Impact of cyclosporine dosing frequency on graft function and survival after the conversion from sandimmun to neoral in stable kidney transplanted patients

Circadian and time-dependent variability in tacrolimus pharmacokinetics

Tacrolimus (TAC) is considered a critical dose drug. The purpose of our study was to investigate circadian and time-dependent changes in TAC pharmacokinetics over the first year after kidney transplantation. Pharmacokinetic (PK) studies were performed in 26 recipients of first living donor kidney transplants at day 7 after morning (a.m.) and evening (p.m.) doses of TAC. Additional serial PK studies were carried out in nine patients at month 6 (M6) and month 12 (M12). Blood samples were collected before 1, 1.5, 2, 2.5, 3, 4, 6, 8 and 12 h after TAC administration. Demographics, TAC and adjunctive immunosuppressive doses, hematology, and biochemistry were recorded in each PK study. Mean age was 37 years, body mass index 23 kg/m(2), 58% males, and 85% Caucasian. Higher AUC (231.4 vs. 220 ng.h/mL, P = 0.06) and C(max) (34.1 +/- 12.6 vs. 24.4 +/- 9.8 ng/mL, P < 0.001), and lower T(max) (1.6 +/- 0.8 vs. 2.7 +/- 2.0 h, P = 0.05) values were observed comparing a.m. and p.m. administrations. Comparing D7, M6 and M12, there was a significant increase in dose-normalized AUC (31.4 +/- 22.2 vs. 50.1 +/- 33 vs. 39.2 +/- 24.4 ng.h/mL/mg, P = 0.005), C(max) (4.4 +/- 2.4 vs. 7.8 +/- 3.5 vs. 6.0 +/- 3.3 ng/mL/mg, P < 0.001) and T(max) (1.6 +/- 1.1 vs. 1.7 +/- 0.4 vs. 1.8 +/- 0.8 h, P = 0.006), respectively. Over the first year the intraindividual variability of dose-normalized AUC, C(max) and C(0) were 82%, 72%, and 90%, respectively. No significant changes were observed comparing inter-individual variability of dose-normalized AUC (21%, 24%, 33%), C(max) (46%, 45%, 55%), C(0) (49%, 83%, 81%) at D7, M6 and M12, respectively. We observed a good correlation between a.m. and p.m. TAC AUC (r(2) = 0.90) and C(0) (r(2) = 0.88). Tacrolimus pharmacokinetics display circadian variation suggesting a slower and delayed absorption phase at nighttime. Tacrolimus also showed time-dependent PK changes, suggesting an improvement in absorption during the first 6 months. Despite circadian variation we observed good correlations between a.m. and p.m. TAC AUC (r(2) = 0.90) and C(0) (r(2) = 0.88) and between C(0) and total daily TAC exposure (a.m. + p.m. AUC) suggesting that trough-guided therapeutic monitoring is still a reliable and simple strategy to optimize the clinical use of TAC.

Long-term kidney transplant outcomes in patients receiving oil-based or microemulsion formulations of cyclosporine

In the last 20 years long-term experience with cyclosporine use in kidney transplantation has increased, allowing a more precise identification of its benefits.

METHODS

We performed a retrospective analysis of 1619 kidney transplants that received cyclosporine-based immunosuppressive therapy. Patients were divided into three groups (1) oil-based cyclosporine (SIM) with trough monitoring (GI, n=617); (2) microemulsion formulation (NEO) with trough monitoring (GII, n=962); and (3) NEO with C2 monitoring (GIII, n=40). Information was obtained on transplant demography; adjunctive immunosuppressive agent; living (LD) versus cadaveric (CAD) recipients; delayed graft function; any treated acute rejection; graft function at 3, 6, and 12 months, patient and graft survival, as well as causes of graft loss and death.

RESULTS

At 15 years follow-up, patient and graft survival were 67.5% and 41.6%, being superior, among LD versus CAD recipients (patient: 78.7% vs 57.7%, P<.001; graft: 56.4% vs 30.5%, P<.001). In LD (54% vs 32%, P<.001) and CAD (69% vs 55%, P<.001) NEO reduced the incidence of AR and improved 8-year patient (LD: 81.8% vs 94.7%; CAD: 66.4 vs 79.9%, P<.01) and graft survival (LD: 58.3 vs. 80%; CAD: 40.2% vs. 59.5%, P<.01), compared to SIM. Overall 8-year graft survival was inferior among patients with increased 1-year creatinine values (< or =1.5, 1.6-2.5 and >2.5 mg/dL) level (74% vs 63.9% vs 22.4%, P<.001) or change in Cr (< or =0.1, 0.2-0.4, >0.5 mg/dL) level (73.1% vs 61.9% vs 37.2%, P<.001). In patients at the same level of graft function, those receiving NEO showed superior 8-year patient and graft survival compared with SIM.

CONCLUSION

Compared to SIM, NEO reduced the incidence of acute rejection and produced superior long-term patient and graft survival.