ACVR1 gene replacement for heterotopic ossification in FOP

A gene therapy that delivers a functional copy of ACVR1 and silences the hyperactive ACVR1 allele that drives about 97% of cases of fibrodysplasia ossificans progressiva (FOP) could reduce heterotopic ossification, a disabling feature of the disease.

The gene therapy consisted of a recombinant AAV9 vector, with tropism for fibroadipogenic progenitor cells, encoding a codon-optimized version of ACVR1 and a miRNA targeting the disease-driving allele that was designed to reduce toxicity and off-target activity...