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Biomedical subjects

B Kamen

Publications and source records attributed to B Kamen.

17 recordsLinked to original sources
PubMed1997

Seven-week continuous-infusion paclitaxel plus concurrent radiation therapy for locally advanced non-small cell lung cancer: a phase I study.

The goal of this National Cancer Institute-sponsored phase I trial is to determine the feasibility, toxicity, and pharmacokinetics of continuous-infusion (24 hr/d, 7 d/wk, 7 weeks total) intravenous paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) when combined with standard, curative-intent radiation therapy (RT) for previously untreated, locally advanced non-small cell lung cancers. Eligible patients have locally advanced (T4NXM0 or TXN2-3M0) non-small cell cancer ineligible for potentially curative surgical resection, a good performance status, adequate hematologic, hepatic, and renal functions, and no distant metastases. All patients receive a total tumor dose of 64.8 Gy megavoltage RT in 7 weeks at 1.8 Gy once daily, 5 d/wk. Paclitaxel is delivered by continuous intravenous infusion starting 48 hours before RT and continuing for its duration. The dose of paclitaxel is escalated in cohorts of three patients in a standard phase I design. To date, 16 patients have entered the trial, and 15 are evaluable for toxicity in this ongoing study. Paclitaxel dose is currently at a 6.5 mg/m2/d dose level, with no dose-limiting toxicity recorded thus far. One patient at the highest dose level has had grade 2 pneumonitis. With the exception of anemia, toxicities are those that would be expected from RT alone. A slowly progressive normocytic anemia with no renal dysfunction was found to be associated with an acquired hypoerythropoietin state. These findings indicate that this therapy is feasible and well tolerated through current dose levels, with no dose-limiting toxicity. Dose escalation is ongoing.

Antineoplastic Agents, Phytogenic↗
PubMed1997

Folate and antifolate pharmacology.

Folic acid is a water-soluble vitamin associated with the other B vitamins. In its fully reduced form (tetrahydrofolate), folate serves as a 1-carbon donor for synthesis of purines and thymidine as well as in the remethylation cycle of homocysteine to methionine. Folate is essential for normal cell growth and replication. It therefore is not surprising that folate analogues have served and continue to serve well as antibiotics and cytotoxic drugs in the treatment of cancer, autoimmune diseases, psoriasis, and bacterial and protozoal infections. During the past 50 years, many of the enzymes requiring folate as a co-factor (ie, thymidylate synthase), and molecules critical in folate homeostasis (ie, the reduced folate carrier, folylpolyglutamate synthase), have been purified and even crystallized. The genes have been cloned, sequenced, and mapped, providing detailed knowledge of their regulation and three-dimensional structure. This has, in part, led to the rational synthesis of a large number of folate analogues that differ from methotrexate, the "classical antifolate," in transport, metabolism, and intracellular targets. Currently, several new folate analogues with unique biochemical properties and clinical applications are being tested. The goals of this brief review are to review folate homeostasis, to highlight the similarities and differences between natural folate and antifolates with respect to biochemistry and metabolism, and to present the pharmacology of methotrexate and several next-generation folate analogues, such as trimetrexate and raltritrexed, with an emphasis on mechanisms of drug resistance.

Antimetabolites, Antineoplastic↗
PubMed1997

Seven-week continuous-infusion paclitaxel with concurrent radiotherapy for locally advanced head and neck squamous cell cancer: a phase I study.

