Suppression of acute rejection in allogeneic rat lung transplantation: a study of the efficacy and pharmacokinetics of rapamycin derivative (SDZ RAD) used alone and in combination with a microemulsion formulation of cyclosporine.

BACKGROUND: The novel immunosuppressant SDZ RAD, 40-0 (2-hydroxyethyl)rapamycin, is an orally active rapamycin analogue developed for use in combination with cyclosporine (Neoral). The present study was designed to evaluate the efficacy of SDZ RAD, Neoral, or a combination of both drugs for suppression of acute rejection in an allogeneic, unilateral rat lung transplant model. METHODS: Brown-Norway (RT1n) donor lungs were implanted into Lewis (RT1l) recipients that were observed for 21 days. Postoperative evaluation included daily weights, serial chest radiographs, drug trough levels, and histology scores of the transplanted lung on the day of sacrifice. Treatment groups were comprised of rats treated orally with the RAD vehicle as controls (n = 6); SDZ RAD 2.5 mg/kg/day (n = 9); Neoral 7.5 mg/kg/day (n = 8); Neoral 2.5 mg/kg/day (n = 6); SDZ RAD 2.5 mg/kg/day plus Neoral 7.5 mg/kg/day (n = 7); and Neoral 2.5 mg/kg/day plus SDZ RAD 2.5 mg/kg/day (n = 6). RESULTS: The results of this study showed that neither monotherapy with 2.5 mg/kg/day of Neoral, nor 2.5 mg/kg/day of SDZ RAD prevented severe acute rejection in unilateral lung transplant recipients. Furthermore, despite high dose (7.5 mg/kg/day) Neoral treatment, graft histology showed moderate rejection. However, addition of 2.5 mg/kg/day of SDZ RAD to 7.5 mg/kg/day of Neoral completely prevented histologic rejection in four of seven grafts, although the remaining 3 grafts showed minimal rejection. This combination resulted in significantly higher RAD trough levels when compared to SDZ RAD treatment alone. Combining a lower dose of Neoral (2.5 mg/ kg/day) with 2.5 mg/kg/day of SDZ RAD resulted in less weight loss and improved animal health; however, the histology of lung grafts in these rats showed mild rejection. CONCLUSIONS: This is the first study on the efficacy of the novel rapamycin derivative SDZ RAD for the control of acute lung allograft rejection. Results showed that acute unilateral rat lung allograft rejection is refractory to monotherapy with either high dose Neoral or SDZ RAD. The two regimens of combined treatment with Neoral plus SDZ RAD used in these studies produced either minimal rejection and reduced tolerability or mild rejection and better tolerability and showed potentiation of immunosuppression when both drugs were used together. Additional investigation of these two drugs is needed, however, to devise regimens that produce both high immunosuppressive efficacy and good tolerability.     

Coadministration of neoral and the novel rapamycin analog, SDZ RAD, to rat lung allograft recipients: potentiation of immunosuppressive efficacy and improvement of tolerability of staggered versus simultaneous treatment

BACKGROUND: Neoral and rapamycin derivative (RAD) have complementary mechanisms for inhibition of lymphocyte activation and are substrates for the same pathways of drug metabolism. Therefore, we investigated treatment regimens designed to minimize pharmacokinetic interactions and to potentiate immunosuppressive efficacy in a highly stringent rat lung allograft model. METHODS: Lewis recipients of Brown Norway lungs received the following daily oral doses: (A) RAD at 2.5 mg/kg (n=9); (B) Neoral at 7.5 mg/kg (n=8); (C) RAD at 2.5 mg/kg + Neoral at 7.5 mg/kg simultaneously (n=8); or (D) RAD at 2.5 mg/kg + Neoral at 7.5 mg/kg (n=6) staggered 6 hr apart. Rats were assessed by daily weights, chest radiographs, drug trough levels (high-performance liquid chromatography/mass spectrometry), and blinded scoring of graft histology at death (day 21). RESULTS: Radiographs were completely opacified in all grafts of control and RAD monotherapy groups on days 7 and 14, respectively. Grafts were mildly opacified (Neoral monotherapy) and completely clear (both RAD + Neoral groups) on day 21. Simultaneous or staggered combined treatment dramatically reduced histologic rejection compared with treatment with either drug alone. Simultaneous treatment caused poor tolerability (poor grooming, lethargy) and significantly higher day-14 RAD and cyclosporine (CsA) trough levels (49+/-5 and 638+/-106 ng/ml; P<0.04) than in the staggered group (28+/-3 and 318+/-25 ng/ml) in which all animals were clinically normal. RAD and CsA day-14 trough levels in the staggered group were the same or lower than trough levels in animals treated with either drug alone (RAD 27+/-3/Neoral 815+/-67 ng/ml). CONCLUSIONS: (1) Administration of RAD + Neoral suppressed lung rejection more effectively than treatment with either drug alone. (2) Trough levels did not differ between monotherapy and staggered combination therapy for RAD but were lower for CsA. These results suggested that pharmacological, rather than pharmacokinetic, interactions between the parent drugs were responsible for the potentiation of immunosuppression when these drugs were coadministered. 3) Staggered administration of RAD+Neoral avoided the pharmacokinetic interactions that caused the elevated drug blood levels and poor tolerability caused by simultaneous administration. Thus, we could potentiate efficacy and improve tolerability by staggering administration of RAD and Neoral.     

