As India wrestles with its patent laws and a Jan. 1 deadline for compliance with World Trade Organization regulations, a dispute over a popular cancer drug shows that law and not medicine is often at the root of pharmaceutical battles.

Last year, the Indian government granted exclusive marketing rights, a precursor to a product patent, to the Swiss-based company Novartis for its anti-leukemia drug Gleevec.

That infuriated the Indian firm Natco Pharma and six other Indian firms already producing generic equivalents of Gleevec at dramatically lower prices. A month’s dose of Gleevec costs the equivalent of about $2,700. The generic equivalent from Natco Pharma - Veenat - costs about $220.

So Natco Pharma challenged the decision in court, arguing no company should get exclusive marketing rights for a product if its generic version is already available.

Three months later, Novartis filed suit in a different Indian court, seeking a stay on the sale of the generic Gleevec brands in India. The court ordered an interim stay, forcing all but one of the Indian manufacturers to recall their products.

Natco Pharma escaped the order. Novartis didn’t name it in its petition because the second judge could have waited for the verdict from the first legal suit, delaying an injunction.

The result: Gleevec sales have soared in India - as have sales of Veenat.

But, say the Cancer Patient Aid Association, hundreds of cancer patients who can’t afford Gleevec or can’t get the limited supply of Veenat have suffered. The association has filed its own petition, this one with the Supreme Court, seeking compensation from Novartis for cancer patients and a court-ordered price cut for Gleevec.

One drug - three unresolved legal disputes.

“The Gleevec episode is the prelude,” said A.D. Damodaran, a scientist and patent expert.

“There will be many more disputes. No matter what the government does there will be many loopholes in the law and many interpretations of its provisions,” Damodaran said. “You don’t need to be smart in research and innovation, but in law.”