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| |  Dramatic Benefits of Merck's AIDS Drug Crixivan(r) Demonstrated WASHINGTON, Jan. 30, 1996 -- Patients taking Crixivan(R) (Indinavir sulfate), Merck's investigational protease inhibitor, in combination with two other AIDS medications achieved reductions in the level of HIV in the bloodstream, according to a new open-label study presented here today at the Third Conference on Retroviruses and Opportunistic Infections. Crixivan(R), when taken with the AIDS medications AZT and ddI, reduced median virus levels by approximately 99.9 percent or 1,000-fold (2.9 log10 copies/ml) (see note A). Moreover, the level of virus in the bloodstream was reduced to below detectable levels (200 copies/ml) in 59 percent of patients (13 of 22) after five months of therapy. Patients began the study with median viral levels of approximately 100,000 copies/ml. These patients also experienced significant immune system recovery. On average, patients' CD4 cell (immune system cell) counts increased by about 90 cells/mm3 (see note B). Patients began the study with a median CD4 count of 150 cells/mm. "This study was designed to test the principle of triple combination with protease inhibitors, and these significant results showing almost complete suppression of the virus in many patients could help change the way doctors treat HIV disease and AIDS," said Dr. Ferdinand Massari, Director, Clinical Research of Merck Research Laboratories. "The use of a potent protease inhibitor in combination therapy is very promising, and we are now studying this approach to determine its duration of effect and impact on clinical outcomes." After six months of treatment, patients taking Crixivan alone had a median increase of 85 CD4 cells/mm3, while patients taking AZT plus ddI had a median increase of 30 cells/mm3. On Thursday, February 1, data will be presented from a study on a different triple combination, with Crixivan, AZT and 3TC, by Dr. Roy Gulick of The New York University School of Medicine. HIV, the virus that causes AIDS, destroys CD4 cells which orchestrate the body's immune response -- its natural defense against infection and disease. The number of CD4 cells in the blood, or CD4 cell counts, are an indicator of the health of the immune system. People with healthy immune systems generally have CD4 cell counts of 750 to 1,000 cells/mm3 or more; while people with HIV who have CD4 cell counts below 200 cells/mm3 (or an AIDS-related opportunistic infection) have AIDS, according to the definition used by the U.S. Centers for Disease Control and Prevention. In the study, all medications were generally well tolerated. No cases of nephrolithiasis (defined as flank pain, blood in urine or kidney stones) occurred in this study, but it has been reported in 2-3 percent of patients in other Crixivan studies. Patients in current clinical trials are encouraged to regularly drink water to maintain hydration, and the vast majority of patients that have experienced nephrolithiasis continued on therapy without dose reduction. Clinically significant drug interactions have not been seen except with rifabutin and ketoconazole, which have been managed with dose adjustments. To be eligible for enrollment, patients had to be HIV-positive with less than 500 CD4 cells and more than 20,000 copies/ml of virus in the bloodstream, and they could not have previously taken AZT. The study's 78 patients were randomized to receive Crixivan alone, Crixivan plus AZT plus ddI, or AZT plus ddI. Crixivan is a potent and highly specific compound in a new class of AIDS drugs called protease inhibitors. Unlike earlier AIDS therapies, Crixivan attacks HIV at a later stage in its life-cycle. Crixivan is not a cure for AIDS, but the promising effects of Crixivan on virus level reductions and CD4 cell recovery, combined with the generally good tolerability seen in ongoing clinical trials, reinforces Merck's commitment to developing Crixivan as rapidly as possible. Merck is currently continuing Phase III trials of Crixivan. Investigators participating in the trial presented today include Dr. Marcus Conant, Conant Medical Group, San Francisco; Dr. John Mellors, University of Pittsburgh; Dr. Roy Steigbigel, State University of New York at Stony Brook; Dr. Donna Mildvan, Beth Israel Medical Center, New York; Dr. Richard Greenberg, University of Kentucky; Dr. Charles Carpenter, Brown University, Providence; Dr. Robert Murphy, Northwestern University; Dr. Kathleen Squires, University of Alabama, Birmingham; Dr. Michael Rigsby, West Haven VA Medical Center, Connecticut; Dr. Dan Stein, Albany Medical College; Dr. George McKinley, St. Lukes/Roosevelt Hospital, New York. Merck & Co., Inc. (NYSE: MRK) is a leading research-driven pharmaceutical products and services company. Merck discovers, develops, manufactures and markets a broad range of innovative products to improve human and animal health. Crixivan(R) is the Merck-registered trademark for Indinavir sulfate. (A) In "(2.9 log10 copies/ml)," the 10 is superscript. (B) In "mm3," the 3 is superscript.
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