The investigators have conducted a Phase1b study to test the safety of various doses of Saracatinib in LAM subjects. The purpose of the Phase1b trial was to determine the optimal dose in terms of safety and tolerability in LAM population. Three escalating doses of saracatinib; 50, 125 and 175 mg were studied. Saracatinib was given orally once a day. Overall, subjects tolerated Saracatinib well. The investigators chose the dose of 125 mg to conduct further testing of both safety and efficacy in this Phase 2a trial.