The medicines include tuberculosis (TB) drug moxifloxacin, antipsychotic olanzapine and valgancicloivir, a medicine often needed for HIV / AIDS patients.

The groups allege that none of these drugs qualified the criteria specified under the Indian Patents Act and were given patent protection because the patent examiners overlooked the legal safeguards meant to avoid grant of patents to known substances or their mere improvements.

According to researchers associated with the Delhi-based Centre for Trade and Development (Centad), Moxifloxacin was among the 80 patent applications for TB drugs which they had identified as non-patentable.

"The fact that no new TB drug has come in the last 15 years itself is a proof that none of these applications are patentable," a Centad researcher said.

"The basic patent for this important second-line TB drug was granted to Bayer in Germany 20 years ago. Despite that, the patent office in Mumbai granted patents on various forms and dosages of moxifloxacin," he said.

Similar doubts were raised over the Kolkata patent office decision to grant patent for a different form (polymorph) of the known molecule olanzapine. Activists say that the draft patent manual, the guidebook for patent examiners, clearly states that polymorphs such as the one claimed in the case of olanzapine should not get patent protection.

The case of valganciclovir is even more interesting as the Chennai patent office granted patents for this drug without even hearing the pre-grant opposition filed by public interest groups.

"In contravention of the explicit rules on granting hearings for oppositions, civil society was not allowed to present its case before grant of patent. The claims that were granted in the patent of valganciclovir clearly do not appear to satisfy Section 3(d) of the Patents Act," Chan Park of Lawyers Collective said.

"The Chennai patent office recently granted a patent entitled ‘A Pharmaceutical Tablet' (Application No. 7/MAS/1997A; Patent No. 203534). This patent relates to the combination of an already known pharmaceutical substance — famciclovir — with traditional excipients such as lactose and cellulose, to manufacture the drug in the form of a tablet.