ARAC REJECTS EXPANDED AIDS VACCINE TRIALS

The AIDS Research Advisory Committee to the US National Institutes of Health has rejected a proposal to conduct large-scale efficacy studies on the two AIDS vaccines developed by Genentech and Biocine, a joint venture between Chiron and Ciba. Instead, further small-scale studies testing the safety and immunogenicity of the vaccines should continue, said the Committee.

Large-scale tests should wait until compelling new data becomes available or a different type of vaccine shows promise, said the panel. The two vaccines are based on gp120, a glycoprotein component of the viral coat. The studies would have involved thousands of Americans who are not infected with HIV but who are at high risk of developing the disease.

Among the reasons for rejecting the expanding trials were the large cost ($20 million a year for four years or longer), uncertainty about the degree of protection that the experimental vaccines might offer, and uncertainty about whether enough volunteers could be recruited for clinical trials. The panel was also concerned about the public not understanding the concept of partial protection with a vaccine that might protect only 30% or 50% of volunteers. 23 members of the panel voted for the recommendation, four abstained and three left before the vote.