Idiopathic Pulmonary Fibrosis
What is Idiopathic Pulmonary Fibrosis (IPF)?
Idiopathic pulmonary fibrosis (IPF) is a chronic, devastating, and ultimately fatal disease characterized by a progressive decline in lung function. It is a specific type of interstitial lung disease in which the small air sacs of the lung, the “alveoli,” gradually become replaced by fibrotic (scar) tissue and is the cause of worsening dyspnea (shortness of breath). IPF is usually associated with a poor prognosis. The term ‘idiopathic’ is used because the cause of pulmonary fibrosis is still unknown. IPF usually occurs in adult individuals of between 50 and 70 years of age, particularly those with a history of cigarette smoking, and affects men more often than women.
Acute exacerbation of IPF (AE-IPF) is defined as a sudden acceleration of the disease or an idiopathic acute injury superimposed on diseased lung tissue that leads to a significant decline in lung function. An AE-IPF is associated with a mortality rate as high as 85%, with mean survival periods between 3 to 13 days.
Prevalence of IPF:
IPF affects about 130,000 people in the United States, with about 48,000 new cases diagnosed annually. Approximately 40,000 people die each year with IPF, a similar number of deaths to those due to breast cancer. The 5-year mortality rate for patients with IPF is estimated to range from 50% to 70%.
Orphan drug development for IPF:
Liminal has announced positive results from its completed open label Phase 2 clinical trial in subjects suffering from idiopathic pulmonary fibrosis (“IPF”). In addition to demonstrating that PBI-4050 is safe and very well tolerated, an objective of this study was to seek early evidence of a clinical benefit with PBI-4050 treatment, whether administered alone or in addition to either of the drugs approved for the treatment of IPF, nintedanib or pirfenidone.
A total of 40 subjects were enrolled in the study conducted in 6 sites across Canada and all have completed the 12 weeks of treatment; 9 subjects received PBI-4050 alone, 16 received PBI-4050 & nintedanib and 15 received PBI-4050 & pirfenidone. The baseline characteristics of the subjects enrolled in this study were similar to those enrolled in prior IPF randomized controlled studies conducted by other pharmaceutical companies, namely ASCEND and INPULSIS.
As was demonstrated in these previously mentioned large clinical trials, IPF subjects typically experience a progressive decline in respiratory function. In contrast, in the Liminal clinical study, the respiratory function of the subjects, measured as the forced vital capacity (FVC (ml)), remained stable after 12 weeks of treatment, in subjects treated with PBI-4050 alone and in those receiving PBI-4050 combined with nintedanib for the treatment of IPF and was superior to that of those subjects treated with PBI-4050 combined with pirfenidone for the treatment of IPF.