Clinical trials for phase one of the HIV/AIDS vaccine

Clinical trials for phase one of the HIV/AIDS vaccine being developed in India enter the final stage this month with scientists from the
Tuberculosis Research Centre (TRC), Chennai, and the National AIDS Research Institute (NARI), Pune, giving the last round of shots to 32 candidates enrolled in trials.

"For the next World AIDS Day, we will probably have the answer to how close we are to bringing out an efficient vaccine for prevention of HIV/AIDS," said V D Ramanathan, principal investigator of the study, in an interview to The Times of India on the eve of World AIDS Day. The trial, one among the approximately 150 trials currently underway worldwide, combines a DNA and vector-based vaccine for the dreaded disease.

In August 2008, when TRC reported the first significant progress in the clinical trials of the vaccine, it was only a vector-based vaccine and scientists said the results could be improved substantially. TRC, a permanent centre of?the Indian Council of Medical Research (ICMR), had done the trials along with National AIDS Control Organisation (NACO) and the International AIDS Vaccine Initiative (IAVI).

The prototype was an MVA (vector)-based potential AIDS vaccine (TBC-M4), which was developed by Kolkata-based scientist Sekhar Chakrabarti. The results showed that it was safe and generated some immunity. "We were happy as for the first time the vaccine had been proven safe and had shown some stimulating immune response. But we thought immunity in the volunteers was not adequate enough to prevent infection, and we saw even that level of immunity reducing after one year," Ramanathan said. The current study aims to improve upon the results achieved with the vector-based vaccine.

For the second round of trials, TRC and NARI have recruited 16 healthy volunteers. Of these, six have already received two shots of the DNA vaccine at the beginning of the trial and subsequently after a month, followed by the MVA vaccine in the third month; six received two doses of the MVA vaccine. All of them will receive the last shot of MVA this month. Four other volunteers would receive placebos (shots of saline water). "The purpose of doing this is to ensure that the researcher has no prejudice towards the results," he said.

For the next one year, the health of the volunteers will be monitored. "When we do that we will know if it is safe enough for us to conduct phase II of the clinical trial. It will take us a lot of time from then before we take the vaccine to the bedside. But then, unlike some years ago, we now have the hope," he said.

It has been estimated that more than 33.4 million people are living with HIV/AIDS, with more than 2.5 million in India. The quality of life of people with HIV has improved due to the beneficial effects of antiretroviral therapy given free of cost by several governments. But ART is a huge financial burden on the government and global researchers have been waiting to crack the vaccine.

In September, researchers announced one of the first breakthroughs when they revealed that a two-vaccine combination cut the risk of becoming affected with HIV by more than 31% in a trial of over 16,000 volunteers in Thailand. To date, there have been at least nine MVA vaccine candidates that have been tested or are being tested in labs around the world. Indian scientists hope they will be able to make significant strides if the vaccines prove efficient in phase 1. Quoting the latest issue of Science magazine, Ramanathan said, "We have learnt to expect the unexpected in our search to generate an effective vaccine for AIDS."