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Batoclimab MG

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Year of Publication: 2024

Journal: JAMA Neurology

Link: https://doi.org/10.1001/jamaneurol.2024.0044

PDF: https://jamanetwork.com/journals/jamaneu...article/2816254

Clinical Question

Does the FcRn inhibitor batoclimab improve MG-ADL in patients with generalized myasthenia gravis compared with placebo?

Bottom Line

In 131 antibody-positive patients with generalized MG randomized to batoclimab 680 mg SC weekly x6 or placebo, sustained MG-ADL improvement (≥3-point reduction for ≥4 consecutive weeks) occurred in 58.2% vs 31.3% (OR 3.45; 95% CI 1.62-7.35; p=0.001). Batoclimab is the third FcRn inhibitor to show efficacy in generalized MG after efgartigimod and rozanolixizumab, with similar magnitude of IgG reduction and clinical benefit.

        Major Points
        Phase 3 multicenter double-blind placebo-controlled RCT at 27 centers in China (Yan & Zhao 2024, JAMA Neurology)
N=132 adults with generalized myasthenia gravis, MGFA IIa-IVa, MG-ADL ≥5; 131 antibody-positive
Randomized 1:1 to batoclimab 680 mg SC weekly for 6 weeks per cycle vs placebo; up to 2 cycles (24 weeks)
Primary endpoint: sustained MG-ADL improvement (≥3-point reduction for ≥4 consecutive weeks) in Ab+ patients
Primary met: 58.2% batoclimab vs 31.3% placebo; OR 3.45 (95% CI 1.62-7.35); p=0.001
Max MG-ADL reduction at day 43: -3.6 vs -1.7; difference -1.9 (95% CI -2.8 to -1.0); p<0.001
Total IgG reduced ~75% at peak with batoclimab; AChR/MuSK antibody titers similarly reduced
Onset of separation from placebo visible by week 2 — rapid onset typical of FcRn inhibitors
TRAEs 70.1% batoclimab vs 36.9% placebo; severe TEAEs 3.0% vs 7.7%; no treatment-related SAEs
Key class-effect AEs: hypercholesterolemia and hypoalbuminemia (reversible)
Third FcRn inhibitor with phase 3 evidence in MG after efgartigimod (ADAPT) and rozanolixizumab (MycarinG)
Single-ethnicity (Chinese Han) cohort limits generalizability

      

Design

Study Type: Phase 3 multicenter randomized double-blind placebo-controlled parallel-group trial

Randomization: 1

Blinding: Double-blind

Follow-up Duration: Up to 24 weeks (two 10-week cycles)

Sample Size: 132

Analyzed: 131

Analysis: ITT with logistic regression for dichotomous outcomes; Hwang-Shih-DeCani alpha spending

Baseline Characteristics

Characteristic	Control	Active
N	65	67
Age mean	~43.8	~43.8
Female	~67%	~67%
AChR+	Majority	Majority
MGFA IIa-IVa	Yes	Yes
MG-ADL baseline	≥5	≥5

Arms

Field	Control	Batoclimab
N	65	67
Intervention	Matching placebo SC injection weekly for 6 weeks per cycle + standard of care	Batoclimab 680 mg SC weekly for 6 weeks per cycle + standard of care
Duration	Up to 2 cycles (24 weeks total)	Up to 2 cycles (24 weeks total)

