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Augmentation of mycophenolate mofetil pharmacokinetics in renal transplant patients receiving prograf and cellcept in combination therapy
Mycophenolate
ELSEVIER
Augmentation of Mycophenolate Mofetil Pharmacokinetics in Renal Transplant Patients Receiving Prograf and Cellcept in Combination Therapy K. Zucker, A. Rosen, A. Tsaroucha, and J. Miller
M
L. de Faria, D. Roth, G. Ciancio,
YCOPHENOLATE mofetil (MMF) has been shown to be a potent immunosuppressive agent in experimental animals as well as humans.’ In clinical trials, MMF was able to significantly prolong allograft survival in combination with cyclosporine A (Sandoz Pharmaceuticals, Basel, Switzerland) and is currently approved for use in humans under the trade name CellCept (Roche Biosciences, Santa Clara, Calif). After absorption, MMF is rapidly hydrolyzed to its active form, mycophenolic acid (MPA).’ MPA serves as a noncompetitive inhibitor of the enzyme inosine monophosphate dehydrogenase, which is essential in the de novo pathway of purine biosynthesis and thus DNA replication.3 In vivo the majority of the MPA is converted to a glucuronide form that is inactive.4 There is no evidence that the glucuronide form of MPA may serve as a source of active MPA in vivo. The present report is a pharmacokinetic (pK) analysis of renal allograft recipients receiving tacrolimus (Prograf, Fujisawa Pharmaceuticals, Ltd., Tokyo, Japan) in combination with CellCept. The trough, peak, and area under the curve (AUC) values for both drugs were compared against control groups receiving either Prograf in combination with azathioprine (Imuran, Burroughs-Wellcome, Research Triangle Park, NC) or cyclosporine (CyA) in combination with CellCept. Additional comparison has been made using the same parameters for the microemulsion formulation of CyA’ (Neoral). This study was performed to gain insight into selecting a rational dose range for use of the two newer agents (PrografiCellCept) in combination clinically. 0041-1315/97/$17.00 PII SO041 -1345(96)00292-8
MATERIALS
V. Esquenazi,
AND
G. Burke, A. Tzakis,
METHODS
In the pK experiments all study subjects were first-cadaver or living-related donor renal transplant recipients who were stable with respect to renal function and general health status. The subjects were grouped according to the maintenance immunosuppressive drug combinations administered, ie, tacrolimus or CyA, and the dose of CellCept (0,2, or 3 g/d). They had been receiving their specific drug regimen for at least 3 weeks before testing. For analysis, blood was collected into one heparin and one ethylenediaminetetraacetic acid tube 30 minutes prior to CellCept administration, and then 30 min, 1, 1.5, 2, 3, 4, 6, 8, and 12 hours after CellCept administration. MPA and its glucuronide derivative (MPAG) levels were determined with high performance liquid chromatography by the method of Tsina et al.6 Cyclosporine levels were determined from whole blood collected in the ethylenediaminetetraacetic acid tube using the TDx assay system (Abbott Labs, North Chicago, Ill). FK506 levels were determined from whole blood using the IMx assay system (Abbott Labs).
From the Department of Surgery, Division of Transplantation at the University of Miami School of Medicine, and the Miami Veterans Administration Medical Center, Miami, Florida. Supported by Miami Veterans Administration Hospital Research Support, NIH grant ROlDK25243-15, Roche Biosciences, and Fujisawa Pharmaceuticals, Ltd., Tokyo, Japan. Address reprint requests to Dr. Keith Zucker, Dept. of Surgery, Div. of Transplantation, University of Miami School of Medicine, P.O. Box 012440 (R-440), Miami, FL 33101.
