Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.4.4 (adenosine deaminase)
 5,136 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fludarabine phosphate is the 2-fluoro, 5'-monophosphate derivative of vidarabine (ara-A) with the advantages of resistance to deamination by adenosine deaminase (ADA) and improved solubility. The mechanism of cytotoxic action of the compound appears to involve metabolic conversion to the active triphosphate. Fludarabine phosphate has substantial activity against lymphoid malignancies, particularly chronic lymphocytic leukemia (CLL) and low-grade non-Hodgkin's lymphoma (NHL). Its single-agent activity in CLL appears at least comparable to those of other conventional combination regimens. Its activity in Hodgkin's disease, mycosis fungoides, and macroglobulinemia, although suggestive, needs to be further defined and clinical trials are warranted in hairy cell leukemia, prolymphocytic leukemia, and previously untreated myeloma. The compound does not appear active against most common solid tumors. Early clinical trials indicated significant myelosuppression and the potential for severe neurotoxicity. Toxicity on the currently used low-dose schedules includes transient and reversible myelosuppression, nausea and vomiting, diarrhea, somnolence/fatigue, and elevations of liver enzymes and/or serum creatinine. Possible pulmonary toxicity has been suggested in several patients. The currently used low-doses of fludarabine phosphate, even with repeated administration, are well tolerated and appear safe with a negligible risk for severe neurotoxicity. Based on its single-agent activity and tolerability, the Food and Drug Administration recently granted group C designation of the drug for the treatment of patients with refractory CLL outside the clinical trials setting. The use of fludarabine phosphate in combination regimens and its impact on the natural history of the lymphoid malignancies is yet to be determined. Fludarabine phosphate may well occupy a pivotal role in the management of CLL and low-grade NHL.
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PMID:Fludarabine phosphate: a synthetic purine antimetabolite with significant activity against lymphoid malignancies. 170 43

Pentostatin, a novel inhibitor of adenosine deaminase, has shown activity in various lymphoid malignancies of both the T and B cell lineage. This agent has unique side effects and in general myelosuppression has been mild. Interferon has both antiviral and antineoplastic properties. This agent has shown activity in hairy cell leukemia, chronic granulocytic leukemia, low grade lymphoma, and myeloma. Side effects from interferon are in general dissimilar to those that have been seen with pentostatin and in particular myelosuppression has not been a major toxicity with low doses of interferon. This current trial explored the combination of pentostatin and interferon in hematologic malignancies. Fifteen patients were enrolled in this phase I trial at a fixed dose of pentostatin of 4 mg/m2 biweekly and interferon at doses of 0.5, 1, 2, or 4 million units/m2 of interferon. At the first three dose levels of interferon nausea and vomiting were the predominant toxicity and appeared to worsen with time on study. Fatigue also was seen at the lowest level of interferon and was severe enough to cause two individuals to discontinue the study medications. At higher dose levels of interferon, myelosuppression, nausea and vomiting, and fatigue were the predominant toxicities. One patient with hairy cell leukemia had a complete response and a second patient with T cell cutaneous lymphoma had a partial response which lasted for 6 to 7 weeks. The maximum tolerated dose of interferon with pentostatin in this patient population was four million units/m2.
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PMID:A phase I trial of alpha-interferon in combination with pentostatin in hematologic malignancies. 205 72

2'-Deoxycoformycin (pentostatin [dCF]), a potent inhibitor of adenosine deaminase (ADA), was administered in a biweekly low-dose (2 to 4 mg/m2) intravenous (IV) schedule to patients with advanced hairy cell leukemia. Twenty-three patients were treated, including 12 patients previously treated by splenectomy and five patients treated with interferon. Twenty-one of 23 patients had objective responses, including 20 who achieved a complete remission (CR). Responses occurred rapidly, with an average time to CR of 5.4 months. Treatment was not continued once CR was achieved, and 15 of 20 patients remain in remission with an average duration of 12.6 months. CRs were achieved in both patients previously treated with interferon (three of five) and patients with marked splenomegaly (three of three). Relapses, when seen, have occurred in the bone marrow alone and the one patient who required retreatment was reinduced into CR. Toxicity has been mild and reversible, with nausea and vomiting, conjunctivitis, and skin rash as the main complications of treatment. dCF is the most effective single agent in the treatment of hairy cell leukemia, inducing a high percentage of CRs in all subgroups. Two multiinstitutional trials are now underway to compare its effectiveness v alpha interferon.
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PMID:Pentostatin in the treatment of advanced hairy cell leukemia. 278 31

