Also known as SRK-015 · SRK-439
A monoclonal antibody that selectively blocks pro/latent myostatin — the muscle brake — studied to preserve lean mass during GLP-1 weight loss.
Apitegromab is a fully human monoclonal antibody (Scholar Rock) and the first of the anti-myostatin biologics in this catalog. Where myostatin is the growth factor that brakes muscle and follistatin is the body’s natural antagonist, apitegromab is an engineered antagonist: an antibody that binds the inactive precursor forms of myostatin (pro- and latent myostatin) and prevents their activation. Its selectivity for those precursors — rather than mature myostatin or the related GDF11/activins — is its defining design feature.
Apitegromab’s lead program is in spinal muscular atrophy (SMA), where it is added on top of SMN-targeted therapy to build motor-relevant muscle. The same mechanism underlies its forward-looking metabolic use: in the Phase 2 EMBRAZE study, adding apitegromab to tirzepatide preserved lean mass during weight loss compared with tirzepatide alone, and its precursor-selectivity was framed as a potential tolerability advantage over broader myostatin/activin blockers.
As a biologic it sits a full step beyond the protein hormones elsewhere in this catalog: it is an antibody (~150 kDa), produced in mammalian cells, designed to deplete a specific target. It is investigational — not an approved drug — and is included here as the antibody arm of the myostatin axis that myostatin and follistatin introduce.
Binds pro-myostatin and latent myostatin, blocking the proteolytic activation that releases mature, active myostatin. Lowering active myostatin disinhibits muscle growth via the ActRIIB/Smad pathway.
Behind every vial of Apitegromab is the same exacting pipeline every research peptide runs — but the chemistry plays out differently for this molecule. Here is how Apitegromab, specifically, is brought into being.
On paper, Apitegromab weighs in at roughly 150,000 daltons. Before a single bond is made, the target sequence, salt form, and purity threshold are written down as the contract the finished material must meet.
Apitegromab is assembled by solid-phase peptide synthesis — the chain grows one protected residue at a time on resin, and what you fail to build cleanly here you pay to remove later.
The crude mixture — Apitegromab plus its deletions and side products — is then separated on preparative HPLC, and where the cut is taken decides the difference between a genuinely pure peptide and a barely-passable one.
A real batch of Apitegromab proves itself: identity confirmed by mass spectrometry against its ~150,000 Da, purity read directly off an analytical HPLC trace, water and counterion content measured. That batch-specific certificate of analysis is the only honest way to know what is actually in a vial of Apitegromab — and a short, cold, accountable chain of custody is how that purity survives the trip to your bench.
Apitegromab is a recombinant monoclonal antibody (~150 kDa) produced in mammalian cell culture — the most complex biologic class in this catalog, far removed from solid-phase peptide synthesis. Characterization is antibody-grade: glycan and charge-variant profiling, identity by mass spectrometry, and target-binding/cell-based potency, with host-cell-protein and endotoxin limits.
Don't judge a vial by its cake. A fluffy, good-looking lyophilized powder reflects bulking agents and freeze-drying parameters — not purity. Insist on a batch-specific certificate of analysis.
Recent clinical trials and publications mentioning Apitegromab, pulled automatically from ClinicalTrials.gov and PubMed and refreshed daily. Listings are unfiltered search results, not curated endorsements.
A monoclonal antibody that selectively blocks the precursor forms of myostatin, the growth factor that limits muscle. It is studied in spinal muscular atrophy and, in combination with GLP-1/GIP drugs, to preserve muscle during weight loss.
Apitegromab targets pro- and latent (inactive) myostatin before it is activated, rather than the mature protein — a selectivity intended to avoid hitting related factors and improve tolerability.
No — this is a research and educational reference. Apitegromab is an investigational antibody, not an approved drug.