The world's leading pharmaceutical companies will on Thursday undertake to publish more data about clinical trials of their drugs, in an effort to reassure patients about the safety of their medicines.

The move, which is also designed to head off legislation demanding disclosure, comes as fresh allegations surface that US scientists manipulated trials of an anti-Aids drug in order to make it seem more effective, thereby endangering of patients.

From Thursday, drug industry associations in the US, Europe and Japan will co-ordinate an industry-wide plan to publish on the internet detailed information on completed and current clinical trials of their drugs. Although the scheme is voluntary, drugs companies will be under great pressure to take part in it.

The move comes at a time of growing concern over drugs safety in the wake of the withdrawal of Vioxx, the painkiller, and accusations that data about Seroxat, an antidepressant, had been suppressed because it showed no benefit in adolescents.

The plan will be seen as an attempt to pre-empt legislation, with medicine-related hearings under way in the UK parliament and the US Senate. The move comes as a legal group representing a former official of the US National Institutes of Health (NIH) alleged it had uncovered widespread misconduct in clinical trials of Aids treatments funded by the agency.

Lawyers for Dr Jonathan Fishbein, who has accused the NIH of endangering the lives of patients in an Aids trial in Uganda, said the allegations involved a number of trials, including some outside Africa. Dr Fishbein was director of the Office for Policy in Clinical Research at the NIH's Aids division. His lawyers are set to submit the data early next week to the Inspector General of the Health and Human Services Department, the NIH's parent.

“We will be presenting evidence that questions the validity of other trials and also shows a pattern of harassment and intimidation at the NIH of any employees who raise questions about those trials,” said Stephen Kohn, Dr Fishbein's lawyer. “People were threatened with termination [of contract] if they took their concerns public.”

More than 350 Aids trials are under way at the NIH. The US uses the results to help form its international policy on Aids, which has a $2.9bn (€2.2bn) budget for this year.

On Tuesday Dr Fishbein told investigators from the National Academy of Sciences the Uganda trials may have ignored thousands of serious side-effects and deaths among pregnant women taking the Boehringer Ingelheim drug, Nevarapine, to prevent transmission to their unborn children. Last month, South Africa's ruling party accused US officials of using mothers in the Ugandan experiments as guinea pigs. Concern has also emerged over drug resistance developing after treatment with Nevarapine.

The NIH did not comment on Wednesday, but has said Dr Fishbein was fired for poor performance. “This is not an Aids issue; this is a scientific integrity issue,” he said. “I want the NIH held accountable.”