A phase 2 clinical trial evaluating NP-120 (ifenprodil) for the potential treatment of idiopathic pulmonary fibrosis (IPF) and chronic cough has met its primary endpoint, according to a press release from Algernon Pharmaceuticals, the developers of the treatment. 

Results of the study showed that the majority of patients (65%) had stable or improved forced vital capacity (FVC), a measure of lung function, over the 12-week treatment period. This was statistically significant compared to an anticipated placebo effect of 40%.

Moreover, 30% of patients showed a 50% reduction in the average number of coughs per hour over 24 hours, though this was not statistically significant compared to an anticipated placebo effect of 25%.

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“The IPF data looks quite good,” said Martin Kolb, PhD, a professor of respirology at McMaster University in Hamilton, Ontario, Canada. “As a result, I am confident that [Algernon] should begin planning a sufficiently powered phase 2b study to investigate ifenprodil as a possible new treatment for IPF patients, including those who have associated cough.”

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Ifenprodil is an N-methyl-D-aspartate (NMDA) receptor antagonist that specifically targets the NMDA-type subunit 2B, which prevents glutamate signaling. Experiments in a mouse model of IPF have shown that it mediates anti-inflammatory responses and reduces pulmonary fibrosis.

During the single-arm, open-label trial, 20 participants with IPF, aged up to 85 years, received 20 mg of ifenprodil 3 times a day for 12 weeks.

The primary outcome measure was a minimum of 50% reduction in the average number of coughs per hour over 24 hours from baseline to week 12 and no worsening in FVC.

In addition to the stable or improved FVC observed in 65% of patients, many of the serum markers such as proC3, C3M, C6M, reC1M, proC8, and ELP-3—the elevation of which has been associated with increased mortality and disease progression risk—showed a trend to reduction, though the changes were not statistically significant.

The safety profile of the treatment was consistent with findings from previous studies.


Algernon Pharmaceuticals hits co-primary endpoint in its phase 2 study of ifenprodil for idiopathic pulmonary fibrosis and chronic cough. News release. Algernon Pharmaceuticals; July 18, 2022.

Efficacy, safety and tolerability of NP-120 on idiopathic pulmonary fibrosis and its associated cough. US National Library of Medicine. Last updated July 19, 2022. Accessed July 25, 2022.