Oral efficacy of the macrolide immunosuppressant SDZ RAD and of cyclosporine microemulsion in cynomolgus monkey kidney allotransplantation

BACKGROUND: 40-O-(2-Hydroxyethyl)-rapamycin (SDZ RAD) is a novel, potent, macrolide immunosuppressant. Its efficacy in rodent transplantation models provided the rationale for us to evaluate the compound in a more relevant, large animal transplantation model. METHODS: Life-supporting kidney allotransplantation was performed in cynomolgus monkeys: rejection was inferred from a rise in serum creatinine or urea and was subsequently confirmed by histopathology. This model was validated with the microemulsion formulation of cyclosporine (i.e., Neoral). Two studies with a microemulsion formulation of SDZ RAD were performed. First, in a dose-finding study, the SDZ RAD dose was reduced in a stepwise fashion until rejection occurred, either with SDZ RAD as monotherapy, or in combination with a fixed, suboptimal dose of cyclosporine. Second, an efficacy study was performed in which two fixed SDZ RAD doses (0.75 and 1.50 mg/kg/ day) were evaluated in monotherapy and compared with the same doses of rapamycin (sirolimus). All immunosuppressants were administered once daily by gastric gavage. RESULTS: Untreated control animals rejected their grafts between 4 and 8 days after transplantation. Cyclosporine (initially at 150 mg/kg/day, reduced to 100 mg/kg/day 2 weeks after transplantation) yielded long-term (>100 days) rejection-free allograft survival in four of five animals. A 10 mg/kg/day dose of cyclosporine led to rejection between 10 and 27 days after transplantation and was considered suboptimal. In the dose-finding study with SDZ RAD monotherapy, rejection occurred in most of the cases (four of six animals) when a dose level of 0.63 mg/kg/day had been reached. Combined with suboptimal cyclosporine, this threshold SDZ RAD dose was about 2-fold lower. In the efficacy study, median graft survival with histologically proven rejection was 32 days (range 8-91 days, n=6) for 0.75 mg(kg/day SDZ RAD and 59 days (range 28-85 days, n=6) for 1.50 mg/kg/day SDZ RAD. For sirolimus, median graft survival was 43 days (range 5-103 days, n=7) for the 0.75 mg/kg/day dose and 56 days (range 8-103 days, n=8) for the 1.50 mg/kg/day dose. There was no statistically significant difference in efficacy between SDZ RAD and sirolimus. CONCLUSION: SDZ RAD, in the absence of any other immunosuppressant and at doses that do not show any overt toxicity, considerably prolongs rejection-free survival of cynomolgus monkeys after life-supporting kidney allotransplantation.     

Prevention of acute allograft rejection in nonhuman primate lung transplant recipients: induction with chimeric anti-interleukin-2 receptor monoclonal antibody improves the tolerability and potentiates the immunosuppressive activity of a regimen using low doses of both microemulsion cyclosporine and 40-O-(2-hydroxyethyl)-rapamycin

BACKGROUND: In previous studies of cynomolgus monkey lung allograft recipients, we demonstrated significant immunosuppressive efficacy but reduced tolerability after combined treatment with high doses of microemulsion cyclosporine (CsA) and SDZ RAD (40-O-(2-hydroxyethyl)-rapamycin). The current study was designed to compare efficacy and tolerability of a combination of low-dose CsA and high-dose SDZ RAD (CTL group) to triple therapy using the chimeric anti-interleukin-2 (IL-2) receptor (CD25) monoclonal antibody (mAb) basiliximab (anti-IL-2 receptor mAb) for induction therapy (basiliximab: 5 mg intravenously on days 0 and 4) plus low-dose CsA and low-dose SDZ RAD for maintenance immunosuppression (CD25 group). CsA and anti-IL-2 receptor mAb are drugs that reduce cytokine synthesis and block IL-2-mediated lymphocyte stimulation, respectively. SDZ RAD blocks lymphocyte stimulation by other cytokines (e.g., IL-15) that are not inhibited by anti-IL-2 receptor mAb. METHODS: Twelve unilateral lung transplants were performed. Recipients were observed for 49 days by daily weight assessment, hemograms, blood chemistries, radiographs, and lung biopsies. Monkeys were euthanized before day 49 in the event of excessive weight loss (>25%) or organ failure. Target CsA trough levels were 100-200 ng/ml. Target SDZ RAD trough levels in the CTL group (no mAb) were 20-40 ng/ml, and 10-20 ng/ml in the CD25 group. RESULTS: None of the monkeys in the CD25 group needed to be euthanized early due to signs of drug toxicity. In contrast, four monkeys in the CTL group were sacrificed on days 28-35 as a result of excessive weight loss (n=3) and renal functional impairment (n=1). Three recipients in the CD25 group were euthanized on days 36, 38, and 46 as a result of persistent high fever associated with severe rejection. The median animal survival in the CTL group was 32 vs. 46 days in the CD25 group (P<0.04). The only two long-term survivors in the CTL group showed moderate rejection at day 49. The median rejection scores at day 14 (A0) and day 28 (A2) were identical in the two groups, despite the fact that the mean SDZ RAD trough level was significantly lower in the CD25 group (CTL: 38+/-3 ng/ml, CD25: 18+/-2 ng/ml, P<0.0001). After basiliximab levels fell below the minimum therapeutic level (1 mg/ml) on day 28, the median rejection score at day 49 increased to A4 in the CD25 group. CONCLUSION: This is the first study to combine an anti-IL-2 receptor mAb with a drug from the rapamycin class plus CsA. Our study shows that induction therapy with basiliximab enabled SDZ RAD blood levels to be significantly reduced, which led to improved tolerability without the penalty of increased rejection.     

