pentostatin and Hematologic-Neoplasms

The nucleoside analogues are a group of antimetabolite cytotoxics which generally have to be metabolised to the equivalent nucleotide before incorporation into DNA. Cytarabine is a well established component of the treatment of acute leukaemias and has its principal action on dividing cells. New formulations include a liposome encapsulated product for intrathecal use and oral cytarabine ocfosfate which may be suitable for long-term outpatient use. Pentostatin acts by causing accumulation of deoxynucleotides and, although active against hairy cell leukaemia, is associated with a poor tolerance profile. Cladribine and fludarabine have substantial activity in the treatment of chronic lymphocytic leukaemia (CLL) and low-grade non-Hodgkin's lymphoma (NHL). Fludarabine is the more thoroughly investigated of the two and is currently being developed in combination therapies for CLL and NHL and also in a combination with cytarabine for acute myeloid leukaemia. Fludarabine's immunosuppressive activity is being exploited in the conditioning of patients for non-myeloablative stem cell transplantation. Gemcitabine is an established agent in the treatment of a number of solid tumours but also has activity in haematological malignancies which might be exploited by the use of extended infusion schedules. Newer agents including nelarabine, clofarabine and troxacitabine are undergoing clinical evaluation and show promising activity.

Topics: Antimetabolites, Antineoplastic; Arabinonucleosides; Biological Transport; Cladribine; Clinical Trials as Topic; Cytarabine; Cytosine; Deoxycytidine; Dioxolanes; Economics, Pharmaceutical; Gemcitabine; Guidelines as Topic; Hematologic Neoplasms; Humans; Molecular Structure; Nucleosides; Pentostatin; Vidarabine

Pentostatin (2'-deoxycoformycin, dCF) is a purine nucleoside analog and a product of the fermentation of Streptomyces antibioticus. It is a tight-binding inhibitor of adenosine deaminase (ADA), an enzyme essential in the cellular metabolism of purines. Children with congenital absence of ADA suffer from atrophy of lymphoid tissues and severe combined immune deficiency (SCID) syndrome. It was hypothesized that pentostatin would be lymphocytotoxic and this proved to be true; this finding prompted its investigation in lymphoid neoplasms. It was anticipated that pentostatin would be most active in neoplasms with high intracellular concentrations of ADA, e.g. acute lymphocytic leukemia (ALL), particularly of the T-cell variety. Although pentostatin proved to be active in ALL, large doses were required and major toxic effects outweighed therapeutic benefits. By contrast, pentostatin proved to be exceptionally active in hairy cell leukemia (HCL), a B-cell neoplasm with low intracellular concentrations of ADA. Pentostatin has since been shown to possess activity in chronic lymphocytic leukemia, prolymphocytic leukemia, cutaneous T-cell lymphomas, adult T-cell lymphoma-leukemia, and low grade non-Hodgkin's lymphomas. It potentiates the activity of vidarabine against viruses and against the cells of acute myeloid leukemia. Pentostatin is inactive in melanoma and renal carcinoma, but has not been adequately evaluated in other solid tumors. The toxic effects of pentostatin include renal failure, central nervous system (CNS) depression, immunosuppresion, keratoconjunctivitis, and opportunistic infections. In the absence of pre-existing bone marrow compromise, pentostatin produces only mild myelosuppression. Aside from its use as an antineoplastic agent, pentostatin has potential applications as an immunosuppressive drug, as an antiviral agent, as an antimalarial compound, and in the protection of cells of the CNS from damage induced by ischemia and anoxia. Clinical studies with pentostatin are ongoing, and its roles in the management of neoplastic and non-neoplastic diseases have yet to be fully defined.

Topics: Adenosine Deaminase Inhibitors; Animals; Antimetabolites, Antineoplastic; Antineoplastic Combined Chemotherapy Protocols; Clinical Trials as Topic; Drug Synergism; Enzyme Inhibitors; Forecasting; Hematologic Neoplasms; Humans; Immunosuppressive Agents; Kidney Diseases; Mice; Molecular Structure; Neoplasm Proteins; Nervous System Diseases; Pentostatin; Vidarabine

Three new purine nucleoside analogues, pentostatin, cladribine and fludarabine, have demonstrated remarkable clinical activity in a variety of hematologic malignancies. Although they share structural similarities, their plasma pharmacology, metabolism, and mechanisms of action differ qualitatively and quantitatively. The plasma pharmacokinetics and the cellular pharmacodynamics are reviewed to provide a basis for dose schedules and rationales for combinations with other anticancer drugs.

