Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Tacrolimus”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

In vitro release of Tacrolimus from Tacrolimus ointment and its speculated mechanism.

The in vitro release profiles and the bleeding phenomenon of Tacrolimus and propylene carbonate (PC) as a dispersing solvent for Tacrolimus drug substance in Tacrolimus ointment were investigated when changing concentrations of Tacrolimus and PC in the ointment were used, respectively. The bleeding test result indicated that Tacrolimus was in equilibrium between inside and outside of PC droplets in intact ointment base. A cumulative release amount of Tacrolimus from ointment, plotted against the square root of time, showed a straight line initially with a slope of q1 followed to change a slope to be q2 at a certain time, where the relation of these slopes being q1<q2. The q1 values increased with the concentration of Tacrolimus but decreased with PC concentration in Tacrolimus ointment. And the q2 values increased with Tacrolimus concentration but were independent of PC concentration. These profiles indicated that there were two phases for Tacrolimus release from ointment, namely, first phase was related with the period during PC release and the second phase was related with the state of ointment after PC release. When the PC release was applied to the Higuchi's release equation, the above slope q1 was found to be correlated to the parameter of A/phi(0), where A was a parameter of release rate of PC and phi(0) was an initial volume fraction of PC droplets. It should be indicated that more rapid release rate of PC rather than that of Tacrolimus resulted in the generation of amorphous phase of Tacrolimus outside of remaining PC droplets. During PC release, the slope q1 could be influenced by the thermodynamic activity of Tacrolimus dissolved in PC droplets. After PC release, it would be reasonable to speculate that the amorphous cluster of Tacrolimus with a constant thermodynamic activity would give constant q2 values regardless of PC contents in Tacrolimus ointment.

Chemistry, Pharmaceutical↗

A multicenter trial of FK506 (tacrolimus) therapy in refractory acute renal allograft rejection. A report of the Tacrolimus Kidney Transplantation Rescue Study Group.

A multicenter trial was conducted to evaluate the efficacy and safety of tacrolimus in the treatment of refractory renal allograft rejection. Renal transplant recipients experiencing biopsy-proven recurrent acute allograft rejection were eligible if the current rejection episode was refractory to corticosteroids. A total of 73 patients were enrolled, of whom 59 (81%) had previously received at least one course of antilymphocyte antibody as rejection therapy. One-year follow-up was available in 93% of patients. Median time to tacrolimus rescue therapy was 75 days after transplantation (range, 18-1448 days). Therapeutic responses to tacrolimus included improvement in 78% of patients, stabilization in 11%, and progressive deterioration in 11%. The risk of experiencing progressive deterioration was related to the pretacrolimus serum creatinine level: serum creatinine < or = mg/dl, 3%; 3.1-5 mg/dl, 16% (P < 0.04); > 5 mg/dl, 23% (P < 0.02). Twelve-month (from the time of initiation of tacrolimus therapy) actuarial patient and graft survival rates were 93% and 75%. Graft loss occurred in 19 patients (25%) at a median time of 108 days. Fourteen episodes of recurrent rejection were diagnosed in 10 patients (14%), at a median time of 101 days. Eleven episodes of recurrent rejection were treated (three patients underwent transplant nephrectomy), with resolution achieved in nine patients. Antilymphocyte antibody therapy was not used to treat recurrent rejection. Serum creatinine values improved during tacrolimus therapy: median serum creatinine level before tacrolimus, 3.2 mg/dl; median at 1 year after tacrolimus, 1.8 mg/dl. Twelve infections were documented in 11 patients (15%), including cytomegalovirus infection in three patients (4%). Posttransplant lymphoproliferative disorder was diagnosed in a single patient. Tacrolimus whole blood levels averaged 15.0 +/- 9.9 ng/ml at day 7 of tacrolimus therapy and 9.4 +/- 5.1 ng/ml at 1 year, and were consistent among individual centers. Treatment outcome did not correlate with tacrolimus blood levels. The most commonly observed adverse events were neurological and gastrointestinal. Seventy-four percent of patients received tacrolimus for at least 1 year. Tacrolimus therapy was discontinued in 18% of patients for rejection (11% for progressive, unrelenting rejection, and 7% for recurrent rejection). Tacrolimus therapy was discontinued in 8% of patients due to adverse events. In conclusion, tacrolimus rescue therapy provides (1) prompt, effective reversal of refractory renal allograft rejection, (2) good long-term renal allograft function, (3) a low incidence of recurrent rejection, and (4) an acceptable safety profile in renal allograft recipients experiencing refractory rejection.

