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.