2'-Deoxycoformycin, a potent inhibitor of adenosine deaminase, was administered to three patients with cutaneous T cell lymphoma refractory to multiple treatment modalities. Patient 1, who received 5 mg/m2/day for 3 days at 35- to 71-day intervals, has achieved a complete remission greater than 16 months in duration. Patient 2 had progressive disease despite two courses of 2'-deoxycoformycin at a dose of 5 mg/m2/day for 3 days at 28-day intervals. The third patient, who was treated with 4 mg/m2 2'-deoxycoformycin weekly to biweekly, had an initial response, but the disease progressed after eight treatments. Only one patient had any side effects: Patient 1 developed reversible episcleritis, mild elevation of liver enzymes, and persistent nausea and vomiting. In red blood cells of all patients, there was near complete inhibition of adenosine deaminase (91% to 96%) and S-adenosylhomocysteine hydrolase (89% to 95%) activities with treatment. In peripheral blood lymphocytes, adenosine deaminase was inhibited by 85% to 98% and S-adenosylhomocysteine hydrolase by 51% to 88%. The deoxyadenosine triphosphate level, reflected by the total cellular adenine deoxyribonucleotide measurement in erythrocytes, was noted to be modestly elevated during treatment, with the highest level in the patient who demonstrated the only complete response and the only toxic effects. Low-dose 2'-deoxycoformycin appears to be safe but may be an insufficiently intensive regimen to treat refractory cutaneous T cell lymphoma. With proper biochemical monitoring, higher doses may be both safe and more effective.
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PMID:Treatment of cutaneous T cell lymphoma with 2'-deoxycoformycin (pentostatin). 326 1

Five patients from the Kyushu area in Japan with adult T-cell leukaemia (ATL) refractory to conventional chemotherapeutic agents were treated with 5 mg/m2 of the adenosine deaminase inhibitor, 2'-deoxycoformycin (DCF), intravenously (i.v.) for 3 consecutive days, followed by 5 mg/m2 i.v. weekly. Two patients showed a good response, and three were resistant to DCF. One patient with ATL receiving DCF had a continuous remission without further therapy. Another patient in the terminal stage received three daily injections of 7.5 mg of DCF. The most prominent change was the drop in the leucocyte count. The cell count fell from 116.4 X 10(9)/l to 2.0 X 10(9)/l on day 7. The only adverse effects of DCF therapy were gastrointestinal toxicity, nausea and vomiting. These results suggest that DCF may be a valuable drug for treating refractory ATL.
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PMID:Clinical consequences of 2'-deoxycoformycin treatment in patients with refractory adult T-cell leukaemia. 348 40

The purpose of this study was to determine the efficacy and toxicity of pentostatin (2'-deoxycoformycin) administered in a five day schedule every 28 days to patients with B-cell chronic lymphocytic leukaemia (B-CLL) relapsed from or refractory to at least one line of prior chemotherapy. The initial dose level of 2 mg/m2/day was adjusted up or down by 0.5 mg/m2 in subsequent cycles on the basis of haematological and non-haematological toxicities. The five day schedule was selected because published pharmacokinetic studies had indicated that although pentostatin had an elimination half-life of approximately six hours and could inhibit plasma adenosine deaminase activity for 24 hours, recovery of enzyme activity rapidly took place and accumulation of dATP which has a toxic effect on non-replicating lymphoid cells could be increased by repeated dosing. Twenty-nine patients were entered into the study and dose-escalation was possible in nine, while dose reductions were required for five patients. Of the 24 patients evaluable for response, complete responses were achieved in two and partial responses in five for an overall response rate of 29.2%. Toxicity consisted of myelosuppression, infection, nausea and vomiting and hepatotoxicity but was experienced at acceptable levels considering the heavily pre-treated nature of the patient population. Pentostatin in this schedule has salvage activity in previously treated or resistant patients with B-CLL.
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PMID:Phase I/II evaluation of pentostatin (2'-deoxycoformycin) in a five day schedule for the treatment of relapsed/refractory B-cell chronic lymphocytic leukaemia. 984 79