CHEST
Volume 151, Issue 3, March 2017, Pages 619-625
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Original Research: Diffuse Lung Disease
Use of Mycophenolate Mofetil or Azathioprine for the Management of Chronic Hypersensitivity Pneumonitis

https://doi.org/10.1016/j.chest.2016.10.029Get rights and content

Background

The treatment of chronic hypersensitivity pneumonitis (cHP) often includes systemic oral corticosteroids, but the optimal pharmacologic management remains unclear. The morbidity associated with prednisone has motivated the search for alternative therapies. We aimed to determine the effect of treatment with mycophenolate mofetil (MMF) or azathioprine (AZA) on lung function in patients with cHP.

Methods

Patients with cHP treated with either MMF or AZA were retrospectively identified from four interstitial lung disease centers. Change in lung function before and after treatment initiation was analyzed using linear mixed-effects modeling (LMM), adjusting for age, sex, smoking history, and prednisone use.

Results

Seventy patients were included: 51 were treated with MMF and 19 with AZA. Median follow-up after treatment initiation was 11 months. Prior to treatment initiation, FVC and diffusion capacity of the lung for carbon monoxide (Dlco) % predicted were declining at a mean rate of 0.12% (P < .001) and 0.10% (P < .001) per month, respectively. Treatment with either MMF or AZA was not associated with improved FVC (0.5% at 1 year; P = .46) but was associated with a statistically significant improvement in Dlco of 4.2% (P < .001) after 1 year of treatment. Results were similar in the subgroup of patients treated with MMF for 1 year; the FVC increased nonsignificantly by 1.3% (P = .103) and Dlco increased by 3.9% (P < .001).

Conclusions

Treatment with MMF or AZA is associated with improvements in Dlco in patients with cHP. Prospective randomized trials are needed to validate their effectiveness for cHP.

Section snippets

Study Population

The study cohort included patients from four different centers with specialized ILD clinics: University of California, San Francisco (UCSF), University of British Columbia (UBC), Centre Hospitalier de l’Université de Montréal (CHUM), and University of Calgary (UCalgary). Patients were identified from prospective ILD databases at UCSF and UBC and from retrospective review of medical records from the ILD clinics at CHUM and UCalgary. Patients were included if they had a multidisciplinary team

Cohort Formation and Study Population

One hundred one patients with a diagnosis of cHP treated with MMF or AZA were identified from the four ILD centers. Of these patients, 31 were excluded (30 from UCSF and one from UBC) due to lack of follow-up data after the initiation of therapy; 70 patients were included in the final cohort (Fig 1). Patients included in the study were younger and more likely to have undergone a surgical lung biopsy than those who were excluded for lack of follow-up. Other baseline characteristics were similar

Discussion

In this multicenter retrospective study, we demonstrated that treatment of cHP with MMF or AZA is associated with improved gas exchange and a reduction in prednisone dose. MMF and AZA appeared well tolerated, with low rates of medication discontinuation and similar adverse effects compared with previous reports.11, 13, 16 To our knowledge, this is the first study to describe the effects of MMF or AZA on the clinical course of cHP.

There is a pressing need to identify alternative therapeutic

Acknowledgments

Author contributions: J. M. takes responsibility for the content of the manuscript, including the data and analysis and is guarantor of this paper. J. M., K. A. J., H. R. C., C. J. R., and B. L. contributed to the conception and design, acquisition of data, and analysis and interpretation of the data. J. M., J. J. S., A. F., and H. R. C. contributed to the analysis and interpretation of the data. C. A., B., M. E., K. D. J., C. D. F., H. M., and B-P. D. contributed to the acquisition of the

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    Drs Morisset and Johannson contributed equally to this manuscript.

    FUNDING/SUPPORT: This work was supported by the Nina Ireland Program for Lung Health.

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