Two generic drug products by the Indian drug maker Cipla for treating HIV/AIDS have been reinstated on the World Health Organisation’s recommended list six months after being removed, a senior WHO official said on Tuesday.

The two, lamivudine and lamivudine combined with zidovudine, were returned to the list of WHO approved products after fresh inspections proved they were bioequivalent to their patented counterparts, Jim Kim, director of WHO’s HIV department, told a news briefing. “These are two extremely important drugs,” Kim said.

With their return, some 50 life-extending antiretroviral drugs are on the list, set up two years ago to guide buying by aid agencies battling the epidemic in Africa and Asia.

Earlier this month, two other Indian firms, Hetero Drugs and Ranbaxy opted to withdraw their generic antiretrovirals following similar concerns about laboratory test findings.

Both concerns say they plan to repeat the studies and resubmit the results for consideration by WHO.

The United Nations agency last August began routine inspections of contract research organisations, independent labs which do bioequivalence testing, the last stage of the lengthy process of approving a product.

The WHO has launched a campaign to get antiretrovirals to three million people in the developing world by the end of 2005. Only 440,000 of the six million AIDS patients are getting them.

The WHO has said that countries should suspend the use of de-listed medicines and switch to other prequalified products.

But if these were difficult to obtain immediately, it was recommended patients continue the use of de-listed products.