We aimed to compare patient-reported and clinician-reported outcomes in 1. MG patients receiving azathioprine (AZT) vs. mycophenolate mofetil (MMF); 2. Patients receiving adequate doses and duration of AZT or MMF vs. not receiving adequate doses/duration.

PROMISE-MG is the first comparative effectiveness study of MG immunosuppressive treatments.

One hundred and sixty-seven patients were enrolled. Eighty-two received either MMF or AZT. A similar proportion of participants receiving either treatment had clinically meaningful improvement in MGQOL-15r (≥5 point reduction: MMF -75%, AZT -65%,  weighted difference 3% favoring MMF, 95% CI -22% to 15.8%, p=0.8, mean difference in maximum improvement 2.6 points favoring MMF, CI 0.42 to 4.85, p=0.02). Two percent more participants receiving MMF achieved the co-primary outcome measure (95% CI -15% to 19%, p=0.8). The proportion of participants achieving meaningful improvement in MG-QOL15r were similar in those who did or did not receive adequate treatment dose/duration (71% v. 70.6%,  weighted difference in proportions 5% favoring MMF, 95% CI -24% to 14%, p=0.6).

Patients receiving either MMF or AZT achieved clinically meaningful improvements, and there was no difference between them. Those who received adequate dose/duration of these drugs achieved similar improvement to those who did not. Further analyses will evaluate secondary outcomes, adverse effects of AZT/MMF and the effective doses of these agents in real-world practice.

Narayanaswami and  Sanders contributed equally