XOMAZYME-CD5 PLUS POISED TO ENTER PHASE III RHEUMATOID ARTHRITIS TRIALS

XOMAZYME-CD5 PLUS POISED TO ENTER PHASE III RHEUMATOID ARTHRITIS TRIALS, Xoma Chairman Steven Mendell told the annual Robertson Stephens medical conference in New York City Nov. 27. "Those studies will be starting next month," Mendell said, "and will carry on for the next two years." The immunotoxin product (formerly called XomaZyme-H65) has had a PLA pending for the treatment of graft v. host disease since Dec. 22, 1988. It was the first PLA for Xoma, and the first submission to FDA for any monoclonal antibody-based immunotoxin. CD5-Plus is also being studied for the prevention of GvHD as well as the treatment of Type I diabetes and lupus. Mendell reported that the drug has been clinically examined in 95 arthritis patients to date. The company presented data from a 60-person Phase II trial to an Oct. 30 meeting of the American College of Rheumatology. All patients had failed treatment with either azathioprine (Burroughs Wellcome's Imuran) or methotrexate. All were given a single five-day course of treatment with CD5 Plus. The study resulted in 50%-75% of the patients having benefit for at least 30 days, over 50% for two months, and 10%-30% for at least five months. Some patients were retreated to evaluate multiple uses of the drug. In the battle of monoclonal antibody gram negative sepsis and septic shock treatments between Xomen-E5 and Centocor's Centoxin, Mendell stressed that Xoma would be supported by the 750-person detail force of Pfizer's Roerig subsidiary under a June 1987 licensing agreement. Asked what would differentiate Xomen-E5 from Centoxin if the Centocor product makes it first to the market, Mendell said: "The primary thing we have going for us, the tremendous advantage, is that we have the Pfizer sales force and organization. Here you have an established sales force, that is familiar with the medical community, that understands the advantages of these products, and I think that's the reason we'll lead in terms of worldwide market penetration." Xoma filed the NDA for E5 six months ahead of Centocor's for Centoxin; Mendell's remarks suggest that while Xoma is not counting on being the first septic shock treatment approved. Xoma believes that superior marketing power will even out any advantages Centoxin would have in being first to market. Xoma recently disclosed in financial filings that FDA has requested "additional information" about Xomen-E5 ("The Pink Sheet" Aug. 27, In Brief). Clarifying the misinterpretation that that request raised in the minds of some in the financial community, Mendell stressed that the request was routine: FDA has "not requested any additional clinical trials. They are just responding to data previously submitted." Updating the patient infringement lawsuit filed by Xoma against Centocor, Mendell said "the trial date is set for July of next year." Xoma received a patient for therapeutic use of mammalian-source monoclonal antibodies for treatment of sepsis on April 17, 1990 and filed suit the same day ("The Pink Sheet" April 23, T&G-11). He would not comment on whether Pfizer was participating financially in the suit.