12-month safety and efficacy of everolimus with reduced exposure cyclosporine in de novo renal transplant recipients.

The proliferation signal inhibitor everolimus (Certican), has demonstrated efficacy with full-dose cyclosporine (CsA) (Neoral). Two multicenter randomized controlled studies were performed to compare 12-month efficacy and safety of everolimus 1.5 and 3.0 mg/day with reduced-dose CsA. Study 1 enrolled 237 de novo renal allograft recipients, randomizing 222 nonblack patients to either everolimus 1.5 or 3.0 mg/day, with the Neoral) dose guided by C(2) (monitoring of CsA concentration 2 h after dosing). Study 2 had a similar protocol, with basiliximab included, enrolling 256 recipients and randomizing 243 nonblack patients. In Study 1, there was a lower incidence of acute rejection in nonblack patients on 3 mg/day (16.4%) compared with 1.5 mg/day (25.9%), P = 0.08. In Study 2, the inclusion of basiliximab lowered the overall incidence of acute rejection; 14.3% of nonblack patients (3 mg/day) and 13.6% of nonblack patients (1.5 mg/day) had acute rejection by 12 months (P =0.891). Renal function was preserved throughout the study, with no differences observed between groups within studies. Everolimus was well tolerated with no significant differences between doses. Everolimus, in combination with reduced-dose Neoral), demonstrated efficacy and was well tolerated. Basiliximab allows for utilization of lower doses of everolimus with reduced dosing of Neoral).

Everolimus therapeutic concentration range defined from a prospective trial with reduced-exposure cyclosporine in de novo kidney transplantation.

Prospective therapeutic drug monitoring of everolimus was performed in a 1-year multicenter trial in 237 de novo kidney transplant patients. Trough blood levels, rejection episodes, and safety parameters were evaluated to define an appropriate therapeutic concentration range for everolimus in this setting. Patients were randomized to everolimus starting doses of 0.75 mg bid (n = 112) or 1.5 mg bid (n = 125). Doses were then individualized based on everolimus trough blood levels (C0) in an attempt to maintain troughs > or = 3 ng/mL; no upper limit was specified. The regimen also contained corticosteroids and cyclosporine with an early dose reduction in months 2-3 posttransplant based on concentrations 2 hours postdose (C2). Cyclosporine C0 levels were also collected. Prospective therapeutic drug monitoring of everolimus C0 in patients starting at 0.75 mg bid led to dose adjustments in 52% of patients to an average long-term dose of 0.93 +/- 0.36 mg bid. This gave median (10th to 90th percentile) C0 levels of 5.3 (3.4-7.9) ng/mL. In patients starting at 1.5 mg bid, 55% had dose adjustments leading to an average long-term dose of 1.24 +/- 0.35 mg bid. This yielded C0 levels of 7.2 (4.4-11.6) ng/mL. Cyclosporine dosing began on average at 274 +/- 78 mg bid, was down-titrated in months 2-3 from 181 +/- 80 mg to 81 +/- 33 mg bid, and stabilized at 70 +/- 26 mg bid thereafter. This yielded median C2 levels of 1165 ng/mL in month 1, a down-titration with levels of 853 and 630 ng/mL in months 2 and 3, and a posttitration level of 472 ng/mL. The corresponding median cyclosporine C0 was 242 ng/mL initially and 70 ng/mL in the posttitration phase. In patients starting at 0.75 mg bid everolimus and an early down-titration of cyclosporine, everolimus C0 between 3 and 8 ng/mL was an effective and safe concentration range. Concentrations up to 12 ng/mL were tolerated over the first year posttransplant. This trial demonstrated that therapeutic monitoring of everolimus can be prospectively performed for dose individualization. Maintaining everolimus troughs in the range 3 to 8 ng/mL in the first posttransplant year with reduced-exposure cyclosporine is associated with good efficacy and safety profiles.

Everolimus with optimized cyclosporine dosing in renal transplant recipients: 6-month safety and efficacy results of two randomized studies.

Two prospective, randomized studies evaluated everolimus 1.5 vs. 3 mg/day with steroids and low-exposure cyclosporine (CsA) (C2 monitoring) in de novo renal transplant patients. Everolimus dosing was adjusted to maintain a minimum trough level of 3 ng/mL. Study 1 (A2306; n=237) had no induction therapy; in Study 2 (A2307; n=256) basiliximab was administered (Days 0 and 4). The primary endpoint was renal function at 6 months. CsA C2 target levels, initially 1200 ng/mL in Study 1 and 600 ng/mL in Study 2, were tapered over time post-transplant. Median creatinine levels in Study 1 were 133 and 132 micromol/L at 6 months in the 1.5 and 3 mg/day groups, respectively, and 130 micromol/L in both groups in Study 2. Biopsy-proven acute rejection (BPAR) occurred in 25.0% and 15.2% of patients in the 1.5 and 3 mg/day groups in Study 1, and 13.7% and 15.1% in Study 2. Incidence of BPAR was significantly higher in patients with an everolimus trough <3 ng/mL. There were no significant between-group differences in the composite endpoint of BPAR, graft loss or death, nor any significant between-group differences in adverse events in either study. Concentration-controlled everolimus with low-exposure CsA provided effective protection against rejection with good renal function.

Influence of delayed initiation of cyclosporine on everolimus pharmacokinetics in de novo renal transplant patients.