0 1997 by Elsevier Science Inc. 655 Avenue of the Americas, New York, NY 10010
334
Transplantation
Proceedings,
29, 334-336
(1997)
PROGRAF AND CELLCEPT COMBINATION
RESULTS Pharmacokinetic
THERAPY
Analysis of CellCept Patients
The characteristics of the patient groups studied are as follows: group 1, patients received Prograf and Imuran (n = 9); group 2, patients received Prograf and 2 g/d CellCept (n = 18); group 3, patients received Sandimmune and 2 g/d CellCept (n = 7); group 4, patients received Sandimmune and 3 g/d CellCept (n = 5); group 5, patients received Neoral and 2 g/d CellCept (n = 5). Groups 3 and 5 consisted of two of the same patients revisited after conversion from Sandimmune to Neoral and were a subpopulation of patients in the phase 3 multicenter trial of CyA and CellCept.’ There was no significant difference in group characteristics such as age, race, diabetes, and the presence or absence of liver or renal functional abnormalities other than those defined by the group itself (ie, CellCept dose). There was no significant difference in the FK506 values between groups 1 and 2, suggesting that there was little effect of CellCept on FK506 pK (12.8 ? 1.3 ng/mL versus 13.3 -+ 0.7 ngimL FK506 trough levels; 25.1 ? 3.5 ng/mL versus 30.6 2 2.5 ng/mL FK606 peak levels; 194 i 16 ng-hr/mL versus 226 -C 15 ng-h/ml FK.506 AUC,,_,,, all P = not significant). There was, however, a significant increase in both the MPA trough level(s) and MPA values of patients receiving Prograf and CellCept AU%,, (group 2) versus patients receiving the same dose of CellCept in combination with Sandimmune (group 3) or Neoral (group 5) (2.8 -+ 0.3 versus 1.2 2 0.4 &mL MPA trough levels, P < .05, and 50.2 2 3.9 versus 32.1 ? 6.3 pg-h/mL MPA AUC,,_,? P < .0.5). Despite a CyA AUC increase in group 5, which was expected,5 the CellCept pK were not effected. Moreover, the observation of the MPA pK values being elevated in patients receiving Prograf rather than CyA was further supported, in that values comparable for MPA trough and AUC,,-,, in group 2 (Prograf and CellCept 2 g/day) were achieved in patients receiving CyA when CellCept was given at a dose of 3 giday (group 4), ie, a 50% higher dose of CellCept than that given to the patients receiving Prograf (2.8 2 0.3 Fg/mL versus 2.6 % 0.4 Fg/mL MPA trough; and 50.2 I? 3.9 pg-h/mL versus 47.1 2 3.1 pg-h/mL MPA AUC). For the MPAG pK analysis, all patients displaying evidence of impaired renal function (ie, serum creatinine greater than 2.0 mg/dL) were eliminated because these patients are known to accumulate high levels of MPAG in their plasma.x When data from the remaining patients were analyzed, it was observed that Prograf patients receiving 2 g/d CellCept (group 2, n = 14) averaged significantly lower levels of MPAG (peak and AUC,,-,?) than Sandimmune or Neoral patients (n = 5 and n = 3, respectively) receiving the same dose of CellCept. ie, the AUC for MPAG being 755 2 8 1 pg-h/mL for group 2 versus 1230 +- 112 kg-h/mL for group 3, P = .Ol; or versus 1.168 -C 208 for group 5. P = .Ol. respectively. Patients receiving Sandimmune with 3 g/day CellCept (n = 5) displayed correspondingly higher MPAG AUC,,__, 1 values (1509 2 90 pg-h/mL).
335
The difference in the MPA pK profile of group 2 versus group 3 patients showed that in both group 2 and group 3 the MPA peaks occurred at approximately the same time after administration of CellCept and were equivalent. However, the patients receiving Prograf were able to maintain higher off-peak levels than those receiving Sandimmune (or Neoral), which resulted in the higher AUC,,m,2 values for MPA. The equivalently obtained MPAG pK profile for group 2 versus group 3 patients showed that the opposite result of MPA levels occurred with MPAG. The group 2 (Prograf) patients displayed lower peak levels and sustained lower levels than group 3 Sandimmune patients. This resulted in the significantly lower MPAG AUC,_,, for group 2 versus group 3 patients (P = .Ol). The Neoral group was similar to the Sandimmune group.
