Protease Inhibitors: Ritonavir and Saquinavir Combination Trial Recruiting -- Seven U.S., Canada Sites Including San Fran

The first trial to combine protease inhibitors is now recruiting 120 volunteers in seven sites in the U.S. and Canada. This study is being conducted by Abbott Laboratories, Inc.

There is much interest in combining these two drugs, for several reasons -- but there are also potentially serious safety concerns. Saquinavir is quickly eliminated from the body, making it hard to get sufficient blood levels with the currently approved drug formulation; ritonavir, given with saquinavir, can produce increased and sustained levels of saquinavir because it slows the process used by the body to eliminate saquinavir. Also, the drugs have very different resistance patterns, which may work together well to slow the development of viral resistance to the combination.

But this combination must be tested very carefully. Correct dosing must be used when combining these drugs -- and the doses are not yet known. Blood levels of saquinavir become higher than previously achieved, and the safety of saquinavir at these blood levels is unknown. In addition, if doses are too low, viral resistance could develop. To help avoid these problems, blood levels will be measured in this trial, using a test which is not commercially available.

To be eligible, you must be at least 12 years old, have a CD4 count of 100 to 500, have never taken any protease inhibitor, have no acute opportunistic infection nor inflammation of the pancreas, and not be taking any medication contraindicated with ritonavir. You can be using other approved antiretrovirals (AZT, etc.), but will have to stop them two weeks before beginning treatment in this trial.

For more information about these trials, call Mabrey Whigham at the International Association of Physicians in AIDS Care, 312/419-7295. Or for the San Francisco trial, you could call the HIV Institute at Davies Medical Center, 415/565-6222. We could not determine the other cities before going to press.