The Drug Controller General of India (DCGI) has cleared Pfizer Inc's application to conduct human trials of the new combination drug of azythromycin with chloroquine for the treatment of drug resistant malaria in the country. The company has identified six investigation centers in Assam, Mizoram, Meghalaya, Sikkim, Manipur and Nagaland. The Trials have already started in one of the centres.

A detailed phase 3 trials of this combination in India for drug resistant malaria, the Pfizer Inc's clinical investigation follows the successful Phase II trials abroad and also part of a much larger human trials in Asia, Africa and America. The Indian trials would involve 300 human subjects, the Pfizer sources informed.

According to a senior official in Pfizer Limited, the Indian counterpart, the combination of azythromycin with chloroquine, an older, commonly used malaria treatment, have shown promising results. "The combination has been shown to be three times more effective than chloroquine alone," the official said quoting a press release from Pfizer Inc.

Along with this combination drug for malaria, the Pfizer official said that the company has presently identified two more drug compounds for trials. These drug candidates are identified for the treatment of SARS and smallpox respectively. Currently, there are at least 10 compounds shown significant activity against the SARS virus in Pfizer's laboratory tests.

However, the company has selected only the best candidates for continuing development and potential studies in humans, the official said. For malaria, Pfizer will begin Phase III clinical trials, in the three continents to definitively demonstrate the efficacy of the combination. However, Pfizer cautioned that there are no guarantees that any of these compounds will result in a viable medicine for patients.

Talking about the drug resistant malaria targeted combination treatment, the company sources said since Plasmodium falciparum is the most common form of malaria - a mosquito-borne disease that affects 300 million people worldwide and results in approximately 1.5 million deaths each year. "If untreated, it can cause cerebral malaria leading to death. In this regard, the chloroquine/azythromycin combination Phase III clinical trials represent an important scientific undertaking."

Although chloroquine was introduced more than 30 years ago, it remains a standard treatment. But because the malaria parasite has developed resistance against chloroquine, the medicine now is often ineffective.

Pfizer scientists set out to find a more potent therapy. They found that 28 days after taking chloroquine, only 31 percent of patients were free of symptoms. That number was slightly higher -- 38 percent -- when patients were given azythromycin. But when the two medicines were combined, the success rose to 96 percent, the company official claimed. However, larger scale clinical trials are planned and will involve over 1200 patients in India, Indonesia, Kenya, Peru and South Africa, countries where the prevalence of malaria is high. Pfizer has begun discussions about the program with officials in these countries and with the U.S. Food and Drug Administration. The company source maintained that Pfizer recognizes the commercial prospects for this medicine are limited.