HIV vaccine trial in India to commence from 2003

A Special Correspondent - New Delhi

The International AIDS Vaccine Initiative (IAVI) a global nonprofit organisation working to speed scientific progress toward finding safe, effective and accessible preventive AIDS vaccine is hopeful of beginning phase I human trials on HIV vaccine in India by 2003 end.This is subject to a broad consensus of the various stakeholders and necessary regulatory approvals, IAVI's India leader Mark Chataway told Express Pharma Pulse during the consensus building conference on AIDS vaccine development, trials, access and deployment held in New Delhi last week. The total cost of development is estimated at USD 100 million.
A 32-member advisory board has been put in place to approve and monitor the trials, which will be carried out at three locations in Maharashtra, Tamil Nadu and at an unspecified site in the North East.

The vaccine for the phase I trial will be supplied by Boston-based biotechnology firm Therion Biologics. IAVI has entered into a vaccine development partnership with Therion to bring together researchers from India and Therion to build preventive HIV vaccines designed specifically for India.

IAVI will pay USD 800,000 to Therion over a three-year period for limited access to the technology. Subsequently, Therion will transfer the manufacturing technology to an Indian company with a 10 per cent royalty on cost price (development + manufacturing costs). The product is likely to be ready for trials by end 2002 or early 2003, Chataway said. The vaccine is a modified vaccinia Ankara (MVA) formulation, into which pieces of HIV's genetic material engineered in the laboratory from six HIV genes will be inserted. These genes are env, gag, rev, nef and pol. These genes are cloned from HIV-C found in India. HIV-C is the most predominant strain (91 per cent) found in India.

These genes are believed to be among the critical parts of HIV that, when recognised by the immune system, stimulate the production of HIV-specific killer T cells. Vaccinia Ankara, a harmless version of pox virus, is the vector, or transport mechanism.

Unlike the current vaccination programmes, which are aimed primarily at children, AIDS vaccination efforts will initially target the highest-risk populations including truck drivers, commercial sex workers, adolescents and drug users. One reason for selective vaccination could be the efficacy of the vaccine, which IAVI says could be in the range of 30-90 per cent.

It would be some time before mass vaccination for HIV becomes a reality, says Chataway. ''Let us not be too optimistic. Even if the vaccine has an efficacy rate of 50 per cent, it would help significantly in curbing the spread of the virus,'' Lalit Kant, senior deputy director, division of epidemiology and communicable diseases, ICMR told the media gathering.

Scientific challenges apart, there are numerous social challenges too in AIDS vaccine development. For instance, persons who are targeted for recruitment into large-scale phase III trials are likely to be drawn from communities that have been historically marginalised and disenfranchised where HIV is most prevalent. Targeted communities, say experts, often exhibit a strong distrust of the federal government and public health research, especially around the issue of HIV/AIDS.

Also, immunization may result in participants developing vaccine-induced HIV antibodies and because HIV antibody testing is sometimes a requirement for accessing insurance, medical care, and employment, trial participants may be exposed to discrimination based on antibody test results, experts add. Importantly, trial participants may become careless after vaccination and may neglect prevention altogether. This could be hazardous if the efficacy of the vaccine is not more than 90 per cent, says Dr Subhash Hira, chief of Arcon and a member of the advisory board.