Potentiation of immunosuppressive efficacy by combining the novel leflunomide analog, HMR 279, with microemulsion cyclosporine in a rat lung transplant model

BACKGROUND: The novel leflunomide (LFM) analog, HMR 279, potentiates the immunosuppressive efficacy of microemulsion cyclosporine (Neoral) in rodent heart transplantation. The present study was designed to evaluate the immunosuppressive efficacy of this combination in comparison to the combination of Neoral and LFM in a stringent allogeneic rodent lung transplant model. METHODS: Donor lungs from Brown Norway rats were implanted into Lewis recipients and were followed for 21 days. Postoperative monitoring included daily weight assessment, chest radiographs, drug trough levels measured by high-performance liquid chromatography (LFM/HMR 279) and high-performance liquid chromatography/mass spectrometry (Neoral), and blinded histology assessment of the transplanted lung on the day of death based on the International Society for Heart and Lung Transplantation working formulation. Untreated lung recipients served as controls (group I, n=5). Rats were assigned to the following treatment groups: II, 7.5 mg/kg/day Neoral (n=6); III, 10 mg/kg/day LFM (n=6); IV, 10 mg/kg/day HMR 279 (n=6); V, 10 mg/kg/day LFM plus 7.5 mg/kg/day Neoral given simultaneously (n=13); and VI, 10 mg/kg/day HMR 279 plus 7.5 mg/kg/day Neoral given simultaneously (n=6). Drugs were given daily by oral gavage. RESULTS: All rats except for one in the HMR 279 monotherapy group survived the follow-up period. The chest radiographs in the control, LFM, and HMR 279 monotherapy groups showed moderate to complete opacification of the left chest by postoperative day 7 (controls) and day 14 (LFM, 279). At postoperative day 21, the Neoral monotherapy and the combination groups showed no signs of opacification in the radiographs. Combination therapies of Neoral plus HMR 279 or Neoral plus LFM were most successful in preventing histologic allograft rejection. Combining Neoral and HMR 279 resulted in a significant decrease in the cyclosporine trough levels. Co-administration of LFM plus Neoral resulted in significantly higher LFM trough levels when compared to LFM monotherapy. Of all treatments studied, the combination of HMR 279 plus Neoral was tolerated best as assessed by percentage of weight change. CONCLUSIONS: This study showed for the first time in a stringent rodent lung transplant model that combined treatment of LFM or HMR 279 plus Neoral potentiates the immunosuppressive efficacies of these drugs and successfully prevents allograft rejection.     

Successful treatment of acute, ongoing rat lung allograft rejection with the novel immunosuppressant SDZ-RAD

BACKGROUND: Recent experimental data have shown that coadministration of microemulsion cyclosporine and the novel immunosuppressant SDZ-RAD potentiates the immunosuppressive efficacies of both drugs to suppress allograft rejection. Our study was designed to assess the potential of delayed SDZ-RAD administration, in addition to cyclosporine maintenance therapy, to reverse acute rejection in an allogeneic rat lung transplant model. METHODS: Unilateral left lung transplantation was performed using Brown-Norway donors implanted into Lewis recipients. An untreated control group and a cyclosporine monotherapy group (7.5 mg/kg) were followed for 7 days. An additional cyclosporine monotherapy group (7.5 mg/kg), and a combined therapy group treated with cyclosporine (7.5 mg/kg) plus SDZ-RAD (2.5 mg/kg), were followed for 21 days. For treatment of ongoing rejection, 7.5 mg/kg cyclosporine was given as maintenance therapy, and SDZ-RAD (2.5 mg/kg) was added on postoperative day 7. Drugs were given orally, and in the combined therapy regimens, administered 6 hours apart. Outcome variables included daily weight, radiographs, and histology. RESULTS: Radiographs on postoperative day 7 showed mild and moderate opacification of the left chest in the cyclosporine monotherapy groups and the untreated control group. Addition of SDZ-RAD to cyclosporine treatment on postoperative day 7 reversed opacification by postoperative days 14 and 21. Monotherapy with microemulsion CsA resulted in mild histological rejection by day 7, which progressed to moderate rejection by day 21. Addition of SDZ-RAD on postoperative day 7 reversed acute rejection, resulting in none or minimal rejection at day 21. CONCLUSIONS: SDZ RAD reverses acute rejection under cyclosporine maintenance therapy in a stringent lung allotransplant model.     

The influence of the rapamycin-derivate SDZ RAD on the healing of airway anastomoses.

