Clinical trials for rare lung diseases: lessons from lymphangioleiomyomatosis.

Lymphangioleiomyomatosis (LAM) is a rare, slowly progressive neoplasm that causes gradual but often life-threatening cystic destruction of the lung. Advances in our understanding of the molecular and cellular pathogenesis have LAM have identified a number of promising targets for testing in therapeutic trials. However, the design, prioritization, organization, and implementation of clinical trials in rare lung diseases poses unique challenges, including geographically disperse populations, sluggish enrollment, off- label drug use, burdensome regulations, and paucity of validated surrogate endpoints.