DISCUSSION In a previous report, extensive pK analysis of CellCept had been performed in both normal volunteers and renal transplant patients in conjunction with the clinical drug trials.” All patients participating in that study were receiving Sandimmune as the primary immunosuppressive drug. There was no evidence for any effect (augmentory or detrimental) of either drug on the other. Also noted was a positive correlation with CellCept doses of up to 3 g/day Our results for Sandimmune patients with MPA AUC,,-,,. appear to mirror those findings in that there was no effect of increasing the CellCept dose from 2 gid to 3 g/d in the CyA pK, and the MPA pK values were roughly proportional to CellCept dose within the Sandimmune groups. Patients receiving the microemulsion formulation of CyA (Neoral) did not show significantly different MPA pK values from their Sandimmune counterparts on the same dose of CellCept, although there was a marked effect on the CyA peak and AUC,,_,, values between the groups, which has been reported previously.5 This observation is strengthened by the fact that two of the five patients in group 5 were converted from group 3 (ie, Sandimmune to Neoral), showing the same MPA pK profile before and after conversion. What is novel in the present report is the augmentation of MPA pK in renal transplant patients receiving Prograf rather than Sandimmune, which resulted in a significant increase in both the MPA trough and AUC,,-,, values, but only a marginal (and not significant) increase in the peak MPA level. This was in contrast to simply increasing the CellCept dose, which resulted in an increase in all three pK parameters (group 3 versus 4). Two negative statements can be made: (1) the effect of Prograf on MPA pK is probably not due to increased absorption of CellCept; and (2) the effect of Prograf on MPA levels was not equivalently reciprocal, that is. there was little if any effect seen on FK506 pK in patients receiving CellCept versus a matched group receiving Imuran. This result suggests that there is probably no direct interaction between the two drugs in vivo. which might be expected to result in a bilateral effect
ZUCKER, ROSEN, TSAROUCHA
336 of the two drugs in combination. It is also unlikely that Prograf affected the hydrolysis of MMF to MPA because this step is rapid and absolute in all study subjects receiving CellCept regardless of their primary immunosuppressive drug. Other steps in CellCept metabolism, however, that may be affected in the Prograf patients are the conversion of MPA to MPAG and the subsequent renal excretion of MPAG. For example, if FK.506 has an inhibitory effect, either directly or indirectly, on the enzymatic conversion of MPA to MPAG, this would have resulted in higher levels of plasma MPA. Evidence from the pK analysis of MPAG from the same patient samples support this notion, in that Prograf patients actually displayed significantly lower levels of plasma MPAG in conjunction with higher MPA levels. An additional consideration is with the observation in previous reports’ that, at least with patients receiving CyA, MPA levels increase significantly the longer the patients have been on CellCept. The majority of the Sandimmune patients in this study were part of the multicenter trial for MMF and, as a consequence, have been receiving CellCept for a significantly longer time period (than the more recently treated) Prograf patients, although at least a 3-week interval was allowed to elapse before these pK studies were instituted in the Prograf groups. Although the specific mechanism for this observed increase in plasma MPA is not known, one might presume that the same
ET AL
phenomenon of increasing MPA levels would occur in patients receiving more prolonged Prograf courses as well, although this assumption remains to be proved. The data indicate that significantly higher MPA drug concentrations are attained in renal transplant patients receiving Prograf versus patients receiving Sandimmune or Neoral on the same dose of CellCept. Equivalent MPA levels can be obtained in CyA patients by increasing the dose of CellCept by approximately 50% (2 g/d versus 3 g/d). These observations warrant that special consideration be given when dosing renal transplant patients with this specific drug combination regimen.
