The leveling occurred when PBI-4050 was used by itself and when it was used in one of two combination therapies. IPF progressed when PBI-4050 was used in the other combo, however.
Prometic presented the trial results at the American Thoracic Society International Conference in Washington, which ended today. The presentation was titled “PBI-4050 Is Safe and Well Tolerated and Shows Evidence of Benefit in Idiopathic Pulmonary Fibrosis.”
The trial (NCT02538536) examined changes in a measure of lung function known as forced vital capacity in 40 IPF patients who received one of three therapies for 12 weeks. Nine received PBI-4050 alone, 16 a combination of PBI-4050 and Ofev (nintedanib), and 15 a combination of PBI-4050 and Esbriet (pirfenidone).
Forced vital capacity, or FVC, refers to the amount of air a person can force from their lungs after taking a breath that filled their lungs to capacity.
The FVC scores of the patients who took PBI-4050 by itself or a combination of PBI-4050 and Ofev changed very little between the start of treatment and the end. Since IPF is a progressive disease, the minimal change in FVC scores suggested PBI-4050 had slowed or stopped the disease’s progression — a sign it had been effective.
In contrast, the FVC scores of patients receiving the combination of PBI-4050 and Esbriet dropped significantly, indicating they had experienced a loss in lung function.
The research team speculated that PBI-4050 and Esbriet interacted in a way that reduced both’s effectiveness.
Another presentation that Prometic made at the conference also suggested that PBI-4050 was effective against IPF. It focused on the therapy’s impact on disease biomarkers.
PBI-4050 generated much larger reductions in biomarkers of harmful IPF processes, including inflammation, extracellular matrix accumulation and pulmonary vascular remodeling, than Ofev and Esbriet.
Prometic is now planning two placebo-controlled Phase 2/3 clinical trials in the second half of 2017. One will test PBI-4050 in combination with Ofev. Another will evaluate PBI-4050 alone in patients unable to tolerate Ofev or Esbriet.
“PBI-4050 presented a highly compelling safety and tolerability profile throughout all clinical trials,” Dr. Joseph Parker, senior director of clinical development at Prometic, said in a press release. “Because PBI-4050 was well-tolerated and appeared to demonstrate a dose response relationship in the Phase 2 study, the planned pivotal Phase 2/3 trial will include three arms – two dose levels of PBI-4050 and placebo.”