OBJECTIVE: Among the many immunosuppressive effects of SDZ RAD (40-0(2-hydroxyethyl)-rapamycin), a rapamycin derivative, is the inhibition of fibroblast proliferation. Since the long-term success of lung transplantation is limited by the development of bronchiolitis obliterans, a fibroblast-associated progressive luminal obstruction of the terminal bronchioli, the use of SDZ RAD as immunosuppressive in pulmonary graft recipients may counteract this process. However, reduction of fibroblast activity, posttransplant, may impair the healing of the bronchial anastomoses. MATERIALS AND METHODS: The cervical trachea in pigs was denuded, divided and re-anastomosed with Prolene 4-0 single stitches. Control animals (group 1, n=4) were without, and study animals (group 2, n=6) were with SDZ RAD therapy (1.25 mg/kg/day, p.o., 14 days). After 14 days, the pigs were sacrificed. The anastomoses were examined histologically, and breaking strength of tracheal strips of 5-mm width was measured. RESULTS: All animals survived without complications. Serum levels of SDZ RAD were 30.9+/-8.7 ng/ml (recommended level 20-40 ng/ml). All anastomoses healed macroscopically without difference between the two groups. Breaking strength was significantly lower in the treated animals (group 1 vs. group 2: 11.75+/-0.35 vs. 7.69+/-1.39 N, P=0.01). Histology did not show a significant change in histoarchitecture between the groups. CONCLUSIONS: Although SDZ RAD significantly reduced the breaking strength of the tracheal anastomosis, no obvious histological differences between treated and untreated animals could be detected. Since this model does not reflect the clinical situation, further investigations are necessary to reveal the effect of SDZ RAD on airway wound healing in concert with a contemporary clinically used multidrug immunosuppressive regimen in allograft recipients.     

Oral efficacy of the new immunomodulator FTY720 in cynomolgus monkey kidney allotransplantation,given alone or in combination with cyclosporine or RAD

BACKGROUND: FTY720 is a novel immunomodulator with a unique mechanism of action, i.e. chemokine-dependent lymphocyte homing into secondary lymphoid organs associated with profound lymphocyte depletion in blood. We investigated its efficacy, either FTY720 alone or together with cyclosporine or the rapamycin derivative rapamycin derivative (RAD), in cynomolgus monkey kidney allotransplantation. METHODS: Life-supporting allotransplantation was performed in bilaterally nephrectomized hosts. Compounds were given once daily by oral gavage. Monitoring was done by serum creatinine and urea, and rejection was concluded when values exceeded 500 micromol/L and 50 mmol/L, respectively (5-6 times the upper limit of reference values). Rejection was confirmed by graft histology. The termination point was set to 100 days after transplantation. In addition, animals were monitored for 24 hr drug concentrations and thorough inspection of potential adverse side effects. RESULTS: FTY720 given alone at 3.0 mg/kg per day prolonged rejection-free survival (33-85 days, mean 24 hr concentration between 54 and 66 ng/mL [n=3]), but it was not efficacious at a 0.3 mg/kg per day dose. For cyclosporine alone, 30 mg/kg per day during maintenance was efficacious (average concentration above 100 ng/mL, historical data from our group), and for RAD alone 0.75 mg/kg per day (concentration above 10 ng/mL). Efficacious FTY720-cyclosporine-A (CsA) or FTY720-RAD combinations were established using 0.1-0.3 mg/kg per day FTY720, 10-30 mg/kg per day cyclosporine, and/or 0.25-0.50 mg/kg per day RAD. Compared with single-compound treatment, FTY720 effective doses and 24 hr trough concentrations were at least tenfold lower in combination treatment and those of cyclosporine and RAD about twofold lower, indicative of effective synergy between the compounds. Already at the lowest FTY720 dose tested (0.03 mg/kg per day), there was a profound lymphocyte depletion down to about 30% of pretransplant values, which further increased at the highest dose (3.0 mg/kg per day, to about 14% of pretransplant values). Lymphocyte depletion was reflected by a decrease in T and B subpopulations. CONCLUSION: FTY720 is an effective immunosuppressant in prevention of acute kidney allograft rejection in cynomolgus monkeys and synergizes with cyclosporine and/or RAD in yielding rejection-free allograft survival.     

Pharmacokinetics of cyclosporine in monkeys after oral and intramuscular administration: relation to efficacy in kidney allografting

In cynomolgus and rhesus monkeys, the dose-normalized exposure of cyclosporine administered orally as microemulsion preconcentrate (Neoral) was lower than that upon intramuscular administration. For oral administration, mean values ( ± SD) of C_max, 24-h area-under-the curve (AUC) and 24-h trough level, all normalized for a 1 mg/kg dose, were 20 ± 9 ng kg/mg ml, 210 ± 70 ng h kg/mg ml and 2.6 ± 0.9 ng kg/mg ml, respectively. For intramuscular administration, levels were about 5.5-fold, 9-fold and 22-fold higher. Based on pharmacokinetic data, the efficacy of oral cyclosporine treatment (without any other immunosuppressant) was evaluated in life-supporting cynomolgus monkey kidney allotransplantation. Rejection-free kidney allograft survival could be achieved using oral cyclosporine monotherapy with average 24-h trough concentrations above 100 ng/ml during maintenance treatment. Typically, daily oral doses of 100 mg/kg–150 mg/kg during the first two weeks post-transplantation, followed by daily 30 mg/kg–100 mg/kg dose levels during subsequent maintenance can result in long-term allograft survival, with 24-h average trough levels in individual animals during maintenance between 110 ng/ml and 700 ng/ml. Received: 1 October 1997 Revised: 20 April 2001 Accepted: 7 June 2001     

