Delhi Patent Office Refuses Patent on Pediatric Aids Drug Nevirapine Hemiydrate

21 Jun 2008

Following a pre-grant opposition by HIV/AIDS patient groups, the Delhi Patent Office has refused Boehringer Ingelheim’s patent application for the pediatric drug nevirapine hemihydrate (syrup).

Other than finding the patent application novel, the patent office agreed with all the grounds raised in the statement of opposition we prepared for the patient groups. A copy of the decision can be found here.

The reasoning given in the decision raises a number of important points. Of particular note, the assistant controller relied on a definition of efficacy given in the recent Novartis v Union of India case, requiring the applicant to show data that the aqueous suspension of the hemihydrate form of nevirapine could demonstrate an enhanced therapeutic efficacy over the known forms. The controller dismissed the applicant’s evidence of improved particle size stability as not translating to enhancing the therapeutic efficacy of the various known forms of nevirapine, but merely improving storage of the product. The application also failed on the grounds of s3(e), the applicant failing to show a synergystic effect between the composition of matter claimed, and inventive step.

If any criticism can be levelled at the decision, it is from a practice point of view. As with the Novartis/Gleevec decision, the patent offices seem intent to go through the novelty, inventive step tests first before considering what are not inventions under the Patents Act i.e s3(d) and s3(e). Logically, and as evidenced in case law from other jurisdictions,  the patent office should deal whether a patent application even meets the threshold of an invention, as set out in s3 of the Indian Patents Act, before moving on. Therefore, s3d should be applied first. In the event the application fails the s3d test, then the patent office need not entertain the issue of novelty and inventive step – though it might as the decision could be appealed.

Boehringer is entitled to appeal the decision. However, the stance taken by the patent office in its interpretation of s3d bodes well for future oppositions. Indeed many of the secondary patent applications over existing forms of drugs tend to claim unexpected or superior stability with respect to storage at elevated temperatures as being the problem solved. The patent applications for Tenofovir Disoproxil Fumarate and heat stable Kaletra  are examples in case. If this decision is anything to go by, then such patents should also be found wanting under s3(d).

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