Acute Disease↗

Role of diltiazem on tacrolimus pharmacokinetics in tacrolimus-induced nephrotoxic rats.

The effects of diltiazem on tacrolimus pharmacokinetics during tacrolimus-induced nephrotoxicity were studied. In normal rats, co-administration of diltiazem significantly increased AUC(0-infinity) of tacrolimus and reduced total body clearance, Cltot, after intravenous and oral administration. In tacrolimus-induced nephrotoxicity, AUC(0-infinity) of tacrolimus increased 40.7%, while the apparent volume of initial distribution space, Vd1, the apparent volume of steady-state distribution space, Vdss, and Cltot decreased 27.4%, 19.5% and 27.4%, respectively, as compared with the control. Co-administration of diltiazem lowered the AUC(0-infinity) of tacrolimus 36.2% and increased Vd1i.v. 62.8% in Vdss 45.9% and Cltot(i.v) 59.0% in tacrolimus-induced nephrotoxicity, resulting in partial improvement in renal function. These pharmacokinetic alterations due to diltiazem contrasted with those seen in normal rats. As a result, the pharmacokinetic parameters in tacrolimus-induced nephrotoxicity with coadministration of diltiazem resembled those in control rats. Mean tacrolimus concentrations in kidney cortex and medulla in a tacrolimus nephrotoxic group given diltiazem were 33.1% and 44.7% lower than those in a nephrotoxic model due to tacrolimus alone. But the tissue/blood concentration ratio of tacrolimus did not change regardless of the presence of diltiazem. Our findings suggest that co-administration of diltiazem has an advantageous effects on tacrolimus pharmacokinetics to protect against tacrolimus-induced nephrotoxicity.

Animals↗

Tacrolimus in pancreas transplantation: a multicenter analysis. Tacrolimus Pancreas Transplant Study Group.

This follow-up multicenter analysis is based on 362 pancreas allograft recipients at 14 institutions who were given tacrolimus between 1 May 1994 and 15 November 1995. Three groups were studied: (1) recipients given tacrolimus initially for induction and maintenance therapy (n = 250; 215 without, 35 with, a concurrent bone marrow transplant), (2) recipients who converted to tacrolimus for rescue or rejection therapy (n = 89), and (3) recipients who converted to tacrolimus for other reasons (n = 23). Of 215 recipients without a bone marrow transplant in the induction group, 166 (77%) underwent a simultaneous pancreas-kidney transplant (SPK), 29 (14%) a pancreas transplant alone (PTA), and 20 (9%) a pancreas after previous kidney transplant (PAK). Initial antibody therapy was given to 185 (86%) recipients. All 215 received tacrolimus and prednisone; 202 (94%) also received azathioprine (AZA) and 11 (5%) mycophenolate mofetil (MMF). The most common side effects of tacrolimus were neurotoxicity in 21%, nephrotoxicity in 21%, gastrointestinal (GI) toxicity in 13%, and diabetogenicity in 13% of these recipients. No recipient in this group developed new-onset insulin-dependent diabetes mellitus. Of 89 recipients in the rescue group, 71 (79%) had an SPK, 11 (13%) a PTA, and 7 (8%) a PAK. Before conversion, all had been on cyclosporine (CsA)-based immunosuppression; 74% of them had 2 or more rejection episodes previously. The most common side effects were nephrotoxicity in 27%, neurotoxicity in 26%, GI toxicity in 18%, and diabetogenicity in 8% of these recipients. No recipient in this group developed new-onset insulin-dependent diabetes mellitus. In the induction group patient survival at 1 yr was 98% for SPK, 79% for PTA, and 100% for PAK recipients. According to a matched-pair analysis, pancreas graft survival for SPK recipients at 1 yr was 88% with tacrolimus vs. 73% with CsA (p = 0.002); for PTA recipients, 68% vs. 70% (p > 0.35); and for PAK recipients, 85% vs. 65% (p = 0.13). Graft loss from rejection was not different with tacrolimus vs. CsA in all 3 pancreas recipient categories. At 1 yr, 17% of recipients had converted from tacrolimus to CsA for diabetogenicity, nephrotoxicity, or rejection; 23% had converted from AZA to MMF. The incidence of post-transplant lymphoma was < 2%. In the rescue group, patient survival rates at 1 yr were 96% for SPK, 100% for PTA, and 86% for PAK recipients (p < 0.08). Pancreas graft survival at 1 yr was 89% for SPK, 58% for PTA, and 69% for PAK recipients (p = 0.004). Graft loss from rejection was significantly lower for SPK vs. PTA or PAK recipients. At 1 yr, 20% of recipients had reconverted from tacrolimus to CsA for rejection, neurotoxicity, or nephrotoxicity; 19% had converted from AZA to MMF. There were no post-transplant lymphomas in the rescue group. This follow-up multicenter analysis shows that tacrolimus after pancreas transplantation is associated with high graft survival rates when used for induction and with high graft salvage rates when used for rescue therapy. The rate of graft loss from rejection is low in all 3 pancreas recipient categories. The overall incidence of new-onset insulin-dependent diabetes mellitus is < 1%, as is the incidence of post-transplant lymphoma. Converting from tacrolimus to CsA and, in patients on tacrolimus, from AZA to MMF, is safe; interchangeable use of drugs appears to be of immunologic benefit. To determine the best immunosuppressive regimen after pancreas transplantation, a prospective randomized study comparing tacrolimus and MMF vs. Neoral plus MMF is mandatory.

