HYDERABAAD - Indian cancer researchers have taken a giant step on the road to discovering the ultimate cancer cure by developing a drug that selectively targets the cancer cells without harming the healthy ones.

Researchers in Kolkata claim that patients in "very advanced stages" of cancer for whom all other treatments had failed have been brought back to "excellent" health with the help of a drug formulation they have developed after research spanning more than a decade.

"We have what we think magic bullet against cancer," says Manju Ray, a biochemist at the Indian Association of the Cultivation of Science (IACS) where the drug was developed under a project funded by the Department of Science and Technology and the Council of Scientific and Industrial Research.

Most currently available anti-cancer drugs are toxic because they also damage the normal cells. Ray says the IACS formulation, containing "Methylglyoxal" as the lead ingredient, combats only the diseased cells, the cherished goal of cancer researchers worldwide. Methylglyoxal is a metabolite in the human body produced during glucose breakdown.

Others involved in the project are Swapna Ghosh of IACS, Manoj Kar and Subhankar Ray of the University College of Science, and Santajit Datta, a medical practitioner. Results of human trial conducted by them with the new drug have recently appeared in the Indian Journal of Physics.

While Americans are going ga-ga with their new anti-cancer drug "Glivec" - that was featured on the cover of May 28 issue of Time magazine - the low-profile, cash-strapped Kolkata researchers have been working quietly for over a decade shuning publicity until they obtained proof from human trials nine weeks ago.

According to their published paper, the Methylglyoxal-based forumulation had "a dramatic positive effect on the patients".

For instance, the condition of 11 out of the 19 patients treated - most of them in a very advanced stage when the treatment began -- are now stated to be in "excellent physical condition". Five are in stable condition and only three died during the course of the study.

Since the submission of the paper, the number of patients treated has crossed 40 mark with more than 70 per cent success, according to Manju Ray.

Most remarkable fact, according to the scientists was that Methylglyoxal was successful against different types of cancer unlike "Glivec" which targets only the chronic myeloid leukemia.

Those whose health returned to "excellent" condition after treatment with Methylglyoxal included patients in "a very advanced stages" of colon cancer, acute myeloid leukemia, non-Hodgkin's lymphoma, and cancers of ovary, breast, liver, lung, bone, gall bladder, pancreas and oral cavity.

The patients were inducted for the trial, from January to June 2000, after obtaining permission from the Drug Controller General of India, the scientists said. The drug was administered orally for about six months with gradual reduction of daily dosage from the initial 25 milligrams per kilogram of body weight.

Researchers said development of the drug was preceded by years of basic research involving human cancer cells in culture and animal experiments that showed that Methylglyoxal selectively killed the cancer cells without affecting normal cells by exploiting "a very significant" biochemical difference between the two.

Explaining the mechanism of action, the scientists said cancer cells required a large amount of energy providing substance called ATP (Adenosine-5-Triphosphate) for survival.

"Methylglyoxal inactivates the enzyme (Glyceraldehyde-3- Phosphate Dehydrogenase) needed for ATP production in cancer cells and thereby starves tem to death. Normal cells remain unaffected."

Manju ray said that chemists knew Methylglyoxal molecule for about four decades and its anti-cancer effects in animals had also been studied. "But surprisingly, no one bothered to initiate further research leading to human trials," she said.

The researchers said concern in some quarters about safety of Methylglyoxal were not borne out from the clinical trials, which showed that in combination with protective agent like Ascorbic Acid and vitamins, the drug Methylglyoxal had no major toxic effect. They said there was scope for further enhancing the drug's efficacy.