LUMINESCE
Safety and efficacy of satralizumab in patients with generalised myasthenia gravis (LUMINESCE): a randomised, double-blind, multicentre, placebo-controlled phase 3 trial
Clinical Question
Is satralizumab, an IL-6 receptor inhibitor, safe and effective for treating seropositive generalised myasthenia gravis compared to placebo?
Study Overview
Objective
To assess the safety and efficacy of satralizumab, a humanised monoclonal antibody targeting the IL-6 receptor, in patients with seropositive generalised myasthenia gravis
Study Summary
- Satralizumab showed statistically significant but small improvement in MG-ADL score vs placebo at week 24 (difference −1.02 points, p=0.020)
- Improvement observed as early as week 4 and sustained through week 24, but effect size was modest
- Satralizumab was well-tolerated with a safety profile similar to placebo; no deaths or adverse events of special interest
Intervention
Satralizumab 120 mg (≤100 kg) or 180 mg (>100 kg) subcutaneously at weeks 0, 2, 4, then every 4 weeks vs placebo
Patients per Arm
Satralizumab: 96, Placebo: 92 (mITT: 86 vs 80 AChR-IgG+)
Bottom Line
Satralizumab was well tolerated and resulted in statistically significant but small improvements in MG-ADL and QMG scores at week 24 in AChR-IgG-positive generalised myasthenia gravis patients. However, the effect size was modest, and no difference was seen in quality of life measures. The sponsor halted further development for this indication.
Major Points
- Primary endpoint met: Satralizumab significantly improved MG-ADL score vs placebo at week 24 (difference −1.02; 95% CI −1.88 to −0.16; p=0.020)
- QMG score also showed significant improvement (difference −1.63; p=0.0062)
- Response observed as early as week 4 and sustained through week 24
- No significant difference in MG-QoL15r total score (p=0.11), breaking the hierarchical testing
- 48% of satralizumab patients achieved ≥3-point QMG reduction vs 29% placebo
- Safety profile similar to placebo with no deaths or adverse events of special interest
- Open-label extension terminated early due to sponsor's decision to halt further development
- IL-6 receptor occupancy >95% achieved across bodyweight ranges
Design
Study Type: Randomized, double-blind, placebo-controlled, multicentre, phase 3 trial
Randomization: 1
Blinding: Double-blind; sponsor, investigators, and patients masked; prefilled syringes identical in appearance; dual-assessor approach with separate treating (safety) and examining (efficacy) investigators
Enrollment Period: October 19, 2021 to August 15, 2023
Follow-up Duration: 24 weeks double-blind period (plus optional 2-year open-label extension, terminated early)
Centers: 105
Countries: Multiple countries across Europe, North America, South America, Australia, Asia
Sample Size: 188
Analysis: ANCOVA model adjusting for treatment group, visit, stratification factors, and baseline score; mixed model repeated measures for missing data imputation; jackknife technique for variance correction; hierarchical gatekeeping for multiplicity; two-sided α=0.05; 85% power for sample size of 160 AChR-IgG+ patients
Inclusion Criteria
- Age ≥12 years
- Diagnosis of seropositive generalised myasthenia gravis (AChR-IgG, MuSK-IgG, or LRP4-IgG positive)
- MGFA severity class II-IV at screening
- MG-ADL score ≥5 with >50% attributed to non-ocular symptoms
- Receiving stable-dose background therapy: acetylcholinesterase inhibitors (stable 2 weeks), oral corticosteroids (stable 4 weeks, ≤30 mg/day), azathioprine (treatment ≥6 months, stable 2 months), or ciclosporine/tacrolimus/mycophenolate (≥3 months treatment, stable 4 weeks)
Exclusion Criteria
- History of thymectomy within 6 months before screening
- Ocular myasthenia gravis (MGFA class I)
- Myasthenic crisis within 3 months before screening (MGFA class V)
- Any known disease that would interfere with the study (e.g., severe rheumatoid arthritis, symptomatic thyroid disease)
- IVIG or SCIG within 6 weeks before randomisation
- Plasma exchange within 8 weeks before randomisation
Arms
| Field | Satralizumab | Control |
|---|---|---|
| Intervention | Subcutaneous satralizumab: 120 mg for bodyweight ≤100 kg or 180 mg for bodyweight >100 kg at weeks 0, 2, 4, and every 4 weeks thereafter until week 24, plus stable background therapy | Matched placebo subcutaneous injection at weeks 0, 2, 4, and every 4 weeks thereafter until week 24, plus stable background therapy |
| Duration | 24 weeks | 24 weeks |
Outcomes
| Outcome | Type | Control | Intervention | HR / OR / RR | P-value |
|---|---|---|---|---|---|