Adult↗

Tacrolimus metabolite cross-reactivity in different tacrolimus assays.

OBJECTIVES: Tacrolimus (FK506) is an immunosuppressive drug with great clinical promise. There is a controversy regarding the role of tacrolimus metabolites in immunosuppression and toxicity, and immunoassays and immunophilin binding assays have not been adequately tested for metabolite cross-reactivity. Methods are limited to HPLC and HPLC-MS for quantifying the parent drug. Mixed lymphocyte culture assay (MLC) is the preferred functional bioassay for the measurement of parent drug and active metabolites but it is not practical for routine laboratory use. Due to differences in assay methods and reagent specificity, the concentration of tacrolimus in a given specimen may vary among different assay kit manufacturers. The objective of this study was to evaluate the degree of cross-reactivity or interference of the three first-generation tacrolimus metabolites [13-O-demethyl (M-I), 31-O-demethyl (M-II) and 15-O-demethyl (M-III)] among two different tacrolimus immunoassays (Immunoassay: PRO-Trac II FK506, Abbott IMx tacrolimus-II); and the radioreceptor assays (RRA) using minor immunophilins (14, 37, and 52 kDa immunophilins) and tacrolimus binding protein (FKBP12). METHODS: First-generation tacrolimus metabolites (M-I, M-II, and M-III) spiked in drug-free whole blood were assayed with RRA using three minor immunophilins (14, 37, and 52 kDa) and two commercial immunoassay procedures (Incstar PRO-Trac II tacrolimus, Abbott IMx tacrolimus II). The results were compared to previously published FKBP-12 RRA data and their immunosuppressive potency. RESULTS AND CONCLUSION: The first generation tacrolimus metabolites (M-I, M-II, and M-III) were tested using concentrations of 10 and 20 ng/mL. The significance of the metabolite interference (% of the total interference) was calculated based on the relative concentration of each metabolite present at steady-state trough concentrations in renal transplant recipients (22). Metabolite I, which has no functional immunosuppressive activity showed minimal interference compared to M-II and M-III in all assays except the 14 kDa RRA. The Incstar PRO-Trac II tacrolimus assay showed the least M-I interference. Metabolite-II, which has a pharmacologic potency similar to the parent drug, showed a significant interference in the immunoassays and significant interference in radioreceptor assays. Metabolite III, which is pharmacologically inactive, produces 3-10% interference in the different assays if its presence in the blood is 6% of the parent drug. The total interference from these three metabolites was greater in the immunoassays than in the receptor assays. Receptor assays for tacrolimus provide results closer to the target value than do immunoassays.

Cross Reactions↗

A short-term trial of tacrolimus ointment for atopic dermatitis. European Tacrolimus Multicenter Atopic Dermatitis Study Group.