RAD in de novo renal transplantation: comparison of three doses on the incidence and severity of acute rejection

BACKGROUND: The effects of three doses of RAD (40-O-[2-hydroxyethyl]-rapamycin), a novel macrolide with potent immunosuppressive and antiproliferative properties, on the incidence and severity of acute rejection episodes as well as its tolerability were evaluated in a dose-ranging study in de novo renal transplant recipients. METHODS: In this double-blind, parallel group, multicenter study, recipients were randomized to receive 1 mg, 2 mg, or 4 mg/day of RAD in combination with Neoral (cyclosporine, USP MODIFIED) and corticosteroids. The incidence and severity of biopsy-proven acute rejection episodes, graft survival, patient survival, infection rates, laboratory measurements, and adverse events were compared across groups after 6 months of therapy. RESULTS: Among the 103 recipients, patients receiving 1, 2, or 4 mg/day experienced a 32.4%, 14.7%, or 25.7% incidence of biopsy-proven acute rejection episodes within the first 6 months posttransplantation, respectively. Even though the study was not powered to demonstrate efficacy, the incidence of moderate and severe acute rejection episodes was found to be significantly lower among patients in the 2 mg and 4 mg/day groups than in the 1 mg/day group (P=0.002 and P=0.006, respectively). Overall graft and patient survival rates were excellent. RAD was generally well tolerated. Although blood lipid levels increased in all groups, changes were manageable with lipid-lowering agents and did not warrant discontinuation of study medication. The incidence of viral and fungal infections was low; however, it was higher among recipients treated with 4 mg/day. CONCLUSIONS: In combination with Neoral and corticosteroids, RAD doses of 2 mg and 4 mg/day resulted in lower rates of acute rejection episodes and efficacy failure than the 1 mg/day dose and were significantly more effective in reducing the severity of rejection. Large-scale, controlled, follow-up studies are currently in progress to confirm these initial findings.     

Synergistic effects of RAD and Neoral in inhibition of host-vs.-graft and graft-vs.-host immune responses in rat small-bowel transplantation

The combined effects of RAD and Neoral were tested in a rat orthotopic small-bowel transplantation model. Seven groups (n = 6) were involved in this study, and each one was included in three rejection models for the evaluation of host-vs.-graft disease (HVG) (LBN-F1 to LEW), graft-vs.-host disease (GVH) (LEW to LBN-F1), and combined HVG and GVH immune responses (BN to LEW). Both drugs were administered orally throughout the study. Low doses of RAD (1.0-2.5 mg/kg/day) combined with Neoral (2.0-5.0 mg/kg/day) produced strong synergistic effects in the prolongation of small-bowel graft survival in HVG (combination index, CI = 0.095, 0.1212), GVH (CI = 0.027, 0.020), and combined HVG and GVH immune responses (CI = 0.070, 0.301). The combination therapy of RAD and Neoral produces a strong synergistic effect toward the inhibition of HVG, GVH, and combined HVG and GVH immune responses in a rat small-bowel transplantation model.     

Comparison of pharmacokinetics of Neoral and Sandimmune in stable pediatric liver transplant recipients.

Cyclosporine (Sandimmune; Novartis Pharmaceuticals UK Ltd) is an effective immunosuppressive drug, but its lipid formulation and variable absorption may expose children to the risk of rejection during episodes of gastroenteritis after liver transplantation. Neoral (Novartis) is a microemulsified form of cyclosporine that may be better absorbed. In this study, the pharmacokinetic profiles of Neoral and Sandimmune were compared in stable children after liver transplantation to evaluate whether Neoral is more predictably absorbed. Eight children, 6 boys and 2 girls, with a mean age of 4.5 years (range, 1.2-12) were studied between 4 and 12 months after liver transplantation. Pharmacokinetic profiles were performed on each child by using the same dose (mg/kg) of Neoral or Sandimmune. Tmax, Cmax, Ctrough, and the area under the curve (AUC) were calculated and side effects were documented in children taking either drug for more than 3 months. Mean peak cyclosporine levels were higher and were achieved significantly sooner with Neoral (Cmax 790.5 +/- 216.5 ng/mL, P =.06; Tmax 1.8 +/- 1.0 hr, P =.01) than with Sandimmune (Cmax 589.4 +/- 313 ng/mL, Tmax 2.5 +/- 1.7 hr), implying more rapid and better absorption. There was no significant difference in overall drug exposure (AUC) and 12-hour trough levels between the two formulations (P >.05). Children with Roux-en-Y loop biliary anastomosis taking Neoral, however, showed greater increases in AUC (mean increase = 37%) than those with duct-to-duct anastomosis (mean increase = 16%). There was no correlation between 12-hour trough level and AUC for either Neoral (r2 = 0.48) or Sandimmune (r2 = -0.08); however, for both drugs, AUC correlated very well with the 2-hour post-dose level (r2 = 0.68 and 0.7, respectively). Hirsutism was reported in 4 of 6 children on Neoral and may be associated with higher peak levels. Neoral is more consistently absorbed than Sandimmune in children after liver transplantation and may be more effective prophylaxis against rejection. Because of the increased peak levels and drug exposure, which may influence side effects, particularly in children with Sandimmune malabsorption, we recommend a 1:0.75 dose conversion ratio in patients being converted from Sandimmune to Neoral.     

