A Single Multipurpose FSH-Blocking Therapeutic for Osteoporosis and Obesity

Pharmacological and genetic studies over the past decade have established FSH as an actionable target for diseases affecting millions, notably osteoporosis, obesity and Alzheimer’s disease (AD). Blocking FSH action prevents bone loss, fat gain and AD–like features in mice. We recently developed a first–in–class, humanized, epitope–specific FSH blocking antibody, MS-Hu6, with a KD of 7.52 nM. Using a GLP–compliant platform, we now report the efficacy of MS-Hu6 in preventing obesity and osteoporosis in mice, and parameters of acute safety in monkeys. Biodistribution studies using 89Zr–labelled, biotinylated or unconjugated MS-Hu6 in mice and monkeys showed localization to bone, bone marrow and fat depots. MS-Hu6 displayed a β phase t½ of 13 days (316 hours) in humanized Tg32 mice, and bound endogenous FSH. We tested 215 variations of excipients using the protein thermal shift assay to generate a final formulation that rendered MS-Hu6 stable in solution upon freeze–thaw and at different temperatures, with minimal aggregation, and without self–, cross–, or hydrophobic interactions or appreciable binding to relevant human antigens. MS-Hu6 showed the same level of “humanness” as human IgG1 in silico , and was non–immunogenic in ELISPOT assays for IL-2 and IFNγ in human peripheral blood mononuclear cell cultures. We conclude that MS-Hu6 is efficacious, durable and manufacturable, and is therefore poised for future human testing as a multipurpose therapeutic. ### Competing Interest Statement M.Z. is an inventor on issued patents on inhibiting FSH for the prevention and treatment of osteoporosis and obesity (U.S. Patent 8,435,948 and 11,034,761). M.Z. is also an inventor on pending patent application on composition and use of humanized monoclonal anti-FSH antibodies, and is co-inventor of a pending patent on the use of FSH as a target for preventing Alzheimer's disease. These patents are owned by Icahn School of Medicine at Mount Sinai (ISMMS), and M.Z. would be recipient of royalties, per institutional policy. M.Z. also consults for several financial platforms, including Gerson Lehman Group and Guidepoint, on drugs for osteoporosis and genetic bone diseases.