BACKGROUND: Tacrolimus (FK 506) is an effective immunosuppressant drug for the prevention of rejection after organ transplantation, and preliminary studies suggest that topical application of tacrolimus is effective in the treatment of atopic dermatitis. METHODS: We conducted a randomized, doubleblind, multicenter study that compared 0.03 percent, 0.1 percent, and 0.3 percent tacrolimus ointment with vehicle alone in patients with moderate to severe atopic dermatitis. The ointment was applied twice daily to a defined, symptomatic area of 200 to 1000 cm2 of skin for three weeks. The primary end point was the change in the summary score for erythema, edema, and pruritus between the first and last days of treatment. RESULTS: After three weeks of treatment, the median percentage decrease in the summary score for dermatitis on the trunk and extremities was 66.7 percent for the 54 patients receiving 0.03 percent tacrolimus, 83.3 percent for the 54 patients receiving 0.1 percent tacrolimus, 75.0 percent for the 51 patients receiving 0.3 percent tacrolimus, and 22.5 percent for the 54 patients receiving vehicle alone (P<0.001). The results for the face and neck were similar. The differences among the three tacrolimus groups were not statistically significant. A sensation of burning at the site of application was the only adverse event that was significantly more frequent with tacrolimus than with vehicle alone (P<0.001). Throughout the study, most patients in all three tacrolimus groups had blood concentrations of tacrolimus below 0.25 ng per milliliter. The highest concentration was 4.9 ng per milliliter, which was reported in the group receiving 0.3 percent tacrolimus. CONCLUSIONS: The short-term application of tacrolimus ointment is effective in the treatment of atopic dermatitis, with the sensation of burning being the main side effect.

Administration, Cutaneous↗

Desoximetasone 0.25% and tacrolimus 0.1% ointments versus tacrolimus alone in the treatment of atopic dermatitis.

Long-term in vitro compatibility of desoximetasone and tacrolimus ointments prompted the current trial in humans. We aimed to evaluate the efficacy of twice-daily simultaneous application of desoximetasone and tacrolimus in the treatment of atopic dermatitis versus tacrolimus monotherapy. Eighty-two subjects were treated in this multicenter, single-group, double-blinded, paired, 3-week follow-up clinical study of desoximetasone 0.25% and tacrolimus 0. 1% ointments versus tacrolimus 0.1% ointment and vehicle. Subjects were treated twice daily for 21 days or until clearing. Safety and efficacy were assessed at days 3, 7, 14, and 21. The combination of desoximetasone and tacrolimus ointment was superior to tacrolimus alone (P=.0002) in treating atopic dermatitis as measured by the summary of the scores for erythema, lichenification, pruritus, scaling/dryness, and oozing/crusting. Of note, pruritus at the application site was diminished in subjects treated with desoximetasone and tacrolimus together compared with tacrolimus alone (P=.04). Combination treatment with desoximetasone and tacrolimus offered increased efficacy and tolerability over tacrolimus alone in patients with atopic dermatitis.

Adolescent↗

Conversion from cyclosporine microemulsion to tacrolimus-based immunoprophylaxis improves cholesterol profile in heart transplant recipients with treated but persistent dyslipidemia: the Canadian multicentre randomized trial of tacrolimus vs cyclosporine microemulsion.

BACKGROUND: Tacrolimus improves lipid profile in renal and liver transplant recipients. The impact of conversion from cyclosporine microemulsion (Neoral) to tacrolimus (Prograf) in a large randomized study of stable heart transplant recipients with treated but persistent mild dyslipidemia is reported. METHODS: One hundred twenty-nine long-term (>or=12 months) cyclosporine microemulsion-treated heart transplant recipients with low-density lipoprotein cholesterol >2.5 mmol/liter and/or a total cholesterol/high-density lipoprotein cholesterol ratio >4 were recruited for the study. Complete lipid profile was assessed before (baseline) and after 6 months of treatment with either cyclosporine microemulsion maintenance (n=64) or tacrolimus conversion (n=65). RESULTS: At 6 months, tacrolimus-converted patients exhibited a greater decrease in total cholesterol (from 5.51 +/- 0.16 to 4.88 +/- 1.22 mmol/liter [tacrolimus], vs 5.61 +/- 1.36 to 5.38 +/- 0.87 mmol/liter [cyclosporine]; p = 0.0078). This decrease in cholesterol was caused largely by a decrease in low-density lipoprotein cholesterol (-0.41 +/- 0.54 [tacrolimus] vs -0.13 +/- 0.55 [cyclosporine]; p=0.0018). There were no changes in high-density lipoprotein cholesterol and triglyceride levels, but apolipoprotein B therapy was reduced in tacrolimus-converted vs cyclosporine-maintained patients (p=0.0003). By 6 months, 23.7% of tacrolimus- vs 6.7% of cyclosporine-treated patients met the target lipid levels for high-risk patients (p=0.0094). Conversion from cyclosporine to tacrolimus resulted in decreases in blood urea nitrogen, creatinine, and uric acid without any changes in glucose, HbA(1C), and insulin levels. CONCLUSIONS: Conversion from cyclosporine microemulsion- to tacrolimus-based immunoprophylaxis resulted in decreased cholesterol, apolipoprotein B, urea, creatinine, and uric acid without any clinically evident perturbation of glucose metabolism in stable heart transplant recipients with treated but persistent mild dyslipidemia.

