mycophenolic-acid and Leukemia

The combination of a calcineurin inhibitor (CNI) such as tacrolimus (TAC) or cyclosporine (CYSP) with methotrexate (MTX) or with mycophenolate mofetil (MMF) has been commonly used for graft-versus-host disease (GVHD) prophylaxis after reduced-intensity conditioning (RIC) allogeneic hematopoietic cell transplantation (alloHCT), but there are limited data comparing efficacy of the 2 regimens. We evaluated 1564 adult patients who underwent RIC alloHCT for acute myelogenous leukemia (AML) and acute lymphoblastic leukemia (ALL), chronic myelogenous leukemia (CML), and myelodysplastic syndrome (MDS) from 2000 to 2013 using HLA-identical sibling (matched related donor [MRD]) or unrelated donor (URD) peripheral blood graft and received CYSP or TAC with MTX or MMF for GVHD prophylaxis. Primary outcomes of the study were acute and chronic GVHD and overall survival (OS). The study divided the patient population into 4 cohorts based on regimen: MMF-TAC, MMF-CYSP, MTX-TAC, and MTX-CYSP. In the URD group, MMF-CYSP was associated with increased risk of grade II to IV acute GVHD (relative risk [RR], 1.78; P < .001) and grade III to IV acute GVHD (RR, 1.93; P = .006) compared with MTX-TAC. In the URD group, use of MMF-TAC (versus MTX-TAC) lead to higher nonrelapse mortality. (hazard ratio, 1.48; P = .008). In either group, no there was no difference in chronic GVHD, disease-free survival, and OS among the GVHD prophylaxis regimens. For RIC alloHCT using MRD, there are no differences in outcomes based on GVHD prophylaxis. However, with URD RIC alloHCT, MMF-CYSP was inferior to MTX-based regimens for acute GVHD prevention, but all the regimens were equivalent in terms of chronic GVHD and OS. Prospective studies, targeting URD recipients are needed to confirm these results.

Topics: Adult; Aged; Allografts; Calcineurin Inhibitors; Disease-Free Survival; Female; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Leukemia; Male; Methotrexate; Middle Aged; Mycophenolic Acid; Myelodysplastic Syndromes; Retrospective Studies; Siblings; Survival Rate; Tacrolimus; Transplantation Conditioning

Haplo-identical transplants (Haplo-Tx) are an important alternative for patients with hematological malignancies who lack a HLA-identical donor. Seventy-one T-replete Haplo-Tx were performed in 70 high-risk patients at our center; 22/70 (31%) patients with refractory/relapsed leukemia received sequential salvage therapy (SeqTh) with high-dose chemotherapy followed by Haplo-Tx during the chemotherapy-induced neutropenia. Graft-versus-host disease (GVHD) prophylaxis consisted of post-transplant cyclophosphamide (days + 3 and + 4) with tacrolimus and mycophenolic acid. After a median follow-up of 29.2 months, 3-year overall survival (OS) and event-free survival (EFS) were 43.8 and 40.2%, while 3-year cumulative incidences (CIs) of non-relapse mortality (NRM) and relapse (RI) were 27 and 33%. Day 100 and day 400 CI of grade III-IV acute and moderate-severe chronic GVHD were 11 and 15%. Three-year RI was significantly lower in patients in complete remission (CR) versus those not in CR at the time of transplant (21.5 vs. 48%, p = 0.009) and in patients who received PBSC as compared to BM (22 vs. 45%, p = 0.009). In patients treated with SeqTh, 3-year OS was 19%, while 3-year RI and NRM were 52 and 28% at a median follow-up of 50 months. Overall, Haplo-Tx was feasible in heavily pretreated high-risk patients without a suitable HLA-identical donor.

Topics: Adult; Aged; Allografts; Cyclophosphamide; Disease-Free Survival; Female; Graft vs Host Disease; Hematologic Neoplasms; Hematopoietic Stem Cell Transplantation; Humans; Incidence; Leukemia; Male; Middle Aged; Mycophenolic Acid; Registries; Retrospective Studies; Risk Factors; Survival Rate; Tacrolimus

Topics: Acute Disease; Adolescent; Adult; Aged; Allografts; Cord Blood Stem Cell Transplantation; Drug Monitoring; Female; Graft vs Host Disease; Humans; Immunosuppressive Agents; Leukemia; Lymphoma; Male; Middle Aged; Mycophenolic Acid

Sclerotic skin manifestations of chronic graft-versus-host disease (ScGVHD) lead to significant morbidity, including functional disability from joint range of motion (ROM) restriction. No superior second-line therapy has been established for steroid-refractory disease. Imatinib mesylate is a multikinase inhibitor of several signaling pathways implicated in skin fibrosis with in vitro antifibrotic activity. We performed an open-label pilot phase II trial of imatinib in children and adults with corticosteroid-refractory ScGVHD. Twenty patients were enrolled in a 6-month trial. Eight received a standard dose (adult, 400 mg daily; children, 260 mg/m(2) daily). Because of poor tolerability, 12 additional patients underwent a dose escalation regimen (adult, 100 mg daily initial dose up to 200 mg daily maximum; children, initial dose 65 mg/m(2) daily up to 130 mg/m(2) daily). Fourteen patients were assessable for primary response, improvement in joint ROM deficit, at 6 months. Primary outcome criteria for partial response was met in 5 of 14 (36%), stable disease in 7 of 14 (50%), and progressive disease in 2 of 14 (14%) patients. Eleven patients (79%), including 5 with partial response and 6 with stable disease, demonstrated a positive gain in ROM (range of 3% to 94% improvement in deficit). Of 13 patients with measurable changes at 6 months, the average improvement in ROM deficit was 24.2% (interquartile range, 15.5% to 30.5%; P = .011). This trial is registered at http://clinicaltrials.gov as NCT007020689.

Topics: Adolescent; Adult; Antineoplastic Agents; Child; Drug Administration Schedule; Fasciitis; Female; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Imatinib Mesylate; Joints; Leukemia; Male; Middle Aged; Mycophenolic Acid; Pilot Projects; Prednisone; Range of Motion, Articular; Recurrence; Skin Diseases; Tacrolimus; Transplantation, Homologous

The study is a randomized phase II trial investigating graft-versus-host disease prophylaxis after non-myeloablative (90 mg/m(2) fludarabine and 2 Gy total body irradiation) human leukocyte antigen matched unrelated donor transplantation. Patients were randomized as follows: arm 1 - tacrolimus 180 days and mycophenolate mofetil 95 days (n=69); arm 2 - tacrolimus 150 days and mycophenolate mofetil 180 days (n=71); arm 3 - tacrolimus 150 days, mycophenolate mofetil 180 days and sirolimus 80 days (n=68). All patients had sustained engraftment. Grade II-IV acute graft-versus-host disease rates in the 3 arms were 64%, 48% and 47% at Day 150, respectively (arm 3 vs. arm 1 (hazard ratio 0.62; P=0.04). Owing to the decreased incidence of acute graft-versus-host disease, systemic steroid use was lower at Day 150 in arm 3 (32% vs. 55% in arm 1 and 49% in arm 2; overall P=0.009 by hazard ratio analysis). The Day 150 incidence of cytomegalovirus reactivation was lower in arm 3 (arm 1, 54%; arm 2, 47%; arm 3, 22%; overall P=0.002 by hazard ratio analysis). Non-relapse mortality was comparable in the three arms at two years (arm 1, 26%; arm 2, 23%; arm 3, 18%). Toxicity rates and other outcome measures were similar between the three arms. The addition of sirolimus to tacrolimus and mycophenolate mofetil is safe and associated with lower incidence of acute graft-versus-host disease and cytomegalovirus reactivation. (clinicaltrials.gov identifier: 00105001).

