Ten years of sirolimus therapy for human renal transplantation: the University of Texas at Houston experience.
Explore the source record for details and available documents.
Cyclosporine↗
Biomedical subjects
K Mahalati
Publications and source records attributed to K Mahalati.
Adequate early cyclosporin exposure is critical to prevent renal allograft rejection: patients monitored by absorption profiling.
This study used receiver operating characteristic analysis to investigate the properties of area under the concentration-time curve during the first 4h after cyclosporin-microemulsion dosing (AUC0-4) and cyclosporin (CyA) levels immediately before and at 2 and 3h after dosing (C0, C2 and C3) to predict the risk of biopsy-proven acute rejection (AR) at 6 months. Ninety-eight kidney transplant recipients treated with CyA-microemulsion-based triple therapy immunosuppression were studied on post-transplant days 3, 5, and 7, and at increasing intervals thereafter. The most sensitive and specific predictor of AR was AUC0-4. Of the single time-point measurements, the measurement properties of C2 were closest to those of AUC0-4, and superior to those of C3. The relationship between C0 and subsequent AR was weak and did not reach statistical significance. On day 3, CyA AUC0-4 > or = 4,400 ng.h/mL and C2 > or = 1,700 ng/mL were each associated with a 92% negative predictive value for rejection in the first 6months. Pharmacokinetic measurements on or after day 5, and measurements on day 3 in patients with delayed graft function, were not predictive of AR. Adequate exposure within the first 3days post transplantation may be critically important in preventing subsequent rejection.
Adult↗
Clinical pharmacokinetics of sirolimus.
Sirolimus (previously known as rapamycin), a macrocyclic lactone, is a potent immunosuppressive agent. Sirolimus was recently approved by the US Food and Drug Administration, on the basis of 2 large, double-blind, prospective clinical trials, for use in kidney transplant recipients at a fixed dosage of 2 or 5 mg/day in addition to full dosages of cyclosporin and prednisone. However, despite the fixed dosage regimens used in these pivotal trials, pharmacokinetic and clinical data show that sirolimus is a critical-dose drug requiring therapeutic drug monitoring to minimise drug-related toxicities and maximise efficacy. Assays using high performance liquid chromatography coupled to mass spectrometry, although cumbersome, are the gold standard for evaluating other commonly used assays, such as liquid chromatography with ultraviolet detection, radioreceptor assay and microparticle enzyme immunoassay. Sirolimus is available in oral solution and tablet form. It has poor oral absorption and distributes widely in tissues, displaying not only a wide inter- and intrapatient variability in drug clearance, but also less than optimal correlations between whole blood concentrations and drug dose, demographic features or patient characteristics. Furthermore, the critical role of the cytochrome P450 3A4 system for sirolimus biotransformation leads to extensive drug-drug interactions, among which are increases in cyclosporin concentrations. Thus, sirolimus is now being used to reduce or eliminate exposure to cyclosporin or corticosteroids. The long elimination half-life of sirolimus necessitates a loading dose but allows once daily administration, which is more convenient and thereby could help to improve patient compliance. This review emphasises the importance of blood concentration monitoring in optimising the use of sirolimus. The excellent correlation between steady-state trough concentration (at least 4 days after inception of, or change in, therapy) and area under the concentration-time curve makes the former a simple and reliable index for monitoring sirolimus exposure. Target trough concentration ranges depend on the concomitant immunosuppressive regimen, but a range of 5 to 15 microg/L is appropriate if cyclosporin is being used at trough concentrations of 75 to 150 microg/L. Weekly monitoring is recommended for the first month and bi-weekly for the next month; thereafter,concentration measurements are necessary only if warranted clinically.
Area Under Curve↗
Conversion to rapamycin immunosuppression in renal transplant recipients: report of an initial experience.