Adult↗

A randomized, vehicle-controlled trial of tacrolimus ointment for treatment of atopic dermatitis in children. Pediatric Tacrolimus Study Group.

BACKGROUND: A topical formulation of tacrolimus, an immunosuppressant currently marketed for the prevention of rejection after solid organ transplant, is a potential therapeutic agent for atopic dermatitis. OBJECTIVE: We sought to determine the safety and efficacy of tacrolimus ointment in pediatric patients with moderate-to-severe atopic dermatitis. METHODS: In this double-blind, vehicle-controlled multicenter trial, children ages 7 to 16 years were treated with twice daily application of tacrolimus ointment at 1 of 3 concentrations (0.03% [n = 43], 0.1% [n = 49], or 0.3% [n = 44]) or vehicle (n = 44) for up to 22 days, with a 2-week follow-up period. RESULTS: The Physician's Global Evaluation of clinical response showed that 69% (95% confidence interval: 53-82) of patients in the 0.03% tacrolimus ointment group, 67% (95% confidence interval: 52-81) in the 0.1% tacrolimus ointment group, and 70% (95% confidence interval: 54-83) in the 0.3% tacrolimus ointment group, compared with 38% (95% confidence interval: 24-54) in the vehicle group, had a marked to excellent (> or =75%) improvement or clearing of their atopic dermatitis (P =.005, .007, and .004, respectively for the 3 tacrolimus groups compared with the vehicle group). The mean percent improvement for a modified Eczema Area and Severity Index at end of treatment for each of the 3 tacrolimus groups (0.03%, 72%; 0.1%, 77%: and 0.3%, 81%) was significantly better than that of the vehicle group (26%; P <.001). The median percent reduction in pruritus was significantly greater for tacrolimus-treated patients (74% to 89%) than for vehicle-treated patients (51%, P = .027). No serious systemic adverse events were noted, and systemic absorption was minimal. CONCLUSION: Tacrolimus ointment appears to be safe and effective in children with atopic dermatitis.

Administration, Topical↗

Hyponatraemia and hyperkalaemia are more frequent in renal transplant recipients treated with tacrolimus than with cyclosporin. Further evidence for differences between cyclosporin and tacrolimus nephrotoxicities.

BACKGROUND: This study was designed to examine the hypothesis that the nephrotoxicities caused by cyclosporin and tacrolimus might differ in respect of sodium and potassium handling. METHODS: 125 patients were studied retrospectively for the first 90 days after renal transplantation. Eighty were treated initially with cyclosporin and 45 with tacrolimus. RESULTS: A serum sodium level of <135 mmol/l was present for 542/5171 (10.5%) days under tacrolimus treatment compared with 377/5486 (6.9%) days under cyclosporin treatment (P < 0.0001). Severe hyponatraemia, below 120 mmol/l, was also more prevalent under tacrolimus than cyclosporin treatment, P < 0.025. Nine patients, all receiving tacrolimus, were treated with fludrocortisone for fluid depletion and/or hyponatraemia. Serum potassium levels were higher in tacrolimus-treated patients (P < 0.0001), and subjects with hyponatraemia were more likely to experience hyperkalaemia (P < 0.0001). CONCLUSIONS: Hyponatraemia and hyperkalaemia were more frequent in tacrolimus-treated subjects. Taken together with previous work showing that hyperuricaemia is more frequent with cyclosporin treatment, and hypomagnesaemia with tacrolimus treatment, these findings are consistent with qualitative differences between the nephrotoxicities of cyclosporin and tacrolimus.

Adult↗

European Multicenter Tacrolimus (FK506) Heart Pilot Study: one-year results--European Tacrolimus Multicenter Heart Study Group.

