Algernon Pharmaceuticals Inc. announced that it is planning a 180 patient, 90-day Phase 2b clinical study of NP-120 for chronic cough to begin in third quarter of 2023. Ifenprodil is an N-methyl-D-aspartate (NMDA) receptor antagonist specifically targeting the NMDA-type subunit 2B (GluN2B), which prevents glutamate signaling. Ifenprodil represents a novel first-in-class potential treatment for chronic cough and is thought to interfere with central signalling in the brain, suppressing the urge to cough.

The decision to advance the study is based on positive data previously reported on July 28, 2022, from the Company's Phase 2a study of Idiopathic Pulmonary Fibrosis (IPF) and chronic cough, where Ifenprodil showed a significant improvement in mean objective 24-hour and waking cough counts in patients after 4 and 12 weeks. Patients with IPF are usually excluded from trials in refractory chronic cough, and cough in this population is regarded as extremely difficult to treat. The analysis showed that: The geometric mean 24-hour cough counts were reduced by 32.0% at 4 weeks (p = 0.023) and 39.5% at 12 weeks (p = 0.001) compared to baseline The geometric mean awake cough counts were reduced by 30.2% at 4 weeks (p = 0.038) and 37.4% at 12 weeks (p = 0.002) compared to baseline Algernon previously announced on January 14, 2022, that it had received positive feedback from the U.S. Food and Drug Administration (U.S. FDA) at its pre-Investigational New Drug (pre-IND) meeting for its investigation of Ifenprodil solely for the treatment of chronic cough.

The Company has since engaged in further discussions with the U.S. FDA, and plans to file an investigational new drug (IND) application shortly. While the Company originally planned to focus on IPF in a Phase 2b study, Algernon has now decided to pursue a chronic cough study first, and to delay planning its IPF Phase 2b study for Ifenprodil until a later date. Study Design The planned study design will include the following elements: Multinational, three-arm, randomized, double-blind, placebo-controlled trial to evaluate NP-120 in approximately 180 patients.

Patients will be randomized 1:1:1 to receive NP-120 (20mg TID) or NP-120 (40mg TID), or placebo for 12 weeks. The primary endpoint will be the reduction in geometric mean 24-hr cough count over 12 weeks compared to placebo. Secondary endpoints will include safety, tolerability and patient-reported quality-of-life measures.