LONDON (AP) ― Gilead Sciences Inc., one of the world’s biggest producers of AIDS drugs, will allow some of them to be made by generic manufacturers - potentially increasing their availability in poor countries, particularly in Africa, officials said Tuesday.

In the first deal of its kind, the Foster City, California-based pharmaceutical company has agreed to allow four of its AIDS drugs to be made by generic drug companies at a cheaper cost in return for a small proportion of royalties, United Nations health officials said.

Most of the 33 million people worldwide who have HIV, the virus that causes AIDS, live in Africa. One of the drugs will also be used to treat people with hepatitis.

The deal was negotiated by the Medicines Patent Pool, part of a U.N.-led partnership that raises money for AIDS, tuberculosis and malaria by things like taxing airplane tickets. Among the partnership’s 29 member countries, only Chile, France, Korea, Mali and Niger are actually implementing the airline tax.

Last year, the U.S. National Institutes of Health allowed one of its patented drugs to be made generically via the same group, but this the first deal with a private company. Several other pharmaceutical companies, including F. Hoffman-La Roche, Sequoia Pharmaceuticals and ViiV Healthcare, a joint venture between GlaxoSmithKline PLC and Pfizer Inc., are in talks with the group.

“We will continue to work with Gilead and others to expand access to all people living with HIV in developing countries,” said Ellen ‘t Hoen, executive director of the Medicines Patent Pool.

Gilead will receive from three to five percent royalties on its four drugs, which will be supplied to about 100 countries.

Gilead Sciences mainly makes drugs for AIDS, liver disease, heart disease and respiratory problems. Last year, it reported revenues of almost $8 billion, a fraction of the amount generated by larger companies like Johnson & Johnson and Pfizer, which make several times that.

Until now, its drugs have been mainly sold in rich countries, and profits from the new deal are expected to be a tiny part of those Gilead gets from the West.

Typically, patients in poor countries have to wait for years until the patents expire on new drugs before they can be made more cheaply by generic companies.

But some experts questioned whether the deal went far enough and pointed out it specifically excludes manufacturers in Thailand and Brazil, which both produce large amounts of generic drugs.

“This agreement is an improvement over what other big pharma companies are doing to ensure access to their patented AIDS medicines in developing countries,” said Michelle Childs, a director at Doctors Without Border’s campaign for access to essential medicines. Still, she warned caution was necessary and that the new deal “should not become the template for future agreements.”

Other major drugmakers including Johnson and Johnson, Abbott Laboratories and Merck & Co. have so far declined to formally negotiate with the U.N.-led group.