Figure 4. Acute and chronic tolerability of MS-Hu6.

Effects on physiological parameters monitored up to 100 min (A) and serum biochemistry (at days 0, 2, and 5) (B) after injecting ⁸⁹Zr-MS-Hu6 as a single i.v. bolus dose (1.3 mg, ~1.3 mCi) into the tail veins of Cynomolgus monkeys (“Andy”, 14 years/9.8 kg, and “Scott”, 15 years/6.15 kg). Normative serum biochemistry data (green) from Koo et al., 2019. In silico assessment of “humanness” using abYsis, with Z-scores comparing humanized MS-Hu6, mouse-human chimeric antibody (Gera et al., 2020), and human IgG1 (C). Table shows narrowly distributed Z-scores after inputting primary sequences of FDA-approved, clinically utilized humanized (“zumab”), and fully human (“mab”) antibodies: bevacizumab (anti-VEGF, Avastin); trastuzumab (anti-HER2, Herceptin); atezolizumab (anti-PD-L1, Tecentriq); adalimumab (anti-TNFα, Humira); alirocumab (anti-PCSK9, Praluent); and canakinumab (anti-IL-β; Ilaris) (C). Assessment of immunogenicity using ELISpot assays for the inflammatory cytokines IFNγ and IL-2 in human peripheral blood mononuclear cell cultures in response to added MS-Hu6, Dulbecco’s Modified Eagle’s Medium (DMEM) (Ctrl), or peptide pool from cytomegalovirus, Epstein-Barr virus, influenza and tetanus toxoid (CEFT) (positive control, Immunospot) (D). Kaplan–Meier survival curves showing that haploinsufficiency of Fshr, which otherwise mimics the effect of MS-Hu6 on bone mass (Sun et al., 2006; Liu et al., 2017), does not reduce lifespan compared with wild-type littermates over 1100 days (3 years; 5, 10 mice for wild-type male and female, and 23, 22 mice for male and female Fshr^+/- mice, respectively) (E).