Domagrozumab
Pfizer's anti-myostatin monoclonal antibody — Phase 2 in DMD discontinued in 2018 after the trial missed its primary endpoint.
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At a glance
A second-generation anti-myostatin antibody from Pfizer, structurally distinct from stamulumab and tested in pediatric Duchenne muscular dystrophy. Discontinued in 2018 after Phase 2 readouts did not show benefit on the four-stair-climb endpoint.
- Class
- Anti-myostatin monoclonal antibody
- Sponsor
- Pfizer
- Stage
- Phase 2 (discontinued 2018)
- Lead use case
- Duchenne muscular dystrophy (DMD)
What it is
Domagrozumab (PF-06252616) is a humanized monoclonal antibody that binds and neutralizes mature myostatin. It was Pfizer's second major anti-myostatin program after the Wyeth-era stamulumab work and represented an attempt to revisit direct myostatin neutralization in a younger patient population (pediatric DMD) where preserved regenerative capacity might allow myostatin blockade to translate into functional benefit.
Current research status
Pfizer advanced domagrozumab through Phase 1 and into a Phase 2 trial of approximately 120 ambulatory boys with Duchenne muscular dystrophy. The program was discontinued in August 2018 after the Phase 2 trial did not show statistically significant benefit on the primary endpoint — the four-stair-climb time at 49 weeks — compared to placebo. Pfizer ended the program and has not pursued further anti-myostatin antibody development since.
Mechanistic rationale
Direct binding and neutralization of mature myostatin, preventing receptor engagement and the downstream Smad2/3 signaling that suppresses muscle protein synthesis. Mechanistically similar in approach to stamulumab but with a distinct molecular structure designed for improved pharmacokinetics and target engagement.
Available evidence
Phase 2 DMD trial (PF-06252616, Wagner et al., Neurology 2020) — 120 ambulatory boys with DMD received domagrozumab or placebo over 48 weeks. The drug was generally well tolerated. However, the primary endpoint (four-stair-climb time) did not show statistically significant improvement compared to placebo, and the program was discontinued.[1]
Target engagement was confirmed pharmacologically — myostatin levels were appropriately reduced — but the engagement did not translate into clinical functional benefit on the specified endpoint.
Why it's interesting
Domagrozumab is the second major data point — after stamulumab — establishing that direct myostatin neutralization alone may not produce meaningful clinical benefit in muscular dystrophy patients, even in younger populations with more preserved regenerative capacity. This reading drove the field's pivot toward (a) different selectivity profiles (apitegromab's latent-myostatin selectivity), (b) different target ligands (bimagrumab's ActRIIB receptor blockade), and (c) different patient populations (GLP-1-induced muscle loss in healthy obese adults rather than dystrophic muscle).
Limitations & risks
The molecule has been discontinued and is not in active development. Like stamulumab, its current relevance is primarily historical — but the historical lesson is important for understanding where the active myostatin-pathway programs have positioned themselves.
Community discussion notes
Like stamulumab, domagrozumab is rarely discussed in contemporary biohacker or fitness communities — the conversation has moved on to bimagrumab and apitegromab. Academic reviews cite it as a key data point in the field's evolution from direct ligand neutralization toward more selective and receptor-targeted approaches.
The takeaway
Domagrozumab is a discontinued Phase 2 anti-myostatin antibody whose negative DMD readout, alongside stamulumab's earlier negative result, reshaped the entire field's strategic positioning. For active myostatin-pathway therapeutics, look to the selective successors (apitegromab, bimagrumab, trevogrumab); for understanding why the field looks the way it does, domagrozumab is part of the foundational history.
References
- Wagner KR, et al. A phase 2, randomized, placebo-controlled trial of domagrozumab in ambulatory boys with Duchenne muscular dystrophy. Neurology. 2020;94(13):e1373-e1383. https://pubmed.ncbi.nlm.nih.gov/32139502/
- Bhattacharya I, et al. A randomized, double-blind, placebo-controlled phase 1 study of domagrozumab. Clin Pharmacol Drug Dev. 2018;7(5):484-493. https://pubmed.ncbi.nlm.nih.gov/29361199/