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Cyclosporine as a milestone in immunosuppression
Cyclosporine as a Milestone in Immunosuppression R. Calne ABSTRACT In this short review I show how cyclosporine fits into the broader picture of immunosuppression for organ allografting. Before cyclosporine there were some good results, particularly in kidney grafting, but also a failure rate of 50% of grafts by 1 year. Cyclosporine changed the graft survival of 1 year to 80%, although at 10 years the graft survival was little different from patients treated with azathioprine and steroids. Nevertheless, many patients achieved good function in their kidneys when treated with cyclosporine; these patients would have lost the kidneys under the old regimen. The cause of the late failure in patients treated with cyclosporine was predominantly nephrotoxicity due to the calcineurine inhibition, damaging the kidneys. Now that this is better understood and new drugs are available, many regimens have been tried but cyclosporine remains an important tool for the clinician in the treatment of patients with organ allografts.
I
MMUNOSUPPRESSION has developed very rapidly in the last few years, but the early history was slow and confusing. Initial approaches to organ grafting following the dramatic identical twin kidney transplants at the Peter Bent Brigham Hospital by Murray and colleagues1 led a few workers to try and follow Billingham et al’s experimental production of immunological tolerance in rodents.2 The goal could be stated fairly simply: if during embryonic development the immune system could be persuaded to accept foreign antigenic protein as if it were its own self-product, then perhaps an adult immune system could be rendered temporarily to have similar attribution. The first approach was to destroy the immune system by total body X-irradiation and provide a new immune system through a bone marrow graft, as bone marrow injected into the blood stream homed to the marrow spaces and provided the recipient with a new immune capacity. The fulfillment of this promise, first experimentally and then in the clinic, has in the course of time been shown to be capable of providing long-term tolerance in humans requiring bone marrow transplantation, but the essential requirement is of very close human leukocyte antigen (HLA) matching of donor and recipient, usually an HLA-identical sibling donor. Early attempts to use X-irradiation without bone marrow grafting or with bone marrow grafting from a poorly matched donor were doomed to failure with the exception of two early nonidentical twin transplants, one in Boston and the other in Paris.
© 2004 by Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010-1710 Transplantation Proceedings, 36 (Suppl 2S), 13S⫺15S (2004)
To use drugs as an alternative to X-irradiation seemed a possibility, and the obvious drugs to investigate were those used to treat leukemias and other malignancies. Schwartz and Damashek in 19593 showed that the antileukemia drug 6-mercaptopurine would prevent rabbits from producing antibodies to a foreign protein antigen injected at the same time, and this inability to react against that antigen was specific and prolonged; 6-mercaptopurine also prolonged kidney allograft survival in dogs,4 and a variety of other antimetabolites were investigated as potential immunosuppressive agents. Azathioprine, a close derivative of 6-mercaptopurine, was found to be slightly more effective than 6-mercaptopurine itself.5 Dogs with renal allografts had survived more than a year before azathioprine was used in the clinic, where the results were disappointing until corticosteroids were added to the protocol.6 Corticosteroids had been known to impair immune responses but Goodwin showed that they had a dramatic effect on acute renal allograft rejection,7 and the use of steroids with azathioprine became established in the clinic, particularly following the meticulous work of Starzl and his colleagues in Denver.8 The other approach to immunosuppression was to use antilymphocyte serum preparations produced in animals From the Department of Surgery, Douglas House Annexe, Cambridge, UK. Address reprint requests to Professor Roy Calne, Department of Surgery, Douglas House Annexe, 18 Trumpington Rd, Cambridge CB2 2AH, UK. E-mail: [email protected] 0041-1345/04/$–see front matter doi:10.1016/j.transproceed.2004.01.042 13S
14S
injected with human lymphocytes or thymocytes. Some of these products were powerful and effective; other batches showed little efficacy, and some were toxic. The main immunosuppressive protocols between 1963 and 1970 were based on azathioprine combined with corticosteroids. In the Sandoz laboratories in Basle, Borel and colleagues had discovered a potent immunosuppressive cyclic peptide, cyclosporine, which inhibited in vitro immune reactions and also prolonged skin graft survival.9 He presented these data at the British Society of Immunology in 1977, and David White was very impressed with these results and suggested that we might investigate cyclosporine in experimental recipients of organ allografts. The first experiments by Kostakis et al using orthotopic heart allografts in rats showed prolonged survival once the dosage and administration of the lipotrophic cyclosporine was understood.10 The use of cyclosporine in large animals, namely pigs with orthotopic heart grafts and dogs with renal allografts, demonstrated that cyclosporine was far more effective than any other agent so far investigated with these experimental models.11,12 Two-week treatment with cyclosporine of rats with heart allografts could result in subsequent prolonged graft acceptance without any further drug treatment13 and some of the pigs treated for 6 months to a year with cyclosporine after orthotopic heart grafting subsequently