RAD in stable lung and heart/lung transplant recipients: safety, tolerability, pharmacokinetics, and impact of cystic fibrosis.

BACKGROUND: RAD is a novel macrolide with potent immunosuppressive and antiproliferative activities. This study characterizes the safety, tolerability, and pharmacokinetics of two different single oral doses of RAD in stable lung and heart/lung transplant recipients with and without cystic fibrosis (CF). METHODS: This was a Phase I, multicenter, randomized, double-blind, two-period, two-sequence, crossover study. Single doses of RAD capsules at doses of 0.035 mg/kg (2.5 mg maximum) or 0.10 mg/kg (7.5 mg maximum) were administered with cyclosporine (Neoral [cyclosporine, USP] modified), steroids, and azathioprine on Day 1. The alternate dose was administered on Day 16. Laboratory assessments, vital signs, and adverse events were recorded throughout the study. RAD pharmacokinetic profiles were assessed over a 7-day period following each dose. Steady-state cyclosporine (CsA) profiles were assessed at baseline and with each RAD dose; RAD and CsA trough concentrations were obtained throughout the study period. RESULTS: Of the 20 patients randomized, 8 had CF and 12 did not. Single doses of RAD were safe and well tolerated. Headache was the most common side effect. RAD produced a mild, dose-dependent, reversible decrease in platelet and leukocyte counts. Cholesterol and triglycerides were minimally affected. At both doses, CF patients had significantly lower peak concentrations of RAD than did non-CF patients (p = 0.03); however, overall exposure (area under the curve/dose) was not different between the groups (p = 0.63). At the higher dose, there was a clinically minor under-proportionality in AUC, averaging -11%. Steady-state pharmacokinetics of CsA were not affected by RAD co-administration.RAD was safe and well tolerated by stable lung and heart/lung transplant recipients with and without CF. The presence of CF did not influence the extent of RAD exposure. Single doses of RAD did not affect the pharmacokinetics of CsA. Ongoing studies are assessing the long-term safety and efficacy of RAD in lung and heart/lung transplantation.     

Coadministration of the new macrolide immunosuppressant RAD and mycophenolate mofetil in experimental corneal transplantation

INTRODUCTION: The effect of RAD, a new macrolide immunosuppressant, was examined as mono- and combination therapy with mycophenolate mofetil (MMF) in prevention of acute allograft rejection in murine corneal transplantation. METHODS: Both drugs were administered orally for 18 days beginning at the day of transplantation. The inbred strains Fisher and Lewis were used as donors and recipients, respectively. Five groups were involved: syngeneic control, allogeneic control, 2.5 mg/kg RAD, 40 mg/kg MMF, and double drug therapy with 1.5 mg/kg RAD and 20 mg/kg MMF. RESULTS: The median transplant survival time in the allogeneic combination was 12 (+/-0.3) days. Monotherapy with 2.5 mg/kg RAD and 40 mg/kg MMF led to a statistically significant prolongation of transplant survival to 25.5 (+/-12.5, P=0.0001) days and 19.5 (+/-13.9, P=0.0053) days, respectively. Combination therapy was superior to both monotherapies (100+/-15.8 days, P=0.03). There was a significant reduction in the number of CD4+, CD8+, as well as CD45RA+ cells in the RAD- and double drug-treated animals when compared with the allogeneic control. This significant reduction in graft-infiltrating lymphocytes has not been found in the MMF monotherapy. CONCLUSIONS: The unique finding of this first study on the combination of RAD and MMF in murine corneal transplantation is that double drug therapy produces a highly synergistic effect in prevention of acute allograft rejection without a higher incidence of complications related to drug toxicity or overimmunosuppression.     

Tacrolimus versus cyclosporine induction therapy in pulmonary transplantation in miniature swine.

