Idiopathic Pulmonary Fibrosis: 5 Things to Know

Aaron B. Holley, MD

Disclosures

January 11, 2019

Idiopathic pulmonary fibrosis (IPF) is a progressive, fibrotic lung disease most common in older men with exposure to tobacco smoke.[1]

Two antifibrotic therapies, nintedanib and pirfenidone, were shown to reduce the rate of functional vital capacity (FVC) decline in patients with IPF.[2] Since the US Food and Drug Administration approved both drugs for patients with IPF in 2014, we have learned a great deal about their efficacy in specific subpopulations. Antacids have been used to modify IPF progression, with observational data yielding conflicting results.[1] Additionally, a recent, randomized controlled trial (RCT) investigated the effects from performing laparoscopic, antireflux surgery in patients with IPF.[3]

This article highlights five things you need to know about these and other important studies and guidelines regarding the diagnosis and management of IPF.

1. Diagnostic Certainty Not Always Necessary Before Prescribing Antifibrotic Therapy

Diagnosing IPF is tricky. Guidelines recommend applying graded criteria that reflect levels of certainty.[4] Often, patients are diagnosed without a biopsy to avoid the morbidity and mortality associated with thoracic procedures.[5] Nintedanib and pirfenidone are expensive medications, estimated to cost more than $100,000 per year,[1] with known side effects. What level of certainty is required to justify a prescription? A post hoc analysis of the INPULSIS trials[6] found that patients with possible usual interstitial pneumonia (UIP) patterns on high-resolution CT (HRCT) scan had similar benefit to those with definite UIP. Disease progression also was the same. The authors concluded that patients with traction bronchiectasis and possible UIP on HRCT have the same response to nintedanib as those with honeycombing on HRCT or biopsy-proven UIP.[7] These data imply that the absence of biopsy or definite UIP pattern on HRCT should not preclude treatment.

2. Debate Over Prescribing Nintedanib or Pirfenidone When FVC Is Normal

The original studies showing benefit from nintedanib and pirfenidone included patients who met specific FVC and diffusing capacity of the lungs for carbon monoxide criteria.[6,8,9] Whether patients with IPF whose lung function testing is outside the inclusion criteria should be given nintedanib or pirfenidone was the subject of a pro–con debate.[10,11] Both drugs are expensive, and the primary outcome affected by both was the rate of FVC decline,[12] so cost-efficacy is in question. It is reasonable to ask whether patients with severe disease (significant FVC decline has already occurred) or preserved function (progression may be very slow) will see benefit with treatment. There is no easy answer. Although limited data have shown benefit for patients with IPF whose lung function is outside the original inclusion criteria,[13,14] inferences are limited. Given the high cost of the drugs, I observe patients with IPF who have preserved function to gauge the rate of decline prior to initiating nintedanib or pirfenidone. This approach focuses on cost at the expense of potential benefit. It also assumes that IPF progresses at a steady rate, which is not the case for every patient. The centers for advanced lung disease I have worked with seem to favor more aggressive treatment.

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