Reply: Adoption of Antifibrotic Medications: A Closer Look at the Data

From the Authors:

We would like to thank Dr. White and colleagues from Boehringer Ingelheim Pharmaceuticals for their suggestions to strengthen our recent publication in AnnalsATS (1). We agree that understanding the real-world adoption rates of novel medications such as antifibrotics is an important undertaking.

Dr. White and colleagues offer a different way of reporting the adoption of the antifibrotics using the same administrative database we did to run our study. As with our data (and the Rogers diffusion of innovation theory cited), they demonstrate an increase in antifibrotic prescriptions over time; however, instead of using a quarterly adoption rate as we did in our analysis, a semiannual calendar year adoption rate is used in theirs. This method leads to the finding that in the first 6 months of 2019, more than a third of patients with idiopathic pulmonary fibrosis (IPF) received a prescription for one of the antifibrotic medications. We appreciate the reevaluation of the data by Dr. White and colleagues. However, as their methods are unclear to us (specifically how they defined their IPF cohort, coverage requirements, and denominator) and only a snapshot of data is offered, it is difficult for us to comment on whether their way of reporting truly provides a “more representative picture” of the antifibrotic landscape. It is possible that their adoption rate is inflated by only capturing patients seen during the first 6 months of 2019 (and therefore those more likely to receive a prescription) or by patients with fibrotic interstitial lung diseases other than IPF. We did our best to avoid such confounding variables in our study by carefully constructing the cohort to only include patients with IPF based on prior local validation work. Thus, it is our continued belief that the rate observed in our study among a cohort of patients with IPF provides a reasonably accurate picture of the adoption of the medications in everyday clinical practice since their approval in 2014.

As discussed in the manuscript, we are in agreement with Dr. White and colleagues that referral to a pulmonary physician (and ideally a multidisciplinary group including chest radiologists, pulmonary pathologists, rheumatologists, and thoracic surgeons) is critical for the management of a complex disease like IPF and that the observed lack of referrals in our study may have contributed to the lower-than-expected adoption rate. This finding likely also explains the significant difference in adoption found in our analysis and those of various U.S. IPF registries where involvement of a pulmonary consultant and multidisciplinary group is an essential component of care (2, 3).

Finally, it is appreciated that pharmaceutical companies such as Boehringer Ingelheim provide generous subsidies for some of their therapies, including the antifibrotics. These prescription-assistance programs provide free or low-cost medications and have undoubtedly had a significant impact for eligible patients. However, these programs also often have complex application processes and strict income requirements and are meant almost exclusively for patients who are uninsured or underinsured (4). As our study included only patients with Medicare Advantage and private insurance prescription drug coverage, the majority of our cohort would likely not qualify to receive financial assistance for the antifibrotics. Thus, we stand by our observation that the out-of-pocket costs for the medications are high and could contribute to the low adoption rate of the drugs. Although data supporting the efficacy of these important medications continue to grow, we remain concerned about the out-of-pocket cost of the antifibrotics observed in our study (and in clinical practice) and believe further cost analyses are needed.