survived for long periods after cessation of cyclosporine treatment. The first cautious use of cyclosporine in the clinic given to recipients of cadaveric renal allografts resulted in completely unexpected nephrotoxicity and a high incidence of lymphoma.14 The drug dosages used in animals were far too high for humans and our animal experiments had given no indication of nephrotoxicity, which occurred even when the dosage was dropped to levels that did not necessarily prevent rejection. Nevertheless, once cyclosporine dose management was clarified, the early results of renal transplantation improved from approximately 50% 1-year functional survival to over 80% and for the first time reasonable results were obtained with liver, heart, and heart-lung allografts, which previously had been very difficult to manage with azathioprine and steroids. THE IMPACT OF CYCLOSPORINE
Once the early results had been repeated in a number of centers, cyclosporine became the “sheet anchor” of immunosuppression and the strategy of combining a low dose of cyclosporine with corticosteroids and azathioprine, socalled “triple therapy,” became the most popular immunosuppressive regimen. The perception of organ grafting changed worldwide. Previously it had been regarded as a pursuit, usually unsuccessful, that was best avoided by clinicians with common sense, but now cyclosporine had changed this negative feeling to one of enthusiasm for organ grafting. Worldwide new centers were established and the number of all organs that could be transplanted increased to a dramatic extent. Now looking back in 2004 it is clear that the impact of
CALNE
cyclosporine on organ grafting was enormous; this drug was responsible for a new form of therapy that has alleviated countless individuals from suffering and death. Cyclosporine is by no means perfect. As has been mentioned, the chief drawback is nephrotoxicity, which tends to be progressive and has been an important cause of morbidity in recipients of nonrenal transplants. Children are distressed by the increase in facial and body hair that can occur with therapeutic doses of cyclosporine. The mode of action of cyclosporine showed that although it had a general toxicity to many cells if given in very high doses, in therapeutic doses most of the activity was directed against interleukin-2 synthesis, and thus it inhibited the response of T cells to antigens. Many new agents were investigated for immunosuppressive properties. Monoclonal antibodies directed against human lymphocyte epitopes were more consistent in activity than most polyclonal antibodies, each monoclonal antibody having a single molecular target epitope. Tacrolimus (Prograf) is a very interesting agent and extremely powerful following administration of minute doses. This drug, originally investigated by the Fujisawa company in Japan, prolonged the survival of rat allografts in a study by Ochiai et al,15 It was later introduced to the clinic by Starzl and colleagues and found to be an extremely important new immunosuppressive drug.16 Like cyclosporine it had a nephrotoxic side effect and could be diabetagenic but it did not cause hirsutism, and in some patients undergoing rejection under cyclospirine, switching to Prograf reversed the rejection. The mode of action of tacrolimus appears to be very similar to cyclosporine, and the nephrotoxic side effect of calcineurine inhibitors has been a cause of concern for doctors involved in transplantation who have looked for alternative agents. A macrolide chemically similar to tacrolimus but with a different form of action called sirolimus is not nephrotoxic and can be a valuable immunosuppressant in recipients of all organ allografts.17 Mycophenolate mofetil is more effective than azathioprine as an antimetabolite in preventing lymphocyte proliferation in response to antigenic challenge and is a very useful adjunct immunosuppressant. We have studied in a monoclonal antibody that depletes lymphocytes, Campath 1H, which has been used as an induction agent followed by low-dose cyclosporine maintenance immunosuppression without any other drugs.18,19 This protocol, which avoids steroid treatment, is very acceptable to patients and has produced encouraging results after 5 years. CONCLUSIONS
Cyclosporine continues to be an extremely valuable immunosuppressive agent. The clinician is embarrassed with too many options, and we are still ignorant as to the best way to use the agents that are available, how to combine them, and what doses to give. Certainly the more potent drugs and antibodies available, the greater the chance of getting a
CYCLOSPORINE AS A MILESTONE
good result, but there is a danger that adding one agent to another and then yet another is a bad therapeutic approach, which probably prevents natural, active graft acceptance mechanisms that could lead to tolerance. Tolerance occurs in liver allografts in some species,20 and approximately a third of patients after some years of good function of liver grafts treated with immunosuppression can stop immunosuppression, but at present we lack a means of testing who can safely come off drug maintenance treatment.21 Nonablative immunosuppression and bone marrow transplantation can result in mixed chimerism with tolerance of kidney grafts even if the chimerism is only temporary, but again close HLA matching of donor and recipient prevents this very interesting approach from being widely applicable at present.22 No doubt new drugs and antibodies will be discovered and efforts will be made to avoid toxicity and procure long-term maintenance immunosuppression in organ allografts even between mismatched donor and recipient combinations. But cyclosporine will still remain the watershed, which changed the way we as a profession regarded organ grafting as a means of helping our patients.