Outcomes

Outcome	Type	Control	Intervention	HR / OR / RR	P-value
Sustained MG-ADL improvement (≥3-point reduction, ≥4 consecutive weeks) in antibody-positive patients during cycle 1	Primary	31.3% (20/64)	58.2% (39/67)		p=0.001
Max MG-ADL reduction at day 43	Secondary	-1.7 (SE 0.3)	-3.6 (SE 0.3)	Diff -1.9 (95% CI -2.8 to -1.0)	nominal p<0.001
Total IgG reduction (peak)	Secondary	~No change	~75% reduction		Highly significant
AChR/MuSK antibody reduction	Secondary	~No change	Parallel to total IgG		Significant
Sustained QMG improvement (≥3-point, ≥4 weeks)	Secondary	Lower	Higher	Favorable	Favored batoclimab
Minimal symptom expression (MG-ADL 0-1)	Secondary	Low rate	Higher rate		Favored batoclimab
Early MG-ADL improvement (within 2 weeks)	Secondary	Less common	More common		Rapid onset
Any TRAE	Adverse	36.9% (24/65)	70.1% (47/67)		Higher with batoclimab
Severe TEAE	Adverse	7.7% (5/65)	3.0% (2/67)		Lower with batoclimab
Hypercholesterolemia / LDL elevation	Adverse	Low	Common (FcRn class effect)		Drug-specific
Hypoalbuminemia	Adverse	Low	Common		Drug-specific (reversible)
Injection-site reactions	Adverse	Low	Modest increase		Expected for SC
Headache	Adverse	Low	Slightly higher		Common
Infections (any)	Adverse	Similar	Similar		No increased infection signal
Discontinuation for AE	Adverse	2/65 (3.1%)	1/67 (1.5%)		Similar
Treatment-related SAE	Adverse	None	None		No TR-SAE in either arm

Subgroup Analysis

Effect consistent across prespecified subgroups (age <65 vs ≥65, sex, body weight, MGFA class, baseline glucocorticoid use). Only Chinese Han patients enrolled — limits generalizability. Separation in MG-ADL began by week 2, with peak effect around day 43 (1 week post last dose). Second cycle was needed in most responders, reflecting the waxing IgG recovery between cycles (typical FcRn inhibitor pharmacodynamics).

Criticisms

Single-ethnicity (Chinese Han) cohort — generalizability to other populations uncertain; FcRn biology should be conserved but immunologic context may differ
Relatively modest N (131 Ab+) compared with ADAPT (efgartigimod N=167) and MycarinG (rozanolixizumab N=200)
Comparison to efgartigimod/rozanolixizumab is indirect — no head-to-head; network meta-analysis suggests similar efficacy
Only includes antibody-positive patients in primary analysis — ~10% seronegative MG not addressed
Hypercholesterolemia and hypoalbuminemia are class-effect AEs requiring long-term monitoring — not fully characterized in 6-week cycles
Cost and access implications in Chinese healthcare system not addressed — pricing vs older therapies (PLEX, IVIG, rituximab) not discussed

Funding

Harbour BioMed (manufacturer of batoclimab)

Based on: Batoclimab MG (JAMA Neurology, 2024)

Content summarized and formatted by NeuroTrials.ai.

Batoclimab MG

(2024)

Objective

Batoclimab 680 mg SC weekly x6 per cycle — to evaluate an FcRn inhibitor for generalized myasthenia gravis in Chinese patients.

Study Summary

• Sustained MG-ADL improvement in 58.2% (batoclimab) vs 31.3% (placebo); OR 3.45 (95% CI 1.62-7.35); p=0.001.
• Mean maximum MG-ADL reduction at day 43: -3.6 (batoclimab) vs -1.7 (placebo); difference -1.9 (95% CI -2.8 to -1.0); p<0.001.
• Separation from placebo visible by week 2 — rapid onset consistent with other FcRn inhibitors.
• TRAEs: 70.1% batoclimab vs 36.9% placebo; severe TEAEs 3.0% vs 7.7% — mostly hypercholesterolemia and hypoalbuminemia.
• No treatment-related serious AEs reported; safety profile comparable to efgartigimod and rozanolixizumab.
• Positions batoclimab as a third SC FcRn inhibitor option for generalized MG, expanding the IgG-lowering therapeutic arsenal.

Intervention

Batoclimab 680 mg SC weekly for 6 weeks + 4-week observation per cycle; second cycle if retreatment criteria met (MG-ADL ≥5 or <3-point improvement, albumin ≥3 g/dL). Standard-of-care continued in both arms. Chinese Han ethnicity.

Inclusion Criteria

Adults ≥18 years with generalized MG, AChR or MuSK antibody positive, MGFA IIa-IVa, MG-ADL ≥5 (ocular <50% of score), QMG ≥11; stable SOC; China-only enrollment.