The goal of this National Cancer Institute-sponsored phase I trial is to determine the feasibility, toxicity, and pharmacokinetics of continuous-infusion (24 hr/d, 7 d/wk, 7-week total) intravenous paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) combined with standard curative radiotherapy (RT) for previously untreated, locally advanced head and neck squamous cell cancers. Eligible patients have squamous cell cancers of the head and neck with expected 5-year survival rates of < or =25%; a good performance status; adequate hematologic, hepatic, and renal functions; and no distant metastases. All patients receive 70 Gy megavoltage RT in 7 weeks (2 Gy/d x 5 d/wk). Paclitaxel is delivered by protracted venous infusion starting 48 hours before RT and continuing for its duration. Biopsies for cell-cycle distribution analyses and paclitaxel tissue levels are obtained, if possible, before beginning paclitaxel and after 48 hours just before RT begins. The dose of paclitaxel is escalated in cohorts of three patients. Eighteen patients are evaluable for toxicity. Treatment has been completed through the 6.5 mg/m2/d dose level and is ongoing at 10.5 mg/m2/d. There has been no dose-limiting toxicity thus far. With the exception of anemia, toxicity is commensurate with what would be expected from RT alone. A slowly progressive normocytic anemia with no renal dysfunction was found to be associated with an acquired hypoerythropoietin state. Tumor biopsies have suggested the possibility of paclitaxel-induced mitotic arrest. This therapy is feasible and has been well tolerated through current dose levels with no dose-limiting toxicity. There is a suggestion of biologic activity evidenced by the anemia and the possibility of alteration in cell-cycle distributions. Dose escalation is ongoing.

Antineoplastic Agents, Phytogenic↗
PubMed1995

Phase I studies of continuous-infusion paclitaxel given with standard aggressive radiation therapy for locally advanced solid tumors.

Currently available therapies are unsatisfactory for locally advanced solid tumors of the lung, head and neck, and brain. Laboratory data suggest that the addition of paclitaxel (Taxol; Bristol-Myers Squibb Oncology, Princeton, NJ), a microtubule-stabilizing drug, to radiation therapy may result in significant radiation sensitization, perhaps because paclitaxel induces cell cycle arrest at G2/M. Relatively low concentrations, 1 to 10 nmol/L, appear to be optimal for direct cytotoxicity and radiosensitization in vitro. Within this dose range, more prolonged exposure seems to result in higher response rates. We are conducting phase I trials designed to test continuous infusion (24 hours per day, 7 days per week) intravenous paclitaxel combined with standard curative-intent radiation therapy. To date, 22 patients are evaluable, and the maximum tolerated dose of paclitaxel has not been reached at up to 2.5 mg/m2/d. Observed toxicities include anemia, lymphopenia, mucositis, and cutaneous erythema/desquamation.

Anemia↗
PubMed1991

Phase II trial of ICRF-187 in children with solid tumors and acute leukemia.

ICRF-187 is the (+) enantiomer of the racemic mixture razoxane (ICRF-159). This compound is much more water soluble and thus could be formulated for parental use. The maximum tolerated dose in children after phase I trials was determined to be 3500 mg/M2/day x 3 days. A phase II trial of ICRF-187 was done in 21 children with solid tumors and 35 children with acute leukemia. All these patients were less than 21 years of age, had recovered from previous chemotherapy, had normal liver and kidney functions, and had a life expectancy of greater than 4 weeks. ICRF-187 was administered at a dose of 3 g/M2/day for 3 days as a 4 hour infusion each day. In patients with leukemia, no objective response was seen in the bone marrow although a few patients had a decrease in peripheral blast count. There were no measurable responses seen in patients with a solid tumor. ICRF-187 was well tolerated. The major toxicity was hematopoietic depression. Significant but rare toxicities included moderate to severe nausea and vomiting, and elevation of bilirubin and transaminases. Although inactive in the current study, ICRF-187 might be more active in another schedule.

Acute Disease↗
PubMed1990

Aziridinylbenzoquinone (AZQ) in the treatment of recurrent pediatric brain and other malignant solid tumors. A Pediatric Oncology Group phase II study.

