DMP 266 takes the place of RTI's (like AZT, DDI, 3TC) in the "AIDS Cocktail" regimen. It is not competitive with protease inhibitors, though it may serve a useful function in treatment of AIDS.
At the 4th Conference on Retroviruses and Oppotunistic Infections, Merck presented information on use of DMP 266 with Crixivan vs. use of Crix alone. Viral load was reduced 4.1 log with the combo, vs. 2.2 log for Crix as a mono-therapy.
The viral load assay used was only sensitive to 400 viral particles per ml. Reporting them as "zero" obviously skewed the results, so Merck also presented the data assigning a viral load of 200 to the "undetectables". In this presentation, the combo reduced vl by 2.4 log vs. 1.5 log for Crix alone.
What does this mean? First, DMP 266, added to Crix, is a more effective therapy than Crix alone. Second, this is not terribly important because Crix is _already_ used in a combo with an RTI or two. The comparison we need to see is DMP 266/Crix vs. AZT/DDI/etc./Crix. That's the standard of treatment!
So why did Merck release this study? Because rival Glaxo has two of the RTI's and is moving toward approval with a possibly better one (1592) _and_ a protease inhibitor (141 or Vrtx 478).
The double PI trials are much more interesting. There, you see results like 5-fold to 20-fold increases in blood concentrations. This offers much more hope than a new RTI, or NNTRI in this case.
The fact that better presentations and analyses are available from patient groups than from drug companies tells me that no amount of "marketing muscle" will displace the best medicines. |