BACKGROUND: The aim of this study is to evaluate the effects of RAPA conversion in patients undergoing cyclosporine (CsA) or tacrolimus (Tac) toxicity. METHODS: Twenty renal transplant recipients were switched to fixed dose rapamycin (RAPA) (5 mg/day) 0 to 204 months posttransplant. Drug monitoring was not initially used to adjust doses. The indications for switch were chronic CsA or Tac nephrotoxicity (12), acute CsA or Tac toxicity (3), severe facial dysmorphism (2), posttransplant lymphoproliferative disorder (PTLD) in remission (2), and hepatotoxicity in 1. Follow-up is 7 to 24 months. RESULTS: In the 12 patients switched because of chronic nephrotoxicity there was a significant decrease in serum creatinine [233+/-34 to 210+/-56 micromol/liter (P<0.05) at 6 months]. Facial dysmorphism improved in two patients. No relapse of PTLD was observed. Five patients developed pneumonia (two Pneumocystis carinii pneumonia, one infectious mononucleosis with polyclonal PTLD lung infiltrate) and two had bronchiolitis obliterans. There were no deaths. RAPA was discontinued in four patients, because of pneumonia in two, PTLD in one, and oral aphtous ulcers in one. RAPA levels were high (>15 ng/ml) in 7 of 13 (54%) patients. CONCLUSIONS: RAPA conversion provides adequate immunosuppression to enable CsA withdrawal. However, when converting patients to RAPA drug levels should be monitored to avoid over-immunosuppression and adequate antiviral and Pneumocystis carinii pneumonia prophylaxis should be given.
Adult↗
Is routine ureteric stenting needed in kidney transplantation? A randomized trial.
BACKGROUND: Whether routine ureteric stenting in low-urological-risk patients reduces the risk of urological complications in kidney transplantation is not established. METHODS: Eligible patients were recipients of single-organ renal transplants with normal lower urinary tracts. Patients were randomized intraoperatively to receive either routine stenting or stenting only in the event of technical difficulties with the anastomosis. All patients underwent Lich-Gregoire ureteroneocystostomy. RESULTS: Between June 1994 and December 1997, 331 kidney transplants were performed at a single center, 305 patients were eligible, and 280 patients were enrolled and randomized. Donor and recipient age, sex, donor source, whether first or subsequent grafts, ureteric length, native renal disease, and immunosuppression were similar in each group. In the no-routine-stenting group 6 of 137 patients (4.4%) received stents after randomization for intraoperative events that in the surgeon's opinion required use of a stent. In an intention-to-treat analysis there was no difference between groups in the primary outcome cluster of obstruction or leak [routine stenting 5 of 143 (3.5%) vs. no routine stenting 9 of 137 (6.6%); P=0.23], or in either of these complications analyzed separately. All urological complications were successfully managed without major morbidity. Living donor organs and shorter ureteric length (after trimming) were univariate risk factors for leaks, although increasing donor age was associated with obstruction. CONCLUSIONS: Routine ureteric stenting is unnecessary in kidney transplantation in patients at low risk for urological complications. Careful surgical technique with selective stenting of problematic anastomoses yields similar results.
Adult↗
Sirolimus-tacrolimus combination immunosuppression.
A series of 32 recipients of liver, kidney, or pancreas transplants who were treated with sirolimus and low-dose tacrolimus experienced a low rate of rejection and excellent graft function without drug-related toxic effects.
Adolescent↗
A 3-hour postdose cyclosporine level during the first week after kidney transplantation predicts acute rejection and cyclosporine nephrotoxicity more accurately than trough levels.
Explore the source record for details and available documents.
Azathioprine↗
Is 3-hour cyclosporine blood level superior to trough level in early post-renal transplantation period?
PURPOSE: Cyclosporine dose is traditionally based on trough blood levels. Cyclosporine trough blood level correlates poorly with acute rejection and cyclosporine nephrotoxicity after renal transplantation. We determined whether cyclosporine blood level at any other time point is superior to cyclosporine trough blood level as a predictor of acute rejection and cyclosporine nephrotoxicity. MATERIALS AND METHODS: Cyclosporine blood level was measured before (trough), and 1, 2, 3 and 4 hours after the dose in 156 initial renal transplant cases 2 to 4 days after the initiation of cyclosporine micro-emulsion formula administration. The cylosporine micro-emulsion dose was based on cyclosporine trough blood level targeting 250 to 400 microg./l. RESULTS: Regression analysis revealed that only delayed graft function (p = 0.007) and cyclosporine blood level after 3 hours (p = 0.008) predicted acute rejection. Mean cyclosporine trough blood level plus or minus standard error was not significantly different in patients with and without acute rejection (293+/-21 versus 294+/-11 microg./l.). Mean cyclosporine blood level after 3 hours was significantly lower in patients with acute rejection (1,156+/-90 versus 1,421+/-50, p = 0.008). Cases were divided into tertiles at levels after 3 hours (1,100 and 1,500 microg./l.). The group in which the level after 3 hours was less than 1,100 microg./l. had the highest acute rejection rate (22 of 50 patients, 44%) and a cyclosporine nephrotoxicity rate of 13% (7 of 52 patients). The group in which the level after 3 hours was 1,100 to 1,500 microg./l. had the lowest acute rejection rate (5 of 46 patients, 11%) without increased cyclosporine nephrotoxicity (7 of 52 patients, 13%). A level after 3 hours of greater than 1,500 microg./l. was associated with a rejection rate of 15% (7 of 47 patients) but significantly higher cyclosporine nephrotoxicity (16 of 52 patients, 30%). CONCLUSIONS: Cyclosporine blood level after 3 hours in the early post-transplantation period is associated with acute rejection and cyclosporine nephrotoxicity. A cyclosporine blood level range after 3 hours of 1,100 to 1,500 microg./l. is associated with an optimal outcome. Our data suggest that cyclosporine blood level after 3 hours may represent a better method of monitoring cyclosporine micro-emulsion dose than cyclosporine trough blood level. This hypothesis must be further studied in randomized trials.
