Preventive AIDS vaccine shows positive results

doi:10.1038/nindia.2008.260 Published online 18 August 2008

The Indian Council of Medical Research, the National AIDS Control Organization and the International AIDS Vaccine Initiative have successfully completed a second Phase-I AIDS vaccine clinical trial in India. The trial of an MVA-based AIDS vaccine candidate (TBC-M4)conducted in Chennai has indicated that the vaccine candidate had acceptable levels of safety and was well tolerated.

The trial was done using two doses of the candidate vaccine. After three injections, 82 percent of the volunteers who received a low dose and 100 percent of those who received a high dose registered immune responses to the vaccine, according to an IAVI release. However the strength and diversity of these immune responses were modest. It may be possible to boost the immune response, if this vaccine is used in combination with other candidate AIDS vaccines, the release said.

"The MVA-based candidate was safe and showed promising initial immune responses. We do not know whether these observed responses will ultimately translate into an effective vaccine," said S K Bhattacharya, Additional Director General of the Indian Council of Medical Research.

The Phase I clinical trial was initiated in January 2006 at the Tuberculosis Research Center (TRC), an Indian Council of Medical Research (ICMR) institute in Chennai, and was completed in February 2008. Chennai-based YRG CARE collaborated with TRC to mobilize the community around the trial.

The objectives of of the trial were to evaluate the safety of the vaccine candidate and to gather preliminary results of immune responses induced by the candidate. The total duration of the trial was approximately 24 months. The volunteers recruited for this trial were 32 healthy, HIV-uninfected men and women between 18 and 50 years of age, from all socio-economic strata. Three intra-muscular injections of TBC-M4 or placebo were administered to the volunteers.

The results of the trial suggest that further research is warranted, the release said. Currently, two additional Phase I trials testing the MVA-based candidate in a prime-boost regime are planned and under review by the relevant authorities in India and approved in the UK. The trials are designed to use different modes of administration of the priming vaccine, different dosages and different vaccine regimens.

Simultaneously, IAVI has undertaken work to modify the vaccine candidate so that it is ready for large-scale manufacturing.