What is the proposed mechanism of action of garetosmab in treating FOP?

Garetosmab is a fully human monoclonal antibody designed to target and bind to activin A, which is a protein involved in the process of bone formation and therefore plays a significant role in conditions like fibrodysplasia ossificans progressiva (FOP). FOP is a rare genetic disorder characterized by the abnormal formation of bone in muscles, tendons, and other connective tissues, leading to significant mobility issues and skeletal deformities.

By specifically binding to activin A, garetosmab helps to modulate the signaling pathways that contribute to the aberrant bone growth associated with FOP. This targeted mechanism is crucial in preventing the progression of the disease and reducing the formation of heterotopic ossification, thereby improving the quality of life for affected individuals.

The other options present mechanisms that either do not directly relate to the treatment of FOP or target different biological processes. For instance, a tyrosine kinase inhibitor would affect signaling pathways differently, and neither an RAR-γ agonist nor an mTOR kinase inhibitor aligns with the specific pathophysiology of FOP as centered around activin A. Garetosmab's mechanism of action aligns closely with the underlying biological processes in FOP, leading to its proposed