Cyclosporine↗
Pharmacological surrogates of allograft outcome.
Because virtually all of the currently available oral immunosuppressive agents show significant inter- and/or intrapatient variability, drug doses do not predict patient exposure, which is the critical parameter of efficacy versus toxicity. Therefore, at least for the critical-dose baseline immunosuppressive agents CsA and tacrolimus, all transplant centers use some sort of therapeutic drug monitoring. However, for CsA, Cminss values show a poor correlation with exposure and therefore are of limited use. Reliable therapeutic drug monitoring demands some measure of CsA absorption profiles with or without an estimate of clearance rates. The suggested methods include full AUC, limited sampling AUC, and a single 2- or 3-hour post-dose blood concentration. For tacrolimus, Cminss displays a reasonable correlation with systemic drug exposure as measured by AUC, however, there is little correlation between Cminss and clinical events within recommended therapeutic ranges. Sirolimus, which has been recently approved for use in kidney transplant recipients by the Food and Drug Administration in 2 or 5 mg doses, also shows the behavior of a critical-dose drug and that therapeutic monitoring using trough levels correlate strongly with drug exposure and the occurrence of adverse events. However, there is no approved automated assay and thus LC estimates must be utilized to estimate exposure. Pharmacodynamic drug monitoring opportunities are available for calcineurin inhibitors, MMF and sirolimus, but none is currently available for clinical use; however, the field of transplant pharmacodynamics is progressing rapidly. In the coming decade it is likely that an array of pharmacodynamic tools will be developed to complement the available pharmacokinetic information and lead to the development of models that predict optimal concentrations at the target sites in order to maximize immunosuppression and minimize toxic effects.
Animals↗
Neoral monitoring by simplified sparse sampling area under the concentration-time curve: its relationship to acute rejection and cyclosporine nephrotoxicity early after kidney transplantation.
BACKGROUND: Cyclosporine (CsA) dosing is traditionally based on trough blood levels (C0) rather than area under the concentration-time curve (AUC), although AUC correlates better with posttransplantation clinical events. For Neoral, AUC based on limited sampling correlates closely with full 12-hr AUC. The purpose of our study was to correlate C0 with AUC based on CsA levels at 0, 1, 2, 3, and 4 hr after dose (PK0-4) and to compare this AUC with C0 in predicting acute rejection (AR) and acute cyclosporine nephrotoxicity (CsANT) in de novo first kidney transplant patients. METHODS: PK0-4 was done 2-4 days after starting Neoral for 156 patients. All received CsA-based triple-drug immunosuppression without antibody induction. AUC was calculated as projected 12-hr (AUC0-12) and actual 4-hr (AUC0-4) from the PK0-4 using the parallel trapezoid rule. Neoral dosing was based on C0 not AUC. AUC was retrospectively compared with C0 as a predictor of AR and CsANT during the first 90 days. RESULTS: C0 correlated poorly with AUC0-12 and AUC0-4 (r=0.61 and r=0.42). C0 (mean+/-SEM) levels were not significantly different in 34 patients with and 109 without AR (293+/-21 vs. 294+/-11 microg/L, P=0.95). AUC0-12 and AUC0-4 were significantly lower in patients with than without AR (AUC0-12 9090+/-598 vs. 10608+/-336 microg x h/L, P=0.01; AUC0-4 3934+/-306 vs. 4802+/-166 microg.h/L, P=0.006). In stepwise regression analysis only AUC0-12 or AUC0-4 (P=0.03/P=0.02) and delayed graft function (P=0.007) predicted AR. AUC0-12, AUC0-4, and C0 were all significantly higher in patients with CsANT than without CsANT (AUC0-12 11746+/-650 vs. 10023+/-301 microg x h/L, P=0.01; AUC0-4 5270+/-358 vs. 4474+/-150 microg x h/L, P=0.01; C0 343+/-18 vs. 287+/-10 microg/L, P=0.01), but in stepwise regression analysis C0 was not an independent predictor of CsANT. Patients with AUC0-12 in the range of 9500 to 11500 microg x h/L or AUC0-4 between 4400 and 5500 microg x h/L had the lowest incidence of AR (13% and 7%, respectively) without significantly higher risk for CsANT. CONCLUSION: C0 correlates poorly with AUC based on PK0-4. Early AUC based on PK0-4 is more closely associated with AR and CsANT than is C0. Our data suggest that a target AUC0-12 of 9500-11500 or AUC0-4 of 4400-5500 microg x h/L may provide optimal Neoral immunosuppression.