BACKGROUND: Tacrolimus (FK506) may represent a major advance in the management of allograft rejection after solid organ transplantation. In August 1994 a European heart transplantation pilot study was initiated to assess the efficacy and safety of tacrolimus when administered exclusively through an oral route. METHODS: Eighty-two heart transplant recipients were randomized to treatment (2:1 ratio) with either tacrolimus- (n=54) or cyclosporine-based therapy (n=28). RESULTS: No significant differences were evident between the two treatment groups in either rejection or survival rates at 1 year. Kaplan-Meier estimates of the freedom from rejection were 26.3% and 18.5%, respectively, for the tacrolimus and cyclosporine treatment groups (p=.444). Survival rates were 79.6% and 92.9% (p=.125). At 3 of the 5 centers, patients received antithymocyte globulin during the immediate postoperative period and fared better than those who did not (with acute rejection-free rates of 49.2% and 26.7% for tacrolimus and cyclosporine, respectively [p=.080], as opposed to 7.1% and 8.3% [p=.965]; patient survival rates of 84.6% and 93.3% [p=.382] vs 75.0% and 92.3% [p=.243]). The overall rates of infection, impaired renal function (31.5% vs 21.4%), and glucose intolerance (7.0% vs 4.3%) did not differ significantly between the tacrolimus and cyclosporine treatment groups. Tacrolimus seemed to possess an advantage with regard to a reduced requirement for antihypertensive therapy (59.5% vs 87.5%, p=.025). CONCLUSIONS: Immunosuppression with oral tacrolimus provides a viable alternative to treatment with cyclosporine, particularly when administered in conjunction with antibody therapy. Further studies are warranted to optimize the administration of tacrolimus in this indication.

Administration, Oral↗

Multicenter randomized trial comparing tacrolimus (FK506) and cyclosporine in the prevention of renal allograft rejection: a report of the European Tacrolimus Multicenter Renal Study Group.

BACKGROUND: To confirm the results of a number of studies conducted in Europe, the United States, and Japan, this multicenter, randomized trial compared the 12-month efficacy and safety of tacrolimus- and cyclosporine-based immunosuppressive regimens in the prevention of renal allograft rejection. METHODS: A total of 448 renal transplant recipients were recruited from 15 centers and assigned to receive triple-drug therapy consisting of tacrolimus (n=303) or cyclosporine (n=145) in conjunction with azathioprine and low-dose corticosteroids. RESULTS: At 12 months after transplantation, tacrolimus therapy was associated with a significant reduction in the frequency of both acute (tacrolimus 25.9% vs. cyclosporine 45.7%; P<0.001 [absolute difference: 19.8%, 95% confidence interval: 10.0-29.6%]) and corticosteroid-resistant rejection (11.3% vs. 21.6%; P=0.001 [absolute difference: 10.3%, 95% confidence interval: 2.5-18.2%]). Actuarial 1-year patient (tacrolimus 93.0% vs. cyclosporine 96.5%; P=0.140) and graft survival rates (82.5% vs. 86.2%; P=0.380) did not differ significantly between the two treatment groups. Overall, the safety profiles of the tacrolimus- and cyclosporine-based regimens were quite comparable. Infections, renal impairment, neurological complications, and gastrointestinal complaints were frequently reported but were mostly reversible in both groups. Higher incidences of elevated serum creatinine, tremor, diarrhea, hyperglycemia, diabetes mellitus, and angina pectoris were reported in the tacrolimus treatment group, whereas acne, arrhythmia, gingival hyperplasia, and hirsutism were more frequent with cyclosporine treatment. CONCLUSIONS: The significant reduction in the incidence of episodes of allograft rejection observed with tacrolimus therapy may have important long-term implications given the prognostic influence of rejection on graft survival.

Adolescent↗

Pilot randomized study of early tacrolimus withdrawal from a regimen with sirolimus plus tacrolimus in kidney transplantation.

We performed a randomized trial to compare two regimens of low-risk kidney allograft recipients in the first year after transplantation. Both regimens initially included sirolimus, tacrolimus and steroids; one with long-term maintenance with these drugs vs. tacrolimus withdrawal. Group I: sirolimus levels of 4-8 ng/mL, plus tacrolimus 8-12 ng/mL for 3 months, and 5-10 ng/mL after month 3. Group II: sirolimus concentration of 8-16 ng/mL, plus tacrolimus 3-8 ng/mL with tacrolimus elimination from month 3 onwards. Owing to difficulties in achieving target levels, the protocol was amended to increase the doses. Eighty-seven patients were recruited. In the intention-to-treat analysis, glomerular filtration rate (GFR) at 12 months, adjusted to zero for graft loss, was similar in both groups (58.8 and 59.9 mL/min). Analysis of patients remaining on protocol showed that GFR was higher in group II only in the patients postamendment (58.4 and 72.9 mL/min, p = 0.03). Rates of biopsy-confirmed rejection (BCAR) were 9.3% and 22.7% in groups I and II, respectively (p = NS). After amendment, BCAR rates were 10.3% and 11.1% (p = NS). Diastolic blood pressure was significantly lower in patients who eliminated tacrolimus (80.4 vs. 75.6 mmHg) (p = 0.03). Combining sirolimus and tacrolimus with adequate loading doses was associated with a low incidence of BCAR, and allowed tacrolimus elimination in a high proportion of patients, which may be followed by amelioration in renal function and blood pressure.