REFERENCES 1. Sollinger HW: Kidney Int 52514, 1995 2. Lee W. Gu L, Miksztal A, et al: Pharm Res 7:161, 1990 3. Franklin TJ, Cook JM: Biochem J 113:515, 1969 4. Sweeney MJ, Hoffman DH, Esterman MA: Cancer Res 32:1803, 1972 5. Noble S, Markham A: Drugs 50:924, 1995 6. Tsina I, Kaloostian 1996 7. Sollinger
M, Lee R, et al: J Chromatogr
HW: Transplantation
681:347,
60:225, 1995
8. Shaw LM, Nowak I: Ther Drug Mon 17:685, 1995 9. Sollinger HW, Deierhoi tion 53:428, 1992
MH, Belzer FO, et al: Transplanta-
ELSEVIER
Augmentation of Mycophenolate Mofetil Pharmacokinetics in Renal Transplant Patients Receiving Prograf and Cellcept in Combination Therapy K. Zucker, A. Rosen, A. Tsaroucha, and J. Miller
M
L. de Faria, D. Roth, G. Ciancio,
YCOPHENOLATE mofetil (MMF) has been shown to be a potent immunosuppressive agent in experimental animals as well as humans.’ In clinical trials, MMF was able to significantly prolong allograft survival in combination with cyclosporine A (Sandoz Pharmaceuticals, Basel, Switzerland) and is currently approved for use in humans under the trade name CellCept (Roche Biosciences, Santa Clara, Calif). After absorption, MMF is rapidly hydrolyzed to its active form, mycophenolic acid (MPA).’ MPA serves as a noncompetitive inhibitor of the enzyme inosine monophosphate dehydrogenase, which is essential in the de novo pathway of purine biosynthesis and thus DNA replication.3 In vivo the majority of the MPA is converted to a glucuronide form that is inactive.4 There is no evidence that the glucuronide form of MPA may serve as a source of active MPA in vivo. The present report is a pharmacokinetic (pK) analysis of renal allograft recipients receiving tacrolimus (Prograf, Fujisawa Pharmaceuticals, Ltd., Tokyo, Japan) in combination with CellCept. The trough, peak, and area under the curve (AUC) values for both drugs were compared against control groups receiving either Prograf in combination with azathioprine (Imuran, Burroughs-Wellcome, Research Triangle Park, NC) or cyclosporine (CyA) in combination with CellCept. Additional comparison has been made using the same parameters for the microemulsion formulation of CyA’ (Neoral). This study was performed to gain insight into selecting a rational dose range for use of the two newer agents (PrografiCellCept) in combination clinically. 0041-1315/97/$17.00 PII SO041 -1345(96)00292-8
MATERIALS
V. Esquenazi,
AND
G. Burke, A. Tzakis,
METHODS
In the pK experiments all study subjects were first-cadaver or living-related donor renal transplant recipients who were stable with respect to renal function and general health status. The subjects were grouped according to the maintenance immunosuppressive drug combinations administered, ie, tacrolimus or CyA, and the dose of CellCept (0,2, or 3 g/d). They had been receiving their specific drug regimen for at least 3 weeks before testing. For analysis, blood was collected into one heparin and one ethylenediaminetetraacetic acid tube 30 minutes prior to CellCept administration, and then 30 min, 1, 1.5, 2, 3, 4, 6, 8, and 12 hours after CellCept administration. MPA and its glucuronide derivative (MPAG) levels were determined with high performance liquid chromatography by the method of Tsina et al.6 Cyclosporine levels were determined from whole blood collected in the ethylenediaminetetraacetic acid tube using the TDx assay system (Abbott Labs, North Chicago, Ill). FK506 levels were determined from whole blood using the IMx assay system (Abbott Labs).
From the Department of Surgery, Division of Transplantation at the University of Miami School of Medicine, and the Miami Veterans Administration Medical Center, Miami, Florida. Supported by Miami Veterans Administration Hospital Research Support, NIH grant ROlDK25243-15, Roche Biosciences, and Fujisawa Pharmaceuticals, Ltd., Tokyo, Japan. Address reprint requests to Dr. Keith Zucker, Dept. of Surgery, Div. of Transplantation, University of Miami School of Medicine, P.O. Box 012440 (R-440), Miami, FL 33101.
