New data from Phase 3 clinical studies of Genentech’s Esbriet (pirfenidone), a drug developed for the treatment of pulmonary fibrosis (PF), showed the treatment’s efficacy over time.
The data presentation, the “Effect of continued treatment with pirfenidone following a clinically meaningful decline in percent predicted forced vital capacity in patients with idiopathic pulmonary fibrosis (IPF),” was made by Dr. Steven Nathan, Medical Director, Advanced Lung Disease and Transplant Program, Inova Fairfax Hospital, at the Pulmonary Fibrosis Foundation’s recent PFF Summit 2015, held in Washington, D.C.
Esbriet is an oral drug with anti-fibrotic properties that acts by decreasing the production of collagen, growth and inflammatory factors, ultimately leading to a reduction in lung fibrosis. Esbriet was reported to slow the decline of lung function in patients with IPF and consequently disease progression. In October 2014, Esbriet became the first IPF drug approved by the U.S. Food and Drug Administration (FDA) for treatment. Now, more than 10,000 people have received Esbriet.
The disease course and progression rate of IPF is quite variable within a patient and between patients (intra- and inter-subject variability), making assessments of therapeutic response difficult and complex.
In the study, researchers combined data obtained from three Phase 3 clinical trials (ASCEND and two CAPACITY trials) and investigated whether continued treatment with Esbriet in IPF patients who exhibited a 10% or greater decline in their predicted forced vital capacity (%FVC, a measure of lung function) offered clinical benefit.
Researchers found that 5.5% of the patients under Esbriet treatment experienced an absolute decline of ≥10% in FVC between baseline and six months of treatment. The percentage in the placebo group was 10.9%.
All patients underwent an additional six-month treatment period either with Esbriet or placebo. Fewer patients in the Esbriet group experienced a ≥10% decline in FVC (5.9% in the Esbriet group and 27.9% in the placebo group). In addition, the proportion of patients who had no further decline in %FVC was higher in the Esbriet group (58.8%) when compared to the placebo group (38.2%). One death was reported in the Esbriet group (out of 34 patients, 2.9%), and 14 deaths in the placebo group (out of 68 patients, 20.6%).
Based on their findings, the researchers suggested that IPF patients who have a greater than 10% FVC decline during the first 6 months of treatment with Esbriet should continue treatment, as it lowered the risk of %FVC decline and death in the following six months. The authors concluded that continued Esbriet treatment offers clinical benefits for IPF patients despite a possible initial decline in lung function.
“This challenges the notion that a 10% decline in FVC represents a treatment failure and underscores that the FVC does not tell the whole story in this complex disease. The practical implications of these findings are profound and suggest that even in those patients with declining lung function, the medication should be continued,” concluded Dr. Nathan.