A gp120 AIDS vaccine produced by The Biocine Co. has shownin a Phase I study that it can incite production in seronegativeadults of antibodies capable of neutralizing the HIV-1 virus,the company annouced Monday.
The vaccine provoked a response that also indicated aneffectiveness against two strains of the virus, according toBiocine of Emeryville, Calif., which is a joint venture of ChironCorp. of Emeryville and Ciba-Geigy of Switzerland. The vaccinewas generally well-tolerated, Biocine said.
Chiron announced Monday that it was granted a relatedEuropean patent that appears to have a broad coverage. Thepatent's claims include env (gp120/gp160), gag (p25) and polantigens, and immunoassays using these antigens, and nucleicacid sequences (DNA probes and polymerase chain reactionprimers).
Chiron was among a half-dozen companies to announceprogress against AIDS before the Eighth InternationalConference on AIDS, meeting in Amsterdam. Other companiesincluded: Immune Response Corp., Vestar Inc., Glaxo Holdingsplc, Liposome Technology Inc. and Genelabs Inc.
Biocine has been testing two vaccine antigens, gp120 and Env2-3, in parallel to study different approaches for controllingHIV infection and immunotherapy for infected individuals.
Additional data will be presented from the preliminary gp120trials later this year, said company spokesman Larry Kurtz.Biocine also expects to start Phase I efficacy trials of gp120 andEnv 2-3 in seropositive adults later this year in San Francisco.The seronegative participants now in the study lack theantibody.
Biocine's gp120 is a recombinant version of a viral coat proteinand is produced through expression in Chinese hamster ovary(CHO) cells. This system produces a recombinant mimic thatlooks like that area of an HIV surface antigen protein, andtherefore can bind to CD4, the primary receptor of HIV. Therecombinant gp120 was designed from a strain of HIV calledSF2, isolated at the University of California, San Francisco(UCSF).
"The initial results of this first study, particularly the level andquality of immune responses after three immunizations,validate the concept of a prophylactic HIV vaccine," said DinoDina, vice president of virology and vaccine development forBiocine/Chiron.
Gp120-specific antibodies were observed in all 12 subjects whoreceived immunizations of gp120/MF59, a proprietaryadjuvant developed by Biocine that boosts the immunesystem's response to foreign proteins. These subjects alsodeveloped HIV-SF2 neutralizing antibodies.
Preliminary results from the study by James Kahn of UCSFshowed that people vaccinated with gp120/MF59 experiencedno serious systemic side effects. Study participants vaccinatedwith gp-120/MF59 combined with MTP-PE, a potent adjuvant,generally had more side effects, including mild muscle aches,headache and low-grade fever.
"These results, along with results observed in other BiocinePhase I vaccine trials, confirm the safety and effectiveness ofMF59 as an adjuvant system that can elicit an enhancedimmune response," Dina said.
Env 2-3 is based on the same sequence of virus envelope asgp120. Made in yeast cells as opposed to CHO cells, Env 2-3displays itself differently to the immune system.
Biocine, formed in 1987 as a 50-50 joint venture betweenChiron and Ciba-Geigy, is developing vaccines for preventive ortherapeutic use against herpes, AIDS, hepatitis C andcytomegalovirus.
Biocine's AIDS vaccine, research and clinical trials have beensupported in part by a series of grants from the state ofCalifornia, in addition to co-sponsorship of certain trials by theNational Institutes of Health.
In other confernce news:
-- Genelabs of Redwood City, Calif., said a Phase IB studyshowed its proprietary, anti-AIDS drug GLQ223 (alpha-trichosanthin), was safe and that it produced measurableincreases in markers of immunologic activity in patients withAIDS or AIDS-related complex (ARC). "A larger Phase II trial,comparing GLQ223 to AZT and combining GLQ223 with AZT, isongoing at several centers to correlate these immunologicfindings with effects on viral load," said Kenneth J. Gorelick,Genelabs's vice president of medical and regulatory affairs.
-- Glaxo said its reverse transcriptase inhibitor, 3TC, was well-tolerated in asymptomatic, ARC and AIDS patients, althoughdata from the higher doses is from a limited number ofpatients and for a short duration.
-- Immune Response Corp. and Rhone-Poulenc Rorer Inc.reported on a dose-ranging clinical trial with their HIVimmunotherapeutic. Treated patients demonstrate cellmediated or antibody responses to a significantly greaterdegree than patients receiving the adjuvant control, ImmuneResponse said. A separate Phase II/III clinical trial, nowunderway, is designed to determine the efficacy of the HIVimmunotherapeutic, the San Diego company said.
-- Vestar Inc. of San Dimas, Calif., said that its liposomalformulation of the anti-cancer drug daunorubicin, DaunoXome,has the potential to produce a high response rate with a lowincidence of side effects in AIDS-related Kaposi's sarcoma.
-- Liposome Technology Inc. said Phase II data indicated thatall 30 evaluable patients treated with Doxil responded totherapy following two courses of treatment. Doxil, aninvestigational drug developed and owned by the Menlo Park,Calif., company, is a long-circulating stealth liposomeformulation of the anti-cancer drug doxorubicin hydrochloride.
-- Studies indicated that patients suffering inhibited immuneresponse after HIV infection can benefit from switching fromWellcome plc's AZT to Bristol-Myers Squibb Co.'s ddI. "What weneed to decide is when" to switch the patients to ddI, saidMargaret Fishl of the University of Miami, who summarized thefindings of three new studies. "What we don't know is why,"she said.
-- Early results from a study at UCSF showed that HIV infectioncan be detected in infants younger that 3 months, a group thathas been difficult to diagnose with standard HIV testing. TheUCSF team said that it was able to detect a specific HIVantibody, named immunoglobulin A, in 11 infants under 3months of age who were born to HIV-positive mothers.
-- MicroGeneSys Inc. of Meriden, Conn., was to report todaythat AIDS patients receiving the company's engineered,recombinant gp160 vaccine (VaxSyn) showed a reduction inthe levels of HIV in their body and a reduction in the rate ofdecline of T4 count.
-- Michelle Slade Associate Editor
(c) 1997 American Health Consultants. All rights reserved.