The Indian Patent Office has begun hearing on the validity of a patent granted to Roche for Pegasys (pegylated interferon alfa 2a), a drug used to treat hepatitis C. Assistant controller of patents at the Chennai Patent Office heard the post-grant opposition filed by Sankalp Rehabilitation Trust against the patent. The patent office is also hearing an opposition to the same patent filed by Wockhardt.

The parties have been given time until September 25 to file their written submissions. After the hearings conclude, the Patent Office will decide whether Roche's patent is valid or whether it should be amended or revoked.

The Indian Patent Office had granted a patent to Roche in 2006 for pegylated interferon alfa 2a. This is crucial for treatment of patients with chronic hepatitis C. The prescribed six-month course of treatment costs about Rs 4.36 lakh (available at a discounted price of Rs 3,14,496. It is to be taken in combination with Ribavarin, which costs another Rs 47,160.

In May 2007, Sankalp Rehabilitation Trust, a Mumbai-based NGO that works with drug users, filed a post-grant opposition against the grant.

Arguing the case, counsel for Sankalp Rehabilitation Trust Anand Grover said that the claimed invention-the branched pegylated form of interferon alfa 2a-did not satisfy the patentability criteria under Indian law. He argued that Roche's patent involves combining interferon-a naturally occurring protein with antiviral effects that has been known for years-with a structure called polyethelyene glycol (PEG), an inert substance that helps to prevent the interferon from being broken down by the body, thus allowing it to remain in the bloodstream longer. This technology of combining interferon and other biologically active proteins with PEG had also been known for years prior to this patent.

Therefore, all Roche did was apply what was already known to interferon alfa 2a. Grover said that, in light of this, the invention was not new and, in the alternative, also was obvious to the person skilled in the art and lacked inventive step. He further argued that Roche had also failed to satisfy section 3(d) of the Patents Act, which requires a showing of enhanced efficacy, because it neither provided adequate data nor proved it. He also argued that pegylated interferon was merely an admixture of known substances, with no showing of synergistic effect, and therefore failed to satisfy section 3(e) of the Patents Act.

Responding to this, counsel for Roche Guru Natraj first questioned the standing of Sankalp Rehabilitation Trust to file a post-grant opposition. He claimed that under the law, only a "person interested" could file a post-grant opposition and Sankalp Rehabilitation Trust did not satisfy this criterion. He claimed that the documents cited by Grover taught pegylation of enzymes and that as interferon was not an enzyme, these documents could not be used to object to the novelty and inventive step involved in the pegylation of interferons. He added that the documents, in fact, taught away from using pegylated interferon of the higher molecular weights claimed by Roche. He also argued that Roche had demonstrated an increase in efficacy.

Countering these arguments, Grover argued that under Indian law, a public interest group was a "person interested" and that the burden of proving inventive step was on the patent holder, Roche in this instance. He clarified that pegylation was known to protein chemistry generally and was not specific to enzymes. He also pointed out that the various patentability requirements such as non-obviousness, technical advance and enhanced efficacy ought not to be conflated.