June 28, 2021 -- Intellia Therapeutics and Regeneron Pharmaceuticals have announced positive interim data from an ongoing phase I study of their in vivo candidate, NTLA-2001, as a single-dose treatment for transthyretin (ATTR) amyloidosis. The interim results support the clinical efficacy and safety of in vivo CRISPR genome editing therapy in humans.
The interim data were published in the New England Journal of Medicine on June 26 and are drawn from a study of the first six patients across two single-ascending dose cohorts in the U.K. and New Zealand. Treatment with NTLA-2001 led to dose-dependent reductions in serum TTR, with mean reductions of the protein ranging from 52% in a low-dose group (0.1 mg/kg) to 87% in a higher-dose group (0.3 mg/kg). NTLA-2001 was generally well tolerated, with no serious adverse events.
The companies will continue to evaluate NTLA-2001 at a higher dosage as part of the dose-escalation portion of the study to determine if a higher dose could result in a deeper reduction in protein levels leading to the potential for more meaningful clinical benefit. The third cohort, evaluating NTLA-2001 at the 1 mg/kg-dose level, is actively enrolling participants.
Following the identification of a recommended dose, Intellia expects to begin a single-dose expansion cohort in part two of the phase I trial later this year. After completion of the phase I trial, the company plans to study NTLA-2001 for both polyneuropathy and cardiomyopathy manifestations of ATTR amyloidosis.