Shares of Myovant Sciences Ltd. /zigman2/quotes/201447012/composite MYOV +0.11% shot up 27.2% in premarket trading Monday toward an 11-month high, after the biopharmaceutical company confirmed over the weekend that it received an unsolicited buyout bid from Sumitovant Biopharma Ltd. and Sumitomo Pharma Co. Ltd. that values Myovant at about $2.18 billion. The company, which is developing treatments for women's health and endocrine diseases said late Sunday that Sumitovant and Sumitomo will pay $22.75 per share in cash for each Myovant share that they don't already own, which represents a 26.7% premium to Friday's closing price of $17.96. Myovant said after a special committee formed to evaluate the buyout bid determined that the bid "significantly undervalues" the company and therefore believes it isn't in the best interest of the company or shareholders. The company said it is open to considering a bid that reflects "full and fair value" of the company. The stock has run up 38.6% over the past three months through Friday, while the iShares Biotechnology ETF /zigman2/quotes/206189322/composite IBB +1.17% has slipped 2.7% and the S&P 500 /zigman2/quotes/210599714/realtime SPX -0.16% has lost 6.3%.