the lucrative oncology sector, as it seeks new businesses to compensate for flagging diabetes revenues.

Medivation had previously argued that Sanofi's offer had failed to value fairly the prospects for Xtandi, as well as two other key products currently in clinical trials - Talazoparib and Pidilizumab, which is being developed for the treatment of blood cancers.

(Reporting by Michael Flaherty and Greg Roumeliotis in New York; Additional reporting by Carl O'Donnell and Pamela Barbaglia in London; Editing by Bernard Orr and Cynthia Osterman)