Dosing and Outcomes of Conversion to Extended-Release Tacrolimus in Lung Transplant Recipients

Abstract

Extended release tacrolimus (LCP-Tac) is a novel once daily formulation with improved pharmacokinetic parameters compared to immediate release tacrolimus (IR-Tac). LCP-Tac use in renal transplant is associated with reduced tremor and decreased dose requirements; minimal data in lung transplant exist. We sought to assess the outcomes of conversion from IR-Tac to LCP-Tac in a cohort of lung transplant recipients (LTRs). All LTRs converted from IR-Tac to LCP-Tac from 10/2018-9/2019 were evaluated. Patient demographics, reason for and dose at time of conversion, conversion dose, and dose needed to achieve goal levels were recorded. Tac variability was calculated using coefficient of variability (CV). To normalize dose requirements across LTRs with variable goals, tac level to dose ratios were calculated. Conversion occurred in 8 LTRs with a median of 181 days of follow-up. LTRs converted were 65±7.8 years old, 75% male, and 75% Caucasian at a median of 124 (IQR 85.5-156) days post-transplant. Seven (87.5%) were converted due to tremor and 1 (12.5%) for high dose requirements. Of those converted for tremor, 5/7 (71.4%) reported improvement in baseline tremor. 50% of LTRs were on concurrent systemic azole. As expected, median overall tac dose requirements were decreased by 9.1%, however two LTRs required dose increases to maintain adequate trough levels. One LTR discontinued systemic azole during IR-Tac to LCP-Tac conversion. No change in tac CV was seen. Conversion from IR-Tac to LCP-Tac in LTRs was successful in this limited series. Most LTRs converted for tremor saw improvement. We observed decreases in dose requirements, however not to the degree recommended by package labeling (20%). Tac variability remained consistent with conversion. Further research is needed to determine the long-term clinical impact of conversion.