Positive final results from a phase 1 clinical trial of alunacedase alfa (APN01), a potential drug candidate for pulmonary arterial hypertension (PAH), have been announced by APEIRON Respiratory Therapies GmbH (AResT).

“I am very happy that our team was able to contribute to the development of this potential treatment for patients suffering from different forms of severe respiratory disease,” said Professor Markus Zeitlinger, head of the department of clinical pharmacology at the Medical University of Vienna and principal investigator for the study. “The inhaled route of administration may enable the achievement of very high concentrations at the site of action, without compromising patient safety due to systemic side effects. We were able to confirm a good tolerability profile from a clinical perspective.”

Aerosolized alunacedase alfa met all primary and secondary safety endpoints. The treatment was safe and well-tolerated in all doses tested, with no dose-limiting toxicities observed. No adverse events above grade 2 were reported, and no patients withdrew from the trial.

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“The results of this study allow further clinical development of novel inhaled APN01 and expand its potential as a treatment for a range of respiratory diseases,” said Romana Gugenberger, PhD, chief medical and scientific officer of AResT. “In addition to meeting all primary endpoints regarding the safety and tolerability of APN01 via a new route of administration, the observed low systemic concentrations of ACE2 indicate that inhaled APN01 may be an effective treatment for chronic conditions such as pulmonary arterial hypertension as well as acute indications like COVID-19.”

Alunacedase alfa is a soluble recombinant version of the angiotensin-converting enzyme 2 receptor, the host receptor for the virus SARS-CoV-2. Results from a completed double-blind, placebo-controlled phase 2 trial showed potential clinical benefit in treating COVID-19 with intravenous alunacedase alfa.


APEIRON Respiratory Therapies announces positive results from phase I trial of inhaled APN01. News release. APEIRON Respiratory Therapies GmbH; November 03, 2022.