Topics: Adolescent; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Female; Follow-Up Studies; Graft Rejection; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Incidence; Leukemia; Lymphoma; Male; Middle Aged; Mycophenolic Acid; Recurrence; Sirolimus; Tacrolimus; Transplantation Chimera; Transplantation Conditioning; Transplantation, Homologous; Treatment Outcome; Unrelated Donors; Young Adult

Improvement of current GVHD prophylactic therapies remains an important goal in the allo-HSCT. We have described a novel prophylaxis regimen in a single institution trial. The Chinese Bone Marrow Transplant Cooperative Group (CBMTCG) initiated a phase II multicenter study.. The study was designed as a prospective, single arm phase II open-label, multicenter clinical trial. The primary endpoint was improvement of aGVHD by 25% over historical control (40%) in Chinese patients. 508 patients were enrolled. All of the patients received cyclosporine A (CsA), methotrexate (MTX) and mycophenolate mofetil (MMF) (0.5-1.0 g daily for 30 days) as GVHD prophylaxis regimen.. The primary endpoint was met with cumulative incidences of grades 2 to 4 and grades 3 to 4 aGVHD of 23.2% and 10.3%, respectively. Incidence for cGVHD was 67.4%. The non-relapse mortality (NRM) rate was 18.4% at 2 years. The probabilities of leukemia free survival (LFS) for non-advanced stage and advanced stage patients at 2 years were 69.7% and 44.8% respectively (p = 0.000). Recipient age ≥ 40 years, advanced stage and Busulfan-Fludarabine(BuFlu) conditioning regimen were identified as major risk factors for aGVHD. Recipient age ≥ 40 years, BuFlu conditioning regimens, female donor/male recipient and prior aGVHD were associated with cGVHD. Despite lower RM (relapse mortality), patients with grade 2-4 aGVHD had higher NRM and worse OS and LFS compared to patients with grade 0-1 aGVHD. In contrast, patients with cGVHD had better OS and LFS and lower RM compared to patients without cGVHD.. The novel GVHD regimen decreased the risk for aGVHD by 42% without improving the risk for cGVHD compared to historical controls. Development of aGVHD was associated with worse OS and LFS as well as higher NRM. In contrast, cGVHD was associated with improved OS and LFS likely attributed to a GVL effect.

Topics: Adolescent; Adult; Bone Marrow Transplantation; Cyclosporine; Drug Combinations; Female; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Immunosuppressive Agents; Incidence; Kaplan-Meier Estimate; Leukemia; Male; Methotrexate; Middle Aged; Mycophenolic Acid; Risk Factors; Transplantation Conditioning; Young Adult

Certain leukemias have a high relapse risk even after allo-SCT, and GVHD prophylaxis with calcineurin inhibitors (CNIs) may interfere with a possible GVL effect. Therefore, we replaced CYA by sirolimus in patients with high relapse risk. In contrast to CNIs, sirolimus promotes the generation of regulatory T-cells and has potent antineoplastic activity. Sirolimus has been used in combination with CNI for GVHD prophylaxis in hematopoietic SCT. However, no CNI-free prophylactic regimen with sirolimus has been evaluated so far. Within the FLAMSA-RIC protocol, 15 patients received GVHD prophylaxis with sirolimus and mycophenolate mofetil (MMF). The underlying diagnoses were relapsed or refractory T-ALL (n=3), AML with FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) or mixed-lineage leukemia-partial tandem duplication (MLL-PTD; n=10; 5 with refractory disease) and CML in refractory myeloid blast crisis (n=2). All evaluable patients (n=14) were engrafted. Grades II-IV acute GVHD occurred in 21% and chronic GVHD in 30% of patients. Non-relapse mortality rate was 14%. No thrombotic microangiopathy or sinusoidal obstruction syndrome was observed. Three patients with FLT3-ITD+ AML relapsed after a median of 112 days. At a median follow-up of 10 months after transplantation, 10 patients are alive and in complete remission. In conclusion, sirolimus-based GVHD prophylactic regimens deserve further investigation.

Topics: Adult; Calcineurin Inhibitors; Cohort Studies; Female; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Immunosuppressive Agents; Leukemia; Male; Middle Aged; Mycophenolic Acid; Premedication; Salvage Therapy; Sirolimus; Survival Rate; Transplantation, Homologous; Young Adult

A hematopoietic cell transplantation (HCT) approach was developed for elderly or ill patients with hematologic malignancies that employed nonmyeloablative conditioning to avoid common regimen-related toxicities and relied on graft-versus-tumor effects for control of malignancy. Eighty-nine patients, median age 53 years, were given fludarabine (90 mg/m2) and 2 Gy total body irradiation. Marrow (n = 18) or granulocyte colony-stimulating factor (G-CSF)-stimulated peripheral blood mononuclear cells (G-PBMCs; n = 71) were transplanted from unrelated donors matched for human leukocyte antigen A (HLA-A), -B, -C antigens and -DRB1 and -DQB1 alleles. Postgrafting immunosuppression included mycophenolate mofetil and cyclosporine. Donor T-cell chimerism was higher for G-PBMCs compared with marrow recipients. Durable engraftment was observed in 85% of G-PBMCs and 56% of marrow recipients. Cumulative probabilities of grade II, III, and IV acute graft-versus-host disease (GVHD) were 42%, 8%, and 2%, respectively. Nonrelapse mortality at day 100 and at 1 year was 11% and 16%, respectively. One-year overall survivals and progression-free survivals were 52% and 38%, respectively. G-PBMC recipients had improved survival (57% vs 33%) and progression-free survival (44% vs 17%) compared with marrow recipients. HLA-matched unrelated donor HCT after nonmyeloablative conditioning is feasible in patients ineligible for conventional HCT. G-PBMCs conferred higher donor T-cell chimerism, greater durable engraftment, and better progression-free and overall survivals compared with marrow.

