AstraZeneca. Wockhardt has issued a post-grant challenge to Roche’s hepatitis C drug, Pegasys.

All this is unexceptionable.

But Cipla has manufactured a generic version of a newly patented drug, therefore invited litigation and only then challenged the validity of the patent. So it has questioned a patent by violating it. And since it is already marketing its anti-cancer generic drug, the question about Roche’s patent has now got linked with market price in popular discourse. Prices of lifesaving drugs are not a non-issue. But it has to be understood that the validity of Roche’s Tarceva patent is a matter of chemistry, not economics.

Let us clarify here that we have no position on whether Roche’s Tarceva patent is scientifically valid or not; the court will decide that. What we have argued against is the manner the patent was challenged.

If Cipla succeeds, this will become an attractive option for generic manufacturers — produce a cheap copycat version and when sued, bet on price differentials complicating the issue. This strategy doesn’t seem to set much store by India’s patent law. But the patent law, let us remind ourselves, is a law.

A quick look at the chemistry of Roche’s patent. It is being questioned on the ground that the key element, Erlotinib, is a derivative of Gefatinib, an earlier anti-cancer formulation, and that Erlotinib doesn’t demonstrate “increased efficacy”. This concerns Section 3(d) of the patent law that says new forms of an existing substance or new use of a known compound cannot be patented. This is controversial. Novartis challenged this provision while fighting for its anti-cancer drug, Glivec, but didn’t get a favourable verdict from the Chennai high court. The patent appellate authority is now hearing Novartis’s argument. We have argued in these pages (‘Why be a pill pauper?’, February 21, 2007) that Section 3(d) is too restrictive in terms of defining patents. That incremental innovation defines much of genuine, patentable progress in medical research. But Section 3(d) is not being challenged in Roche versus Cipla. The issue here is whether Erlotinib passes the 3(d) test.

... contd.