Roche Ends Emugrobart Obesity Program, Returns Anti-Myostatin Antibody Rights to Chugai
核心洞察
Chugai said Roche will discontinue development of the anti-latent myostatin (搜索) antibody emugrobart (搜索) in obesity (搜索) and return all licensed rights to the Japanese originator.
The decision followed an interim analysis of the Phase II GYMINDA study testing emugrobart (搜索) plus GLP-1/GIP receptor (搜索) agonists in patients with obesity (搜索) or overweight.
Chugai concluded that clinically meaningful weight loss was unlikely to be achieved, though emugrobart (搜索) was well tolerated with no new safety signals.
Chugai Pharmaceutical has announced that clinical development of emugrobart (搜索) (GYM329) for obesity (搜索) will be discontinued and that Roche, which had licensed the drug, will end all future development of the subcutaneously administered anti-latent myostatin (搜索) sweeping antibody. All rights previously licensed to Roche will return to Chugai, which has begun preparing to resume development in spinal muscular atrophy (搜索) (SMA) while considering out-licensing opportunities.
The decision followed a comprehensive assessment of data obtained to date, including an interim analysis from the ongoing Phase II GYMINDA study. In that trial, emugrobart (搜索) was evaluated in combination with GLP-1/GIP receptor (搜索) agonists in patients with obesity (搜索) or overweight. Chugai said it concluded that achieving the pre-specified efficacy objectives of clinically meaningful weight loss is unlikely.
Emugrobart (搜索) was well tolerated in the study and no new safety signals were observed, according to Chugai.
A myostatin approach aimed at preserving muscle
Emugrobart (搜索) belongs to a group of myostatin (搜索)-targeting therapies in development that are designed to promote muscle growth in obesity (搜索), offsetting the loss of muscle mass that can accompany current weight-loss drugs. The antibody was described as a potential best-in-class myostatin inhibitor because, unlike other antibodies that bind the mature, active form of the protein, it targets the inactive (latent) and precursor forms. That mechanism cuts off myostatin activity without affecting similar proteins in the TGF-beta family such as GDF11 (搜索) or activin A, which was expected to improve efficacy and reduce side effects relative to active myostatin-targeting drugs such as Scholar Rock's apitegromab, Biohaven Pharma's taldefgrobep alfa and Eli Lilly's bimagrumab.
The obesity (搜索) setback follows the earlier collapse of other emugrobart (搜索) programs. In March 2026, Roche announced discontinuation of clinical development of emugrobart for SMA and for facioscapulohumeral muscular dystrophy (搜索) (FSHD). With the end of the obesity program, Roche has surrendered all interests in the drug.
Chugai revives an SMA path
Chugai said that based on emugrobart (搜索)'s subcutaneous administration, its obtained safety profile, pharmacodynamics, clinical signals including long-term data, and Phase III study design modifications, it has identified an opportunity to support a Phase III study in SMA. The company has initiated preparations to resume development and is also exploring potential out-licensing opportunities with third parties.
"Chugai will continue to evaluate the potential of emugrobart (搜索) to offer a new treatment option for patients with SMA and will determine the next steps for development with the aim of delivering innovative medicines to patients as rapidly as possible," the company said.
Chugai added that it is focusing on anti-obesity (搜索) drug discovery research across multiple modalities, with plans to advance several development candidates into clinical trials over the next few years, aiming to address unmet medical needs in current anti-obesity treatments.
Roche's remaining obesity pipeline
Roche has made weight-loss and obesity (搜索) drug development a key part of its R&D strategy, with several candidates in clinical development and an ambition to become a top three player in a category currently dominated by Novo and Eli Lilly. Its pipeline includes the injectable GIP/GLP-1 agonist enicepatide (搜索), the injectable amylin analogue petrelintide and the oral GLP-1 agonist CT-996, all in late-stage clinical development and among roughly 20 new products Roche hopes to launch by the end of the decade.
Chugai said the emugrobart (搜索) announcement is not expected to have an impact on its consolidated financial forecast for the fiscal year ending December 2026, which was announced on January 29, 2026.