Topics: Adolescent; Adult; Aged; Antibiotics, Antineoplastic; Child; Child, Preschool; Female; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Histocompatibility Antigens Class I; Histocompatibility Testing; Humans; Immunosuppressive Agents; Incidence; Leukemia; Leukemia, Lymphocytic, Chronic, B-Cell; Leukemia, Myelomonocytic, Acute; Lymphocyte Transfusion; Lymphoma, Non-Hodgkin; Male; Middle Aged; Multiple Myeloma; Mycophenolic Acid; Myeloproliferative Disorders; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Survival Rate; Tissue Donors; Vidarabine; Whole-Body Irradiation

Despite prophylaxis with immunosuppressive drugs, severe graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality following allogeneic stem cell transplantation. T cell depletion of the graft has decreased incidence and severity of GVHD but has resulted in a higher incidence of graft failure and relapse. To reduce the risk of severe GVHD, but at the same time to maintain the graft-versus-tumor effect, we administered a fixed low number of 1 x 10(5) donor T cells per kilogram of body weight to recipients of CD34(+) cell-enriched allogeneic peripheral blood stem cells (PBSCs). Donor lymphocyte infusions (DLI) were then given in incremental doses when mixed chimerism persisted or signs of relapse occurred. A total of 23 patients receiving allografts from related and unrelated donors were treated according to this protocol after myeloablative or reduced intensity conditioning. One patient did not engraft and 3/20 evaluable patients developed acute (a) GVHD > or = grade II, with a corresponding estimated cumulative incidence of 15.6% (95% CI 0-30.5%). DLI (n = 13) induced aGVHD > or = II in 6 patients, but the severity of the syndrome was reduced. Overall GVHD-related mortality was low (13%). The probability of disease-free survival and overall survival at 2 years was 0.40 (95% CI 0.21-0.75) and 0.36 (95% CI 0.21-0.63). Progression-free survival and overall survival was significantly better in patients with acute or chronic myelogenous leukemia compared to patients with lymphoproliferative disorders (p = 0.002; p = 0.02). We conclude that the combination of allografts with a T cell content of about 1 x 10(5)/kg and escalating doses of DLI is a viable transplant strategy in patients with myeloid leukemias, which results in stable engraftment and a reduction of mortality from aGVHD.

Topics: Adult; Antigens, CD; Antigens, CD34; CD3 Complex; Cell Separation; Cyclosporine; Disease-Free Survival; Drug Therapy, Combination; Female; Graft Survival; Graft vs Host Disease; Humans; Immunosuppressive Agents; Leukemia; Lymphoma, Non-Hodgkin; Male; Methotrexate; Middle Aged; Multiple Myeloma; Mycophenolic Acid; Stem Cell Transplantation; Survival Analysis; Time Factors; Transplantation, Homologous

To evaluate the efficacy and safety of mycophenolate mofetil (MMF) in combination with cyclosporine A (CsA) and methotrexate (MTX) for prevention of acute graft versus host disease (GVHD) after unrelated donor allogeneic bone marrow transplantation (allo-BMT).. Twelve cases of unrelated donor allo-BMT were evaluated in a single center trial. The acute GVHD was prevented with 1 g MMF daily in addition to CsA 3 mg x kg(-1) x (-1) and MTX 10 - 15 mg at post BMT day1, day3, day6 and day11.. Acute GVHD was found in one case (Grade IV) at the seventh day and two cases (Grade II) at the tenth day and seventeenth day after BMT. These patients were treated with a combination of MMF, methyprednisolone and CsA. The common adverse hematologic events of MMF was leukopenia.. The preliminary study showed that MMF could be used effectively and safely for prevention of acute GVHD in unrelated donor allo-BMT.

Topics: Acute Disease; Adolescent; Adult; Bone Marrow Transplantation; Child; Cyclosporine; Drug Therapy, Combination; Female; Graft vs Host Disease; Humans; Leukemia; Male; Methotrexate; Mycophenolic Acid; Transplantation, Heterologous; Young Adult

Topics: Acute Disease; Bone Marrow Transplantation; Chronic Disease; Cyclosporine; Drug Therapy, Combination; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Immunosuppressive Agents; Leukemia; Living Donors; Mycophenolic Acid; Nuclear Family; Prednisolone

Immunoglobulin replacement therapy is recommended in case of severe hypogammaglobulinemia after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, the supposed increased risk of infection in case of hypogammaglobulinemia has not been confirmed in allo-HSCT. In this study, we assessed the relationship between the gamma globulin level and the risk of infection during the 100 days following the allo-HSCT.. We gathered the weekly laboratory tests from day 7 to day 100 of 76 allograft patients, giving a total of 1 044 tests. 130 infections were documented clinically, by imaging, or microbiologically.. Average gamma globulin levels between D-7 and D100 did not differ between patients with or without infection (642 ± 232 and 671 ± 246 mg/dL, respectively, P = .65). Gamma globulin level <400 mg/dl was not associated with the occurrence of infection between the test studied and the next one (aOR 1.33 [0.84-2.15], P = .24). The gamma globulin level was not predictive of bacterial or fungal infections (AUC 0.54 [95%CI: 0.47-0.61]) nor of viral reactivations (AUC 0.51 [95%CI: 0.43-0.60]).. This confirmed that the humoral deficiency is a minor part of the immune deficiency in the 100 days post-transplant. This questions the relevance of the indications of immunoglobulin substitution during this period.

Topics: Aged; Bacterial Infections; Cyclosporine; Female; gamma-Globulins; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Immunoglobulins, Intravenous; Immunologic Deficiency Syndromes; Immunosuppressive Agents; Leukemia; Lymphoma; Male; Middle Aged; Mycophenolic Acid; Mycoses; Myeloablative Agonists; Myelodysplastic Syndromes; Opportunistic Infections; Prognosis; ROC Curve; Transplantation Conditioning; Transplantation, Homologous; Virus Activation

Topics: Adolescent; Busulfan; Child; Child, Preschool; Cyclophosphamide; Cyclosporine; Female; Hematopoietic Stem Cell Transplantation; Humans; Infant; Leukemia; Leukemia, Myeloid, Acute; Male; Mycophenolic Acid; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Retrospective Studies; Treatment Outcome

Recently, haploidentical transplantations have been performed with unmanipulated BM or PBSC. This approach is becoming more widely adopted with the use of PTCY. However, there is limited evidence about this approach in children. We present 15 children who received 16 haploidentical HSCT with unmanipulated BM or PBSC using PTCY for GVHD prophylaxis. Post-transplant CY(50 mg/kg IV) was given on the third and fifth day, and CsA or tacrolimus with MMF or MP was also used for GVHD prophylaxis. All patients engrafted at a median of 16 and 18 days for neutrophil and thrombocyte recovery, respectively. Grades II-III acute GVHD developed in seven patients, and mild chronic GVHD was found in two patients. Two patients died within the first 100 days due to sepsis (TRM 12.5%). Eleven patients are currently alive, with a median follow-up of 12 months (range 6-22 months). The 12-month OS and DFS were 75 ± 10.8% and 68.8 ± 11.6%, respectively. Our results with these high-risk patients are encouraging for haploidentical HSCT in pediatric patients. Future studies should continue to assess haploidentical HSCT, including comparison of other modalities, in a primary pediatric population.

Topics: Adolescent; Blood Platelets; Child; Child, Preschool; Cyclophosphamide; Cyclosporine; Female; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Leukemia; Lymphoma; Male; Methylprednisolone; Mycophenolic Acid; Neutrophils; Retrospective Studies; Risk; Sepsis; Tacrolimus; Tissue Donors; Transplantation Conditioning

