thioguanine-anhydrous and beta-2--deoxythioguanosine

The Southeastern Cancer Study Group conducted a post-remission induction randomized trial in adult acute myelogenous leukemia to assess the efficacy of alternate drug therapy during consolidation and of immunotherapy during maintenance. Of 508 evaluable patients entered into the study, 335 (66%) achieved a complete remission treated with a 7-day infusion of cytosine arabinoside at a dose of 100 mg/sq m/day and 3 days of daunorubicin at a dose of 45 mg/sq m/day. Those in remission were randomized to receive 3 courses of 1 of 3 consolidation regimens: (A) a continuous infusion of 5-azacytidine, 150 mg/sq m/day for 5 days; (B) 5-azacytidine plus beta-deoxythioguanosine, 300 mg/sq m/day for 5 days; or (C) cytosine arabinoside, 100 mg/sq m/day intravenously, and thioguanine, 100 mg/sq m orally every 12 hr, plus daunorubicin, 10 mg/sq m every 24 hr daily for 5 days. There was no difference in relapse rate among the 3 arms. Those completing consolidation and remaining in remission were randomized to 1 of 3 maintenance regimens: (D) chemotherapy, 5-day infusion of cytosine arabinoside and 2 days of daunorubicin (same doses as induction) given every 13 wk for 1 yr; (E) BCG given twice weekly for 1 mo and then monthly for 1 yr; or (F) the combination of regimens D and E. The median duration of remission was significantly better on regimen D (17.4 versus 9.4 and 9.5 mo), and median survival was 29 mo compared to 21 mo for the other regimens. Those given different drugs during consolidation than used for induction (regimens A and B) and subsequent chemotherapy for maintenance (regimen D) had the longest remission durations and survival. Immunotherapy was not as good as intensive chemotherapy for maintenance.

Topics: Adolescent; Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Azacitidine; BCG Vaccine; Clinical Trials as Topic; Combined Modality Therapy; Cytarabine; Daunorubicin; Deoxyguanosine; Female; Humans; Immunotherapy; Leukemia, Myeloid, Acute; Male; Middle Aged; Random Allocation; Thioguanine; Thionucleosides; United States

In a randomized multi-institutional trial of the Eastern Cooperative Oncology Group, 316 patients with advanced measurable colorectal adenocarcinoma were treated with a weekly schedule of 5-fluorouracil given orally and intravenously with oral-5-fluorouracil in combination with cyclophosphamide or 6-thioguanine, or with oral Methyl CCNU administered once every eight weeks. On failure or progression, 133 protocol patients crossed-over to a secondary therapy, while 116 other patients previously treated with 5-fluorouracil off protocol were randomized to treatment with Methyl CCNU or B-2'-deoxythioguanosine. Response rates among patients who had received no prior chemotherapy were 18% to oral 5-FU, 15% to intravenous 5-FU and to MeCCNU, 12% to 5-FU and 6-thioguanine and 5% to cyclophosphamide and 5-FU, with little activity (3% response rate) in crossover or previously treated patients. Treatment with 5-FU, particularly oral 5-FU was associated with the least drug-related toxicity. Hematologic toxicity was greatest with Methyl CCNU, but was no more frequent in previously treated than in untreated patients. A tendency toward cumulative bone marrow depression was noted. 5-FU was effective only in ambulatory patients, whereas responses among non-ambulatory patients were seen only in the group treated with Methyl-CCNU.

Topics: Adenocarcinoma; Antineoplastic Agents; Bone Marrow; Clinical Trials as Topic; Colonic Neoplasms; Cyclophosphamide; Deoxyguanosine; Drug Therapy, Combination; Female; Fluorouracil; Humans; Male; Neoplasm Metastasis; Rectal Neoplasms; Semustine; Thioguanine; Thionucleosides

