LONDON, March 30 (Reuters) - British drugmaker GSK has signed deals with three companies allowing them to make inexpensive generic versions of its long-acting HIV preventive medicine for use in lower-income countries, where the majority of new cases occur.

The injected drug cabotegravir was approved by regulators in the United States in late 2021. Last July, GSK announced a program with the United Nations-backed healthcare organisation, the Medicines Patent Pool, which aims to get poor countries access to new HIV therapies far earlier than they did for previous HIV medicines.

During the HIV/AIDs epidemic in Africa in the 1990s and early 2000s, in which many millions of people died, treatments used widely in wealthy countries were unavailable on the continent.

GSK said last year the new program could result in the generic form of its injection being available in lower-income countries beginning in 2026.

The drugmaker's HIV treatment division, ViiV Healthcare, said in a statement on Wednesday it had issued voluntary licenses - waiving intellectual property rights - to Aurobindo Pharma, Cipla and Viatris, which will manufacture the generic versions of cabotegravir.

The generics will be supplied in 90 countries, subject to regulatory approvals there, the statement said.

Indian drugmaker Cipla will make the injections in India and has plans to manufacture in South Africa, which is trying to grow its drugs manufacturing industry to meet the continent's needs and reduce a dependency on imports that was exposed by the COVID-19 pandemic.

Pre-exposure prophylaxis (PrEP) is an effective way for an at-risk HIV-negative person to reduce the risk of infection. But until recently, PrEP was only available in pill form. GSK's product is the first non-pill option.

Describing the licences as "welcome" in a statement, Médecins Sans Frontières (MSF)/Doctors Without Borders said that GSK should provide more information on the current availability and price of the drug in low- and middle-income countries while waiting for generic production to begin.

The medical NGO said it had been in negotiations with ViiV for months to get enough supplies of the drug, but was still unable to meet demand.

"ViiV should be ashamed: it has a lifesaving HIV prevention drug at its fingertips but is failing to ensure there’s enough available for people who need it," said Dr. Helen Bygrave, chronic disease adviser for MSF's access campaign.

A GSK spokesperson said the company shared MSF's ambition to enable broad access to the drug.

"We are moving at pace to increase capacity... to meet the demand," the spokeperson said, adding that it planned to update partners including MSF "in the coming weeks" to share its progress. (Reporting by Maggie Fick, additional reporting by Jennifer Rigby; Editing by David Holmes and Bill Berkrot)