To investigate the safety and effectiveness of HLA-mismatched allogeneic hematopoietic stem cell transplantation (allo-HSCT) combined with related haploidentical bone marrow infusion for treatment of hematologic malignancies and to explore the mathod for reduction of aGVHD incidence and clinical significance.. A total of 30 patients with hematologic malignancies (8 cases of AML, 17 AML, 2 MDS and 3 Mix-AL) received related haploidentical and unrelated HLA-mismatched allo-HSCT combined with related haploidentical bone marrow infusion. Among them 20 cases received related haploidentical transplantation of the first donor, 10 cases received unrelated HLA-mismatched treaplantation. The new conditioning regimen for the patients underwent allo-HSCT consisted of fludarabine, busulfan, Me-CCNU and cyclophosphamide. The drugs for GVHD prophylaxis included cyclosporine A and methotrexate, while mycophenolate mofetil and rabbit anti-T-lymphocyte globulin (ATG) were used.. All the patients achieved full engraftment. The median time for neutrophils to reach over 0.5 × 10(9)/L was 14 days (8-26 days), while the median time for platelets to reach over 20 × 10(9)/L was 11.5days (10-24 days). The incidence of I-II grade of aGVHD at 100 d was 22.28% (95% CI 9.9%-34.7%), the incidences of II-IV and III-IV grade of aGVHD were 22.7% (95% CI, 10%-35.4%) and 12.7% (95% CI 6.9%-15.5%) respectively. The incidences of I-II and III-IV cGVHD were 13.3% (95% CI, 1.4%- 26.8%) and 3.3 % (95% CI, 0%-12.2%), one case (3.3%) was in extensive cGVHD. DFS and OS of 2 years were 81.1% (95% CI, 66.0%-96.2%) and 68.2% (95% CI 51.0%-85.4%).. These data suggest that the incidence of grade II-IV grade of aGVHD in recipients of 2 partially HLA-matched units was lower, co-infusion of haplo-BM and partially matched units in allogeneic transplantation is safe and effective for reducing the incidence of aGVHD and improving the survival in DFS.

Topics: Antilymphocyte Serum; Busulfan; Cyclosporine; Graft vs Host Disease; Hematologic Neoplasms; Hematopoietic Stem Cell Transplantation; HLA Antigens; Humans; Incidence; Leukemia; Mycophenolic Acid; Stem Cell Transplantation; Tissue Donors; Transplantation Conditioning; Transplantation, Homologous; Vidarabine

Development of liver disease after hematopoietic cell transplantation is common and the causes diverse. Infection by hepatitis C virus (HCV) can be seen in patients who are chronically infected before transplant or from passage of virus from an infected donor; the normal 10-year course of hepatitis C after transplant is one of waxing and waning of serum aminotransferase enzymes, with little morbidity. In the series of 3 patients reported here, the course of hepatitis C was rapidly fatal, with the onset of jaundice at day 60 to 80 after transplant and liver histology typical of fibrosing cholestatic hepatitis (marked bile ductular proliferation, ballooned hepatocytes, and associated collagenous fibrosis centered around ductules). The bile ductular reaction pattern varied from elongated structures without a recognizable lumen to a pattern of cuboidal cells with a clear lumen. There was significant cholestasis with bile within hepatocytes and canalicular bile plugs. In situ HCV RNA hybridization studies from 1 patient showed a robust infection with high levels of HCV-infected hepatocytes and active viral replication. All 3 patients were on immunosuppressive drugs after transplant, including mycophenolate mofetil (MMF), which irreversibly inhibits inosine monophosphate dehydrogenase, on which T and B lymphocytes are dependent. We speculate that fatal fibrosing cholestatic hepatitis C in these cases was related to the immunosuppressive effects of MMF, as we had not recognized this presentation of HCV infection before the introduction of MMF.

Topics: Adult; Cholestasis; Fatal Outcome; Fibrosis; Hematopoietic Stem Cell Transplantation; Hepatitis C; Humans; Immunocompromised Host; Immunosuppressive Agents; Leukemia; Male; Middle Aged; Mycophenolic Acid

We hypothesized that in patients with early post allogeneic transplantation toxicities, the omission of the 3rd dose of methotrexate with concomitant starting of MMF would favorably affect complications. We found a higher incidence of grade 2-4 acute GVHD in patients given two doses methotrexate and MMF (n=31) compared to those given three courses of methotrexate (n=70) (p=.004), while grade 3-4 was similar. Other transplantation outcomes, including overall regimen-related-toxicity, were comparable. We conclude that tailoring the GVHD prophylaxis regimen may decrease the early post transplantation complications, however this come at the extent of a higher incidence of non-severe acute GVHD.

Topics: Adult; Aged; Drug Administration Schedule; Drug Substitution; Female; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Immunosuppressive Agents; Leukemia; Lymphoma; Male; Methotrexate; Middle Aged; Mycophenolic Acid; Survival Analysis; Transplantation Conditioning; Young Adult

We evaluated the efficacy of a post-grafting immunosuppressive regimen consisting of tacrolimus, methotrexate, and mycophenolate mofetil (MMF) in 21 adults (median age, 55 years) with poor-risk hematologic malignancy who underwent unrelated bone marrow transplantation after fludarabine-based reduced-intensity conditioning (RIC). In combination with intravenous tacrolimus and minidose methotrexate (5 mg/m2 on days 1, 3, and 6), MMF was orally administered at 30 mg/kg daily in three divided doses between days 7 and 27. All patients achieved neutrophil recovery with donor-type chimerism at a median of 19 days (range, 13-35). Cumulative incidences of grades II-IV and III-IV acute graft-versus-host disease (GVHD) were 33% (95% CI, 15-53%) and 5% (95% CI, 0.3-20%), respectively. Five of 20 evaluable patients developed extensive chronic GVHD. Toxicities associated with the use of MMF were acceptable, although one patient experienced intractable GVHD immediately after the cessation of MMF. With a median follow-up of 24 months, overall survival at 3 years was 38% (95% CI, 14-63%). No late graft failure was observed. In conclusion, post-transplant MMF combined with tacrolimus and methotrexate was well tolerated and conferred stable donor cell engraftment, low risk of severe acute GVHD, and encouraging overall survival in unrelated donor marrow transplantation after RIC regimens.

Topics: Acute Disease; Adult; Aged; Bone Marrow Transplantation; Chronic Disease; Dose-Response Relationship, Drug; Graft vs Host Disease; Humans; Leukemia; Methotrexate; Middle Aged; Mycophenolic Acid; Survival Rate; Tacrolimus; Transplantation Conditioning

To prevent acute graft-versus-host disease (GVHD), mycophenolate mofetil (MMF) combined with calcineurin inhibitors have been used in allogeneic hematopoietic stem cell transplantation (allo-SCT). Previous studies commonly utilize MMF treatment until day 30 after allo-SCT. However, the feasibility of continuous administration after day 30 has not been well evaluated. We retrospectively assessed the safety and efficacy of extended drug administration. Twenty-five patients ceased MMF at day 30 (group A); whereas, 16 patients (group B) received extended regimens depending on individual risk factors for GVHD. No severe adverse events were observed in either group. Although the cumulative incidence (CI) of grade I to IV GVHD at day 100 was comparable between the 2 groups, the CI of grade II to IV GVHD was less among group B (12.5%) compared with group A (42.3%). Extended MMF administration may be safe and beneficial as preemptive therapy to reduce the development of moderate-to-severe acute GVHD.

