XOMA E5 REVIEW BEING HANDLED BY FDA's DIVISION OF BACTERIAL PRODUCTS

XOMA E5 REVIEW BEING HANDLED BY FDA's DIVISION OF BACTERIAL PRODUCTS after a recent switch in reviewing responsibilities. The head of the bacterial products division of the Center for Biologics Evaluation & Research, Bascom Anthony, MD, is now the head of the reviewing group for the PLA application. The FDA review was previously being directed by a different division within CBER, the Division of Hematology. Thomas Hoffman, MD, was the original lead reviewer. The appointment of Anthony to head the E5 PLA review committee brings both Xoma's product and Centocor's Centoxin within the Bacterial Products Division. Centoxin was recommended for approval at the Sept. 4 meeting of FDA's Vaccines and Related Biologics Advisory Committee ("The Pink Sheet" Sept. 9, p. 14). The Centoxin PLA review committee is chaired by Kathryn Stein, PhD, who is a reviewer in the Division of Bacterial Products. Stein is also a member of the E5 review committee. At the advisory committee meeting, Hoffman had presented an unenthusiatic critique of Xoma's application for the monoclonal antibody anti-endotoxin for treatment of gram-negative sepsis ("The Pink Sheet" Sept. 9, p. 17). At the beginning of his presentation, Hoffman told the committee members that they would not be considering the Xoma application for approval. While Hoffman's announcement took observers from the financial community by surprise, it is not unusual for an FDA reviewer to inform a committee of the status of an application and the agency's internal review as an introduction to an advisory committee discussion. In June, for example, the chairman of the review committee for Xoma's XomaZyme CD5 + PLA told the Biological Response Modifiers Advisory Committee that the data did not support licensure of monoclonal antibody for the treatment of steroid-resistant acute graft-versus-host disease. That committee, however, recommended approval of XomaZyme CD5 + over the objection of the FDA review committee ("The Pink Sheet" June 17, p. 19). In the case of E5, the advisory committee agreed with FDA that the data presented did not demonstrate sufficient efficacy of the product for approval and recommended that Xoma conduct further analyses of its second E5 study. FDA's decision to switch the product review groups for E5 may even out the reviews for the similar products. However, making the change in the context of the intense market speculation on the two products may create a dangerous image within FDA. It would be understandable for FDA reviewers to feel extra outside pressure as a result of the E5 experience. The E5 and Centoxin reviews were being headed by staff from two different areas possibly because of the difference in the dates of submissions. Xoma made its filing six months before Centocor. At that point, FDA may have been still unclear on how to handle the products and placed E5 under the review of Hoffman who is in the division responsible for monoclonal antibodies. The Centoxin review, on the other hand, was placed under the direction of the Bacterial Products Division, reflecting how the product would ultimately be used. It remains unclear whether the change in review committee stewardship will accelerate the consideration of Xoma's application. Anthony will take some time to familiarize himself with the E5 data. While he was present at the advisory committee, Anthony did not offer his personal impression of the data.