REFERENCES 1. Murray JE, Merrill JP, Harrison JH: Renal homotransplantation in identical twins. Surg Forum 6:432, 1955 2. Billingham RE, Brent L, Medawar PB: Actively acquired tolerance of foreign cells. Nature 172:603, 1953 3. Schwartz R, Damashek W: Drug induced immunologic tolerance. Nature 183:1682, 1959 4. Calne RY: The rejection of renal homografts. Inhibition in dogs by using 6-mercaptopurine. Lancet 1:417, 1960 5. Calne RY: Inhibition of the rejection of renal homografts in dogs by purine analogues. Transplant Bull 28:445, 1961 6. Murray JE, Reid DE, Harrison JH, et al: Prolonged survival of human kidney homografts by immunosuppressive drug therapy. New Engl J Med 269:341, 1977
15S 7. Goodwin WE, Kaufman JJ, Mims MM, et al: Human renal transplantation. I. Clinical experiences with six cases of renal transplantation. J Urol 89:13, 1963 8. Starzl TE: Experience in Renal Transplantation. W.B. Saunders: Philadelphia and London; 1964 9. Borel JF, Feurer C, Gubler HU, et al: Biological effects of cyclosporine A: a new antilymphocytic agent. Agents Actions 6:468, 1976 10. Kostakis AJ, White DJG, Calne RY: Toxic effects in the use of cyclosporine A in alcoholic solution as an immunosuppressant of rat heart allografts. IRCS Med Soc 5:280, 1997 11. Calne RY, White DJG: Cyclosporin A—a powerful immunosuppressant in dogs with renal allografts. Surgery and Transplantation 5:595, 1977 12. Calne RY, Rolles K, White DJG, et al: Prolonged survival of pig orthotopic heart grafts treated with cyclosporine A. Lancet June 3, 1183, 1978 13. White DJG, Rolles K, Ottawa T, et al: Cyclosporin A induced long-term survival of fully incompatible skin and heart grafts in rats. Transplant Proc 12:2, 1980 14. Calne RY, Rolles K, White DJG, et al: Cyclosporin A initially as the only immunosuppressant in 34 recipients of cadaveric organs: 32 kidneys, 2 pancreases, and 2 livers. Lancet 2:1033, 1979 15. Ochiai T, Sakamoto K, Nagata M, et al: Studies on FK506 in experimental organ transplants. Transplant Proc. 20:209, 1988 16. Starzl TE, Fung J, Jordan M, et al: Kidney transplantation under FK 506. JAMA 264, 1990 17. Calne RY, Collier D, Lim S, et al: Rapamycin for immunosuppression in organ allografting. JAMA 264:63, 1989 18. Calne RY: Prope, (almost) tolerance. The WOFIE hypothesis. Tranplantationsmedizin. Berlin: Pabst Science Publishers, 1999 19. Calne RY, Moffatt SD, Friend PJ, et al: Campath 1H allows low-dose cyclosporin monotherapy in 31 cadaveric renal allograft recipients. Transplantation 68:1613, 1999 20. Calne RY, Sells RA, Pena JR, et al: Induction of immunological tolerance by porcine liver allografts. Nature 223:472, 1969 21. Mazariegos GV, Reyes J, Marino IR, et al: Transplantation 63:243, 1997 22. Buhler LH, Spitzer TR, Sykes M, et al: Induction of kidney allograft tolerance after transient lymphohematopoietic chimerism in patients with multiple myeloma and end-stage renal disease. Transplantation 74:1405, 2002
I
MMUNOSUPPRESSION has developed very rapidly in the last few years, but the early history was slow and confusing. Initial approaches to organ grafting following the dramatic identical twin kidney transplants at the Peter Bent Brigham Hospital by Murray and colleagues1 led a few workers to try and follow Billingham et al’s experimental production of immunological tolerance in rodents.2 The goal could be stated fairly simply: if during embryonic development the immune system could be persuaded to accept foreign antigenic protein as if it were its own self-product, then perhaps an adult immune system could be rendered temporarily to have similar attribution. The first approach was to destroy the immune system by total body X-irradiation and provide a new immune system through a bone marrow graft, as bone marrow injected into the blood stream homed to the marrow spaces and provided the recipient with a new immune capacity. The fulfillment of this promise, first experimentally and then in the clinic, has in the course of time been shown to be capable of providing long-term tolerance in humans requiring bone marrow transplantation, but the essential requirement is of very close human leukocyte antigen (HLA) matching of donor and recipient, usually an HLA-identical sibling donor. Early attempts to use X-irradiation without bone marrow grafting or with bone marrow grafting from a poorly matched donor were doomed to failure with the exception of two early nonidentical twin transplants, one in Boston and the other in Paris.