Topics: Adult; Aged; Cyclosporine; Drug Administration Schedule; Female; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Immunosuppressive Agents; Leukemia; Male; Middle Aged; Mycophenolic Acid; Myelodysplastic Syndromes; Safety; Tacrolimus; Time Factors; Transplantation, Homologous; Young Adult

Depletion of guanine and deoxyguanine nucleotides by inhibition of inosine 5'-monophosphate dehydrogenase (IMPDH, EC 1.1.1.205) or introduction of 6-thioguanine nucleotide antimetabolites are two principles of retarding cell proliferation by interference with the cellular purine nucleotide pool. IMPDH activity may be a promising pharmacodynamic biomarker during immunosuppressive and anticancer pharmacotherapy. The aim of the study was to investigate the impact of mycophenolic acid (MPA) and 6-thioguanosine (tGuO) on IMPDH basal activity.. We studied the IMPDH basal activity (i.e. the enzyme activity following inhibitor exposure, but measured in absence of the inhibitor) in response to increasing concentrations of the IMPDH inhibitor MPA and the antimetabolite tGuO in MOLT-4 human leukaemia cells. In parallel, IMPDH gene expression and cellular purine nucleotide concentrations were examined.. A biphasic concentration-dependent influence of MPA on the IMPDH basal activity was observed. At concentrations < or =IC50, MPA increased the IMPDH basal activity. The increase was associated with elevated expression of IMPDH2. Despite increased expression, the basal enzyme activity decreased following exposure to high MPA concentrations. The IMPDH2 expression increased modestly in response to tGuO exposure. However, the IMPDH basal activity decreased when the cells were exposed to a proliferation-blocking tGuO concentration.. These findings demonstrate that IMPDH basal activity is influenced by MPA and tGuO, and suggest that reduced IMPDH basal activity is related to the proliferation-blocking effects of these agents.

Topics: Cell Line, Tumor; Cell Proliferation; Cell Survival; Gene Expression Regulation, Leukemic; Guanosine; Humans; IMP Dehydrogenase; Intracellular Space; Leukemia; Mycophenolic Acid; Purines; Thionucleosides

The objective of this paper was to study the incidence, risk factors, clinical outcome, management and prevention of pure red cell aplasia (PRCA) following major ABO-incompatible allogeneic hematopoietic stem cell transplantation (allo-HSCT). We retrospectively analyzed 11 cases of PRCA from a series of 42 patients undergoing major ABO-incompatible allo-HSCT from April 1997 to December 2005. Eleven out of the 42 patients developed PRCA (26.1%). All the 11 cases of PRCA were in blood group O recipients of grafts from blood group A donor (n = 9) or blood group B donor (n = 2). The following factors were associated with an increased risk of PRCA: (1) blood group O recipient; (2) blood group A donor; and (3) blood group O/A in recipient/donor pair. Only blood group O/A in recipient/donor pair was identified as being significantly associated with the occurrence of PRCA by multivariate analysis. Six patients who received donor-type plasma exchange did not develop PRCA and among them 5 cases were the blood group O recipients. Eight patients obtained spontaneous remission and in the remaining 3 patients 2 with long-lasting PRCA were successfully treated with plasma exchange with donor-type plasma replacement and the other one who was also complicated by EBV-associated lymphoproliferative disorder (EBV-PTLD) responded rapidly to anti-CD20 monoclonal antibody and achieved complete resolution of clinical finding and symptom of both EBV-PTLD and PRCA. We conclude that blood group A/O in donor/recipient pair is identified as being significantly associated with the occurrence of PRCA by multivariate analysis. Donor-type plasma exchange and anti-CD20 monoclonal antibody is an effective approach for the treatment of PRCA. PRCA could be prevented by plasma exchange prior to transplantation.

Topics: ABO Blood-Group System; Adult; Antibodies, Monoclonal; Antibodies, Monoclonal, Murine-Derived; Antigens, CD20; beta-Thalassemia; Blood Group Incompatibility; Busulfan; Child, Preschool; Cyclosporine; Epstein-Barr Virus Infections; Female; Graft Survival; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Immunosuppressive Agents; Leukemia; Lymphoproliferative Disorders; Male; Methotrexate; Middle Aged; Mycophenolic Acid; Plasma Exchange; Red-Cell Aplasia, Pure; Remission, Spontaneous; Retrospective Studies; Risk Factors; Rituximab; Transplantation Conditioning; Transplantation, Homologous; Vidarabine; Whole-Body Irradiation

Topics: Drug Monitoring; Female; Hematopoietic Stem Cell Transplantation; Humans; Infant; Leukemia; Mycophenolic Acid; Peritoneal Dialysis

The combination of Cyclosporin A (CSA) and Methotrexate (MTX) is considered to be the standard regimen for the prevention of graft-versus-host disease (GVHD) after stem cell transplantation (SCT) from HLA-identical siblings. Mycophenolate Mofetil (MMF) has been widely used for GVHD prophylaxis after nonmyeloablative SCT, but experience following myeloablative therapy is still limited. We retrospectively compared CSA/MTX and CSA/MMF in 93 patients (median age 35 years, range 17-59 years, male subjects 48, female subjects 45) with acute myeloid leukemia (n=33), myelodysplastic syndrome (MDS) (n=3), acute lymphoblastic leukemia (ALL) (n=20) or chronic myeloid leukemia (n=37) who received CSA/MMF (n=26) or CSA/MTX (n=67) as GVHD prophylaxis following high-dose therapy and allogeneic SCT from HLA-identical siblings. No statistically significant differences were found in overall survival, relapse rate, treatment-related mortality and acute or chronic GVHD. Time to myeloid recovery was significantly shorter in patients who received CSA/MMF. We conclude that the combination of CSA/MMF appears equivalent to CSA/MTX for GVHD prophylaxis in patients receiving conventional-intensity SCT from HLA-identical siblings.

Topics: Adolescent; Adult; Cyclosporine; Female; Graft vs Host Disease; Histocompatibility; Histocompatibility Testing; HLA Antigens; Humans; Immunosuppressive Agents; Leukemia; Living Donors; Male; Methotrexate; Middle Aged; Mycophenolic Acid; Myelodysplastic Syndromes; Recurrence; Retrospective Studies; Siblings; Stem Cell Transplantation; Time Factors; Transplantation Conditioning; Transplantation, Homologous; Treatment Outcome

Corticosteroid-resistant graft-versus-host disease (GvHD) is difficult to manage and is associated with high morbidity and mortality. The purpose of our study was to evaluate the safety and efficacy of mycophenolate mofetil (MMF) as the salvage therapy for steroid-refractory GvHD. Twenty one patients (10 with acute GvHD and 11 with chronic GvHD) were studied retrospectively. Steroid-resistant GvHD was defined as acute or chronic GvHD not responding to a first-line regimen of cyclosporine A and corticosteroids in a dose equivalent to 2 mg/kg methylprednisolone for at least 7 days. MMF was added at a dose of 2 g daily, and corticosteroids were tapered. Thirteen (62%) of 21 patients responded to the treatment with MMF, including 6 (60%) of 10 patients with acute refractory GvHD and 7 (64%) of 11 patients with chronic refractory GvHD. The most common adverse effects were infectious complications (67%, 14 of 21 patients) and hematological toxicity (29%, 6 of 21 patients). Median duration of MMF administration was 6 months (range 1-27 months). Sixteen of 21 patients were alive after the median follow-up of 27 months (range 1-72 months) after the initiation of MMF therapy. All 16 surviving patients were in good clinical condition and in remission of their hematological malignancy. Five patients died--two of relapses of leukemia and three of refractory intestinal GvHD. These results suggest that MMF can be an effective treatment for some cases of steroid-refractory GvHD.

