New York, NY Stemline Therapeutics Inc., a leading clinical stage biopharmaceutical company that’s been a sub-tenant in recent years at Charles Cohen’s office tower at 750 Lexington Ave., has signed a direct lease for the entire 13,000 s/f 11^th floor in the building. Also known as International Plaza, the 31-story skyscraper, designed by world renowned architect Helmut Jahn, occupies the entirely westerly blockfront of Lexington Ave. between 59^th and 60^th Sts., directly across from Bloomingdales department store. “We’re delighted that this innovative medical company engaged in the war against cancer has chosen our signature office tower as its home,” said Cohen, President and CEO of Cohen Brothers Realty Corp. Stemline develops clinical stage products and therapies that target cancerous cells and tumors. Marc Horowitz, senior vice president and national director of office leasing for Cohen Brothers Realty Corp., represented both the tenant and the landlord in the 5-year leasing transaction. Asking rent in the space was $70 per s/f. Charles Cohen heads a multi-faceted real estate development company that owns and manages over eleven million s/f of prime class A New York, West Side Los Angeles, South Florida and Houston commercial space. Among the other signature Manhattan office buildings owned and managed by Cohen Brothers are  623 Fifth Ave., 135 East 57^th St., 805 Third Ave., 3 Park Ave., 622 Third Ave.,   3 East 54^th St., 475 Park Ave. South and the D&D Building at 979 Third Ave.