| Mean change from baseline in total MG-ADL score at week 24 in AChR-IgG-positive patients (modified intention-to-treat population) | Primary | −2.57 (SE 0.35; 95% CI −3.25 to −1.88) | −3.59 (SE 0.29; 95% CI −4.15 to −3.02) | 0.020 | |
| Mean change from baseline in QMG score at week 24 (AChR-IgG+) | Difference: −1.63 (SE 0.60; 95% CI −2.80 to −0.46) | Secondary | −1.78 (SE 0.46; 95% CI −2.67 to −0.88) | −3.41 (SE 0.41; 95% CI −4.21 to −2.61) | 0.0062 | |
| Mean change from baseline in MG-QoL15r total score at week 24 (AChR-IgG+) | Difference: −1.51 (SE 0.94; 95% CI −3.36 to 0.34) | Secondary | −4.69 (SE 0.71; 95% CI −6.09 to −3.30) | −6.20 (SE 0.69; 95% CI −7.56 to −4.85) | 0.11 (not significant - hierarchy broken) | |
| Mean change from baseline in MGC total score at week 24 (AChR-IgG+) | Difference: −2.99 (SE 0.81; 95% CI −4.57 to −1.41) | Secondary | −4.14 (SE 0.62; 95% CI −5.35 to −2.92) | −7.13 (SE 0.58; 95% CI −8.27 to −5.99) | Not inferential (hierarchy broken) | |
| Proportion receiving rescue therapy | Difference: −6.77% (95% CI −17.25 to 3.70) | Secondary | 13.8% (11 patients; 95% CI 5.58-21.92) | 7.0% (6 patients; 95% CI 1.01-12.94) | Not inferential (hierarchy broken) | |
| Mean change from baseline in Neuro-QoL Fatigue subscale at week 24 | Difference: −2.20 (SE 1.10; 95% CI −4.36 to −0.04) | Secondary | −3.29 (SE 0.90; 95% CI −5.05 to −1.53) | −5.50 (SE 0.75; 95% CI −6.97 to −4.02) | Not inferential (hierarchy broken) | |
| ≥2-point reduction in MG-ADL at week 24 (responder analysis) | Difference: −12.7% (95% CI −27.3 to 1.9) | Secondary | 59% (47 patients) | 71% (61 patients) | ||
| ≥3-point reduction in QMG at week 24 (responder analysis) | Difference: −18.7% (95% CI −33.5 to −3.9) | Secondary | 29% (23 patients) | 48% (41 patients) | ||
| Minimal symptom expression (MG-ADL 0-1) at week 24 | Difference: −1.7% (95% CI −19.4 to 15.9) | Secondary | 13% (10 patients) | 14% (12 patients) | ||
| Any adverse event | Adverse | 73% (67/92 patients; 261 events) | 90% (86/96 patients; 286 events) | ||
| AEs related to study treatment | Adverse | 22% (20/92 patients; 47 events) | 47% (45/96 patients; 102 events) | ||
| AEs leading to discontinuation | Adverse | 1% (1/92 patients) | 2% (2/96 patients) | ||
| Serious adverse events | Adverse | 7% (6/92 patients; 9 events) | 3% (3/96 patients; 3 events) | ||
| Serious AEs related to study treatment | Adverse | 0% | 2% (2/96 patients) | ||
| Infections | Adverse | 42% (39/92 patients; 59 events) | 45% (43/96 patients; 56 events) | ||
| Serious infections | Adverse | 4% (4/92 patients; 4 events) | 2% (2/96 patients; 2 events) | ||
| Injection-related reactions | Adverse | 7% (6/92 patients; 18 events) | 15% (14/96 patients; 39 events) | ||
| Headache | Adverse | 10% (9/92) | 9% (9/96) | ||
| COVID-19 | Adverse | 10% (9/92) | 13% (12/96) | ||
| Upper respiratory tract infection | Adverse | 9% (8/92) | 6% (6/96) | ||
| Urinary tract infection | Adverse | 7% (6/92) | 5% (5/96) | ||
| Deaths | Adverse | 0% | 0% | ||
| Adverse events of special interest | Adverse | 0% | 0% |
Subgroup Analysis
Subgroup analyses for the primary endpoint showed consistent but small improvements in MG-ADL score with satralizumab compared with placebo across baseline and demographic characteristics including sex, age at diagnosis, race, region, background therapy, baseline disease severity, and dose level. No significant difference was observed in MuSK-IgG-positive patients (n=16), though the study was not powered for this subgroup. Only one LRP4-IgG-positive patient was randomised to satralizumab, precluding independent evaluation.
Criticisms
- Effect size was small (MG-ADL difference of −1.02 points) with uncertain clinical meaningfulness
- MG-QoL15r endpoint not significant (p=0.11), breaking the hierarchical testing and limiting inferences for downstream endpoints
- No further improvement observed during open-label extension beyond week 24 effect
- Imbalance in refractory MG at baseline (52% placebo vs 38% satralizumab)
- Underpowered for MuSK-IgG-positive and LRP4-IgG-positive subgroups
- Only 3 adolescent patients enrolled, precluding efficacy/safety assessment in this age group
- Limited North American representation (10 patients total) with only 2 Black patients
- Sponsor terminated open-label extension and halted further development for this indication
- Cross-trial comparisons with C5 inhibitors and FcRn antagonists difficult due to design differences
- 24-week duration may not capture long-term efficacy and durability of response
Funding
F Hoffmann La Roche
Based on: LUMINESCE (Lancet Neurology, 2025)
Authors: Ali A Habib, Chongbo Zhao, Inmaculada Aban, ..., Hiroyuki Murai
Citation: Lancet Neurol 2025; 24: 117–27
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