Topics: Acute Disease; Adult; Chronic Disease; Drug Evaluation; Female; Graft vs Host Disease; Humans; Immunosuppressive Agents; Leukemia; Male; Middle Aged; Mycophenolic Acid; Peripheral Blood Stem Cell Transplantation; Recurrence; Salvage Therapy; Transplantation, Homologous

To analyze the incidence and the effective prevention and treatment of graft-versus-host disease (GVHD) for the allogeneic peripheral blood stem cell transplantation (allo-PBSCT) for the treatment of leukemia.. Fifty patients with acute leukemia (n = 29) and chronic myeloid leukemia (n = 21) were treated with allo-PBSCT. The conditioning regimens were TBI plus CTX and Vp16 or TBI plus CTX. Two regimens were used for prophylaxis of GVHD: one was the combination of low dose cyclosporine (CsA, 2 - 3 mg x kg(-1) x d(-)1 i.v. or 4 - 6 mg x kg(-1) x d(-1) p.o.) and short course methotrexate (MTX, 15 approximately 10 mg, +1, +3, +6, +11 d) (CsA/MTX group, 32 patients), the other was short course of mycophenolate mofetil (MMF, 1.0 bid, +1 - +28 d) in addition to CsA and MTX (MMF/CsA/MTX group, 18 patients).. All patients were successfully engrafted and the median times to ANC > 0.5 x 10(9)/L and to platelet > 20 x 10(9)/L were 14 (10 - 22) and 20 (10 - 68) days post PBSCT respectively. The incidence of acute GVHD (aGVHD) was 40% (20/50) and of grade III - IV was 12% (6/50). The chronic GVHD (cGVHD) occurred in 22 out of 33 (66.7%) evaluable patients (survived longer than 6 months post PBSCT) and extensive cGVHD in 11 out of 33 (33.3%) patients. Patients with aGVHD displayed significantly higher sIL-2R levels [(277.3 +/- 26.4) U/L] and CD(25)(+) cells [(8.1 +/- 3.4)%] than those without GVHD [(128.1 +/- 96.7) U/L and (3.6 +/- 1.7)%] (P < 0.05). The incidences of aGVHD (16.7%) and extensive cGVHD (9.1%) in MMF/CsA/MTX group were significantly lower than that in CsA/MTX group (53.1% and 45.5%, P < 0.05). The median follow-up duration was 30 (3 - 70) months and 33 patients were still alive. The relapse rate was significantly higher in GVHD negative group (47.1%) than in GVHD positive group (0, P < 0.05). The 3 year disease-free-survival (DFS) rate was 66%.. The incidence of aGVHD was low, but of cGVHD was high in allo-PBSCT. sIL-2R and CD(25)(+) cells after PBSCT may provide predictive markers for aGVHD. The MMF/CsA/MTX regimen for prevention of aGVHD in allo-PBSCT is more effective than the CsA/MTX one. There was a strong antileukemic effect of GVHD in the allo-PBSCT.

Topics: Adolescent; Adult; Cyclosporine; Drug Therapy, Combination; Enzyme Inhibitors; Female; Graft vs Host Disease; Humans; Immunosuppressive Agents; Leukemia; Male; Methotrexate; Middle Aged; Mycophenolic Acid; Peripheral Blood Stem Cell Transplantation; Transplantation Conditioning; Transplantation, Homologous

To evaluate the efficacy of quadruple therapy with cyclosporine (CsA), methotrexate (MTX), mycophenolate mofetil (MMF) and low-dose antithymocyte globulin (ATG) for graft-versus-host disease (GVHD) prophylaxis in unrelated donor hematopoietic stem cell transplantation (URD-HSCT).. Thirteen patients with leukemia received URD-HSCT, of whom 11 had HLA genotypes and 2 had mismatch for 1 genetic locus. Another 11 leukemia patients all serologically matched underwent related donor (RD)-HSCT. Total body irradiation (TBI) plus cyclophosphamide (CTX) was adopted in 19 cases and modified BuCY conditioning regimen (hydroxyurea, busulfan, Ara-C, Cyclophosphamide ) in the other 5 cases. All the patients received CsA+MTX protocal for GVHD prophylaxis, and in those undergoing URD-HSCT, additional MMF and low-dose ATG were used.. The incidence and severity of regimen-related toxicity differed little between unrelated and related transplantation. Acute GVHD (aGVHD) occurred in 46.2% of the patients undergoing URD- HSCT and in 55.6% of those with RD-HSCT, respectively. Four patients had chronic GVHD (cGVHD), in the 7 ones who could be followed up after URD-HSCT; 6 of the 9 patients with RD-HSCT developed cGVHD postoperatively. One patient with URD-HSCT died of hemorrhagic cystitis and another with RD-HSCT died of cytomegalovirus (CMV) pneumonia. The at one-year disease-free survival rate was 87.5% and 90.9% in patients with unrelated and related transplantation respectively. Significant difference was not noted in the positivity rate of CMV antigen between the patients receiving URD-HSCT or RD-HSCT.. CsA+MTX in combination with MMF and low-dose ATG may decrease the incidence and severity of aGVHD without increasing transplant-related mortality or CMV infection.

Topics: Adolescent; Adult; Antilymphocyte Serum; Cyclosporine; Cytomegalovirus Infections; Drug Therapy, Combination; Female; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Immunosuppressive Agents; Leukemia; Male; Methotrexate; Middle Aged; Mycophenolic Acid

Novel mycophenolic adenine dinucleotide (MAD) analogues have been prepared as potential inhibitors of inosine monophosphate dehydrogenase (IMPDH). MAD analogues resemble nicotinamide adenine dinucleotide binding at the cofactor binding domain of IMPDH; however, they cannot participate in hydride transfer and therefore inhibit the enzyme. The methylenebis(phosphonate) analogues C2-MAD and C4-MAD were obtained by coupling 2',3'-O-isopropylideneadenosine 5'-methylenebis(phosphonate) (22) with mycophenolic alcohols 20 and 21 in the presence of diisopropylcarbodiimide followed by deprotection. C2-MAD was also prepared by coupling of mycophenolic methylenebis(phosphonate) derivative 30 with 2',3'-O-isopropylideneadenosine. Compound 30 was conveniently synthesized by the treatment of benzyl-protected mycophenolic alcohol 27 with a commercially available methylenebis(phosphonic dichloride) under Yoshikawa's reaction conditions. C2-MAD and C4-MAD were found to inhibit the growth of K562 cells (IC(50) = 0.7 microM and IC(50) = 0.1 microM, respectively) as potently as mycophenolic acid (IC(50) = 0.3 microM). In addition, C2-MAD and C4-MAD triggered vigorous differentiation of K562 cells an order of magnitude more potently than tiazofurin, and MAD analogues were resistant to glucuronidation in vitro. These results show that C2-MAD and C4-MAD may be of therapeutic interest in the treatment of human leukemias.

