February 9, 1998

A vaccine for the disease is ready to hit the maket.

By Subhadra Menon

Exactly a hundred years after the first attempts at research into leprosy, a vaccine against the dreaded scourge will finally hit the Indian market by April this year. After two decades of laboratory work and human trials, a team of scientists at the National Institute of Immunology (NII), Delhi, has developed a vaccine that it claims will dramatically shorten the time taken to completely cure the disease. The Drugs Controller of India cleared the vaccine last fortnight for mass production and marketing by the Ahmedabad-based Cadila Pharmaceuticals Ltd.

According to World Health Organisation (who) and Central Government estimates, there are over 5.4 lakh registered leprosy patients in India, nearly 58 per cent of the total number of patients in the world. The situation was worse in the 1970s when G.P. Talwar, now an emeritus scientist at the International Centre for Genetic Engineering and Biotechnology in Delhi, started searching for a vaccine.

The NII team, first led by Talwar and then by Rama Mukherjee, used a strain of the leprosy germ Mycobacterium w. to make the vaccine, which has since been tested on over 80,000 people. The vaccine shortens the recovery time from two years to six months if the patient is given shots every three months along with the usual drugs. Says Talwar: "This immunotherapeutic effect of the vaccine will have a tremendous impact on treating leprosy patients and it has no side effects."

And the price is right too. says N.C. Sharma, head of the biotechnology research division at Cadila: "Once the product hits the market, we expect it to cost around Rs 25 for the complete dosage (eight shots)." Cadila had picked up the technology from NII five years ago for Rs 15 lakh. But the vaccine will be competing for a market share with the already popular multi-drug therapy (MDT). Cautions Dharam Shaktu, deputy director general in charge of the leprosy programme at the Ministry of Health and Family Welfare: "There is no way the vaccine can compare with the efficacy of MDT." Worldwide, the emphasis has been on MDT for some years now. Using the three-drug MDT, a combined dosage of rifampicin, clofa-zamine and dapsone, doctors and health workers have managed to substantially reduce leprosy cases in the country from 40 lakh in 1981 to 7.3 lakh in 1995. But as Talwar says, "the vaccine can be used as a highly effective fourth drug to cure faster." Except that this is one vaccine that is used not for prevention but cure.

But as with many scientific success stories, this vaccine too is dogged by controversy. Of the three different strains studied in the 1980s, one was developed by a team of the Indian Cancer Research Centre (ICRC), Mumbai, led by the then director M.G. Deo. Charging Talwar with "breach of scientific ethics", Deo says, "The bacillus used by Talwar is the same as the one we had isolated way back in 1958. DNA analysis has proved this fact." But Talwar denies the allegation and says his vaccine is the original and made from a unique bacillus.

Officials at the Ministry of Health and Family Welfare and at the Department of Biotechnology (DBT), Delhi, are noncommittal. says Manju Sharma, secretary of the department: "I have no comments to make about the ICRC vaccine, but I am very happy that the NII vaccine is about to reach the people." Understandably so, because the NII project was funded by the DBT and has received a total of Rs 1.5 crore from the department since 1994. This is obviously a lot of money as NII receives around Rs 8.5 crore annually as research funding from the government. The question that follows is why the technology has now been transferred for commercial production at a pittance of Rs 15 lakh. It was in 1994 that DBT found what Sharma calls "very good leads in the NII programme that could really do well with more support". The rest is history.

The controversy notwithstanding, Mycobacterium w. is a unique, non-infectious microbe that will induce in patients what is called a cell-mediated immune response. Nothing unnatural because it's a response that 90 per cent of people infected with the leprosy germ manage to mount on their own anyway. But for the unlucky 10 per cent who succumb to the infection, the vaccine will help build up a war against the germ.

However, Shaktu isn't very confident about its long-term impact. "if at some later stage patients develop resistance to drugs, the vaccine just might help," he says. Not a good omen for a product ready to hit the market, but considering the enormity of the leprosy menace, it's worth a try.

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