Pfizer’s patent for follow-up HIV drug may face opposition

Pfizer’s patent for follow-up HIV drug may face opposition

Mumbai: Pfizer Inc.’s patent for its new HIV/AIDS follow-up treatment drug Celzentry in India may face opposition soon from patient groups and a couple of non-governmental organizations (NGOs).

The drug, whose generic name is Maraviroc, was granted a patent in India by the Mumbai patent office in June. It is a new class of oral AIDS medicines for patients who have already been treated with antiretroviral or ARV drugs, which are the first line of defence for HIV/AIDS patients.

Medicines Sans Frontiers or MSF and the Mumbai lawyers body Lawyers Collective are studying Pfizer’s patent claims to ensure the grant is fair.

The NGOs would also look at the objections raised by the European patent office against the application of Pfizer for the drug there. The opposing groups have one year from the date of patent publication to file a post-grant opposition under Indian patent rules.

Approved by the US Food and Drug Administration in August, Celzentry (Selzentry outside the US) is being positioned as a salvage therapy for patients not responding to other HIV drugs. This drug currently costs $32 (about Rs1,260) for a day’s treatment. Since the treatment is advised for patients only after a pathological test, which cost around $1800, the treatment cost with this drug—which has to be combined with other ARVs—is considered to be “too expensive" even in the US.

There were no pre-grant oppositions in India for Pfizer’s patent application. India’s largest generic drug maker Cipla Ltd’s chairman Yusuf Hamied said: “The generic companies here did not try to develop this drug as they are not convinced about its relevance right now because of low market potential."

According to a Pfizer India spokesperson, globally Maraviroc is approved as a second- line treatment for AIDS. “We are in the process of complying with necessary regulations for registering Maraviroc in India. It is too premature to comment on the launch details," the spokesperson said.

“Since India is a source of cheap generic medicines, the new patent should not hinder the availability of affordable drugs with unjustified patent protection. We will have to evaluate the importance of this drug for HIV patients here," said MSF’s India coordinator Leena Menghaney.

Gopakumar Nair, a leading Mumbai-based patent attorney said: “Though the technical details of the patent grant is yet to be studied, it doesn’t seem to be a new invention as this class of drugs has been available in the market." If the date of original patent was before 1995, a patent is not grantable on this drug under Indian law, he added.

The European patent office had three applications for this invention under file numbers EP1013276, EP1140085 and EP1140920.

While the first application was withdrawn on technical grounds, the other two applications have been opposed and are being examined currently. The outstanding objections against EP1140085 are that the application does not sufficiently describe the invention.

“This means that currently there is no European patent for Maraviroc. At the same time, the US Orange Book has two patents listed for this drug—US6586430 and US6667314. The Indian patent corresponds to the 6586430 patent. Indian patient groups are studying this," said a patent expert familiar with the development, who requested anonymity. The Orange Book is a national registry of patients in the US.

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