The FDA approved the Pfizer drug rapamycin (chemical name: sirolimus or rapamycin) that day for the treatment of pulmonary lymphangioleiomyomatosis (LAM), a rare progressive lung disease seen primarily in women of childbearing age, according to a U.S. Food and Drug Administration (FDA) news release dated May 28, 2015. Rapamycin is the first drug approved for the treatment of this disease. LAM is an extremely rare disease characterized by abnormal growth of smooth muscle cells that invade lung tissue, including airways, blood vessels and lymphatic vessels, causing destruction of the lungs, resulting in airflow obstruction and restriction of the lungs’ ability to deliver oxygen to the body. According to the U.S. National Library of Medicine, only two to five out of every million women worldwide have the disease. Rapamycin was originally approved in 1999 as an immunosuppressant for use in patients 13 years of age and older who have received a kidney transplant to assist in preventing organ rejection. The drug is available in both tablet and oral solution formulations. Because rapamycin proved to be more effective than other therapies for LAM, it received FDA Breakthrough Therapy Drug designation. The drug also received Priority Review status, which is an expedited review for drugs that have the potential to provide significant improvements in safety or efficacy in the treatment of serious diseases or conditions. Because LAM is a rare disease or condition, Repamycin has also received orphan drug designation for this indication. The drug’s development was also supported in part by the FDA’s Orphan Drug Funding Program, which provides funding for clinical studies of the safety and/or efficacy of orphan drugs. ”Orphan drug and breakthrough therapy designation provides financial incentives for manufacturers and increases interaction and advice from the FDA to facilitate the development and timely approval of innovative therapies for rare diseases that may not have been developed under the regular process,” said FDA Center for Drug Evaluation and Research’s Office of New Drugs Director John? Jenkins, PhD, had this to say. “The FDA assists pharmaceutical manufacturers through these special programs to get life-saving drugs to people in need faster.” The safety and efficacy of rapamycin for LAM was studied in a clinical trial comparing rapamycin to an inactive drug (placebo) in 89 patients with a 12-month treatment period and a subsequent 12-month observation period. The primary endpoint was the difference in the rate of change in the volume of exhaled gas in one second (first second exhaled volume or FEV1) in one person in the different trial groups. the difference in the mean reduction in FEV1 over the 12-month treatment period was approximately 153 mL. after discontinuation of rapamycin, the reduction in lung function returned to a rate similar to that of the placebo group. The most frequently reported side effects associated with rapamycin treatment for LAM are mouth and lip ulcers, diarrhea, abdominal pain, nausea, sore throat, acne, chest pain, calf swelling, upper respiratory tract infection, headache, dizziness, myalgia, and elevated cholesterol. Serious side effects, including hypersensitivity and swelling (edema), have been observed in kidney transplant patients. Repamycin is manufactured by Wyeth Pharmaceuticals, a subsidiary of Pfizer Pharmaceuticals. The FDA is the U.S. health and human services agency that protects public health by ensuring the reliability, efficacy, and safety of human and veterinary drugs, vaccines, and other biologics and medical devices. The agency is also responsible for the reliability and safety of the nation’s food supply, cosmetics, dietary supplements and products that release ionizing radiation, as well as regulating tobacco products.