Mycophenolate Mofetil in AChR-
ab Positive Myasthenia Gravis:
Outcomes in 102 patients
M.K. Hehir, T.M. Burns, J. Alpers,
M.R. Conaway, M.Sawa,
D.B.Sanders
Muscle & Nerve In press
Mycophenolate mofetil (MMF)
in MG
There are published reports on more than 200
MG pts who have been treated with MMF
60-90% of reported patients after MMF
However, two recent RCTs failed to
demonstrate benefit of MMF in MG
What did we learn from these studies?
MMF is not better than prednisone alone as
initial treatment in mild-moderate MG, and has
no steroid-sparing effect within the time frame of
these studies.
=> It may take longer than predicted to show
benefit from MMF.
Prednisone was more effective than predicted,
and at lower doses than expected.
=> In a head-to-head comparison of efficacy,
prednisone will win.
Retrospective Review- Hypotheses
The published RCTs of MMF in MG were
limited by:
Their short duration
Comparison with prednisone
Methods
Reviewed all patients with AChR-ab+ MG
treated with MMF >3 mos (with or without
prednisone).
102/116 met entry criteria
MMF Monotherapy - 36
MMF + prednisone - 66
Outcome measures, at selected
intervals
% Achieving Minimal Manifestations or
better (MGFA Post-Intervention Status)
% Taking prednisone dose of:
24 mos on MMF:
>70% achieved MM or better
More than 95% were taking <20 mg/d prednisone;
60% were taking <7.5 mg/d
50% were off prednisone altogether
This is not
consistent with the
natural history of
untreated MG.
Comments: MMF in AChR-ab + MG
Limitations:
Retrospective, observational study, subject to observer
bias
Inclusion was subject to selection bias
Strengths:
Large, comprehensive cohort
Long follow-up
Consistent evaluation by experienced observers, using
standardized assessment tools
Rigorous, accepted criteria of response
Conclusions: MMF in AChR-ab + MG
The MMF trials were limited by their short
duration and by the doses and schedule of
prednisone tapering.
Longer steroid sparing studies or a placebo
study would be necessary to demonstrate
efficacy of MMF in MG.
It may be feasible to do a placebo-controlled
study of MMF (or other agents) in new-onset,
mild-to-moderate MG.