The World Health Organisation is reinstating two generic AIDS antiretroviral drugs delisted earlier this year after the Indian manufacturer carried out new studies to confirm that they are as effective as their brand-name counterparts.

"This is good news for patients and another important step forward in our progress towards the 3 by 5 target," WHO director-general Lee Jong-wook said on Tuesday, referring to the WHO's initiative to get 3 million people living with HIV/AIDS in developing and middle-income countries on antiretroviral treatment by the end of 2005.

The medicines - Lamivudine 150mg tablet and Lamivudine 150mg plus Zidovudine 300mg tablet - from Cipla were removed from the list of medicines available to developing countries because the manufacturer had not ensured they were equivalent to the original medicines they were supposed to copy.

The manufacturer carried out new bio-equivalence studies, and further WHO scientific assessment and inspections have validated the compliance of these new studies.

In such tests, volunteers take the generic medicines and their blood is tested after a certain time to determine whether the concentration of the generics is similar to that of the brand-name medicines in other volunteers.

"This shows that generic manufacturers are reacting responsibly to recent de-listings," said Vladimir Lepakhin, WHO assistant director-general for health technology and pharmaceuticals.