Acute Disease↗
Predictable recovery from myasthenia gravis crisis with plasma exchange: thirty-six cases and review of current management.
Adult, acquired, idiopathic, autoimmune myasthenia gravis has a well-characterized IgG anti-acetylcholine striated-muscle receptor antibody. Removal by plasma exchange is effective, established therapy to augment anti-cholinesterase and immunosuppressive therapy and is the treatment of choice for myasthenia gravis crisis. We report 36 consecutive patients referred and accepted for plasma exchange, 32 of whom were in or entering myasthenia crisis, over a 10 year period. An average of 7.8 (range 1 to 16) plasma exchange procedures were done, with uniform, significant improvement, including extubation of 13 in myasthenic crisis and discharge from hospital in all. We conclude that this is the best treatment for myasthenia gravis crisis in hospital. From recent cases, most, if not all, crises can be prevented by IVIgG or plasma exchange as out-patients with use of corticosteroid and or azathioprine.
Adolescent↗
Persistant pre-eclampsia post partum with elevated liver enzymes and hemolytic uremic syndrome.
The spectrum of complications with pre-eclampsia, which may include AFLP (acute fatty liver of pregnancy) as well as the HELLP syndrome (hemolysis, elevated liver enzymes, and low platelets), is resolved by early delivery. However, the ravages of HUS/TTP (hemolytic uremic syndrome/thrombotic thrombocytopenic purpura) require therapy usually by plasma exchange. Overlap between these two groups of syndromes has occurred on rare occasions and usually requires the therapy of the predominant or more dangerous or threatening form. Such overlap can be appreciated and then treated successfully without residual morbidity. The index case is presented and an extensive review of the two groups of syndromes is provided.
Adult↗
Influence of drug formulation on utilization and outcomes: Neoral and monitoring by sparse sample area under the curve.
Explore the source record for details and available documents.
Acute Disease↗
Multicentricity in renal cell carcinoma.
OBJECTIVE: To find the incidence of multicentric renal cell carcinoma and its possible relationship to the other clinical and pathologic findings. METHODS: A total of 40 patients with renal cell carcinoma underwent radical nephrectomy between March 1994 and January 1996 at Hacettepe University, School of Medicine, Department of Urology. All of the materials were examined grossly and histologically by the same pathologist. RESULTS: Among 40 kidneys 4 had satellite carcinoma (10%), 3 of them had been shown by preoperative imaging techniques, 1 was found histopathologically. CONCLUSION: If preoperative imaging techniques do not show additional lesion in the kidney besides the small early stage primary in incidentally discovered patients, the incidence of satellite renal cell carcinoma is low enough to justify nephron sparing surgery.
Adult↗
The management of brain metastasis in nonseminomatous germ cell tumours.
