McCormack et al randomized 89 women with lymphangioleiomyomatosis to receive 2 mg rapamycin or placebo daily for 12 months, followed by 12 months of drug-free observation. Women receiving sirolimus had stable lung function on spirometry, fewer symptoms, fewer "respiratory events," and better quality of life during the treatment period. This was tempered by GI, dermatologic, hematologic, and metabolic side effects, along with an episode of pericarditis, in the treated group. Symptoms and lung function decline resumed upon stopping rapamycin. Pfizer paid much of the tab, but reportedly didn't participate otherwise. (n=89). NEJM 2011; March 16 online