Gene editing company YolTech Therapeutics announced on Saturday updated data from its ongoing Phase I/IIa clinical trial of YOLT-201, a first-in-class CRISPR/Cas9-based in vivo gene-editing therapy for ATTR amyloidosis.

The study has dosed eight subjects, which includes six patients with ATTR amyloidosis with polyneuropathy (ATTR-PN), and two subjects with ATTR amyloidosis with cardiomyopathy (ATTR-CM), across two dose cohorts. It has not seen any Grade three adverse events (AEs), dose-limiting toxicities (DLTs), or serious adverse events (SAEs) resulting in treatment discontinuation.

All ATTR-PN subjects have completed dosing and follow-up. Preliminary data suggests that subjects in the higher dose cohort achieved more than a 90 percent decrease in circulating TTR protein levels, with robust safety and tolerability.

YT-YOLT-201-101 trial, a multicentre, open-label, single-dose phase I/IIa clinical study, is assessing the safety, tolerability, pharmacokinetics, and pharmacodynamic parameters of YOLT-201 in subjects with transthyretin amyloidosis polyneuropathy (ATTR-PN) and transthyretin amyloidosis cardiomyopathy (ATTR-CM). The trial includes two stages, a first stage open-label, single-dose, dose-escalation study to assess the optimal biological dose (OBD) of YOLT-201, and a second stage open-label, single-dose, dose-expansion study to study the safety and preliminary efficacy of the product at the OBD.