Luther Vandross, upset by his drummer's suicide Monday, did not attend a party held in his honor that night by Epic Records. The midnight gala aboard the yacht Princess was to celebrate Vandross' series of sold-out concerts at Madison Square Garden and some 300 people--Eddie Murphy and Run-DMC among them--showed up to party and hear the music of New Orleans legend Allen Toussaint. But Vandross was still mourning after learning that his drummer, Yogi Horton, 33, committed suicide by leaping from the 17th-floor window of his hotel. Horton had told his wife he was tired of working in Vandross' shadow. Vandross is expected to perform as scheduled at the Rose Bowl on June 20.