IMMUNOGENICITY OF MERCK’s PEDVAXHIB WILL BE FDA ADVISORY COMMITTEE TOPIC

Executive Summary

IMMUNOGENICITY OF MERCK's PEDVAXHIB WILL BE FDA ADVISORY COMMITTEE TOPIC at the Vaccines and Related Biological Products Advisory Committee meeting slated for Oct. 28-29. On the first day, the committee will discuss the incidence of low seroconversion rates that occurred in some lots of Merck's PedvaxHIB Haemophilus b conjugate vaccine. Merck notified FDA in June that during postmarketing studies of PedvaxHIB some lots of the vaccine, in certain children, did not produce the level of antibodies considered protective ("The Pink Sheet" July 20, T&G-12). Of the children who received two doses of PedvaxHIB, 85% seroconverted to the expected antibody level. Children who did not initially make the expected antibody level seroconverted after getting boosters. The company has been conducting tests on vaccine lots to determine the source and scope of the problem. On Oct. 28, the advisory committee also is scheduled to discuss Lederle's combination diphtheria-tetanus- pertussis/Haemophilus b vaccine Tetramune. The DTP vaccine is already marketed separately by Lederle as Tri-Immunol, the Haemophilus b vaccine as HibTITER. Also on the agenda is Pasteur- Merieux' Haemophilus b conjugate vaccine Act HIB. On the second day, the advisory committee will review Pasteur- Merieux' vaccine Typhim Vi for the prevention of typhoid fever. The meeting will be held at the Holiday Inn Silver Spring, International Ballroom, 8777 Georgia Ave., Silver Spring, Md. The committee will convene at 8:30 a.m. on both days. On the second day, the committee will have closed deliberations beginning at 11 a.m.