Oct 24 (Reuters) - Japan's Sumitomo Pharma Co and its subsidiary said on Sunday they would purchase the remaining shares of Myovant Sciences at an improved $27 per share, after the U.S. drugmaker rejected a lower offer earlier this month.

Sumitomo and its wholly owned unit, Sumitovant Biopharma, hold about 52% of Myovant's outstanding stock and will acquire the rest in a deal that values Myovant at about $2.59 billion, the companies said in a statement.

Myovant had rejected Sumitomo's previous proposal to acquire the remaining shares at $22.75 each, saying the bid significantly undervalued the company.

The deal provides Sumitomo access to Myovant's clinical assets being developed for preventing pregnancy and treating infertility in women, in addition to the company's FDA-approved drugs for prostate cancer and managing menstrual bleeding.

Sumitomo's shares rose 0.2% on Monday in Tokyo, while Myovant Sciences jumped nearly 8% in U.S. premarket trading as the new offer is at a premium of 10% to the stock's last close.

The two companies have been working together since 2019, when Sumitomo Pharma agreed to pay $3 billion for a 10% stake in Swiss drugmaker Roivant Sciences Ltd and a controlling interest in Myovant. The stake gave the Japanese company a drug pipeline for treatments of prostate cancer, urinary diseases, pediatric illnesses and respiratory ailments.

For the quarter ended June 30, 2022 Myovant reported $36 million in U.S. sales of its prostate cancer drug Orgovyx, and $4 million in sales of Myfembree which is used to help manage heavy menstrual bleeding.

Myovant's contraceptive medicine, which it is developing in collaboration with Pfizer, is currently being tested in a late-stage study.

The deal will be funded through cash on hand and external debt and is not subject to a financing condition, the companies said. (Reporting by Ann Maria Shibu and Bhanvi Satija in Bengaluru, Rocky Swift in Tokyo; Editing by Shailesh Kuber and Vinay Dwivedi)