India's top court has dismissed a petition from Swiss drugmaker Novartis AG for a patent protection in India for an updated version of its cancer drug Glivec.

The court held that the drug did not qualify for a patent according to Indian law as it contains a known substance Imatinib Mesylate and lacks any genuine inventions.

The pronouncement of the highest court, which is widely seen as a landmark judgement against western drug companies, comes as a serious blow to Novartis which has been fighting the case since 2006. The apex court also dismissed the pharma major's plea seeking to bar other Indian drug companies from manufacturing generic drugs.

Novartis filed a case with the Supreme Court in 2009 to overturn the decision of the Indian authorities to deny a fresh patent for the amended version of Glivec on the grounds that the revised version was modified to make it easier to absorb.

But Indian officials rejected the application on the basis of a law which did not allow new patents for drugs with minor improvements to the existing one, a practice known as "evergreening".

Glivec is used to treat chronic myeloid leukemia and other cancers and costs $2,600 (£1,710/€2,031) a month, while the generic version is available for $175 in India.

Western pharma giants point out that such a ruling would discourage further investment in research and development in India.

However, critics of the drugmakers opine that if the pharma majors continue to claim patent for minor improvements in their drugs, it would affect the generic competitions resulting in the price rise of many life-saving medicines in India as well as in other developing countries.

"This (judgement) will go a long way in providing affordable medicine for the poor," Anand Grover, a lawyer representing Cancer Patients Aid Association told the BBC.