A gene therapy for inherited deafness reaches its first child

Skylark Bio, based in Cambridge, Massachusetts, said on 11 August 2026 that it has dosed the first patient in SONIX, an open-label multicentre Phase 1/2 trial of SKY-GJB2. The company emerged from stealth with the announcement.

Mutations in GJB2 are the leading single cause of inherited hearing loss worldwide. The gene encodes connexin 26, a protein that forms the gap junctions linking the supporting cells of the inner ear; without it, the cochlea cannot maintain the ionic conditions that hearing depends on. SKY-GJB2 delivers a working copy of the gene to those supporting cells in a single injection into one cochlea. The trial enrols children between nine months and seven years old.

Preliminary data are expected by the end of 2026, with further readouts in 2027. Skylark also lists SKY-PEN, aimed at hearing loss caused by SLC26A4 mutations, and an undisclosed central nervous system programme.

Chief executive Jodi Cook framed the dosing as a step toward treatment options for children born with genetic hearing loss. One patient has been dosed; nothing is known yet about whether the therapy restores hearing.