AIDS TREATMENT NEWS #219, March 24, 1995
Merck and Co. has devoted extraordinary resources and taken
the lead in overcoming production problems of the current
generation of protease inhibitors. In mid March it announced
that its comparative trial and open-label protocol for
persons with a CD4 (T-helper count) under 50 -- expected to
start in mid 1995 -- could be expanded from 150 to over 1400
by the end of 1995. Merck also updated the community on its
plans for large trials in other groups of patients.
The following phase III studies are currently planned:
* 780 AZT-naive patients, with CD4 counts from 50 to 500,
will be randomized to MK-639 (the current name of Merck
protease inhibitor, formerly called L-735,524), AZT, or the
combination. This one-year trial will look for changes in
viral load and CD4 count. Screening and enrollment have
begun in the U.S., Canada, and Europe.
* 540 AZT-experienced patients with CD4 counts from 50 to 500
will be randomized to MK-639, d4T, or the combination. This
one-year trial will begin in May in the U.S. and Europe.
* In Brazil, 750 AZT-naive patients, with CD4 count from 50 -
250, will be randomized to MK-639, AZT, or the combination.
This study will look for clinical endpoints, but will
analyze CD4 counts after six months. This study is planned
to begin in March 1995.
* 90 AZT-experienced patients (with CD4 count between 50 and
400) will be randomized to MK-639, AZT plus 3TC, or the
triple combination. Enrollment will begin in April in the
* For those with CD4 count under 50, 300 patients will be
randomized to MK-639, AZT plus 3TC, or the triple
combination. Those for whom AZT or 3TC would be medically
inappropriate will be assigned to receive open-label
MK-639. After the comparative trial is enrolled, the
open-label arm will be expanded to allow at least 1400
patients, by the end of 1995. This trial will start
enrollment in June.
* Another large trial is planned for AZT-experienced
patients, starting in late 1995. The treatment arms will be
determined based on results of earlier trials.
Assuming all goes well, Merck plans to file for accelerated
approval for MK-639. The company currently has no other AIDS
drugs in development.
For information on enrolling in trials of MK-639, call
800/379-1332, 8 a.m. to 7 p.m. Eastern time.