Bimagrumab
Bimagrumab, a biologic. A human monoclonal antibody against the activin type II receptors ActRIIA and ActRIIB, occupying the ligand-binding site competitively and so…
A human monoclonal antibody against the activin type II receptors ActRIIA and ActRIIB, occupying the ligand-binding site competitively and so blocking myostatin, activin A and GDF11 signalling through Smad2/3, which relieves the negative regulation of skeletal muscle mass. PMID:29109273 verbatim: "bimagrumab binds to both ActRIIA and ActRIIB ligand binding domains in a competitive manner at the critical myostatin/activin binding site, hence preventing signal transduction through either ActRII". PMID:33264516 full text adds: "Bimagrumab is a human monoclonal antibody that blocks the ActRIIs, preventing the activity of myostatin and other negative skeletal muscle regulators".
NO MOLECULAR WEIGHT IS STORED. PubChem returns PUGREST.NotFound for `bimagrumab`, and none of the three full texts read prints a kDa figure for it, so the familiar ~150 kDa IgG mass is not citable from anything fetched. That absence BLOCKS an occupancy row even though a real affinity exists, because the schema's ec50_mg_l needs the mass for the nM-to-mg/L conversion. AFFINITY, VERBATIM AND CORRECTLY ATTRIBUTED (PMID:29109273 full text, SPR against human ActRIIA-Fc and ActRIIB-Fc): "The affinity of the bimagrumab Fab for ActRIIA ( K d = 973 pM) is >50-fold lower in comparison with ActRIIB ( K d = 16 pM)". NOTE THESE ARE FAB AFFINITIES, NOT WHOLE-IgG. The same paragraph prints affinities for the LIGANDS (myostatin, activin A) and for two OTHER antibodies, CSJ089 and CQI876 — none of which belongs on this record. SINGLE-DOSE IV Cmax, verbatim from PMID:33264516 full text, established as single-dose by "The concentration-time profile following a single i.v. infusion of bimagrumab 3 or 30 mg/kg": "In older adults administered bimagrumab 3 and 30 mg/kg, mean C max was 90.7 and 982 microg/mL ... obese participants administered bimagrumab 30 mg/kg had a mean C max of 944 microg/mL". SUBCUTANEOUS BIOAVAILABILITY IS AN ESTIMATE, not a measurement: PMID:36527600 says "The absolute subcutaneous bioavailability was estimated at approximately 40%", so under R17 it is recorded here and not stored in an F slot, and it would belong to the SC route only. That paper also gives three formulations in one study — IV infusion, SC infusion and SC bolus — so any future ka or F is formulation-specific. A COMPARATOR NOT TO IMPORT: the semaglutide 1.0 and 2.4 mg SC weekly arms in the BELIEVE trial (PMID:41772149) are semaglutide's doses, not this compound's.
Sources: PMID:33264516, PMID:29109273, PMID:36527600, PMID:33439265, PMID:41772149