© 2004 by Elsevier Inc. All rights reserved. 360 Park Avenue South, New York, NY 10010-1710 Transplantation Proceedings, 36 (Suppl 2S), 13S⫺15S (2004)
To use drugs as an alternative to X-irradiation seemed a possibility, and the obvious drugs to investigate were those used to treat leukemias and other malignancies. Schwartz and Damashek in 19593 showed that the antileukemia drug 6-mercaptopurine would prevent rabbits from producing antibodies to a foreign protein antigen injected at the same time, and this inability to react against that antigen was specific and prolonged; 6-mercaptopurine also prolonged kidney allograft survival in dogs,4 and a variety of other antimetabolites were investigated as potential immunosuppressive agents. Azathioprine, a close derivative of 6-mercaptopurine, was found to be slightly more effective than 6-mercaptopurine itself.5 Dogs with renal allografts had survived more than a year before azathioprine was used in the clinic, where the results were disappointing until corticosteroids were added to the protocol.6 Corticosteroids had been known to impair immune responses but Goodwin showed that they had a dramatic effect on acute renal allograft rejection,7 and the use of steroids with azathioprine became established in the clinic, particularly following the meticulous work of Starzl and his colleagues in Denver.8 The other approach to immunosuppression was to use antilymphocyte serum preparations produced in animals From the Department of Surgery, Douglas House Annexe, Cambridge, UK. Address reprint requests to Professor Roy Calne, Department of Surgery, Douglas House Annexe, 18 Trumpington Rd, Cambridge CB2 2AH, UK. E-mail: [email protected] 0041-1345/04/$–see front matter doi:10.1016/j.transproceed.2004.01.042 13S
14S
injected with human lymphocytes or thymocytes. Some of these products were powerful and effective; other batches showed little efficacy, and some were toxic. The main immunosuppressive protocols between 1963 and 1970 were based on azathioprine combined with corticosteroids. In the Sandoz laboratories in Basle, Borel and colleagues had discovered a potent immunosuppressive cyclic peptide, cyclosporine, which inhibited in vitro immune reactions and also prolonged skin graft survival.9 He presented these data at the British Society of Immunology in 1977, and David White was very impressed with these results and suggested that we might investigate cyclosporine in experimental recipients of organ allografts. The first experiments by Kostakis et al using orthotopic heart allografts in rats showed prolonged survival once the dosage and administration of the lipotrophic cyclosporine was understood.10 The use of cyclosporine in large animals, namely pigs with orthotopic heart grafts and dogs with renal allografts, demonstrated that cyclosporine was far more effective than any other agent so far investigated with these experimental models.11,12 Two-week treatment with cyclosporine of rats with heart allografts could result in subsequent prolonged graft acceptance without any further drug treatment13 and some of the pigs treated for 6 months to a year with cyclosporine after orthotopic heart grafting subsequently survived for long periods after cessation of cyclosporine treatment. The first cautious use of cyclosporine in the clinic given to recipients of cadaveric renal allografts resulted in completely unexpected nephrotoxicity and a high incidence of lymphoma.14 The drug dosages used in animals were far too high for humans and our animal experiments had given no indication of nephrotoxicity, which occurred even when the dosage was dropped to levels that did not necessarily prevent rejection. Nevertheless, once cyclosporine dose management was clarified, the early results of renal transplantation improved from approximately 50% 1-year functional survival to over 80% and for the first time reasonable results were obtained with liver, heart, and heart-lung allografts, which previously had been very difficult to manage with azathioprine and steroids. THE IMPACT OF CYCLOSPORINE
Once the early results had been repeated in a number of centers, cyclosporine became the “sheet anchor” of immunosuppression and the strategy of combining a low dose of cyclosporine with corticosteroids and azathioprine, socalled “triple therapy,” became the most popular immunosuppressive regimen. The perception of organ grafting changed worldwide. Previously it had been regarded as a pursuit, usually unsuccessful, that was best avoided by clinicians with common sense, but now cyclosporine had changed this negative feeling to one of enthusiasm for organ grafting. Worldwide new centers were established and the number of all organs that could be transplanted increased to a dramatic extent. Now looking back in 2004 it is clear that the impact of