0 1997 by Elsevier Science Inc. 655 Avenue of the Americas, New York, NY 10010
334
Transplantation
Proceedings,
29, 334-336
(1997)
PROGRAF AND CELLCEPT COMBINATION
RESULTS Pharmacokinetic
THERAPY
Analysis of CellCept Patients
The characteristics of the patient groups studied are as follows: group 1, patients received Prograf and Imuran (n = 9); group 2, patients received Prograf and 2 g/d CellCept (n = 18); group 3, patients received Sandimmune and 2 g/d CellCept (n = 7); group 4, patients received Sandimmune and 3 g/d CellCept (n = 5); group 5, patients received Neoral and 2 g/d CellCept (n = 5). Groups 3 and 5 consisted of two of the same patients revisited after conversion from Sandimmune to Neoral and were a subpopulation of patients in the phase 3 multicenter trial of CyA and CellCept.’ There was no significant difference in group characteristics such as age, race, diabetes, and the presence or absence of liver or renal functional abnormalities other than those defined by the group itself (ie, CellCept dose). There was no significant difference in the FK506 values between groups 1 and 2, suggesting that there was little effect of CellCept on FK506 pK (12.8 ? 1.3 ng/mL versus 13.3 -+ 0.7 ngimL FK506 trough levels; 25.1 ? 3.5 ng/mL versus 30.6 2 2.5 ng/mL FK606 peak levels; 194 i 16 ng-hr/mL versus 226 -C 15 ng-h/ml FK.506 AUC,,_,,, all P = not significant). There was, however, a significant increase in both the MPA trough level(s) and MPA values of patients receiving Prograf and CellCept AU%,, (group 2) versus patients receiving the same dose of CellCept in combination with Sandimmune (group 3) or Neoral (group 5) (2.8 -+ 0.3 versus 1.2 2 0.4 &mL MPA trough levels, P < .05, and 50.2 2 3.9 versus 32.1 ? 6.3 pg-h/mL MPA AUC,,_,? P < .0.5). Despite a CyA AUC increase in group 5, which was expected,5 the CellCept pK were not effected. Moreover, the observation of the MPA pK values being elevated in patients receiving Prograf rather than CyA was further supported, in that values comparable for MPA trough and AUC,,-,, in group 2 (Prograf and CellCept 2 g/day) were achieved in patients receiving CyA when CellCept was given at a dose of 3 giday (group 4), ie, a 50% higher dose of CellCept than that given to the patients receiving Prograf (2.8 2 0.3 Fg/mL versus 2.6 % 0.4 Fg/mL MPA trough; and 50.2 I? 3.9 pg-h/mL versus 47.1 2 3.1 pg-h/mL MPA AUC). For the MPAG pK analysis, all patients displaying evidence of impaired renal function (ie, serum creatinine greater than 2.0 mg/dL) were eliminated because these patients are known to accumulate high levels of MPAG in their plasma.x When data from the remaining patients were analyzed, it was observed that Prograf patients receiving 2 g/d CellCept (group 2, n = 14) averaged significantly lower levels of MPAG (peak and AUC,,-,?) than Sandimmune or Neoral patients (n = 5 and n = 3, respectively) receiving the same dose of CellCept. ie, the AUC for MPAG being 755 2 8 1 pg-h/mL for group 2 versus 1230 +- 112 kg-h/mL for group 3, P = .Ol; or versus 1.168 -C 208 for group 5. P = .Ol. respectively. Patients receiving Sandimmune with 3 g/day CellCept (n = 5) displayed correspondingly higher MPAG AUC,,__, 1 values (1509 2 90 pg-h/mL).
335
The difference in the MPA pK profile of group 2 versus group 3 patients showed that in both group 2 and group 3 the MPA peaks occurred at approximately the same time after administration of CellCept and were equivalent. However, the patients receiving Prograf were able to maintain higher off-peak levels than those receiving Sandimmune (or Neoral), which resulted in the higher AUC,,m,2 values for MPA. The equivalently obtained MPAG pK profile for group 2 versus group 3 patients showed that the opposite result of MPA levels occurred with MPAG. The group 2 (Prograf) patients displayed lower peak levels and sustained lower levels than group 3 Sandimmune patients. This resulted in the significantly lower MPAG AUC,_,, for group 2 versus group 3 patients (P = .Ol). The Neoral group was similar to the Sandimmune group.
