ProMetic Life Sciences recently announced that the U.S. Food and Drug Administration (FDA) agreed with the design of the first Phase 2/3 clinical trials evaluating PBI-4050 for idiopathic pulmonary fibrosis (IPF) treatment.

PBI-4050 is an oral drug designed to treat fibrosis, a condition characterized by the replacement of normal tissue by fibrotic scar tissue.

The planned Phase 2/3 clinical trials for IPF are based on positive Phase 2 trial results of the drug’s effectiveness and tolerability as a monotherapy and in combination with Ofev (nintedanib) or Esbriet (pirfenidone).

This open-label, single-arm, Phase 2 clinical trial (NCT02538536) enrolled 40 IPF patients and assessed the effectiveness, safety, and tolerability of PBI-4050 (800 mg daily, oral administration) on lung function and disease progression.

Results reported in February showed that after 12 weeks of treatment, the forced vital capacity (FVC, a measure of lung function) remained stable in patients treated with PBI-4050 alone (nine patients), and in patients treated with PBI-4050 in combination with Ofev (15 patients). In patients treated with PBI-4050 in combination with Esbriet (16 patients), FVC declined significantly.

The plasma concentration of PBI-4050 was sub-therapeutic at 50 percent of the expected level in patients that received the PBI-4050 in combination with Esbriet, indicating negative drug-drug interaction.

“This early evidence of efficacy observed with PBI-4050 alone or in combination with nintedanib [Ofev] points toward very promising treatment options that will be further tested in two separate Phase 2/3 clinical trials. We are very pleased that the FDA concurs with our decision to exclude a combined pirfenidone [Esbriet] and PBI-4050 treatment arm in the upcoming phase 2/3 add-on study,” John Moran, chief medical officer of ProMetic said in a press release.

In the new study, planned to begin in a few months, IPF patients currently treated with Ofev will be randomly assigned to additional treatment with either PBI-4050 or a placebo.

The company is also considering conducting another Phase 2/3 placebo-controlled clinical trial with PBI-4050 in IPF patients who did not tolerate Ofev or Esbriet.

“To date, PBI-4050 has presented a remarkable safety and tolerability profile throughout all clinical trials,” said Pierre Laurin, president and CEO of ProMetic. “We are also very pleased that our Phase 2 open label study in IPF patients has served the very important strategic purpose of allowing us to optimize the design of our pivotal clinical program for this devastating medical condition.”