Topics: Adenine Nucleotides; Antineoplastic Agents; Cell Differentiation; Diphosphonates; Drug Screening Assays, Antitumor; Enzyme Inhibitors; Humans; IMP Dehydrogenase; Isoenzymes; K562 Cells; Leukemia; Mycophenolic Acid; Structure-Activity Relationship

Based on our encouraging results of G-CSF-primed HLA-matched related marrow transplants for high-risk leukemia, we extended the study from matched related to haploidentical transplants using G-CSF primed marrow and sequential immunosuppressants to prevent both graft-versus-host disease (GVHD) and host-versus-graft rejection (HVGR). Fifteen high-risk leukemia patients, who needed urgent transplantation but lacked an HLA-matched donor, underwent G-CSF-primed haploidentical marrow transplantation without ex vivo T cell depletion. Donors were given G-CSF (Lenograstim) at 3-4 microg/kg/day for 7 days prior to marrow harvest. GVHD and HVGR prophylaxis were combined in the sequential usage of cyclosporin A, methotrexate, anti-thymocyte globulin and mycophenolate mofetil. All patients established sustained trilineage engraftment at a median of 19 days and 21 days for neutrophil and platelets respectively. G-CSF priming significantly increased CD34(+) and CFU-GM cells, reduced total lymphocytes and reversed the CD4(+)/CD8(+) ratio in the donor marrow. The incidence of grade II-IV acute GVHD was 33.3%. Nine patients survived more than a year with a Karnofsky performance status of 100%. Estimated overall disease-free survival at 2 years was 60 +/- 7%. In conclusion, using G-CSF priming marrow grafts along with sequential immunosuppressants provided an excellent alternative for the treatment of high-risk hematological malignancy in patients who lack matched donors.

Topics: Adolescent; Adult; Antilymphocyte Serum; Bone Marrow; Cell Lineage; Child; Cyclosporine; Disease-Free Survival; Female; Graft Survival; Graft vs Host Disease; Granulocyte Colony-Stimulating Factor; Haplotypes; Histocompatibility; HLA Antigens; Humans; Immunosuppressive Agents; Lenograstim; Leukemia; Life Tables; Lymphocyte Depletion; Male; Methotrexate; Middle Aged; Mycophenolic Acid; Peripheral Blood Stem Cell Transplantation; Recombinant Proteins; Recurrence; Risk Factors; Survival Analysis; T-Lymphocytes; Treatment Outcome

It is now well established that after conventional allogeneic hematopoietic stem-cell transplantation (HSCT), erythropoietic recovery is impaired because erythropoietin (Epo) production remains inadequate for prolonged periods of time. However, erythropoietic reconstitution after nonmyeloablative SCT (NMSCT) has never been characterized.. Twelve patients received a nonmyeloablative conditioning regimen consisting of 2 Gy total body irradiation (TBI) alone (n=6), 2 Gy TBI and fludarabine (n=3), or cyclophosphamide and fludarabine (n=3), followed by transplantation of allogeneic peripheral blood stem cells. Graft-versus-host-disease (GvHD) prophylaxis was carried out with mycophenolate mofetil (from day -1 to day 28) plus cyclosporine (from day -1 to day 120 or longer in case of chronic GvHD). Erythropoiesis was quantitated by soluble transferrin receptor (sTfR) levels, and the adequacy of Epo production was evaluated by the observed-to-predicted Epo ratio (O/P Epo).. Mean sTfR levels decreased following the conditioning regimen but remained well within the normal range throughout the posttransplant period. The O/P Epo ratio presented an initial surge quite similar to that observed after conventional conditioning. Thereafter, the O/P Epo ratio normalized rapidly, and Epo levels remained adequate during the whole observation period.. Contrarily to what is observed after myeloablative transplant, Epo levels remained adequate after NMSCT, resulting in normal erythropoiesis. These results suggest that the administration of erythropoietin therapy (rHuEpo) could be less effective after NMSCT than after conventional allogeneic transplant.

Topics: Adult; Cyclosporine; Erythropoiesis; Erythropoietin; Female; Graft Rejection; Hematopoietic Stem Cell Transplantation; Humans; Immunosuppressive Agents; Leukemia; Lymphoma; Male; Middle Aged; Mycophenolic Acid; Receptors, Transferrin; Recombinant Proteins; Transplantation Conditioning; Transplantation, Homologous

Topics: Acute Disease; Adult; Bone Marrow Transplantation; Chronic Disease; Cyclosporine; Female; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Histocompatibility Testing; Humans; Immunosuppression Therapy; Immunosuppressive Agents; Leukemia; Male; Methotrexate; Middle Aged; Mycophenolic Acid; Nuclear Family; Recurrence; Retrospective Studies; Survival Rate; Whole-Body Irradiation

Despite immunosuppressive therapy using cyclosporine (CsA) and prednisolone and methotrexate (MTX), the incidence for aGVHD grade II to IV after transplantation from HLA matched unrelated donors (MUD) is 78%, the incidence for grade III and IV 36%. Since GVHD contributes to morbidity and mortality after MUD-BMT, a more effective prophylactic regimen is needed in order to prevent these transplant-associated complications. Recently, we described that mycophenolate mofetil (MMF, CellCept), an immunosuppressive agent successfully used for the prevention of acute rejection in renal allograft recipients, can safely and effectively be used for the treatment of aGVHD in hematopoietic stem cell transplantation. Information on the i.v. formulation of mycophenolic acid (MPA) is not yet available. Here we report on the i.v. formulation of MMF in hematopoietic stem cell recipients. MMF is effective in the prophylaxis of acute GVHD after stem cell transplantation; the optimal dosage needs further investigation. At the present time the relevance of measurement of plasma MPA concentrations on MMF dosage is not yet understood and further evaluation is required.

Topics: Acute Disease; Adult; Female; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Immunosuppressive Agents; Injections, Intravenous; Leukemia; Male; Middle Aged; Mycophenolic Acid; Prospective Studies

Mycophenolic acid, an inhibitor of the enzyme IMP dehydrogenase, antagonizes the CTP synthetase inhibitor 3-deazauridine in its anti-proliferative effects on MOLT-3 human T leukemia cells. No depletion of CTP occurred, and decreased amounts of 3-deazuridine-triphosphate were measured in cells incubated with mycophenolic acid and 3-deazuridine. Most probably, these phenomena are related to the increased amounts of PRPP observed, which can result in an increased pyrimidine biosynthesis de novo and, as a consequence, a decreased metabolism of 3-deazauridine via the salvage pathway.

Topics: 3-Deazauridine; Carbon-Nitrogen Ligases; Cell Division; Cell Survival; Dose-Response Relationship, Drug; Enzyme Inhibitors; Humans; IMP Dehydrogenase; Leukemia; Ligases; Mycophenolic Acid; Phosphoribosyl Pyrophosphate; Ribonucleotides; Tumor Cells, Cultured

Inhibitors of IMP dehydrogenase (EC 1.2.1.14), including mizoribine (Bredinin) and mycophenolic acid, have significant antitumor and immunosuppressive activities. Studies were aimed at determining the mechanism by which intracellular GTP depletion induced by these agents results in inhibition of DNA synthesis. Incubation of human CEM leukemia cells for 2 hr with IC50 concentrations of either mizoribine (4 microM) or mycophenolic acid (0.5 microM) reduced cellular GTP levels an average of 68% or 58%, respectively, compared with the levels in control cells. Under similar conditions, mizoribine and mycophenolic acid decreased the amount of [3H]adenosine incorporated into primer RNA by 75% and 70%, respectively, relative to the untreated controls, but had no significant effect on total RNA synthesis. Repletion of the guanine nucleotide pools by coincubation of CEM cells with guanosine plus 8-aminoguanosine prevented both the inhibition of primer RNA synthesis and the inhibition of tumor cell growth induced by these agents. Additional studies demonstrated that GTP depletion alone was capable of directly inducing inhibition of primer RNA synthesis. Primer RNA synthesis was inhibited an average of 84% in whole-cell lysates that lacked GTP but contained all remaining ribo- and deoxyribonucleoside triphosphates. On an M13 DNA template, RNA-primed DNA synthesis catalyzed by the purified complex of DNA primase (EC 2.7.7.6) and DNA polymerase alpha (EC 2.7.7.7) was decreased an average of 70% in the absence of GTP, compared with synthesis in the presence of 0.5 mM GTP. These results provide evidence that mizoribine and mycophenolic acid inhibit DNA replication by inducing GTP depletion, which suppresses the synthesis of RNA-primed DNA intermediates.

