Indian AIDS vaccine trials successful

23 October, 2007

The results of the first phase of the clinical trials conducted in India to develop a vaccine for the acquired immunodeficiency syndrome (AIDS) have been published.

One of the two vaccines, which underwent trials, has met the expectations of the researchers.

The National AIDS Research Institute (NARI), based in Pune, India, had taken up two possible vaccines for trial in February 2005. The results were analyzed after completion of one year’s follow-up of the last vaccinated volunteer.

The results indicate that the first vaccine - which used adeno-associated viral (AAV) vector - failed to generate desired results.

The second vaccine, using the modified vaccinia Ankara (MVA) vector, met the expectations of the scientists.

Dr Sanjay M Mehendale, deputy director of the National AIDS Research Institute, said the researchers analyzed the results and found that the MVA vaccines have matched their expectations on the safety parameters. However, the other vaccine, the AAV, was not very successful in generating desired immune response.

As the next step, scientists at the National AIDS Research Institute, the Indian Council of Medical Research, the National AIDS Control Organization, and the International AIDS Vaccine Initiative are discussing how to go ahead with further trials of the vaccine, which has been successful so far.

The phase two trials may start in six months if India’s Health Ministry approves it, according to Dr Sanjay M Mehendale.

The phase one trial was meant to study the safety of the vaccine in humans and its ability to stimulate immune responses against HIV/AIDS.

The healthy candidates, numbering 30, who underwent the trials did not show any adverse effects on safety parameters. However, the immunity response using the AAV vector vaccine fell below the researchers’ expectations.

In the trials conducted at the National AIDS Research Institute, data was also collected on the ideal dosage. The 30 volunteers were divided into three groups to receive three different dosages - low, medium, and high.

The trials on the AIDS vaccine work on two strategies - either neutralizing antibodies or cell-mediated immune response. In the first instance, the vaccine would be able to prime the immune system to kill the human immunodeficiency virus (HIV) even as it enters the body. In the second approach, a cell would perform the protective function.