We quantified the influence of delayed initiation of cyclosporine on everolimus pharmacokinetics in order to provide dosing guidance for kidney transplant patients. In a randomized multicenter study, 56 de novo kidney transplant patients received everolimus, basiliximab, corticosteroids and either immediate (n = 40) or delayed (n = 16) initiation of cyclosporine based on renal function. Everolimus and cyclosporine predose blood levels (Cmin) were obtained over the first 3 months post-transplant. Everolimus Cmin averaged 9-11 ng/mL in the immediate cyclosporine group over the first 3 months. In the delayed cyclosporine group, average everolimus Cmins were significantly lower by 2.9-fold in the absence vs. presence of cyclosporine: 2.9 +/- 2.8 vs. 8.3 +/- 3.7 ng/mL (p < 0.001). Likewise, the within-patient ratio of everolimus Cmins in the presence/absence of cyclosporine averaged 2.9 (range, 0.7-5.6). Both everolimus and cyclosporine blood concentrations need to be monitored in kidney transplant patients with delayed graft function during the period when cyclosporine is withheld and shortly after its initiation. Dosing of everolimus needs to be adjusted to take into account an average threefold increase in everolimus exposure when cyclosporine is added to the regimen.

A three-arm study comparing immediate tacrolimus therapy with antithymocyte globulin induction therapy followed by tacrolimus or cyclosporine A in adult renal transplant recipients.

BACKGROUND: Induction therapy with antithymocyte globulin (ATG) reduces the incidence of acute rejection after transplantation. A study was undertaken to assess the efficacy and safety of ATG induction on tacrolimus-based and cyclosporine A (CsA)-based therapies compared with immediate tacrolimus triple therapy in kidney transplant recipients. METHODS: In a 6-month, open-label, randomized, prospective study conducted in 30 European centers, 555 renal transplant patients were randomly assigned to tacrolimus triple therapy (Tac triple, n=185), ATG induction with tacrolimus (ATG-Tac, n=186), or ATG induction with CsA microemulsion (ATG-CsA, n=184); all were combined with azathioprine and corticosteroids. The primary endpoint was incidence and time to first acute rejection episode confirmed by biopsy. RESULTS: Patient demographics and clinical parameters at baseline were similar. Patient and graft survival rates were similar in all groups. The incidence of clinically apparent acute rejection was significantly higher (P=0.003) for Tac triple (33.0%) compared with ATG-Tac (22.6%) and the incidence for ATG-Tac was significantly lower (P=0.004) than for ATG-CsA (37.0%). The incidences of acute rejection confirmed by biopsy (primary endpoint) were 25.4%, 15.1%, and 21.2% for Tac triple, ATG-Tac, and ATG-CsA, respectively (Tac triple vs. ATG-Tac, P=0.004). The incidences of corticosteroid-resistant acute rejection were 7.0% (Tac triple), 4.8% (ATG-Tac), and 10.9% (ATG-CsA) (ATG-Tac vs. ATG-CsA, P=0.038). In the ATG groups, the incidences of leukopenia, thrombocytopenia, serum sickness, fever, and cytomegalovirus infection were significantly higher (P<0.05). CONCLUSIONS: Acute rejection was significantly lower in the ATG-Tac group compared with the ATG-CsA and Tac triple groups. Significantly more hematologic and infectious adverse events were observed in both ATG induction groups.

Autosomal dominant hypocalcemia caused by a novel mutation in the loop 2 region of the human calcium receptor extracellular domain.

We report a novel missense mutation N124K in the extracellular calcium receptor (CaR) identified in two related subjects with the phenotypic features of autosomal dominant hypocalcemia (ADH). Expression of the N124K mutant receptor created by site-directed mutagenesis and transfected into HEK-293 cells was comparable with that of the wild-type (WT) receptor and two other mutant receptors N118K and L125P identified in subjects with ADH. Functional characterization by the extracellular Ca2+ ion ([Ca2+]0)-stimulated phosphoinositide (PI) hydrolysis in transfected HEK-293 cells showed that the N124K mutant receptor was left-shifted in Ca2+ sensitivity. This biochemical gain-of-function is comparable with that seen in other missense mutations of the CaR identified in subjects with ADH. We tested a series of missense substitutions (R, Q, E, and G) in addition to K for N124 and found that only the N124K mutation and to a much lesser extent N124R caused a left shift in Ca2+ sensitivity. Thus, a specific substitution, not merely a mutation of the N124 residue, is required for receptor activation. The N124K mutation is one of eight naturally occurring mutations in subjects with ADH identified in a short segment A116-C129 of the CaR extracellular domain (ECD). We present a hypothesis to explain receptor activation by mutations in this region based on the recently described three-dimensional structure of the related metabotropic glutamate type 1 receptor (mGluR1).

Renal cysts and diabetes syndrome linked to mutations of the hepatocyte nuclear factor-1 beta gene: description of a new family with associated liver involvement.

BACKGROUND: Mutations in the hepatocyte nuclear factor (HNF)-1beta gene (TCF2) are responsible for a syndrome characterized by maturity-onset diabetes of the young, a nondiabetic renal disease, genital malformations, and liver dysfunction. METHODS: The HNF-1beta gene was screened for mutations in four members of an Italian family with early-onset, nonketotic diabetes or a familiar, nondiabetic renal disease and nonprogressive liver disorder. RESULTS: The genetic analysis revealed an already described nonsense mutation in codon 177 of HNF-1beta gene (R177X) in the four related subjects. Clinical features included diabetes in three of four patients, monolateral renal hypoplasia with cysts in the controlateral kidney in two patients, and bilaterally small hyperechoic kidneys without cysts in the other two patients. Renal function impairment was severe in one patient, requiring dialysis treatment, and mild in three. Three patients had nonprogressive liver dysfunction, with long-lasting enzyme alterations but no liver insufficiency or jaundice. CONCLUSION: HNF-1beta gene mutations are associated with a wide variability in severity and pattern of clinical symptoms within the same kindred regarding diabetes and renal impairment. Moderate liver dysfunction may be a so far overlooked component of the syndrome.