Topics: Adenosine Triphosphate; Cell Survival; DNA Primase; DNA, Neoplasm; Guanosine Triphosphate; Humans; IMP Dehydrogenase; Leukemia; Mycophenolic Acid; Nucleosomes; Ribonucleosides; RNA Nucleotidyltransferases; RNA, Neoplasm; Tumor Cells, Cultured

Cultured tumor cell lines, tumor xenografts grown in athymic nude mice, and a murine experimental metastasis model were used to assess the in vitro and in vivo anti-tumor activity of the potent IMP dehydrogenase (IMPDH) inhibitor, mycophenolic acid (MPA), and its morpholinoethyl ester pro-drug, mycophenolate mofetil (MM). The growth of all the cell lines tested was inhibited by MPA in vitro, with EC50 values ranging from less than 0.1 microM to 3.9 microM. Mice were monitored for s.c. tumor outgrowth in the case of human tumor xenograft models or survival time for the murine experimental metastasis model. Treatment with MM p.o. was started 24 hr after tumor challenge or after tumors became palpable. Treatment of athymic nude mice bearing A3.01 (T-lymphoblast), Molt-4 (T-cell leukemia), CaPan-2 (pancreatic adenocarcinoma), CaLu-3 (non-small-cell lung adenocarcinoma), LS174T and T84 (colon adenocarcinoma), and Daudi (B-cell lymphoma) human tumor xenografts with MM significantly inhibited s.c. tumor growth. Treatment of BALB/c mice with MM after i.v. injection of murine RAW117-H10 lymphoma cells in an experimental metastasis assay resulted in increased survival time for treated animals. No significant inhibitory effect on s.c. tumor outgrowth was seen with MM treatment of SK-Hep-1, a human hepatic endothelioma, or Hep-3B, a liver adenocarcinoma, at any of the doses tested.

Topics: Animals; Antineoplastic Agents; Cell Division; Disease Models, Animal; Drug Screening Assays, Antitumor; Female; Humans; IMP Dehydrogenase; Leukemia; Lymphoma; Mice; Mice, Inbred BALB C; Mice, Nude; Mycophenolic Acid; Neoplasm Metastasis; Neoplasm Transplantation; Neoplasms; Neoplasms, Experimental; Transplantation, Heterologous

Inosine monophosphate dehydrogenase (IMPDH, EC 1.1.1.205) inhibitors including mycophenolic acid (MPA) were reported to induce K562 human leukemia cells to differentiate into erythroid cells. A shuttle vector plasmid pMSG containing E. coli xanthine-guanine phosphoribosyl transferase (Eco gpt) gene was transfected into K562 cells (K562-pMSG cells) to investigate the role of IMPDH in both K562 cell proliferation and erythroid differentiation. Eco gpt provides K562 cells with an additional salvage pathway for GMP production from xanthine. In the presence of xanthine, K562-pMSG cells continued to proliferate and did not differentiate to erythroid cells regardless of the presence of MPA, but they discontinued proliferating and differentiated into the erythroid lineage in the absence of xanthine. Proliferation and differentiation of control K562 cells into erythroid cells were suppressed by MPA regardless of the presence or absence of xanthine. Addition of guanosine maintained the proliferation and blocked the erythroid differentiation of K562 and K562-pMSG cells induced by MPA even in the absence of xanthine. These data indicate that a decrease in the activity of IMPDH and a subsequent decline in the concentration of guanine nucleotides caused by MPA resulted in the induction of the erythroid differentiation and discontinuation of the proliferation of K562 cells.

Topics: Blotting, Southern; Cell Differentiation; Cell Division; Erythrocytes; Escherichia coli; Gene Expression Regulation, Bacterial; Humans; IMP Dehydrogenase; Kinetics; Leukemia; Mycophenolic Acid; Pentosyltransferases; Tumor Cells, Cultured

In RBL-2H3 rat basophilic leukemia cells, Ag that crosslink IgE-receptor complexes stimulate the turnover of inositol phospholipids, the mobilization of Ca2+ from intra- and extracellular sources, the release of serotonin and other substances from granules and the transformation of the cell surface from a microvillous to a lamellar architecture. This study explores the role of GTP-binding proteins (G proteins) in the control of these biochemical and functional responses. We report that incubating RBL-2H3 cells for 4 h with 10 microM mycophenolic acid (MPA), an inhibitor of de novo GTP synthesis, reduces GTP levels by over 60% and causes an average reduction of 50% in Ag-stimulated serotonin release. This inhibition of secretion is associated with a 50% decrease in the rate of 45Ca2+ influx in MPA-treated cells. In contrast, Ag-stimulated inositol trisphosphate production is only slightly reduced, indicating that the phosphatidylinositol-specific phospholipase C can be activated by Ag in GTP-depleted cells. The membrane responses to IgE receptor cross-linking are unaffected by incubating cells with MPA. Exogenous guanine or guanosine protects the GTP pools in MPA-treated cells and permits normal ion transport and secretory responses to Ag; adenine does not. These results implicate a guanine nucleotide-binding protein in the control of IgE receptor-dependent signal transduction in RBL-2H3 cells. This protein may particularly control the Ca2+ influx pathway that is essential for secretion.

Topics: Animals; Antigens, Differentiation, B-Lymphocyte; Basophils; Calcium; Cell Line; Cell Membrane; Chromatography, High Pressure Liquid; Cytoplasmic Granules; Guanine Nucleotides; Hydrolysis; Immunoglobulin E; Immunosuppressive Agents; Inositol Phosphates; Leukemia; Microtubules; Mycophenolic Acid; Rats; Receptors, Fc; Receptors, IgE

K562 cells are human leukemia cells inducible for hemoglobin synthesis by a variety of agents. This report demonstrates that hypoxanthine, which alone has no inductive effect, enhances induction by thymidine, resulting in a greater absolute, as well as relative, percentage of benzidine positive cells. This effect is seen over a 20-fold concentration range for both thymidine and hypoxanthine. This enhancement involves commitment, i.e., a process in which the induction of hemoglobin synthesis is coupled to a limitation in the number of subsequent cell divisions. Although thymidine alone increases the percentage of cells in S phase, hypoxanthine does not augment this. Purines other than hypoxanthine also enhance induction by thymidine. This enhancement by hypoxanthine of thymidine induction is inhibited by pyrimidine nucleosides. Mycophenolic acid, an inhibitor of IMP dehydrogenase, itself an effective K562 inducer, is not additive to thymidine and hypoxanthine, suggesting that hypoxanthine may act by reducing the supply of guanosine nucleosides.

Topics: Adenine; Cell Cycle; Cell Division; Cell Line; Drug Synergism; Guanine; Hemoglobins; Humans; Hypoxanthine; Hypoxanthines; Leukemia; Mycophenolic Acid; Thymidine; Xanthine; Xanthines