# Emugrobart

> A "sweeping" anti-myostatin antibody (Roche/Chugai) that not only blocks but actively clears myostatin — a cautionary case after its rare-disease trials failed.

- Also known as: GYM-329, RG6237, RG-70240
- Class: Growth Hormone, Metabolic
- FDA approved: No
- Canonical page: https://www.americanpeptide.com/catalog/emugrobart

## Overview

Emugrobart is a humanized IgG1 monoclonal antibody developed by Chugai and Roche, and it is the most mechanistically distinctive entry on the myostatin axis. Beyond binding pro- and latent myostatin to block their activation, it uses a "sweeping antibody" design: pH-dependent binding that ferries captured myostatin into cells for degradation and then releases it, recycling the antibody to capture more. The intent is not just to block myostatin but to actively lower its levels.

Emugrobart is also the catalog’s clearest honest-evidence cautionary tale. Its lead muscular-disease programs failed: in March 2026, Roche/Genentech discontinued development in spinal muscular atrophy (SMA) and facioscapulohumeral muscular dystrophy (FSHD) after the MANATEE trial showed no consistent benefit over risdiplam monotherapy. Notably, the company stated that the scientific rationale in obesity remained, and the Phase 2 obesity program was set to continue.

That split — a failed rare-disease readout but a continuing metabolic program — is exactly the kind of nuance a credible reference should carry, against the marketing that treats every "myostatin antibody" as a guaranteed muscle-builder. Emugrobart is an investigational antibody (~150 kDa); its sweeping-clearance design is its scientific signature.

## Mechanism

Binds pro/latent myostatin to prevent activation, and via pH-dependent (recycling/sweeping) engineering accelerates clearance of bound myostatin — reducing the circulating pool rather than only neutralizing it in place.

## Chemistry

| Property | Value |
| --- | --- |
| Molecular weight | 150000 Da |

## Research areas

Studied in: Spinal muscular atrophy, FSHD, Obesity, Muscle preservation.

Guides on this site:

- [Weight Loss & Metabolic Health](https://www.americanpeptide.com/research-areas/weight-loss): Incretin and metabolic peptides studied for glycemic control and fat loss.

## Key research

- Sweeping/recycling design — pH-dependent binding actively clears myostatin rather than only blocking it.
- MANATEE failure — discontinued in SMA and FSHD (March 2026) after no consistent benefit over risdiplam.
- Obesity program continued — the metabolic rationale was retained even as rare-disease use was dropped.
- Pro/latent myostatin target — binds the inactive precursor forms.
- Investigational — not FDA-approved.

## Storage, handling & synthesis

**Storage.** Stored refrigerated (2–8 °C), protected from light and freezing, not shaken; investigational handling per trial protocol.

**Handling.** A large glycosylated antibody sensitive to freezing, heat, and agitation, which can cause aggregation.

**Synthesis.** Emugrobart is a humanized IgG1 monoclonal antibody (~150 kDa) produced in mammalian cell culture, engineered for pH-dependent recycling. Characterization is antibody-grade (glycan/charge-variant profiling, mass spectrometry, binding/potency bioassay) — not a synthetic peptide.

## FAQs

### What is emugrobart?

A Roche/Chugai anti-myostatin antibody (GYM-329) with a "sweeping" design that actively clears myostatin. It was studied in muscular diseases and obesity.

### What happened in its trials?

Its spinal muscular atrophy and FSHD programs were discontinued in March 2026 after the MANATEE trial showed no consistent benefit over standard therapy; the obesity program was reported to be continuing.

### Is this medical advice?

No — this is a research and educational reference. Emugrobart is an investigational antibody, not an approved drug.

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Source: AmericanPeptide.com — https://www.americanpeptide.com/catalog/emugrobart
Data license: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Attribution: AmericanPeptide.com.
Research reference only — computational and educational content, not medical advice.