Intellia Therapeutics and Regeneron Pharmaceuticals have reported positive interim results from the ongoing Phase I clinical trial of CRISPR/Cas9-based therapy, NTLA-2001, to treat transthyretin (ATTR) amyloidosis.
NTLA-2001 could potentially be the first single-dose treatment for ATTR amyloidosis.
Being developed as a one-dose therapy, NTLA-2001 is a in vivo genome editing candidate given systemically or intravenously for editing genes in humans.
The international, multicentre, two-part, open-label trial is designed to assess NTLA-2001 in adult patients with hereditary transthyretin amyloidosis with polyneuropathy (ATTRv-PN) or transthyretin amyloidosis with cardiomyopathy (ATTR-CM).
In the trial, 15 subjects with ATTRv-PN received the treatment across four single-ascending dose groups.
According to the interim results, NTLA-2001 offered a dose-dependent decline in serum TTR and attained maximal reductions by day 28.
Mean declines of 52%, 87% and 86% were reported among the three subjects in the 0.1, 0.3, and 0.7mg/kg dose cohorts, respectively.
Furthermore, 93% of the six subjects in the 1mg/kg dose cohort experienced mean reductions.
Durable mean serum TTR reductions were seen during the observation period, with patients being followed up for two to 12 months.
In addition, all the four tested doses of NTLA-2001 were reported to be well tolerated with the majority of adverse events observed in the trial being mild in nature.
Dosing of the subjects with 0.7mg/kg of NTLA-2001 will progress in Part 1 of the cardiomyopathy arm. The company also intends to dose escalate to 1mg/kg.
Part 2 of the Phase I trial is anticipated to commence in the first quarter of this year and will be a one-dose ATTRv-PN expansion cohort.
Intellia plans to conclude subject enrolment in the Phase I trial for ATTRv-PN and ATTR-CM and report further data this year.
Intellia president and CEO John Leonard said: “These data suggest that treatment with a one-time, systemically delivered CRISPR-based investigational therapy has the potential to substantially reduce levels of a disease-causing protein.
“We believe this deep and consistent reduction shows promise for halting and even reversing disease progression in people with ATTR amyloidosis.”
In September last year, the US Food and Drug Administration accepted Intellia’s investigational new drug application to evaluate its NTLA-5001 for acute myeloid leukaemia in a Phase I/IIa trial.