Study Design

Arms: Batoclimab 680 mg SC weekly vs Placebo SC weekly

Patients per Arm: Batoclimab 67 (Ab+); Placebo 64 (Ab+); total randomized N=132

Outcome

• Primary: Sustained MG-ADL improvement (≥3-point reduction, ≥4 consecutive weeks) in Ab+ patients cycle 1 — 58.2% (39/67) batoclimab vs 31.3% (20/64) placebo; OR 3.45 (95% CI 1.62-7.35); p=0.001
• Maximum MG-ADL reduction at day 43 (1 week post-last dose): -3.6 vs -1.7; group diff -1.9 (95% CI -2.8 to -1.0); nominal p<0.001
• Total IgG reduction: batoclimab ~75% peak vs no change placebo; AChR/MuSK antibodies similarly reduced
• QMG, MGC, MG-QOL15r all favored batoclimab (secondary endpoints, hierarchically tested)
• Discontinuation for AE: batoclimab 1/67 (1.5%), placebo 2/65 (3.1%)

Bottom Line

Major Points

Phase 3 multicenter double-blind placebo-controlled RCT at 27 centers in China (Yan & Zhao 2024, JAMA Neurology)
N=132 adults with generalized myasthenia gravis, MGFA IIa-IVa, MG-ADL ≥5; 131 antibody-positive
Randomized 1:1 to batoclimab 680 mg SC weekly for 6 weeks per cycle vs placebo; up to 2 cycles (24 weeks)
Primary endpoint: sustained MG-ADL improvement (≥3-point reduction for ≥4 consecutive weeks) in Ab+ patients
Primary met: 58.2% batoclimab vs 31.3% placebo; OR 3.45 (95% CI 1.62-7.35); p=0.001
Max MG-ADL reduction at day 43: -3.6 vs -1.7; difference -1.9 (95% CI -2.8 to -1.0); p<0.001
Total IgG reduced ~75% at peak with batoclimab; AChR/MuSK antibody titers similarly reduced
Onset of separation from placebo visible by week 2 — rapid onset typical of FcRn inhibitors
TRAEs 70.1% batoclimab vs 36.9% placebo; severe TEAEs 3.0% vs 7.7%; no treatment-related SAEs
Key class-effect AEs: hypercholesterolemia and hypoalbuminemia (reversible)
Third FcRn inhibitor with phase 3 evidence in MG after efgartigimod (ADAPT) and rozanolixizumab (MycarinG)
Single-ethnicity (Chinese Han) cohort limits generalizability

Study Design

Study Type: Phase 3 multicenter randomized double-blind placebo-controlled parallel-group trial
Randomization: Yes
Blinding: Double-blind
Sample Size: 132
Follow-up: Up to 24 weeks (two 10-week cycles)

Primary Outcome

Definition: Sustained MG-ADL improvement (≥3-point reduction, ≥4 consecutive weeks) in antibody-positive patients during cycle 1

Control	Intervention	HR/OR	P-value
31.3% (20/64)	58.2% (39/67)	- (1.62 to 7.35)	p=0.001

Limitations & Criticisms

Single-ethnicity (Chinese Han) cohort — generalizability to other populations uncertain; FcRn biology should be conserved but immunologic context may differ
Relatively modest N (131 Ab+) compared with ADAPT (efgartigimod N=167) and MycarinG (rozanolixizumab N=200)
Comparison to efgartigimod/rozanolixizumab is indirect — no head-to-head; network meta-analysis suggests similar efficacy
Only includes antibody-positive patients in primary analysis — ~10% seronegative MG not addressed
Hypercholesterolemia and hypoalbuminemia are class-effect AEs requiring long-term monitoring — not fully characterized in 6-week cycles
Cost and access implications in Chinese healthcare system not addressed — pricing vs older therapies (PLEX, IVIG, rituximab) not discussed

Citation

View Original Publication →

Batoclimab MG

Clinical Question

Bottom Line

Major Points

Design

Baseline Characteristics

Arms

Outcomes

Subgroup Analysis

Criticisms

Funding

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