Topics: Animals; Antineoplastic Agents; Cladribine; Hematologic Neoplasms; Humans; Pentostatin; Purine Nucleosides; Vidarabine

In a multicenter, prospective, phase II study we evaluated the safety and efficacy of pentostatin followed by donor lymphocyte infusion (DLI) in patients with low donor Tcell chimerism after allogeneic hematopoietic cell transplantation (HCT). Thirty-six patients with low donor blood CD3 chimerism were enrolled in this study. Thirty-five patients received a total of 41 DLIs after a dose of pentostatin, and 1 patient received pentostatin only. Median donor CD3 chimerism prompting the initiation of pentostatin and DLI was 28% (range, 5% to 47%). Responses (defined by increases in donor CD3 chimerism ≥10% maintained to day 56 post-DLI) were seen in 16 patients (44.4%) with a median rise in CD3 donor chimerism to 64% (range, 48% to 100%). There was a trend for better responses among 21 patients who received first treatment within 100 days after transplant (57% response rate) compared with15 patients who received first treatment more than 100 days after HCT (27% response rate, P = .07). Fourteen patients (39%) developed grades II to IV acute graft-versus-host disease (GVHD) at a median of 10 days (range, 0 to 83) after DLI. Ten patients (28%) developed extensive chronic GVHD. Seventeen patients (47%) developed new grade 4 cytopenias after DLI. There was no difference in relapse between nonresponders and responders. Twenty-eight patients (78%) died, most (n = 21) because of relapse. Five of 16 responders (31%) are alive, all disease-free, at a median of 60 months (range, 21 to 132) after DLI. Six of 20 nonresponders (30%) are alive at a median of 47 months (range, 16 to 100) after DLI, 3 in complete remission. Pentostatin and DLI had acceptable toxicity and appeared to increase low donor CD3 chimerism after HCT but had no impact on mortality.

Topics: Adult; Aged; CD3 Complex; Chimerism; Female; Hematologic Neoplasms; Hematopoietic Stem Cell Transplantation; Humans; Lymphocyte Transfusion; Male; Middle Aged; Pentostatin; Survival Analysis; Treatment Outcome

One limitation of reduced-intensity preparative regimens is potential for graft failure. We have developed a regimen that targets CD4(+) lymphodepletion to ensure early and durable engraftment. The primary endpoint was achievement of ≥50% CD3(+) donor chimerism by day +28. Forty-two patients (median age, 53 years; range, 29 to 73 years) received pentostatin 4 mg/m(2) i.v. on days -28, -21, and -14 when the CD4(+) cell count was >100 cells/μL and on days -4 and -3 regardless of CD4(+) level. Rituximab 375 mg/m(2) was administered to patients with CD20(+) malignancies on days -21, -14, -7, +1, and +8. Busulfan 200 mg/m(2) i.v. was administered on days -4 and -2 at a dose to target a cumulative AUC dose of 16,000 (±10%) μmol·min/L. Graft-versus-host disease (GVHD) prophylaxis consisted of tacrolimus plus methotrexate in 86% of patients. Donors were matched-related (47%), matched unrelated (43%), or mismatched unrelated (10%). Chronic lymphocytic leukemia (45%) and follicular non-Hodgkin lymphoma (14%) were the most common diagnoses. Disease status at initiation of the preparative regimen was complete remission in 22%, partial response in 55%, and stable/progression in 24%. The median percent CD4(+) cell count decrease from baseline (day -28) was 52% to day -21, 66% to day -14, 62% to day -7, and 91% to day 0. At day +28, all 42 patients (100%) had ≥50% CD3(+) donor chimerism. No patient experienced graft failure. Overall response rate was 82% (complete remisson, 67%). The day +100 cumulative incidence of grade II-IV acute GVHD was 59% (grade III-IV acute GVHD, 19%), and the 2 year cumulative incidence of chronic GVHD was 69% (moderate/severe, 58%). Nonrelapse mortality was 2% at day +100 and 17% at 2 years. Two-year PFS was 55%, and OS was 68%. This regimen ensures durable engraftment, is effective against persistent disease, and results in relatively low mortality from causes other than relapse.

Topics: Acute Disease; Adult; Aged; Antineoplastic Agents; Busulfan; CD4 Lymphocyte Count; CD4-Positive T-Lymphocytes; Chronic Disease; Female; Graft vs Host Disease; Hematologic Neoplasms; Hematopoietic Stem Cell Transplantation; Humans; Lymphocyte Depletion; Male; Middle Aged; Molecular Targeted Therapy; Pentostatin; Survival Analysis; Transplantation Conditioning; Transplantation, Homologous

Hematopoietic-cell-transplantation-specific-comorbidity-index (HCT-CI) has been reported as a predictor of survival in allogeneic-transplant recipients; however its validity has recently been challenged. We evaluated the association of HCT-CI with survival of transplant recipients who underwent reduced-intensity-conditioning (RIC) with photopheresis, pentostatin, and total-body-irradiation. Median age of 103 patients selected was 55 years. Most patients (58.3%) had high (≥ 3) HCT-CI. Median OS was 298 days. Age, disease-type, disease-status, HCT-CI correlated with survival on bivariate analysis. On multivariate analysis, only HCT-CI was significantly associated with OS (low HCT-CI HR=0.29, CI 0.091-0.886; intermediate HCT-CI HR=0.41, CI 0.226-0.752). Our findings suggest HCT-CI as an independent predictor of survival in the setting of RIC transplants.

