Novartis reaps little glee from Gleevec

Novartis (Basel, Switzerland) has lost a patent claim for a polymorphic form of its anticancer drug Gleevec (imatinib mesylate) before the office of the Indian Controller of Patents and Designs.

The decision comes following a submission by Natco Pharma (Hyderabad, India) - who have launched a generic version of Gleevec under the name `Veenat' - to the Controller, which pointed out that, despite Novartis' claims that the patent application claims a new substance: 'As per Section 3(d) of the Patents Act, any salt, polymorph or derivative of known substance is not patentable unless such salt, polymorph or other substance shows enhanced efficacy of the substance.'

Natco accompanied the claim with study information showing only a 30% difference in bioavailability of the free base with that of beta-crystal form.

'The present patent specification [of Novartis] does not bring out any improvement in the efficacy of the beta-crystal form over the known substances; rather it states the base can be used equally in the treatment of diseases or in the preparation of pharmacological agents wherever the beta-crystal is used. Even the affidavit submitted on behalf of [Novartis] does not prove any significant enhancement of known efficacy,' reads a Natco submission to the Controller.

Mr V Rengasamy, assistant controller of Patents & Designs, accordingly ruled that: 'It is found that this patent application claims only a new form of a known substance without having any significant improvement in efficacy.'

Meanwhile, in America, there was other bad news for Novartis and Gleevec, which is used in the treatment of gastrointestinal stromal tumours (GIST), as the US Food and Drug Administration (FDA) approved Pfizer's (New York, US) Sutent (sunitinib), a targeted anticancer treatment for patients with GIST, specifically for patients whose disease has progressed or who are unable to tolerate treatment with Gleevec.

The drug, which received a priority review and consequently gained approval in less than six months, is a tyrosine kinase inhibitor that works through multiple targets to deprive the tumour cells of the blood and nutrients needed to grow. It has been shown to delay the time it takes for tumours or new lesions to grow in GIST patients, with the median time-to-tumour progression (TTP) averaging 27 weeks, in comparison to six weeks for patients who were not treated.

It will be used to treat patients with GIST, around 5,000 of which are diagnosed each year according to the American Cancer Society.

The approval also represents a landmark for the FDA, as, following Sutent's additional approval in the treatment of patients with advanced renal cell carcinoma (RCC), it is the first time a new oncology product has been approved for two indications simultaneously

This approval was based on Sutent's ability to reduce the size of the tumours in patients. It showed an overall response rate of 26-37% in patients with metastatic kidney cancer whose tumours had progressed following cytokine-based therapy.