Successful Rituximab Therapy in Steroid-Resistant, Cryptogenic Organizing Pneumonia: A Case Series

Cryptogenic organizing pneumonia (COP) is an interstitial lung disease that is usually responsive to corticosteroid treatment. The treatment of COP has not been studied in randomized controlled trials; thus, treatment decisions are based on practice guidelines. We herein present, for the first time, 4 cases of patients with biopsy-proven COP who did not respond to corticosteroids but benefited from rituximab therapy. This report consists of a retrospective case series of patients who experienced steroid-resistant, biopsy-proven COP. Patients included in this case series suffered from acute or chronic COP and did not respond to corticosteroid treatment for a few weeks to months but later responded to rituximab. In a series of 4 patients, 1 patient had a complete radiological and clinical response after rituximab therapy, and the steroids could be gradually tapered. Three patients had a chronic course but had been able to lower steroid dosage or even discontinue the drug after being treated with rituximab. Since 40% of the patients with COP do not respond to or stay dependent on steroids, we think that even the ability to lower the steroid dosage by using rituximab as a steroid-sparing agent with a good safety profile is worth the effort. However, further studies are warranted.