Resistance to the antileukemic agent 6-thioguanine (TG) inevitably develops in animal tumors. However, a new agent, beta-2'-deoxythioguanosine (beta-TGdR) can overcome TG resistance in animal tumor models and is therefore of potential clinical use. The pharmacokinetics of radiolabeled TG were compared with those of beta-TGdR in patients with cancer after intravenous administration. [35S]-beta-TGdR (5.4 mg/kg, 200 mg/m2, 200 microCi total) was administered to five patients; the radiolabel in the plasma declined with an initial half-life (t1/2) of 14 min and a terminal t1/2 of 19.3 h. Within 24 h, 65% of the radiolabel was excreted in the urine. In contrast, after administration of [35S]-6-TG (3.4 mg/kg, 125 mg/m2, 200 microCi total) the average initial t1/2 was 40 min while the terminal phase t1/2 was 28.9 h. Urinary excretion of the radiolabel was 75% of the dose 24 h after administration. Both thiopurines were rapidly and extensively degraded and excreted as 6-thioxanthine, inorganic sulfate, S-methyl-6-thioxanthine, and 6-thiouric acid in addition to other products. Small amounts of unchanged drug were also excreted. These studies suggest that beta-TGdR is merely a latent form of TG.

Topics: Allopurinol; Antineoplastic Agents; Deoxyguanosine; Drug Interactions; Humans; Kinetics; Neoplasms; Thioguanine; Thionucleosides

The anticancer agent beta-2' deoxythioguanosine (beta-TGdR, NSC-71261) has potential utility for the treatment of hematologic tumors resistant to 6-thioguanine (TG). We have studied the pharmacology and metabolism of these two agents in the beagle dog. [35S] beta-TGdR was administered as an IV bolus to five dogs at a dose of 10 mg/kg. Plasma radioactivity declined biphasically with an average terminal t 1/2 of 3.7 h. Cumulative urinary excretion of the radiolabel 5 h after administration was 19% of the total dose. In another four dogs that received 100 mg/kg (2.71 g), the average terminal plasma t 1/2 was 7.7 h and the 5-h cumulative urinary excretion was 28% of the total dose. [35S]Thioguanine, 5 mg/kg was similarly administered IV to three beagle dogs. The average terminal t 1/2 of [35S]TG and metabolites was 4.6 h, and the 5-h cumulative urinary excretion of the [35S] label was 47%. Similar studies were conducted in three beagle dogs that received the same dose of [8(14)C]TG. In these studies, however, the terminal phase t 1/2 of 14C in plasma was 1.9 h. Cumulative urinary excretion of the 14C was 40% in 5 h. Both TG and beta-TGdR were rapidly and extensively degraded. Neither of these agents and none of their metabolites was found in the cerebrospinal fluid in significant concentrations. In the dog, beta-TGdR was rapidly metabolized to TG and may serve as a slow release form of TG.

Topics: Allopurinol; Animals; Antineoplastic Agents; Biotransformation; Blood Proteins; Deoxyguanosine; Dogs; Female; Half-Life; Kinetics; Male; Protein Binding; Thioguanine; Thionucleosides

Beta-thioguanine deoxyriboside (betaTGdR) is a purine nucleoside derivative which was studied alone or in combination with arabinosyl cytosine (Ara-C) in patients with solid tumors and acute leukemia. No significant responses were observed in 22 patients with solid tumors. The response rate with betaTGdR alone in acute leukemia was 26% and in combination with Ara-C was 24%. Responses were generally of short duration. Toxicity included myelosuppression, nausea, stomatitis, hyperpigmentation, photosensitivity, and liver function abnormalities.

Topics: Acute Disease; Adolescent; Adult; Aged; Child; Child, Preschool; Cytarabine; Deoxyguanosine; Deoxyribonucleosides; Drug Therapy, Combination; Female; Guanosine; Humans; Leukemia; Leukopenia; Male; Middle Aged; Neoplasm Metastasis; Neoplasms; Remission, Spontaneous; Thioguanine; Thionucleosides; Thrombocytopenia; Time Factors

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Cattle; Chromatography; Deoxyguanosine; Mammary Neoplasms, Animal; Mammary Neoplasms, Experimental; Metabolism; Mice; Neoplasms, Experimental; Nucleosides; Pharmacology; Research; Sulfhydryl Compounds; Thioguanine; Thionucleosides; Ultraviolet Rays

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Chemistry, Pharmaceutical; Deoxyguanosine; DNA; DNA, Neoplasm; Mammary Neoplasms, Animal; Mammary Neoplasms, Experimental; Metabolism; Mice; Nucleosides; Pharmacology; Research; RNA; RNA, Neoplasm; Thioguanine; Thionucleosides