The U.N. health agency has removed two versions of antiretroviral drugs - commonly used in developing countries - from its list of approved HIV medicines, saying it’s uncertain they are biologically the same as the patented drugs.

“We made a random check on the laboratory (testing the drug) and it did not meet good clinical and laboratory practice,” said Daniela Bagozzi, a spokeswoman for the World Health Organization.

She said there wasn’t necessarily anything wrong with the drugs or the facilities, but that there were problems with the way the tests were being carried out, and “in view of that, we’ve had to pull (the drugs) off the list.”

The versions of the drugs - known as lamivudine (3TC) and zidovudine (AZT) - are made by Cipla, an Indian firm that specializes in providing generic drugs to developing countries.

WHO did not find any problems during its original inspection of the company, but another laboratory carrying out what are known as bioequivalency tests for Cipla could not provide the required documentation.

“When Cipla presented the information it was all absolutely perfect - everything squared,” Bagozzi said. “That sufficed for us to believe that everything had been done properly and there was no quality problem. (The drugs) seemed to be effective and fine.”

It was only when the WHO checked the testing laboratory that the problem emerged, she said.

The health agency has asked Cipla to resubmit its documentation to get the drugs back on the approved list. If the laboratory used by Cipla then meets WHO’s requirements, the medicines will be accepted again.

Cipla has told WHO that it is contracting a new laboratory and conducting new bioequivalency tests.

“We are submitting bioequivalency studies done at another laboratory by the end of July,” Amar Lulla, Cipla’s joint managing director, told The Associated Press. “The bioequivalency study done at one contract research organization was found to be inadequate in documentation.”

Lulla said that there was no problem with the quality of Cipla’s products and the facilities.

“Sometimes laboratories fail to meet the standards of good clinical and laboratory practice when they don’t provide enough documentation,” he explained. “The quality of the product and the facilities are not in question at all.”

“It’s really up to them (Cipla) - obviously it’s in their interests (to get the drugs approved),” Bagozzi noted.

In a push to expand treatment, WHO is aiming to put 3 million people in the developing world on HIV drugs by 2005. About 40 million people worldwide are infected with the AIDS virus and 5 million new infections are recorded every year. Sub-Saharan Africa is worst hit, but the epidemic is now pushing deep into Asia.

The United States has recently announced a change in its AIDS policy to help provide cheaper drugs to sufferers in Africa and the Caribbean. That marks a significant shift from U.S. demands for more stringent standards for foreign companies which manufacture low-cost generic versions of anti-HIV drugs and combine them into single pills.