Global pharma seeks cancer drug patents

The objections by Indian pharma companies to Swiss drug maker Novartis seeking a product patent for its Glivec blood cancer medicine has not deterred other global drug firms from applying for patents in this drug category in India.

At least five multinational pharma companies - Astra Zeneca, Pfizer, GlaxoSmithkline, Bayer and Bristol Myers Squibb - are known to have filed patent applications with various patent offices in India for about six new generation cancer drugs.

These are in the same class as the chronic myeloid leukaemia (a form of blood cancer) drug Glivec by Novartis.

Novartis has also filed a patent application for Tasigna (nilotinib monohydrate), a follow up drug for patients who are resistant or tolerant to Glivec.

Pending list
Applications pending with patent offices are one for Sutent (sunitinab malate) by Pfizer for the treatment of advanced renal cell carcinoma or kidney cancer, three for Tykerb (Lapatinib Ditosylate), GSK's breast cancer drug and its salts, another for Sprycel (dasatinib), a blood cancer drug by Bristol-Myer Squibb and Nexavar (sorafenib tosylate) from Bayer for the treatment of kidney cancer.

All are from the class of Tyrosene Kinase inhibitors, an important group of molecular target agents for the treatment of various cancers.

Indian generic companies, patient groups and healthcare non-governmental organisations (NGO) had also voiced their opposition to two more drugs in this class, that is Iressa (gefitinab) from Astra Zeneca and Tarceva (Erlotinib) from Roche, both used in the treatment of small cell lung cancer. They are opposed to the grant of patents for cancer drugs in the fear that this may allow global pharmas to sell these essential drugs at unaffordable prices and block the entry of cheaper copycat generics.

Some worries
"These drugs are yet to come under the radar of Indian generic companies and NGOs as they are new drugs that have been approved recently by the US Food and Drug Administration (FDA). I am not aware of any opposition against any of these applications so far," said Varun Chonkar, a patent expert who has gathered information on these patents.

Pfizer's Sutent, which got US approval last year, has a mail-box patent application pending with the Delhi patent office. A few weeks ago, the safety and efficacy of this drug was questioned in an article in the Lancet, a renowned medical journal.

Novartis filed a patent application for Tasigna with the Chennai patent office in 2004. The drug was approved by the US FDA in October last year.

Chonkar informed that the drug was 50 times potent than Glivec and a patent for this drug could compensate for the denial of patent protection for Glivec.

Novartis is also facing opposition over the alpha crystalline form of Glivec, though the company has not yet launched a drug of this version.

High cost
GSK's oldest patent application, for Tykerb, is pending with the Kolkata patent office since 1997. Two more patent applications by the company for Lapatinib species and salt are also pending approval. Tykerb was approved in the US in March last year. This breast cancer drug is expected to earn the company $890 million (about Rs 3,500 crore) globally by 2010.

A one-month course of the medicine costs about $2,900 (more than Rs 1 lakh).

A patent application by Bayers is pending with the Mumbai Patent Office. Details on Bristol-Myers' Sprycel were not immediately available.