TreatmentUpdate 71, Volume 8, No 7; October 1996
Scientists at the Merck pharmaceutical company have made a new
group of drugs that reduce production of HIV in lab
experiments. One of these chemicals is DMP 266 (formerly
L743,726) which works by affecting the viral enzyme RT (reverse
transcriptase). The critical effect of DMP 266 is that it has
antiviral activity against HIV that can resist the effect of
delavirdine and nevirapine. In some lab experiments, DMP
266-treated cells were protected from HIV for up to 10 weeks.
Doctors in the US enrolled 16 HIV-infected subjects (3 females,
13 males) who had an average of 221 CD4+ cells and a viral load
averaging 131,000 copies (each copy represents 1 virus).
Thirteen of the 16 subjects had used anti-HIV drugs before
entering this study. During the first 2 weeks of the study, 5
subjects received either fake DMP 266 (placebo) or "DMP 266,
200 mg/day." In the third week all subjects received indinavir
800 mg/8 hours. Those subjects who were receiving DMP 266
during the previous two weeks continued to do so.
Two weeks' use of DMP 266 resulted in a 98% decrease in the
amount of HIV in the blood and an increase of 96 CD4+ cells.
Subjects receiving fake DMP 266 had no changes in viral load or
CD4+ cell counts. After 12 weeks of a combination of both
antiviral agents, technicians found the amount of HIV had
decreased to less than 1/1,000 of its pre-study level. Common
side effects reported included "headache, dizziness, rash and
diarrhea." On average, subjects had increases of 100 CD4+
cells. Use of DMP 266 may decrease levels of indinavir by 37%.
Further studies of this promising combination are underway.
1. Mayers D, Riddler S, Stein D, et al . A double-blind
study to evaluate the antiviral activity, tolerability and
pharmacokinetics of DMP 266 alone and in combination with
indinavir. Abstract LB 08A.