Lymphangioleiomyomatosis (LAM) is a rare, progressive lung disease that primarily affects women of childbearing age. The FDA has approved sirolimus (Rapamune, Pfizer) as the first drug to treat LAM. Rapamune was originally approved to prevent organ rejection.
FDA approved sirolimus (Rapamune, Pfizer) to treat lymphangioleiomyomatosis (LAM) is a rare, progressive lung disease that primarily affects women of childbearing age.
Rapamune is an immunosuppressant agent, available as a tablet and an oral solution.
LAM is characterized by an uncontrollable growth of smooth muscle cells within lung tissue, including the airways, blood vessels, and lymph vessels. The abnormal cells produce materials that break down tissue causing the formation of cysts, which destroy the architecture of the lungs and limit the delivery of oxygen to the rest of the body. Approximately 800 patients in the United States are currently diagnosed with LAM, which is often fatal.
The drug acts to improve lung function in women by inhibiting T-cell activation and proliferation in response to antigenic stimulation while also inhibiting antibody production.
It was originally approved in 1999 to help prevent organ rejection in patients aged 13 years and older receiving kidney transplants. FDA granted Rapamune breakthrough therapy designation and priority review for LAM due to sponsor demonstration that the drug may offer a substantial improvement over available therapies. The drug also received orphan drug designation.
FDA's approval of Rapamune is based on the results from the Multicenter International Lymphangioleiomyomatosis Efficacy of Sirolimus or MILES Trial that compared Rapamune to placebo in 89 patients for a 1-year treatment period, followed by a 1-year observation period. The trial studied the difference between the groups in forced expiratory volume in 1 second (FEV1) The difference between the groups in the average decrease in FEV1 was approximately 153 mL.
Mouth and lip ulcers, diarrhea, abdominal pain, nausea, and sore throat are the most common side effects associated with Rapamune in the treatment of LAM include. Serious side effects including hypersensitivity and edema have been observed in renal transplant patients.