Novel ENV-101 associated with improved lung function in IPF
FROM ATS 2024
SAN DIEGO —
Early efficacy data from a phase 2a safety trial suggest that the novel oral agent, dubbed ENV-101, is associated with improvements in forced vital capacity (FVC) and other measures of lung function, and may be a disease-modifying therapy for IPF, according to Toby M. Maher, MD, PhD, director of the interstitial lung disease program at Keck School of Medicine, University of Southern California, Los Angeles. Dr. Maher presented the results at the American Thoracic Society’s international conference.
“Historically we’ve not been seeing improvements in FVC, which is what we’ve been seeing [with ENV-101], and I think it’s conceivable that you can get remodeling of early areas of fibrosis in the lung,” Dr. Maher said in an interview with Chest Physician.
“We know from histology studies that if you look at IPF lungs you’ll see areas of end-stage fibrosis, but even in advanced disease you’ll see areas where the lung is relatively well preserved and there’s early fibrosis, so I think it’s conceivable that there is remodeling of some of those early areas of fibrosis,” he said.
Vital pathway
The Hedgehog pathway is highly conserved in evolution. The cell-signaling pathway is active embryogenesis, tissue proliferation, and organ development. There is also evidence to suggest that in adult the pathway becomes reactivated following tissue injury, as can occur in lung epithelia, Dr. Maher explained.
Although as the word “idiopathic” in IPF indicates the etiology of the disease is unknown, investigators have found that in IPF repetitive epithelial injury to lung tissue leads to activation of the Hedgehog pathway. Hedgehog signaling in turn induces formation and activation of myofibroblasts that lay down fibrotic matrix and contract lung tissue, leading to significant impairments in gas exchange, Dr. Maher said.
ENV-101 blocks Hedgehog from binding to the PTCH1 receptor, preventing release of the zinc-finger protein GLI1 from the kinase complex into the cell cytoplasm. With signaling blocked, myofibroblasts undergo apoptosis instead of initiating wound repair as they normally would, thereby eliminating an evident mechanism of IPF pathology, he explained.
Study details
In the phase 2a trial, investigators enrolled patients with IPF who were not taking antifibrotic agents and who had a percent predicted FVC greater than 50%, percent predicted diffusing capacity for carbon monoxide (DLCO) of at least 35%, and life expectancy of more than 1 year.
The patients were randomized to receive 200 mg oral ENV-101 daily (18 patients) or placebo (15 patients) for 12 weeks.
The primary endpoint of the trial was safety of the experimental agent. A previous phase 1b study of a different Hedgehog inhibitor — vismodegib (Erivedge), in combination with the antifibrotic agent pirfenidone (Pirespa) — in patients with IPF was discontinued because of poor tolerability.
In the current study, the most common treatment-related adverse events were dysgeusia in 57% of patients who received the drug, alopecia in 52%, and muscle spasms in 43%. The spasms were generally less severe than those seen in the vismodegib/pirfenidone trial mentioned above.
Seven patients (33%) had treatment-emergent events leading to dose interruption. Five patients discontinued treatment: one who withdrew because of taste alterations, one who was lost to follow-up after an IPF exacerbation, and three who withdrew consent.
There were no treatment-related deaths, and no clinically significant findings on labs, vital signs, electrocardiograms, or physical exam.
