As expected, French drugmaker Sanofi has made an unsolicited all cash, non-binding proposal bid to acquire US biopharmaceuticals firm Medivation. In a letter to the board of the San Francisco, California-based company made public by Sanofi on Apr. 28, CEO Olivier Brandicourt said the French company had offered to pay $52.50 per share for the prostate cancer specialist, valuing it at around $9.3 billion.

Combining Sanofi and Medivation “represents a compelling strategic and financial opportunity to drive significant value for the respective companies' shareholders, employees, patients and caregivers,” Brandicourt said, adding that the proposed purchase price represents a premium of over 50% to Medivation's two-month volume weighted average price prior to takeover rumors that surfaced in mid-April.

The California firm acknowledged the Sanofi bid and said it would respond following a meeting of its board on the afternoon of Apr. 28, Pacific Daylight Time. In his letter, Brandicourt noted that he had first spoken to the company’s CEO, David T. Hung, on Mar. 25 but the executive had declined a meeting.

“We do not understand the delay in responding to our letter,” the Sanofi chief said. “The price we put forth represents a very substantial premium, and it would be all cash without any financing condition. In these circumstances we believe it is appropriate to make this letter public, which we are doing today.

“We are excited by the prospect of accelerating Medivation's growth by leveraging Sanofi's infrastructure and capabilities,” Brandicourt added, while saying he is convinced that the company’s employees would find a “very attractive environment” within the Sanofi Genzyme specialty business unit and its R&D organization. He suggested also that he believes Medivation’s shareholders “would find our Proposal to be compelling.”

The biopharmaceuticals manufacturer has drawn considerable attention for its prostate cancer drug Xtandi (enzalutamide), which recently won the backing of the European Medicines Agency’s Committee for Medicinal Products for Human Use. It is currently conducting clinical trials with the drug.

Another drug in the pipeline, Talazoparib, described as a best-in-class PARP inhibitor in late-stage P3 breast cancer trial, is currently being studied for numerous other cancer indications. Medivation also has exclusive worldwide licensing rights to the immuno-modulatory antibody Pidilizumab, which is set to enter registration trial in B-cell Lymphoma and other applications this year.

Other players previously reported to be interested in buying Medivation include Switzerland’s Roche, along with Celgene and Gilead of the US. Commenting on this week’s bid, analyst said they thought Sanofi would be willing to raise the stakes, should the subject of its takeover attempt balk.