OBJECTIVE: Tacrolimus has been shown to provide superior immunosuppression in various solid organ transplant settings. The purpose of our study was to compare the survival of porcine lung allografts after induction with either cyclosporine A (CsA) or tacrolimus. METHODS: Single lung transplantation from MHC mismatched donors was performed in 10 minipigs. Immunosuppression included 1.5 mg/kg per day methylprednisolone and 1.0 mg/kg per day azathioprine. CsA (n=5) was adjusted to trough levels of 300-500 ng/ml, tacrolimus (n=5) was adjusted to 16-26 ng/ml. All immunosuppressive drugs were discontinued on postoperative day (POD) 28. Allograft survival was monitored by sequential chest radiographs, bronchoscopy and transbronchial biopsy histology. Peripheral blood leukocytes were scanned for donor chimerism and CD3, CD4, CD8 and CD25 expression. RESULTS: The animals survived a 4-week course of immunosuppression without radiological or histological signs of rejection on POD 28. Median allograft survival in CsA-treated animals was 55+/-15 days and all animals rejected their grafts within 42 days after withdrawal of immunosuppression. In tacrolimus-treated animals, median survival was 152+/-65 days with the longest survivor being electively sacrificed on POD 390 (P=0.0064). The degree of donor leukocyte chimerism and the frequency of CD4+CD25+ T-cells were higher in the tacrolimus group, however, these differences were not statistically significant. CONCLUSION: The results of our study show that primary immunosuppression with tacrolimus is superior to cyclosporine after pulmonary allotransplantation in a large animal model.     

In the lung aerosol cyclosporine provides a regional concentration advantage over intramuscular cyclosporine.

BACKGROUND: Acute rejection remains an almost universal complication among lung transplant recipients. Refractory rejection as well as chronic systemic immunosuppression is associated with significant morbidity and mortality. Recent studies suggest that aerosol cyclosporine may address these issues by effectively preventing acute cellular rejection while maintaining low systemic drug concentrations. This study was designed to evaluate the concentrations of cyclosporine in blood and lung tissue after aerosol and intramuscular administration. METHODS: Lewis rats were divided into 4 experimental groups: Groups A (n = 33) and B (n = 30) received aerosol cyclosporine 3 and 5 mg/kg, respectively; Groups C (n = 33) and D (n = 30) received systemic cyclosporine 5 and 15 mg/kg, respectively. We used high-performance liquid chromatography to quantitate blood and lung tissue cyclosporine levels at timed intervals. We used the trapezoidal rule to approximate area under the concentration vs time curve (AUC). RESULTS: Aerosol delivery of cyclosporine resulted in higher and more rapid peak drug levels in lung tissue samples than did systemic delivery. At an equivalent 5 mg/kg dose, the cyclosporine AUC was 3 times higher with aerosol delivery than with intramuscular delivery in lung tissue (477,965 vs 157,706 ng x hour/g, respectively). The lung tissue: blood AUC ratio was highest in the aerosol groups (27.3:1 and 17.4:1) compared with the intramuscular groups (8.1:1 and 9.4:1). CONCLUSION: Local aerosol inhalation delivery of cyclosporine provides a regional advantage over systemic intramuscular therapy by providing higher peak concentrations and greater lung tissue exposure.     

Sirolimus (rapamycin) potentiates cyclosporine in prevention of acute lung rejection

BACKGROUND: Cyclosporine-based immunosuppressive regimens (INN: ciclosporin) in human lung transplantation continue to result in a high incidence of acute cellular rejection. We investigated the use of sirolimus, a macrolide with structural similarity to tacrolimus, as monotherapy and in combination with cyclosporine in a rodent lung transplant model. METHODS: Orthotopic left lung transplantation was performed in Lewis recipients from Brown-Norway donor rats with syngeneic Lewis-to-Lewis controls. Open biopsies were performed on postoperative day 7, and the severity of acute lung rejection was graded by a pathologist blinded to the protocol. RESULTS: All recipients survived despite the amount of acute rejection seen on examination of the biopsy tissue. Lewis-to-Lewis isografts demonstrated near normal pulmonary architecture. Allogeneic recipients receiving high-dose cyclosporine (25 mg/kg) monotherapy showed mild to moderate acute rejection with some perivascular focal interstitial infiltrates. Recipients receiving low-dose cyclosporine (5 mg/kg) monotherapy or low- or high-dose sirolimus (0.5 or 2.0 mg/kg, respectively) monotherapy demonstrated massive cellular infiltration leading to necrosis and infarction and could not be graded. However, the addition of low-dose sirolimus (0.5 mg/kg) to low-dose cyclosporine (5 mg/kg) demonstrated a significant potentiating immunosuppressive effect, and the addition of high-dose sirolimus (2.0 mg/kg) to low-dose cyclosporine (5.0 mg/kg) demonstrated an even greater effect, with rejection scores better than those obtained with high-dose cyclosporine monotherapy and similar to those obtained with isografts. CONCLUSIONS: This study demonstrates that low-dose sirolimus has a cyclosporine-sparing effect and that a higher dose of sirolimus in combination with cyclosporine strongly protects lung allografts from acute cellular rejection. These results suggest that sirolimus may be indicated as an adjunct to current cyclosporine-based immunosuppressive regimens in clinical lung transplantation.     

