The United States National Institutes of Health said on Thursday it will share intellectual property rights on some AIDS drugs in a patent pool designed to make treatments more widely available to the poor.

The NIH is the first research institution to join an HIV medicines patent pool launched by UNITAID, a health financing system funded by a tax on airline tickets which was co-founded by Brazil, Britain, Chile, France, and Norway in 2006.

A UNITAID official told Reuters in July several major drugmakers, including Merck, Tibotec and Gilead, were in advanced talks on joining the AIDS drug pool.

But others -- including GlaxoSmithKline and Pfizer's HIV/AIDS drug joint venture, ViiV Healthcare -- have said they would rather agree their own licensing deals with generic makers in developing countries.

The NIH holds multiple patents covering medicines and treatments related to HIV/AIDS. Thursday's agreement relates to a class of AIDS drugs known as protease inhibitors, primarily used to treat drug-resistant HIV infection.

This license underlines the U.S. government's commitment to the Medicines Patent Pool and its goal to increase the availability of HIV medicines in developing countries, NIH director Francis Collins said.

We are now discussing licensing to the Medicines Patent Pool other patents that could have a positive impact on the treatment of HIV/AIDS.

Philippe Douste-Blazy, Geneva-based UNITAID's chairman, welcomed the NIH move and urged other patent holders to follow suit.

Around 33.4 million people around the world are living with the human immunodeficiency virus (HIV) that causes AIDS. The vast majority live in poor regions such as Africa and Asia, where medicines have to be very cheap to allow those who need them to be able to afford them.

UNITAID announced the plan for a patent pool in December. The idea is to allow generic drug makers to make low-cost versions of widely patented new medicines by creating a system for patent holders to license technology in exchange for royalties. It was expected to save poor countries more than $1 billion a year in drug costs.