Abstract
The value of rates of change in forced expiratory volume in 1 s (FEV(1)) and diffusing capacity of the lung for carbon monoxide (D(LCO)) to predict disease progression, and initiation of mTOR (mechanistic target of rapamycin) inhibitor therapy has not been evaluated.In 84 premenopausal lymphangioleiomyomatosis patients, individual rates of change in FEV(1) and D(LCO) and their 95% confidence intervals were used to derive subsequent lowest values of FEV(1) and D(LCO) that would prompt initiation of sirolimus therapy. These treatment criteria were compared with a criterion based on FEV(1) or D(LCO) ≤70% predicted. In 12 patients undergoing sirolimus therapy both methods for determining the optimal point for initiation of therapy were evaluated.27 and 35 patients who experienced greater than expected rates of change in FEV(1) and D(LCO), respectively, would have been excluded from therapy based on an FEV(1) or D(LCO) >70% pred. 25 of the 84 patients were eventually treated, but only when FEV(1) or D(LCO) were ≤70% pred. Applying such treatment criteria to 12 patients undergoing sirolimus therapy would have delayed treatment for many years.Premenopausal females in whom FEV(1) or D(LCO) are declining at rates above the expected based on their individual rates of decline, should be considered for sirolimus therapy before the FEV(1) or D(LCO) falls to ≤70% pred.