To assess the response rates and toxicity of AZQ in children with recurrent brain and other malignant solid tumors, a phase II study was implemented by the Pediatric Oncology Group. Eligible patients received AZQ 18 mg/M2/week i.v. for 4 doses followed by a 2 week rest period. Each dose was given over four hours (1/3 over the initial 20 minutes). After the first year, the dosage was reduced to 13 mg/M2 due to myelotoxicity resulting in treatment delays. No objective responses were observed in 73 evaluable children with various non-central nervous system tumors. Of the 91 patients with brain tumors, there were 4 CR's and 2 PR's in patients with astrocytoma, ependymoma, glioblastoma multiforme, oligodendroglioma, brain stem glioma and intracranial yolk sac tumor (median duration, 10 months; range, 2-20+ months). Three of 4 CR's were achieved with a dosage of 18 mg/M2/week. An additional 13 children with brain tumors experienced stable or improved disease (duration, 2-36 + months; median 7.5 months). The principal toxicity was myelosuppression which was cumulative but there were also 3 allergic reactions to AZQ. We conclude that for selected brain tumors, the rates of objective response and stable disease plus the duration of responses support further assessment of AZQ in combination with other agents. Furthermore, the 18 mg/M2 dosage may provide better responses.

Adolescent↗
PubMed1986

Methotrexate metabolism analysis in blood and liver of rheumatoid arthritis patients. Association with hepatic folate deficiency and formation of polyglutamates.

Serum and red blood cell methotrexate (MTX) levels, as well as hepatic levels of MTX and folate, were analyzed in 24 patients who had received long-term oral MTX weekly for the treatment of rheumatoid arthritis. The serum MTX level peaked rapidly and was insignificant after 24 hours. The red blood cell MTX level was not related to the interval from the last MTX dose. In hepatic tissue obtained by liver biopsy, MTX was found in a predominantly polyglutamated form with depleted hepatic folate stores when compared with baseline specimens. A brief period of therapy with oral folinic acid repleted hepatic folate. It is possible that MTX hepatotoxicity is related to reduced hepatic folate levels and formation of MTX polyglutamates.

Arthritis, Rheumatoid↗
PubMed1980

Folate compartments during gestational maturation.

Studies on 41 healthy preterm infants and 53 term infants revealed that almost 70% of the total folate is present in the bound form. Beyond the enonatal period the increase in bound folate with increasing gestational maturity reflects fetal demands placed on folate transport and affords an explanation for the loss of folate and corresponding increase in unsaturated binder during pregnancy. With the knowledge of folate biology gained from radioligand data, it is reasonable to postulate that effective folate metabolism depends upon a metabolically active transport mechanism.

Biological Transport↗
PubMedDate not supplied

Intensive alternating drug pairs after remission induction for treatment of infants with acute lymphoblastic leukemia: A Pediatric Oncology Group Pilot Study.

PURPOSE: Infants with acute lymphoblastic leukemia (ALL) often enter remission; however, they have a high rate of relapse. To prevent relapse, infants' tolerance of and benefits from early intensive rotating drug pairs as part of therapy were studied. METHODS: After prednisone, vincristine, asparaginase, and daunorubicin induction, 12 intensive treatments (ABACABACABAC) were administered in 30 weeks: A, intermediate dose methotrexate (MTX) and intermediate dose mercaptopurine (MP); B, cytosine arabinoside (Ara-C) and daunorubicin (DNR); C, Ara-C and teniposide (VM-26). Triple intrathecal chemotherapy (Ara-C, MTX, and hydrocortisone) was administered for central nervous system prophylaxis. Continuation therapy consisted of weekly MTX and daily MP for a total of 130 weeks of continuous complete remission. RESULTS: Thirty-three infants (1 year old or younger) with newly diagnosed ALL were treated. Two infants did not respond to induction, 1 died from sepsis during continuation, 1 received a bone marrow transplant, and 24 relapsed. Median time to relapse was 39 weeks. The event-free survival rate at 5 years was 17% (standard error +/- 7.7%). The most significant toxicities occurred during intensification and included fever-neutropenia and bacterial sepsis. CONCLUSION: Although early intensive rotating therapy is tolerable, the relapse-free survival rate remains poor for infants treated with the schedule on this protocol.

Antineoplastic Combined Chemotherapy Protocols↗