Valganciclovir Patent Revoked!

In a matter that was remanded to the Controller of Patents by the IPAB, the patent granted to Valganciclovir was revoked by the Controller.

(For a history of the developments on this matter, you can read our previous posts here)

Valganciclovir is a anti-retroviral drug used for the treatment of active cytomegalovirus retinitis (CMV) infection. This infection if not treated, can cause blindness in persons living with HIV. It is also used for post operative treatment for persons who have received an organ transplant. Roche was granted a patent for Valganciclovir in 2007 in India. The patented drug was priced at Rs. 1040 per tablet (as reported by Lawyers Collective) making it an extremely expensive treatment. The grant of the patent in India also meant that cheaper generic versions could not enter the market.

The patentability of this drug was the issue in the order issued by the Controller early this month. The Controller noted that the three main aspects of determining patentability were disclosure, relevant prior art and judgments available at the time of deciding the case. One of the issues before the Controller was whether expert evidence was prior art publications or disclosures. The Controller held that while expert evidence can be used for understanding prior art documents, it should not be relied on as prior art.  The Controller also noted that expert evidence unlike research documents were not impartial documents. This was also a contributory factor to the decision that lesser weightage should be placed on expert evidence.

The next main issue the Controller considered was whether the Valganciclovir patent was anticipated by the prior art. The main prior art in question was EP’329 and US’924. The Court noted that the present patent was anticipated by the prior art in question. EP ‘329 has a Markush type formula and has signposts planted by the prior inventor. The disclosures made in EP’329 are such that any person skilled in the art could arrive at the claimed invention without any further experimentation. Therefore the Court held that EP’329 clearly anticipates the present patent.

The object that the present patent tries to address is to provide a prodrug of ganciclovir with improved oral bioavailability. The problem in the prior art associated with ganciclovir was poor oral bioavailability. However, the Controller noted that the solution for the same is clearly derivable from the prior art provided by Beauchamp in US’924. Therefore, the Controller stated that US’924, EP’329 and the present patent all use identical steps with identical reagents and any skilled person would know how to prepare the present patent from the prior without any undue burden. Therefore, the Controller stated that all claims including process claims are obvious to a person skilled in the art.

The next issue to be discussed is whether the improvement of oral bioavailability constitutes enhancement of the known efficacy of that substance. The Controller ruled that while bioavailability is one of the factors affecting efficacy, it cannot be directly equated to efficacy. The Controller ruled thus: “lmprovement in bioavailability of the new form cannot be considered directly related to efficacy. Even any unforeseen property observed in new form, unless such property directly relate to efficacy, it will be considered as inherent property of such substance. Since there is no direct relation shown for the improved bioavailability of new form of ganciclovir in the description with regard to significant difference in the efficacy, and therefore such a new form shall be considered as a same substance. Thus new form of the present case Monovaline ester of ganciclovir is considered as a same substance i.e. ganciclovir because,the difference in enhanced efficacy is not
shown in the complete specification. ” The Controller ruled that the present patent was a ‘mere use of a known process’ which was not patentable under S. 3(d), Patents Act.

The last issue discussed by the Controller was whether NGO’s have the locus standi to file a post grant opposition. Under S. 2(1)(t), Patents Act any ‘persons interested’ can file a post grant opposition. The Controller held that NGO’s would fall under the ambit of persons interested. The Court stated: “The locus standi in the post-grant opposition is to be viewed in broader perspective to grant quality patent. Mere filing of patent application would not qualify for enjoying the monopoly right for 20 years, but the inventor has to pass the tests not only in the Patent Office but also from the public. That is the reason why there is a provision incorporated in 2(1)t as ‘person interested’
includes can file a post-grant opposition. There is a limitation in section 2(1)t, but it is reasonable restriction. Therefore, in the present case, section 2(1)t is viewed in broader perspective but well within the ambit of provision,because they are the end users or persons will be directly and severely affected,if the patent is granted.Thus the NGOs have locus standí to oppose the present case.”

Therefore, for all these reasons, the Controller revoked the patent granted to Valganciclovir.

This has clear repercussions as the market is now open for generic drug manufacturers to enter the market. Given the importance and the expensive nature of Valganciclovir, this decision of the Controller is a momentous development for the Indian drug market.