The Safety, Tolerability, Pharmacokinetics, and Clinical Efficacy of the NLRX1 agonist NX-13 in Active Ulcerative Colitis: Results of a Phase 1b Study
Bram Verstockt, Séverine Vermeire, Laurent Peyrin‐Biroulet, Rebecca Mosig, Brian G. Feagan, Jean‐Frédéric Colombel, Britta Siegmund, Florian Rieder, Stefan Schreiber, Andrés Yarur, Remo Panaccione, Marla C. Dubinsky, Simon Lichtiger, Fabio Cataldi, Silvio Danese
Abstract
BACKGROUND AND AIMS: NX-13 activation of NLRX1 reduces intracellular reactive oxygen species and decreases inflammation in animal models of colitis. A phase 1a trial demonstrated a gut-selective pharmacokinetic profile with good tolerability. This phase Ib study aimed to evaluate the safety, tolerability, and pharmacokinetics of NX-13 in patients with active ulcerative colitis [UC]. METHODS: We conducted a multicentre, randomized, double-blind, placebo-controlled trial of NX-13 in patients with active UC. Patients with a Mayo Clinic Score of 4-10 were randomly assigned [3:3:3:1 ratio] to three NX-13 oral dose groups (250 mg immediate release [IR], 500 mg IR, or 500 mg delayed release [DR], or placebo) once daily for 4 weeks. Safety and pharmacokinetics were the primary and secondary objectives, respectively. RESULTS: Thirty-eight patients [11 females] were recruited and randomized to placebo [five], NX-13 250 mg IR [11], NX-13 500 mg IR [11], or NX-13 500 mg DR [11] and received at least one dose. There were no serious adverse events or deaths during the trial. One patient [500 mg DR, 1/11] withdrew due to worsening of UC and a second [500 mg IR, 1/11] on the last day of treatment after a panic attack associated with atrial fibrillation. In the efficacy population [36 patients], clinical improvement in rectal bleeding and stool frequency scores relative to placebo were seen as early as week 2 and endoscopic response was seen at week 4. CONCLUSIONS: NX-13 was generally safe and well tolerated with early signs of rapid symptom and endoscopic improvement. This novel mechanism of action warrants further investigation. ClinicalTrials.gov: NCT04862741.