CALNE
cyclosporine on organ grafting was enormous; this drug was responsible for a new form of therapy that has alleviated countless individuals from suffering and death. Cyclosporine is by no means perfect. As has been mentioned, the chief drawback is nephrotoxicity, which tends to be progressive and has been an important cause of morbidity in recipients of nonrenal transplants. Children are distressed by the increase in facial and body hair that can occur with therapeutic doses of cyclosporine. The mode of action of cyclosporine showed that although it had a general toxicity to many cells if given in very high doses, in therapeutic doses most of the activity was directed against interleukin-2 synthesis, and thus it inhibited the response of T cells to antigens. Many new agents were investigated for immunosuppressive properties. Monoclonal antibodies directed against human lymphocyte epitopes were more consistent in activity than most polyclonal antibodies, each monoclonal antibody having a single molecular target epitope. Tacrolimus (Prograf) is a very interesting agent and extremely powerful following administration of minute doses. This drug, originally investigated by the Fujisawa company in Japan, prolonged the survival of rat allografts in a study by Ochiai et al,15 It was later introduced to the clinic by Starzl and colleagues and found to be an extremely important new immunosuppressive drug.16 Like cyclosporine it had a nephrotoxic side effect and could be diabetagenic but it did not cause hirsutism, and in some patients undergoing rejection under cyclospirine, switching to Prograf reversed the rejection. The mode of action of tacrolimus appears to be very similar to cyclosporine, and the nephrotoxic side effect of calcineurine inhibitors has been a cause of concern for doctors involved in transplantation who have looked for alternative agents. A macrolide chemically similar to tacrolimus but with a different form of action called sirolimus is not nephrotoxic and can be a valuable immunosuppressant in recipients of all organ allografts.17 Mycophenolate mofetil is more effective than azathioprine as an antimetabolite in preventing lymphocyte proliferation in response to antigenic challenge and is a very useful adjunct immunosuppressant. We have studied in a monoclonal antibody that depletes lymphocytes, Campath 1H, which has been used as an induction agent followed by low-dose cyclosporine maintenance immunosuppression without any other drugs.18,19 This protocol, which avoids steroid treatment, is very acceptable to patients and has produced encouraging results after 5 years. CONCLUSIONS
Cyclosporine continues to be an extremely valuable immunosuppressive agent. The clinician is embarrassed with too many options, and we are still ignorant as to the best way to use the agents that are available, how to combine them, and what doses to give. Certainly the more potent drugs and antibodies available, the greater the chance of getting a
CYCLOSPORINE AS A MILESTONE
good result, but there is a danger that adding one agent to another and then yet another is a bad therapeutic approach, which probably prevents natural, active graft acceptance mechanisms that could lead to tolerance. Tolerance occurs in liver allografts in some species,20 and approximately a third of patients after some years of good function of liver grafts treated with immunosuppression can stop immunosuppression, but at present we lack a means of testing who can safely come off drug maintenance treatment.21 Nonablative immunosuppression and bone marrow transplantation can result in mixed chimerism with tolerance of kidney grafts even if the chimerism is only temporary, but again close HLA matching of donor and recipient prevents this very interesting approach from being widely applicable at present.22 No doubt new drugs and antibodies will be discovered and efforts will be made to avoid toxicity and procure long-term maintenance immunosuppression in organ allografts even between mismatched donor and recipient combinations. But cyclosporine will still remain the watershed, which changed the way we as a profession regarded organ grafting as a means of helping our patients.
