NEW YORK (AP) — Astellas Pharma Inc. said Monday it will continue to pursue a purchase of CV Therapeutics Inc. after the Palo Alto, Calif.-based drug maker rejected Astellas' $1 billion offer. On Friday, CV Therapeutics said the unsolicited bid from Tokyo-based Astellas undervalues the company and is not in the best interest of its shareholders. Previously, CV Therapeutics privately turned down the $16-per-share offer in November, but agreed to reconsider the offer after Astellas made the offer public last month. The two companies are already partners in selling Lexiscan, an agent used in patients who cannot exercise sufficiently for a coronary stress test. The offer represents a 41 percent premium to CV Therapeutics' closing price of $11.35 on Jan. 26, the last day of trading before the offer was made public. "We are disappointed that CV Therapeutics' board has rejected our all cash proposal and did not engage us in any discussions as part of their review of our proposal," Astellas said in a statement. Astellas said it remains committed to buying CV Therapeutics and is considering its options.