The first of an anticipated 3,000 AIDS patients will be enrolled todayat medical centers throughout the U.S. to begin evaluation of atherapeutic vaccine designed to stimulate the immune system againstHIV and keep the virus in check.
The HIV immunogen, called Remune, is developed by ImmuneResponse Corp., of Carlsbad, Calif., and the Phase III trial representsthe first late-stage clinical study of an AIDS therapy to help stimulatea patient's own immune defenses to fight the disease.
Stephen Lagakos, of Harvard University, in Cambridge, Mass., andJames Kahn, of the University of California at San Francisco, areleading the three-year clinical investigation.
If Remune demonstrates efficacy and safety, Lagakos said, the drugcould be used in combination with nucleoside analogues and proteaseinhibitors, which are the currently approved antivirals that attack HIVreplication.
As for the best potential combination of AIDS drugs, Lagakos said,"I don't think any one knows. It's a crap shoot. Patients in earlystages of the disease are facing many years of survival."
Lagakos noted the antiviral drugs, whose effectiveness is limited bythe fast-mutating HIV's ability to develop resistance, have only beenevaluated in the short-term. FDA approval of the antiviral drugs hasbeen based on surrogate markers measuring decrease in viral loadand increase in CD4 counts.
The Remune study's endpoint is clinical efficacy as judged bywhether the immunogen can delay progression of the disease andincrease survival. Although the trial, involving 50 medical centers,will take three years to complete, an interim analysis will beconducted after one year.
Patients enrolled in the trials will have CD4 counts between 300 and550 and all of them will continue to receive whatever antiviral drugsthey were taking. Patients receiving Remune will receive it plus theadjuvant once every three months. The placebo control group will getthe adjuvant.
Remune, which is Immune Response's lead product, is not apreventive vaccine. It is inactivated HIV combined with a mineraloil-based adjuvant to help boost the immune system's response to theviral antigens. Through purification, the killed HIV loses theglycoprotein (gp) 120, which is an envelope protein that helps thevirus infect cells. Immune Response officials said loss of the gp120 isa benefit, allowing Remune to stimulate an immune responseindependent of the surface protein, whose quick mutations enable thevirus to avoid attack.
If Remune proves its effectiveness, the goal is to begin using it inearly stages of the disease to help bolster a patient's own immunesystem. The immunogen _ first proposed by the late Jonas Salk, whodeveloped the polio vaccine _ has been in clinical developmentsince 1987. (See BioWorld Today, Feb. 28, 1996, p. 1.)
Immune Response's stock (NASDAQ:IMNR) closed Friday at $6.56,up 6 cents. n
-- Charles Craig
(c) 1997 American Health Consultants. All rights reserved.