Adult↗

A tacrolimus-related immunosuppressant with biochemical properties distinct from those of tacrolimus.

BACKGROUND: Tacrolimus (FK506) is an immunosuppressive drug 50-100 times more potent than cyclosporine (CsA), the current mainstay of organ transplant rejection therapy. Despite being chemically unrelated, CsA and tacrolimus exert their immunosuppressive effects through the inhibition of calcineurin (CaN), a critical signaling molecule during T-lymphocyte activation. Although numerous clinical studies have proven the therapeutic efficacy of drugs within this class, tacrolimus and CsA also have a strikingly similar profile of unwanted side effects. METHOD: Our objective has been to identify a less toxic immunosuppressant through the modification of ascomycin (FK520). Quantitative in vitro immunosuppression and toxicity assays have demonstrated (see the accompanying article, p. 18) that we achieved our goal with L-732,531 (indolyl-ascomycin; indolyl-ASC), a 32-O-(1-hydroxyethylindol-5-yl) ascomycin derivative with an improved therapeutic index relative to tacrolimus. RESULTS: We report that the attributes of indolyl-ASC may result from its distinctive biochemical properties. In contrast to tacrolimus, indolyl-ASC binds poorly to FK506 binding protein 12 (FKBP12), the major cytosolic receptor for tacrolimus and related compounds. However, the stability of the interaction between the FKBP12-indolyl-ASC complex and CaN is much greater than that of the FKBP12-tacrolimus complex. These distinguishing properties of indolyl-ASC result in the potent inhibition of CaN within T lymphocytes but may lower the accumulation of the drug at sites of toxicity. CONCLUSIONS: Indolyl-ASC may define those properties needed to increase the therapeutic efficacy of a macrolactam immunoregulant for treating both human autoimmune disease and organ transplant rejection.

Base Sequence↗

Tacrolimus is a class II low-solubility high-permeability drug: the effect of P-glycoprotein efflux on regional permeability of tacrolimus in rats.

The objective of this study is to investigate the role of P-glycoprotein (P-gp), a membrane efflux pump associated with multidrug resistance (MDR) and a known substrate for tacrolimus, in determining the regional intestinal permeability of tacrolimus in rats. Thus, isolated segments of rat jejunum, ileum, or colon were perfused with tacrolimus solutions containing polyethoxylated hydrogenated castor oil 60 surfactant, and with or without verapamil, a P-gp substrate used to reverse the MDR phenotype. The results indicated that the intrinsic permeability of tacrolimus in the jejunum, calculated on the basis of the concentration of non-micellized free tacrolimus, was quite high ( approximately 1.4 x 10(-4) cm/s). The apparent permeability (P(app)) in the jejunum was unaffected by the presence of verapamil; however, the P(app) in the ileum and the colon increased significantly in the presence of verapamil and were similar to the values observed in the jejunum. The results suggest that systemic absorption of tacrolimus from the gastrointestinal tract could be significantly affected by P-gp efflux mechanisms. It is also possible that differences in P-gp function at various intestinal sites in a subject or at a given intestinal site in various subjects could lead to large intra- and interindividual variability in bioavailability of tacrolimus following oral administration.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Tacrolimus (FK506) and mycophenolate mofetil combination therapy versus tacrolimus in adult liver transplantation.