REFERENCES 1. Murray JE, Merrill JP, Harrison JH: Renal homotransplantation in identical twins. Surg Forum 6:432, 1955 2. Billingham RE, Brent L, Medawar PB: Actively acquired tolerance of foreign cells. Nature 172:603, 1953 3. Schwartz R, Damashek W: Drug induced immunologic tolerance. Nature 183:1682, 1959 4. Calne RY: The rejection of renal homografts. Inhibition in dogs by using 6-mercaptopurine. Lancet 1:417, 1960 5. Calne RY: Inhibition of the rejection of renal homografts in dogs by purine analogues. Transplant Bull 28:445, 1961 6. Murray JE, Reid DE, Harrison JH, et al: Prolonged survival of human kidney homografts by immunosuppressive drug therapy. New Engl J Med 269:341, 1977
15S 7. Goodwin WE, Kaufman JJ, Mims MM, et al: Human renal transplantation. I. Clinical experiences with six cases of renal transplantation. J Urol 89:13, 1963 8. Starzl TE: Experience in Renal Transplantation. W.B. Saunders: Philadelphia and London; 1964 9. Borel JF, Feurer C, Gubler HU, et al: Biological effects of cyclosporine A: a new antilymphocytic agent. Agents Actions 6:468, 1976 10. Kostakis AJ, White DJG, Calne RY: Toxic effects in the use of cyclosporine A in alcoholic solution as an immunosuppressant of rat heart allografts. IRCS Med Soc 5:280, 1997 11. Calne RY, White DJG: Cyclosporin A—a powerful immunosuppressant in dogs with renal allografts. Surgery and Transplantation 5:595, 1977 12. Calne RY, Rolles K, White DJG, et al: Prolonged survival of pig orthotopic heart grafts treated with cyclosporine A. Lancet June 3, 1183, 1978 13. White DJG, Rolles K, Ottawa T, et al: Cyclosporin A induced long-term survival of fully incompatible skin and heart grafts in rats. Transplant Proc 12:2, 1980 14. Calne RY, Rolles K, White DJG, et al: Cyclosporin A initially as the only immunosuppressant in 34 recipients of cadaveric organs: 32 kidneys, 2 pancreases, and 2 livers. Lancet 2:1033, 1979 15. Ochiai T, Sakamoto K, Nagata M, et al: Studies on FK506 in experimental organ transplants. Transplant Proc. 20:209, 1988 16. Starzl TE, Fung J, Jordan M, et al: Kidney transplantation under FK 506. JAMA 264, 1990 17. Calne RY, Collier D, Lim S, et al: Rapamycin for immunosuppression in organ allografting. JAMA 264:63, 1989 18. Calne RY: Prope, (almost) tolerance. The WOFIE hypothesis. Tranplantationsmedizin. Berlin: Pabst Science Publishers, 1999 19. Calne RY, Moffatt SD, Friend PJ, et al: Campath 1H allows low-dose cyclosporin monotherapy in 31 cadaveric renal allograft recipients. Transplantation 68:1613, 1999 20. Calne RY, Sells RA, Pena JR, et al: Induction of immunological tolerance by porcine liver allografts. Nature 223:472, 1969 21. Mazariegos GV, Reyes J, Marino IR, et al: Transplantation 63:243, 1997 22. Buhler LH, Spitzer TR, Sykes M, et al: Induction of kidney allograft tolerance after transient lymphohematopoietic chimerism in patients with multiple myeloma and end-stage renal disease. Transplantation 74:1405, 2002