Prospective randomised study comparing tacrolimus (Prograf) and cyclosporin (Neoral) as primary immunosuppression in cadaveric renal transplants at a single institution: interim report of the first 80 cases

Abstract As part of an ongoing study, 80 patients undergoing cadaveric renal transplantation were randomised to receive either Prograf [PTT (patients receiving Prograf); n = 40]- or Neoral [NTT (patients receiving Neoral); n = 40]-based immunosuppression as part of a triple therapy regimen. Prograf was commenced at a dose of 0.2 mg/kg per day and Neoral at 8 mg/kg per day. Both groups received identical azathioprine and corticosteroid regimens. Trough levels for Prograf were maintained between 5 and 15 ng/ml and for Neoral between 100 and 200 ng/ml. During the 3-month follow up 40% of PTT and 33% of NTT experienced biopsy-proven acute rejection. In each group 81% of rejection episodes were classified as either borderline or grade 1. The median 3-month serum creatinine levels were 128 μmol/1 and 135 μmol/1, respectively, for PTT and NTT. Six grafts were lost in the NTT group including three deaths with functioning grafts whilst none were lost in the PTT group (χ², P < 0.02). The prevalence of other complications was similar for the two groups. We conclude that Prograf represents an effective and safe therapy as a primary immunosuppressive agent following cadaveric renal transplantation and appears to have a similar side-effect profile to Neoral.     

Interaction between cyclosporine and fluconazole in renal allograft recipients

To determine the effect of fluconazole on cyclosporine concentrations, we used a randomized, double-blind, placebo-controlled study design to evaluate 16 stable renal transplant recipients receiving a constant cyclosporine dose. The two groups of patients were given identical capsules of either placebo or fluconazole 200 mg daily for 14 days. Compliance with the protocol was ensured by watching each patient take all the drug doses. Frequent whole-blood cyclosporine trough concentrations, measured by high-performance liquid chromatography, and two area under the blood concentration time curves were determined before and after 14 days of fluconazole or placebo. The results show that cyclosporine trough concentrations, in patients given fluconazole, increased from a mean +/- SD of 27 +/- 16 to 58 +/- 28 ng/ml (P = 0.001) while patients given placebo did not change--35 +/- 26 vs. 37 +/- 35 ng/ml (P = 0.7). Mean cyclosporine AUC increased in the fluconazole patients from 2167 +/- 1039 to 3989 +/- 1675 ng.hr/ml (P = 0.02) while the placebo patients did not change, 3089 +/- 2439 vs. 2954 +/- 2216 ng.hr/ml (P = 0.9). The pre- and post-treatment cyclosporine AUC difference (day 16 minus day 2) for fluconazole vs. placebo was 1822 +/- 1083 vs. -134 +/- 831 ng.hr/ml (P = 0.001). Mean cyclosporine clearance decreased an average of 55% in the fluconazole patients from 1.2 +/- 0.5 to 0.7 +/- 0.4 ml/hr.kg (P = 0.03); the placebo patients did not change--1.4 +/- 1.1 vs. 1.7 +/- 2.3 ml/hr.kg (P = 0.07). During the study period, serum creatinine concentrations did not increase after fluconazole vs. placebo treatment; they were 1.4 +/- 0.3 vs. 1.3 +/- 0.3 mg% (P = 0.8) initially, and 1.4 +/- 0.2 vs. 1.3 +/- 0.3 mg% (P = 0.5) after 14 days. This study indicates that fluconazole 200 mg daily can slowly increase cyclosporine concentrations over two weeks of therapy, approximately doubling the cyclosporine trough concentrations. The management of this interaction requires prospective planning for adjustments in the cyclosporine dosage, guided by cyclosporine concentrations, while transplant recipients are receiving fluconazole.     

Monotherapy with LF 15-0195, an analogue of 15-deoxyspergualin,significantly prolongs renal allograft survival in monkeys

BACKGROUND: LF 15-0195 is a novel, more potent, and less toxic analogue of 15-deoxyspergualin, an antibiotic used as an immunosuppressive agent to prevent rejection of organ transplants. This study was undertaken to determine whether LF 15-0195 monotherapy would prevent renal allograft rejection in a nonhuman primate model. METHODS: In the study groups, recipients received LF 15-0195 monotherapy at doses of 0.065 mg/kg per day (group 2, n=4), 0.13 mg/kg per day (group 3, n=4), or 0.2 mg/kg per day (group 4, n=4), administered subcutaneously, on postoperative days 0 to 14. RESULTS: Group 1 consisted of untreated control recipients, all of which developed advanced graft rejection after surviving for an average of 6.5+/-0.6 days. LF 15-0195 treatment significantly prolonged graft survival in groups 2, 3, and 4, to 20+/-20 days, 49+/-5 days, and 39+/-4 days, respectively. Animals in groups 3 and 4 demonstrated no evidence of rejection during LF 15-0195 treatments. The animals maintained stable renal function for 2 weeks after LF 15-0195 withdrawal but gradually developed rejection at 5 to 6 weeks. Pathologic studies demonstrated that vascular graft rejection was attenuated in LF 15-0195-treated allografts, compared with control specimens. These groups also demonstrated transient reductions in lymphocyte counts during treatment, which returned to normal levels 2 weeks after LF 15-0195 withdrawal. Total serum concentrations of IgM and IgG decreased by a mean of 20.4% and a mean of 31.4%, respectively, at the end of LF 15-0195 treatment (postoperative day 14). LF 15-0195 did not significantly alter thrombocyte counts or hemoglobin levels. Necropsy studies showed no evidence of drug toxicity in the heart, liver, spleen, intestines, stomach, or colon. CONCLUSIONS: LF 15-0195 monotherapy significantly prolonged renal allograft survival in monkeys. These encouraging data suggest that this novel agent may be of future value in clinical transplantation.