Study design

REGAIN was a 26-week, phase 3, randomized, double-blind, placebo-controlled study evaluating eculizumab efficacy and safety [17]. Briefly, patients were randomized 1:1 to receive eculizumab (n = 62; induction: 900 mg for 4 weeks; maintenance: 1200 mg at week 4 and then every 2 weeks until week 26) or placebo (n = 63) [17]. The primary endpoint was the change in MG-ADL total score with eculizumab versus placebo.

The Neuro-QOL Fatigue subscale was used to assess fatigue, and the MG-ADL, QMG, and MG-QOL15 scales were used to measure MG-specific activities of daily living, muscle strength, and quality of life, respectively. In REGAIN, all assessments were performed at baseline (day 1), every 4 weeks to week 20, and at week 26. MG-ADL and QMG assessments were also conducted at weeks 1, 2, and 3. Details of scoring for MG-ADL, QMG, and MG-QOL15 during REGAIN have been reported previously; briefly, for each measure, a reduction from baseline total score indicates improvement [17]. The response scale for Neuro-QOL Fatigue items was: 1 = never; 2 = rarely; 3 = sometimes; 4 = often; and 5 = always. The range of potential total scores was 19–95. Higher Neuro-QOL Fatigue subscale total scores indicate greater fatigue; a reduction from baseline total score indicates improvement [15].

Patients who completed REGAIN could enroll into the extension study [18]. Following a 4-week blinded induction phase, all patients received open-label eculizumab (1200 mg) at week 4 and every 2 weeks thereafter. Assessments occurred as in REGAIN to week 26, then at week 40, week 52, and every 6 months [18].