Prometic Life Sciences announced that PBI-4050, its investigational therapy for idiopathic pulmonary fibrosis (IPF), has been cleared by the U.S. Food and Drug Administration (FDA) to enter a Phase 2/3 combination-treatment trial in the U.S. and elsewhere.

With the agency’s approval of its Investigational New Drug (IND) application, Prometic will soon submit clinical trial applications to regulatory agencies in Canada, Europe, Australia and Japan, it said in its press release. The company also plans to file a protocol with the FDA to test PBI-4050 as a standalone IPF therapy.

PBI-4050 is an oral medication that has demonstrated anti-fibrotic activity in organs that include the kidneys, the heart, the lungs, and the liver.

The potentially pivotal Phase 2/3 clinical trial will be a two-stage study. Initially, 375 IPF patients will be enrolled in Phase 2, and divided into three groups: those receiving Ofev (nintedanib), an approved IPF treatment from Boehringer Ingelheim), and those given Ofev plus PBI-4050 at 800 mg, or Ofev plus PBI-4050 1200 mg. Treatment will run for 26 weeks.

Based on results, an independent Data and Safety Monitoring Board will determine whether the study should continue to  Phase 3 and, if so, which dose of PBI-4050 is optimal.

Up to 450 more patients would participate in trial’s second stage, which will include an Ofev plus placebo group and an Ofev plus PBI-4050 at the designated dose.

“We are very encouraged by the results of our open-label trial of PBI-4050 in combination with nintedanib, and are pleased to advance the clinical development plan with this pivotal study,” John Moran, Prometic’s chief medical officer, said in the release.

“IPF is a very serious condition and we believe that patients may benefit from this novel therapeutic approach,” Moran added.

PBI-4050  demonstrated a positive efficacy and safety profile in a Phase 2, open-label trial (NCT02538536) in about 40 IPF patients. The treatment was given either alone or in combination with Ofev, and was found to slow the decline of lung function or  stabilize respiratory function.

While PBI-4050 was effective when used in combination with Ofev, a significant decline in lung function was seen in the group treated with  PBI-4050 and Esbriet (pirfenidone; another FDA-approved IPF treatment). Researchers speculated that a drug-to-drug interaction might undermine treatment efficacy.

“We are very excited to be entering the pivotal stages of our IPF clinical program, which is another important milestone towards bringing this therapy to patients who suffer from IPF.  We believe that PBI-4050 is an important advancement in this indication and represents a potential significant step forward for helping patients,” said Pierre Laurin, Prometic’s president and chief executive officer.