Long-term efficacy and safety of sirolimus therapy in patients with lymphangioleiomyomatosis

BACKGROUND: Sirolimus has been confirmed to be effective for lymphangioleiomyomatosis (LAM), a rare multisystem neoplastic disease in women. The long-term effects of sirolimus treatment for LAM, however, are largely unknown. We aimed to analyze the long-term efficacy and safety of sirolimus therapy for LAM with 4-year follow-up. METHODS: In total, 142 sporadic LAM patients who took sirolimus for 1–4 years were retrospectively enrolled for this analysis. The variables used for analysis included pulmonary function tests, arterial blood gas analysis, 6-min walking distance (6MWD), St. George’s Respiratory Questionnaires (SGRQ) and serum vascular endothelial growth factor-D (VEGF-D) levels before and after the initiation of sirolimus therapy. The rates of change (slope) in those variables were calculated, and adverse events were also analyzed. RESULTS: In total, 122, 83, 60 and 32 patients out of 142 were followed for 1, 2, 3 and 4 years respectively. Sirolimus treatment improved the change rate in forced expiratory volume in 1 second (FEV(1)) and forced vital capacity (FVC) compared with the data before treatment (FEV(1), − 10 ± 15 vs. − 178 ± 36 ml/y, P < 0.001 and FVC, 54 ± 22 vs.-72 ± 68 ml/y, P < 0.05). In comparison to the baseline measurements, significant improvements were observed in FEV(1) at the first year; FVC at 1–2 years; arterial oxygen levels, 6MWD, and SGRQ at 1–3 years; and VEGF-D at 1–4 years. Overall, all variables stabilized or improved during the 4 years of observation. Adverse events related to sirolimus were mild. CONCLUSION: Sirolimus therapy is effective at improving or stabilizing pulmonary function, oxygen levels, exercise capacity, and quality of life in patients with LAM for up to 4 years. VEGF-D is maintained at a lower level for 4 years after treatment. Adverse events related to sirolimus were mild.