Topics: Aged; Comorbidity; Female; Follow-Up Studies; Hematologic Neoplasms; Hematopoietic Stem Cell Transplantation; Humans; Male; Middle Aged; Pentostatin; Photopheresis; Prognosis; Remission Induction; Retrospective Studies; Survival Rate; Transplantation Conditioning; Transplantation, Homologous; Whole-Body Irradiation

Acute graft-versus-host disease (aGVHD) is a major complication of allogeneic bone marrow transplantation. In steroid-refractory aGVHD, mortality is very high. Pentostatin, a potent inhibitor of adenosine deaminase, induces lymphocyte apoptosis and may be useful in the treatment of this condition.. We have conducted a phase I dose escalation study of pentostatin in patients with steroid-refractory aGVHD. Twenty-three patients were enrolled. Starting dose was 1 mg/m2/d by intravenous injection for 3 days.. The maximum tolerated dose was found to be 1.5 mg/m2/d. Late infections at the 2-mg/m2/d dose level were believed to be dose limiting toxicities. Lymphopenia was universal, but the neutrophil count was generally not affected. Fevers associated with neutropenia were not observed. Otherwise, the drug was well tolerated, with only modest elevations of liver function tests and thrombocytopenia, each being observed in a single patient. Twenty-two patients were assessable for response, including 14 complete responses (63%) and three partial responses (13%). Median survival after therapy for the group was 85 days (range, 5 to 1,258 days).. The suggested intravenous dose for a phase II study will be 1.5 mg/m2/d for 3 days. Pentostatin has activity in patients with steroid-refractory aGVHD that is worth exploring in future trials.

Topics: Acute Disease; Adolescent; Adult; Apoptosis; Bone Marrow Transplantation; Child; Child, Preschool; Dose-Response Relationship, Drug; Female; Graft vs Host Disease; Hematologic Neoplasms; History, 16th Century; Humans; Immunosuppressive Agents; Infant; Infusions, Intravenous; Lymphocytes; Male; Maximum Tolerated Dose; Middle Aged; Pentostatin; Transplantation, Homologous; Treatment Outcome

In all, 55 patients at high risk or ineligible for a conventional allogeneic hematopoietic stem cell transplant (HSCT) received a regimen consisting of extracorporeal photopheresis, pentostatin, and reduced dose total body irradiation. The median age was 49 years (18-70 years); 44 received a sibling and 11 an unrelated HSCT; 44% were over the age of 50 years and 31% had undergone a prior HSCT. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and methotrexate. Full donor chimerism was documented in 98% by day +100. The 1000-day nonrelapse mortality was 11%. The median follow-up is 502 days (154-1104 days). The 1- and 2-year overall survival (OS) and event-free survival (EFS) are 67, 58 and 55%, and 47%, respectively. Patients who had not received a prior HSCT or had less than three prior chemotherapy regimens had a 71% OS and 67% EFS at 1 year. Greater than grade II aGVHD developed in 9% and chronic GVHD (cGVHD) in 43%, and extensive in 12% and limited in 31%. Of the patients, 86% who engrafted had a disease response, 72% had complete and 14% partial responses. This novel reduced intensity preparative regimen was well tolerated and associated with a low incidence of transplant-related mortality and serious acute and cGVHD.

Topics: Adolescent; Adult; Aged; Cyclosporine; Disease-Free Survival; Female; Graft vs Host Disease; Hematologic Neoplasms; Hematopoietic Stem Cell Transplantation; Humans; Male; Methotrexate; Middle Aged; Pentostatin; Time Factors; Transplantation Chimera; Transplantation Conditioning; Transplantation, Homologous; Treatment Outcome; Whole-Body Irradiation

Topics: Acute Disease; Adenosine Deaminase Inhibitors; Adult; Female; Graft vs Host Disease; Hematologic Neoplasms; Humans; Immunosuppressive Agents; Kaplan-Meier Estimate; Male; Middle Aged; Pentostatin; Peripheral Blood Stem Cell Transplantation; Retrospective Studies; Treatment Outcome; Young Adult

Topics: Adenosine Deaminase Inhibitors; Antibiotics, Antineoplastic; Autoimmune Diseases; Enzyme Inhibitors; Hematologic Neoplasms; Humans; Immunosuppressive Agents; Leukemia; Lymphoma; Pentostatin