PMID-38856224 — Sanyal SYNERGY-NASH: Tirzepatide for MASH (Phase 2)

[DRAFT — authored 2026-04-18. Requires Medical Director review.]

Citation

Loomba R, Hartman ML, Lawitz EJ, Vuppalanchi R, Boursier J, Bugianesi E, Yoneda M, Behling C, Cummings OW, Tang Y, Brouwers B, Robins DA, Nikooie A, Bunck MC, Haupt A, Sanyal AJ, on behalf of the SYNERGY-NASH Investigators. Tirzepatide for Metabolic Dysfunction-Associated Steatohepatitis with Liver Fibrosis. N Engl J Med. 2024;391(4):299-310. doi: 10.1056/NEJMoa2401943. PMID: 38856224.

Study Design

Phase: 2
Design: Multicenter, randomized, double-blind, placebo-controlled
Randomization: 1:1:1:1 to tirzepatide 5 mg, 10 mg, 15 mg weekly SC, or placebo
Duration: 52 weeks
N: 190 participants
Setting: Multinational hepatology and endocrinology centers

Population

Adults with biopsy-confirmed metabolic dysfunction-associated steatohepatitis (MASH, formerly NASH) with moderate-to-severe fibrosis (F2 or F3)
Mean age 54, approximately 58% women, 42% with T2D
Biopsy-based diagnosis required at entry

Intervention

Tirzepatide: 5 mg, 10 mg, or 15 mg weekly SC, titrated
Placebo: Matching weekly SC injection
Background standard-of-care liver and metabolic management continued

Outcomes

Primary — Resolution of MASH without worsening of fibrosis at 52 weeks

Placebo: 10%
Tirzepatide 5 mg: 44%
Tirzepatide 10 mg: 56%
Tirzepatide 15 mg: 62%
All tirzepatide doses superior to placebo (P<0.001)

Key Secondary

Fibrosis improvement ≥1 stage without worsening of MASH: 30% placebo vs 51% (5 mg), 51% (10 mg), 51% (15 mg) — numerical improvement, not all statistically significant at all doses.
Body weight: Tirzepatide 15 mg -15.6% vs placebo -1.1%
HbA1c: Improved in T2D subgroup across all tirzepatide arms
Liver-specific biomarkers (ALT, AST, PRO-C3, ELF): Dose-responsive improvement

Key Findings

SYNERGY-NASH is the first Phase 2 trial of a GLP-1/GIP dual agonist in biopsy-proven MASH with fibrosis to demonstrate substantial MASH resolution. The 62% resolution rate at 15 mg is competitive with or superior to the resmetirom FDA-approved approach (approximately 30% MASH resolution in MAESTRO-NASH), though cross-trial comparison is indirect.

Clinical implications:

Tirzepatide exerts MASH-specific hepatoprotective effects beyond weight reduction alone — fibrosis improvement was dose-responsive.
Positions tirzepatide as a credible candidate for expanded MASH indication, pending Phase 3 confirmation.
Supports the hypothesis that GLP-1/GIP dual agonism targets multiple pathways relevant to MASH pathophysiology (weight, insulin resistance, inflammation, direct hepatic effects).

Mechanistic interpretation:

Weight-loss-mediated hepatic fat reduction accounts for part of the benefit.
Additional mechanisms likely include: improved insulin sensitivity, reduced de novo lipogenesis, anti-inflammatory cytokine modulation, and potential direct hepatocyte signaling.

Safety Profile

GI adverse events: Class-consistent — nausea, vomiting, diarrhea, dose-dependent
Discontinuation due to adverse events: Low across all arms
Hepatic: No drug-induced liver injury signal; ALT/AST improvements consistent with MASH resolution
Gallbladder events: Low incidence; rapid weight loss is the principal risk factor
No new unexpected safety signals beyond known tirzepatide profile

Regulatory Status (as of April 2026)

Tirzepatide does not yet carry a MASH indication on US label.
Phase 3 programs for MASH indication in active development (SYNERGY-NASH extension, dedicated Phase 3).
Guideline committees (AASLD, ADA, EASD) beginning to acknowledge tirzepatide as a credible therapeutic option for obesity + MASH pending Phase 3 confirmation.

Relationship to Other MASH Trials

Semaglutide: Newsome PN et al., N Engl J Med 2021;384:1113-1124 (PMID: 33185364) — semaglutide 0.4 mg daily in MASH; 59% MASH resolution at 72 weeks; no significant fibrosis improvement. Tirzepatide data suggests additional benefit on fibrosis.
Resmetirom: First FDA-approved MASH drug (March 2024); thyroid hormone receptor-β agonist; distinct mechanism.
Survodutide: PMID-38847460 – Survodutide Phase 2 MASH and Fibrosis Trial — GLP-1/glucagon dual agonist; also demonstrated Phase 2 MASH efficacy.

Limitations (Author-acknowledged)

Phase 2 sample size (n=190) limits power for secondary endpoints
52-week duration; long-term histologic durability not yet demonstrated
No head-to-head vs resmetirom or semaglutide
Biopsy-based endpoint has inter-reader variability (central read used)
Generalizability to non-biopsied but clinically diagnosed MASH pending Phase 3

Evidence Level

Level Ib (Oxford CEBM) — adequately-powered Phase 2 RCT with biopsy-based primary endpoint. Phase 3 confirmation pending.

Linked Peptides

Tirzepatide

Related Studies

Orchestrator Notes

Funded by Eli Lilly.
Published online June 8, 2024; accompanying editorial commentary.
Senior author Sanyal AJ is a leading MASH clinical investigator.
Lesson 5.3 (tirzepatide deep-dive) should cite this as the MASH evidence anchor.
Reference correction: earlier Phase 1 manifest entry for "Sanyal MASLD" was inconsistently attributed. The correct attribution: Loomba R et al. (first author) with Sanyal AJ as senior/corresponding author. Cite as "Loomba & Sanyal" or "SYNERGY-NASH (Loomba et al.)" per venue convention.

PMID-38856224 – Sanyal Tirzepatide MASH Phase 2 SYNERGY-NASH