OBJECTIVE: To review our experience of patients with brain metastases from nonseminomatous germ cell tumours (NSGCTs) and to indicate important clinical observations. PATIENTS AND METHODS: Between 1990 and 1996, 167 patients with metastatic NSGCT were treated in our department; 11 had brain metastases (eight with solitary metastases and three with multiple lesions, mean age 27 years, range 18-41). These patients were treated initially with either; cisplatin, bleomycin, etoposide and/or cisplatin, vincristin, methotrexate, bleomycin, actinomycin-D, cyclophosphamide, etoposide and intrathecal methotrexate chemotherapy protocols. Six patients received chemotherapy alone, one had chemotherapy plus radiotherapy and four had all three treatments. Patients with brain metastases were classified according to mode of presentation, and their treatments and outcomes analysed. RESULTS: Ten patients presented with symptoms related to intracranial lesions, e.g. intractable headache, seizures, severe vomiting, hallucinations and hemiparesis. All patients with brain metastasis had bulky thoracic disease. The incidence of clinical brain metastases in patients with advanced thoracic disease was 32% (11/34). Four patients with brain metastases at presentation were alive after 3, 12, 34 and 47 months. The only patient with isolated brain relapse died within 7 months, despite combined treatment. Two of the five patients who developed brain metastases during the course of the disease are alive with no evidence of disease at 3 and 6 months after salvage chemotherapy. CONCLUSION: Patients with single brain metastasis seem to have a better prognosis in the present than in other reported series. Chemotherapy was used initially, followed by surgery and radiotherapy in those who did not achieve complete remission with chemotherapy. Patients with progressive disease and multiple brain metastasis do not seem to benefit from initial surgical resection. Importantly, a significant proportion (32%) of patients with bulky lung metastases had or subsequently developed brain metastases. Thus it is suggested that routine cranial imaging should be performed in patients with bulky thoracic disease.
Adolescent↗
Author-abstract index.
Explore the source record for details and available documents.
Journal Article↗
Methotrexate tolerance in patients with ileal conduits and continent diversions.
BACKGROUND: Methotrexate is readily absorbed from the intestinal tract. When given to patients with urinary diversion to the intestinal tract, methotrexate may be reabsorbed into the circulation, thus increasing its serum concentration and potentially increasing its toxicity. METHODS: Forty-eight patients with transitional cell carcinoma of the urinary tract who had undergone cystectomy and either an ileal conduit or a continent diversion were evaluated for their tolerance of chemotherapy. Of the 42 evaluable patients, 23 had a continent diversion and 19 had an ileal conduit. None of the patients with the continent diversion had an indwelling Foley catheter during the course of chemotherapy. RESULTS: There were no statistically significant differences in incidence of fever or neutropenia, mucositis, dose modification, or delay in chemotherapy between the two groups. When compared with a group of patients with native bladders who received the same chemotherapy, patients with continent diversions did not have increased incidence or severe toxicity from chemotherapy. CONCLUSIONS: Patients with continent diversions tolerated chemotherapy as well as patients with ileal conduits.
Antimetabolites, Antineoplastic↗
Characteristics of 73 patients, 1984-1993, treated by plasma exchange for Guillain-Barre syndrome.
Acute Guillain-Barre syndrome (GBS) is a demyelinating polyneuropathy which responds readily to plasma exchange (PEX). According to the North American Acute GBS PEX study there is a 50% or more reduction in the recovery time if PEX is initiated early in the course of the disease. Demyelinating antibodies are usually IgM. IgA antibodies require prolonged PEX. Patients with predominant IgG antibodies have chronic inflammatory demyelinating polyneuropathy (CIDP), which requires an even longer course of PEX, over weeks to months or years. We reviewed records of 73 patients with the initial diagnosis of GBS treated with PEX. Among these patients, 55 had classic GBS, three had the Miller-Fisher variant, two had CIDP, and 13 had demyelinating-like polyneuropathies associated with other conditions including malignancy, vaccine-related myelitis, steroid-induced myopathy, polymyositis, botulism, gram-negative sepsis, Sjogren's, and AIDS. Hughes grading system was used. Patients were graded 3 to 5, with grade 3 patients being unable to walk 5 m without support, grade 4 patients being bed or chair bound, and grade 5 patients being ventilator dependent. Of 60 unassociated (GBS) demyelinating cases receiving a mean of 6.5 PEX procedures, 13 (21%) were intubated early in the treatment, with four (6%) remaining ventilator dependent post-PEX. Of 51 non-intubated patients, 15 became ambulatory post-PEX. Patients with the Miller-Fisher variant showed improvement within 6 hours of PEX initiation. We did not investigate correlation of GBS with infection; however, we did observe a rise in CMV titer among 15% of the 58 patients with acute GBS. Considering our results we believe that intensive PEX on a daily basis for a few days is necessary for severely affected individuals. We advise five to nine procedures at consultation unless early, rapid recovery occurs.
Adolescent↗