DISCUSSION In a previous report, extensive pK analysis of CellCept had been performed in both normal volunteers and renal transplant patients in conjunction with the clinical drug trials.” All patients participating in that study were receiving Sandimmune as the primary immunosuppressive drug. There was no evidence for any effect (augmentory or detrimental) of either drug on the other. Also noted was a positive correlation with CellCept doses of up to 3 g/day Our results for Sandimmune patients with MPA AUC,,-,,. appear to mirror those findings in that there was no effect of increasing the CellCept dose from 2 gid to 3 g/d in the CyA pK, and the MPA pK values were roughly proportional to CellCept dose within the Sandimmune groups. Patients receiving the microemulsion formulation of CyA (Neoral) did not show significantly different MPA pK values from their Sandimmune counterparts on the same dose of CellCept, although there was a marked effect on the CyA peak and AUC,,_,, values between the groups, which has been reported previously.5 This observation is strengthened by the fact that two of the five patients in group 5 were converted from group 3 (ie, Sandimmune to Neoral), showing the same MPA pK profile before and after conversion. What is novel in the present report is the augmentation of MPA pK in renal transplant patients receiving Prograf rather than Sandimmune, which resulted in a significant increase in both the MPA trough and AUC,,-,, values, but only a marginal (and not significant) increase in the peak MPA level. This was in contrast to simply increasing the CellCept dose, which resulted in an increase in all three pK parameters (group 3 versus 4). Two negative statements can be made: (1) the effect of Prograf on MPA pK is probably not due to increased absorption of CellCept; and (2) the effect of Prograf on MPA levels was not equivalently reciprocal, that is. there was little if any effect seen on FK506 pK in patients receiving CellCept versus a matched group receiving Imuran. This result suggests that there is probably no direct interaction between the two drugs in vivo. which might be expected to result in a bilateral effect
ZUCKER, ROSEN, TSAROUCHA
336 of the two drugs in combination. It is also unlikely that Prograf affected the hydrolysis of MMF to MPA because this step is rapid and absolute in all study subjects receiving CellCept regardless of their primary immunosuppressive drug. Other steps in CellCept metabolism, however, that may be affected in the Prograf patients are the conversion of MPA to MPAG and the subsequent renal excretion of MPAG. For example, if FK.506 has an inhibitory effect, either directly or indirectly, on the enzymatic conversion of MPA to MPAG, this would have resulted in higher levels of plasma MPA. Evidence from the pK analysis of MPAG from the same patient samples support this notion, in that Prograf patients actually displayed significantly lower levels of plasma MPAG in conjunction with higher MPA levels. An additional consideration is with the observation in previous reports’ that, at least with patients receiving CyA, MPA levels increase significantly the longer the patients have been on CellCept. The majority of the Sandimmune patients in this study were part of the multicenter trial for MMF and, as a consequence, have been receiving CellCept for a significantly longer time period (than the more recently treated) Prograf patients, although at least a 3-week interval was allowed to elapse before these pK studies were instituted in the Prograf groups. Although the specific mechanism for this observed increase in plasma MPA is not known, one might presume that the same
ET AL
phenomenon of increasing MPA levels would occur in patients receiving more prolonged Prograf courses as well, although this assumption remains to be proved. The data indicate that significantly higher MPA drug concentrations are attained in renal transplant patients receiving Prograf versus patients receiving Sandimmune or Neoral on the same dose of CellCept. Equivalent MPA levels can be obtained in CyA patients by increasing the dose of CellCept by approximately 50% (2 g/d versus 3 g/d). These observations warrant that special consideration be given when dosing renal transplant patients with this specific drug combination regimen.
REFERENCES 1. Sollinger HW: Kidney Int 52514, 1995 2. Lee W. Gu L, Miksztal A, et al: Pharm Res 7:161, 1990 3. Franklin TJ, Cook JM: Biochem J 113:515, 1969 4. Sweeney MJ, Hoffman DH, Esterman MA: Cancer Res 32:1803, 1972 5. Noble S, Markham A: Drugs 50:924, 1995 6. Tsina I, Kaloostian 1996 7. Sollinger
M, Lee R, et al: J Chromatogr
HW: Transplantation
681:347,
60:225, 1995
8. Shaw LM, Nowak I: Ther Drug Mon 17:685, 1995 9. Sollinger HW, Deierhoi tion 53:428, 1992
MH, Belzer FO, et al: Transplanta-