Apitegromab

Apitegromab
Monoclonal antibody
Type	Whole antibody
Source	Human
Target	Promyostatin
Clinical data
Other names	SRK-015
ATC code	M09AX16 (WHO) ;
Identifiers
CAS Number	2278276-46-1;
UNII	UZ54216N0Y;

Apitegromab (SRK-015) is a fully human monoclonal antibody developed to treat spinal muscular atrophy. It works by binding to and inhibiting latent (inactive) myostatin and promyostatin, which is a precursor to myostatin. Myostatin limits the size of skeletal muscle tissue. It does not bind to active myostatin, activin A, active BMP9/10 or TGFβ1, all of which operate on activin type 2 receptors.¹²³

Trials

In the EMBRAZE Phase 2 weight loss trial (102 people, 24 weeks), Tirzepatide + apitegromab reduced muscle loss by 55% compared to tirzepatide + placebo.⁴

References

Barrett D, Bilic S, Chyung Y, Cote SM, Iarrobino R, Kacena K, et al. (2021). "A Randomized Phase 1 Safety, Pharmacokinetic and Pharmacodynamic Study of the Novel Myostatin Inhibitor Apitegromab (SRK-015): A Potential Treatment for Spinal Muscular Atrophy". Advances in Therapy. 38 (6): 3203–3222. doi:10.1007/s12325-021-01757-z. ISSN 0741-238X. PMC 8189951. PMID 33963971.
Crawford T, Darras B, Day J, Song G, Nomikos G, Place A, et al. (3 May 2022). "Apitegromab in Spinal Muscular Atrophy (SMA): An Analysis of Multiple Efficacy Endpoints in the TOPAZ Trial (P15-5.005)". Neurology. 98 (18 Supplement) 1859. doi:10.1212/WNL.98.18_supplement.1859. ISSN 0028-3878.
Crawford T, Place A, Barrett D, Cote S, Nomikos G, Song G, et al. (2021). "Relationship of pharmacokinetics and pharmacodynamics to apitegromab efficacy in patients with later-onset spinal muscular atrophy (Types 2 and 3 SMA): Results from the TOPAZ study". Journal of the Neurological Sciences. 429 118388. doi:10.1016/j.jns.2021.118388. S2CID 238481481.
Pratley RE, Denham DS, Trivedi R, Watkins E, Connery L, Barnes J, Yu D, Hong J, Simard C, Umans K, Liu L, Tirucherai GS, Marantz JL (8 June 2026). "Apitegromab for lean mass preservation during tirzepatide-induced weight loss: a randomized, double-blind, placebo-controlled phase 2 trial". Nat Med. doi:10.1038/s41591-026-04440-4. PMID 42260100. Retrieved 19 June 2026.{{cite journal}}: CS1 maint: multiple names: authors list (link)

[1] Barrett D, Bilic S, Chyung Y, Cote SM, Iarrobino R, Kacena K, et al. (2021). "A Randomized Phase 1 Safety, Pharmacokinetic and Pharmacodynamic Study of the Novel Myostatin Inhibitor Apitegromab (SRK-015): A Potential Treatment for Spinal Muscular Atrophy". Advances in Therapy. 38 (6): 3203–3222. doi:10.1007/s12325-021-01757-z. ISSN 0741-238X. PMC 8189951. PMID 33963971.

[2] Crawford T, Darras B, Day J, Song G, Nomikos G, Place A, et al. (3 May 2022). "Apitegromab in Spinal Muscular Atrophy (SMA): An Analysis of Multiple Efficacy Endpoints in the TOPAZ Trial (P15-5.005)". Neurology. 98 (18 Supplement) 1859. doi:10.1212/WNL.98.18_supplement.1859. ISSN 0028-3878.

[3] Crawford T, Place A, Barrett D, Cote S, Nomikos G, Song G, et al. (2021). "Relationship of pharmacokinetics and pharmacodynamics to apitegromab efficacy in patients with later-onset spinal muscular atrophy (Types 2 and 3 SMA): Results from the TOPAZ study". Journal of the Neurological Sciences. 429 118388. doi:10.1016/j.jns.2021.118388. S2CID 238481481.

[Pratley2006-4] Pratley RE, Denham DS, Trivedi R, Watkins E, Connery L, Barnes J, Yu D, Hong J, Simard C, Umans K, Liu L, Tirucherai GS, Marantz JL (8 June 2026). "Apitegromab for lean mass preservation during tirzepatide-induced weight loss: a randomized, double-blind, placebo-controlled phase 2 trial". Nat Med. doi:10.1038/s41591-026-04440-4. PMID 42260100. Retrieved 19 June 2026.{{cite journal}}: CS1 maint: multiple names: authors list (link)

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