Bristol-Myers Myers Squibb and Gilead Sciences have combined many HIV drugs into a single pill sometimes the best medicine is more than one kind of medicine. Malaria, tuberculosis and HIV/AIDS,2 for example, are all treated with combinations of drugs. But that can mean a lot of pills to take. It would be simpler if drug companies combined all the medicines into a single pill, taken just once a day.

Now, two companies say they have done that for people just starting treatment for HIV, the virus that causes AIDS. The companies are Bristol-Myers Squibb and Gilead Sciences. They have developed a single pill that combines three drugs currently on the market.3 Bristol-Myers Squibb sells one of them under the name of Sustiva.4 Gilead combined the others, Emtriva and Viread, into a single pill in two thousand four.

Combining drugs involves more than technical issues. It also involves issues of competition if the drugs are made by different companies. The new once-daily pill is the result of what is described as the first joint venture agreement of its kind in the treatment of HIV

In January the New England Journal of Medicine5 published a study of the new pill. Researchers compared its effectiveness to6 that of the widely used combination of Sativa and Combivir. Combivir contains two drugs, AZT7 and 3TC.8 The researchers say that after one year of treatment, the new pill suppressed HIV levels in more patients and with fewer side effects.9 Gilead paid for the study. Professor Joel Gallant at the Johns Hopkins School of Medicine in Baltimore, Maryland, led the research. He is a paid adviser to Gilead and Bristol-Meyers Squibb as well as the maker of Combivir, GlaxoSmithKline.

Glaxo Smith Kline reacted to the findings by saying that a single study is of limited value. It says the effectiveness of Combivir has been shown in each of more than fifty studies.

The price of the new once-daily pill has not been announced. But Gilead and Bristol-Myers Squibb say they will provide it at reduced cost to developing countries. They plan in the next few months to ask the United States Food and Drug Administration10 to approve the new pill.

There are limits to who could take it because of the different drugs it contains. For example, pregnant women are told not to take Sustiva because of the risk of birth disorders.11 Experts say more than forty million people around the world are living with HIV