The agreement marks the realisation among scientists that no single drug will combat HIV, and that viral resistance will develop against any compound.
It also reflects the desperation felt at the fact that 12 years into the Aids epidemic, and despite billions of pounds in research, there is no definitive treatment.
The drug companies, based in the United States and Europe, will swap information on drugs that they have developed, provide samples for laboratory and clinical trial work, and keep each other informed about development techniques. However, their collaboration does not cover the basic HIV research that Aids activists demand.
The group includes Wellcome, which manufactures AZT (Retrovir), the first drug to be licensed for Aids. A large clinical trial recently concluded that the drug did not delay the onset of Aids in healthy HIV- positive people. Previous American trials had suggested it did.
Dr Linda Distelrath, of Merck, the American company which initiated the collaboration, said it had only become feasible within the past year. 'We are at a stage where we know that resistance is probably going to develop, and we now have many more compounds effective against HIV, which have been approved or are in the pipeline. What we need to do is find a combination of these drugs.'
Sue Hughes, of Scrip, a pharmaceutical business publication, said many companies were realising that the only way forward was to investigate combination therapies.Reuse content