Tacrolimus Holds Up In Long-Term
MG Trials
Tacrolimus (also called FK506 and marketed
as Prograf) continues to show promise in the treatment
of myasthenia gravis (MG).
Tacrolimus is a potent immune-system suppressant, which is the
basis of its usage in MG, a disorder in which the immune system
attacks specialized areas of muscle cells and prevents them
from receiving signals from nerve cells.
Japanese Group
Confirms Earlier Results
A Japanese research group reported in the March issue of the
Journal of Neurology, Neurosurgery, and Psychiatry that a small,
long-term study of tacrolimus confirmed the drug’s benefit
in a shorter study.
Tetsuro Konishi at Utano National Hospital in Kyoto followed
up on an earlier, four-month study of tacrolimus in 19 people
with MG, in which seven participants showed improvement on a
scale of disease activity, and eight improved on measures of
daily activities.
In the new, longer study, which included 12 people from the
original trial, participants took 2 to 4.5 milligrams per day
of oral tacrolimus for approximately two years. At the end of
the study, eight participants (67 percent) showed improvement
in either an MG muscle strength score or an activities of daily
living score.
Dosage levels of prednisolone (a corticosteroid drug very similar
to prednisone), which has many undesirable side effects, could
be reduced in seven (58 percent) of the participants.
The investigators concluded that “long-term use of FK506
for MG can be more effective than short-tem administration,
with no serious side effects.”
Most Able to Stop Prednisone
In Spanish Study
In a larger long-term study of tacrolimus in MG, conducted
by Jose Ponseti at Hospital General Universitari Vall d’Hebron
in Barcelona, Spain, also showed the drug was effective and
well tolerated.
In this study, 79 patients with MG took tacrolimus for at least
a year, with 76 participants (95 percent) taking the drug for
more than three years.
Five people stopped taking it during the trial because they
developed kidney problems, incoordination or dizziness, because
they became pregnant, or because they developed cancer.
Of the 79 people who took tacrolimus for an average of 2.5
years, all but two were able to stop taking prednisone. Their
undesirable immune-system activity and disease severity scores
decreased significantly, and strength increased by an average
of 39 percent. All resumed full activities of daily living.
Participants began the trial taking 6 to 10 milligrams of tacrolimus
a day, and they reduced their dosage levels after a year of
treatment.
“Tacrolimus was well tolerated,” the investigators
write, “without [the] adverse effects related to long-term
treatment with prednisone and cyclosprine, and might replace
these drugs as a sole immunosuppressive agent for the treatment
of MG.” | 
