AIDS VACCINE PHASE I CLINICAL TRIALS SHOULD USE LOW RISK SUBJECTS AND INCLUDE BOTH PLACEBO AND ANTIGEN CONTROL GROUPS, NIAID RESEARCHER SAYS

AIDS vaccine Phase I clinical trials should enroll individuals at a low risk of getting HIV infection, and include at least two control groups, Director of the AIDS Program at the National Institute of Allergies and Infectious Diseases John La Montagne stated at the third International Conference on AIDS held June 1-5 in Washington, D.C. "We feel that these initial studies must be done in individuals who have a low probability of infection . . . [and] there is a need for a comparison group and we believe two comparison groups are indicated, one being another antigen, an unrelated antigen, and a second one being placebo," said La Montagne. Addressing concerns about the inclusion of a control group within the Phase I trials, La Montagne remarked that "since this vaccine is novel in our experience, it's a vaccine to protect against infection of the immune system, we thought it would be almost essential to have a comparison group that was handled in the same way." He continued that with a control "you can look at questions of effect of the antigen on the immune system itself [and] there is no other way we thought . . . we could do that other than have a comparison group that got a placebo." The design of trials for AIDS vaccine candidates was one of the topics addressed by a panel of experts in a roundtable discussion on vaccine-related issues. La Montagne indicated that isolation of vaccinated subject might also be a necessary part of the clinicals. "For those studies involving one of the vaccines, the live virus such as vaccina, [there] might be a need to maintain subjects in an isolated facility for some time to look at some questions such as virus shedding by this new virus." He added that this practice would also minimize the risk of vaccinating someone who did not sign an informed consent form. Responding to a suggestion that the isolation of vaccinees would make it even more difficult to find volunteers, La Montagne said: "We were not talking about isolating people for a long period of time, for 10 days basically, something like that." La Montagne said the AIDS program at NIH has "in fact developed two vaccine clinical protocols that are structured that way and we believe that we will be able to implement these studies as soon as vaccine candidates are available." The initial studies will have to determine the safety and antigencity of the candidate materials, La Montagne said. The protocols are designed to investigate several aspects of the vaccines. "We felt there were some theorectical considerations regarding the potential of . . . the antigen itself to interfere with the function of the immune system," La Montagne commented. He added that two other basic aspects of early vaccine studies are "the reactigenicity or the ability of the vaccine to produce fever or soreness . . . and to access the antigenicity of this material in terms of the immune antibody responses and also in terms of cell mediated responses." La Montagne noted that there are many questions on how to approach initial studies. "We have very little information at the present time as to what actually constitutes a protective immune response and how one might stimulate one in a vaccinee [and] I think these studies will help us at least understand that a little bit better." He added "I think variation is still a concern and additional Phase I studies may have to be done with vaccines that contain more than one antigenic type." The possible role of using passive immunization with gamma globulins was brought up during the discussion. La Montagne commented that the National Heart, Lung and Blood Institute has a program for the development of passive gamma globulin preparations that can be tested and used in protocols. He noted that the material is being tested in chimpanzees and if the test is positive plans will be made for large human trials. Panel member Fritz Deinhardt, Max v. Pettenkofer Institute, Munich, West Germany, stressed the importance of standardizing vaccine test systems even before the development of vaccines. "I think standardization of our test systems right from the beginning would be most important," he stated.