BACKGROUND: Mycophenolate mofetil (MMF) prolongs allograft survival in experimental animals, prevents acute rejection in humans, and has recently been approved for use in renal transplantation in combination with cyclosporine. Tacrolimus (Prograf) has been shown to be effective for the prevention and treatment of allograft rejection in liver transplantation. However, there has been limited experience with the combination of tacrolimus and MMF in liver transplantation. METHODS: This retrospective pilot study examined the results in 130 primary, consecutive, adult liver transplants under two separate immunosuppressive protocols. Patients in the study group received MMF (1 g p.o. b.i.d.), tacrolimus (0.1 mg/kg p.o. b.i.d.), and a standard steroid taper. MMF was also tapered and then discontinued within 3 months of transplantation. A historical control received tacrolimus (0.15 mg/kg p.o. b.i.d.) and the same steroid taper. RESULTS: Pretransplant demographics, including creatinine, were not significantly different between the groups. The 6-month patient and graft survivals of 96.3% (control) versus 92.0% (study) were not significantly different. The incidence of acute rejection was 45.0% in the control group versus 26.0% in the study group (P = 0.03). The study group had a lower incidence of rejection (mean episodes/patient +/- SEM): 0.28+/-0.07 vs. 0.61+/-0.10 (P = 0.007). All of the study group members responded to high-dose steroids. In the control group, three patients required monoclonal antibody therapy and two patients required the addition of MMF. The incidence of cytomegalovirus was similar in the study group and the control group (13.8% vs. 10.0%, P = NS). Early renal function was better preserved in the tacrolimus/MMF group (mean creatinine +/- SEM): 1.09 mg/dl +/- 0.05 vs. 1.51 mg/dl +/- 0.08 at 30 days, P = 0.0001. The study design required dosing with less tacrolimus (mean mg/day +/- SEM), which was achieved at 1 week (23.2+/-0.7 vs. 13.5+/-0.5); 1 month (18.7+/-0.8 vs. 11.4+/-0.5); 3 months (14.5+/-0.6 vs. 9+/-0.5); and 6 months (11.6+/-0.6 vs. 8.2+/-0.6); P = 0.0001, for all time points. CONCLUSION: Combination therapy with tacrolimus and MMF may significantly reduce the incidence of acute liver allograft rejection, allow a significant reduction in tacrolimus dosage, and decrease the incidence of nephrotoxicity. Long-term analysis will be necessary to assess any increased risk of opportunistic infections.

Drug Therapy, Combination↗

Sirolimus inhibits growth of human hepatoma cells alone or combined with tacrolimus, while tacrolimus promotes cell growth.

AIM: Standard immunosuppression after organ transplantation stimulates tumor growth. Sirolimus has a strong antiproliferative and a tumor inhibiting effect. The purpose is to assess the effect on tumor growth of the immuno-suppressive compounds sirolimus and tacrolimus alone and in combination on cells of human hepatocellular carcinoma. METHODS: We used the human cell lines SK-Hep 1 and Hep 3B derived from hepatocellular carcinoma. Proliferation analyses after treatment with sirolimus, tacrolimus, or the combination of both were performed. FACS analyses were done to reveal cell cycle changes and apoptotic cell death. The expression of apoptosis-related proteins was estimated by Western blots. RESULTS: Sirolimus alone or combined with tacrolimus inhibited the growth of both cell lines after 5 d by up to 35% in SK-Hep 1 cells, and by up to 68% in Hep 3B cells at 25 ng/mL. Tacrolimus alone stimulated the growth by 12% after 5 ng/mL and by 25% after 25 ng/mL in Hep 3B cells. We found an increase of apoptotic Hep 3B cells from 6 to 16%, and a G1-arrest in SK-Hep 1 cells with an increase of cells from 61 to 82%, when sirolimus and tacrolimus were combined. Bcl-2 was down-regulated in Hep 3B, but not in SK-Hep 1 cells after combined treatment. CONCLUSION: Sirolimus appears to inhibit the growth of hepatocellular carcinoma cells alone and in combination with tacrolimus. Sirolimus seems to inhibit the growth stimulation of tacrolimus.

Apoptosis↗

0.3% Tacrolimus gel and 0.5% Tacrolimus cream show efficacy in mild to moderate plaque psoriasis: Results of a randomized, open-label, observer-blinded study.

The efficacy and safety of 0.3% tacrolimus gel and 0.5% tacrolimus cream compared with calcipotriol ointment were evaluated in adults (n = 124) with mild to moderate plaque psoriasis. Treatment was twice daily for a maximum of 12 weeks. Clinical efficacy was assessed by the percentage change in the local psoriasis severity index of a target lesion between baseline and week 12. By week 12, the median percentage changes in local psoriasis severity index of the target lesions in the tacrolimus gel, tacrolimus cream and calcipotriol groups were 55.6%, 50.0% and 58.6%, respectively (no statistically significant differences). Clinical improvement was observed after one week and increased throughout the study. Tacrolimus-treated patients experienced more application site skin burning (tacrolimus gel and cream both 31.0% versus 7.5% for calcipotriol; p = 0.011). Skin burning was mostly mild in intensity and decreased substantially after 1 week of treatment. There were no differences in the nature and incidence of infections and no clinically relevant changes in laboratory values.

Administration, Topical↗