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E K Rowinsky

Publications and source records attributed to E K Rowinsky.

At least 145 records · Page 8Linked to original sources
PubMed1991

Phase I and pharmacokinetic study of hepsulfam (NSC 329680).

Hepsulfam (NSC 329680), a bifunctional alkylating agent structurally related to busulfan, has entered clinical trial based on its broader preclinical antitumor activity compared with that of busulfan and its i.v. formulation which may circumvent the many problems arising from the p.o. administration of busulfan, such as significant individual differences in bioavailability. In this Phase I study, 53 patients received 95 courses of hepsulfam at doses ranging from 30 to 480 mg/m2 administered i.v. over 30 min every 28 days. Hematological toxicity was dose limiting. Leukopenia and thrombocytopenia were dose related, delayed in onset, and sustained for long durations. Toxicity was cumulative in most patients receiving more than one course. This pattern of myelosuppression suggests that hepsulfam is cytotoxic to hematopoietic stem cells. Although hematological toxicity was not particularly severe during most courses, its lengthly duration precluded the prompt administration of subsequent courses. Minimal nonhematological effects were observed. Pharmacokinetic studies revealed that the clearance rate of hepsulfam is linear over the dose range studied and that its plasma disposition is biphasic with mean alpha and beta half-lives of 19 +/- 18 (SE) min and 337 +/- 248 (SE) min, respectively. The area under the plasma clearance curve correlated with the percentage of change in WBC using a sigmoidal Emax model and with the duration of thrombocytopenia in patients with hematological toxicity. Based on the protracted duration of the toxicity of multiple doses that were greater than 210 mg/m2, the recommended starting dose for Phase II trials is 210 mg/m2. However, these trials should be pursued with caution because of the protracted nature of hepsulfam's myelosuppression. Because hepsulfam produced minimal nonhematological toxicity, substantial dose escalation above 480 mg/m2 may be possible with hematopoietic stem cell support.

Adult↗
PubMed1991

The clinical pharmacology and use of antimicrotubule agents in cancer chemotherapeutics.

Although there has been a rapid expansion of the number of classes of compounds with antineoplastic activity, few have played a more vital role in the curative and palliative treatment of cancers than the antimicrotubule agents. Although the vinca alkaloids have been the only subclass of antimicrotubule agents that have had broad experimental and clinical applications in oncologic therapeutics over the last several decades, the taxanes, led by the prototypic agent taxol, are emerging as another very active class of antimicrotubule agents. After briefly reviewing the mechanisms of antineoplastic action and resistance, this article comprehensively reviews the clinical pharmacology, therapeutic applications, and clinical toxicities of selected antimicrotubule agents.

Alkaloids↗
PubMed1991

Current developments in antitumor antibiotics, epipodophyllotoxins, and vinca alkaloids.

The antitumor antibiotics, epipodophyllotoxins, and vinca alkaloids represent a major portion of the therapeutic armamentarium against almost all treatable neoplasms. However, their use has been limited by the acquisition of drug resistance as well as by serious nonhematologic toxicities such as cardiac toxicities with the anthracyclines, pulmonary toxicities with bleomycin, and peripheral nervous system toxicities with the vinca alkaloids. This paper discusses several new developments over the last year, particularly advances in our understanding of 1) the antitumor efficacy and ultimate clinical role of several novel analogues that appear to have improved therapeutic indices in certain malignancies such as idarubicin in acute myelogenous leukemia, epirubicin in breast cancer, and vinorelbine in breast and non-small cell lung cancers; 2) the nature, risks, detection, and prevention of serious nonhematologic toxicities such as the role of the carbon monoxide diffusion capacity test in the early detection of pulmonary toxicity from bleomycin, and youth as a risk factor for anthracycline cardiomyopathy; 3) the optimal scheduling and administration of these agents including chronic low-dose oral, infusional, and intraperitoneal administration schedules for the epipodophyllotoxins and infusional schedules for the vinca alkaloids; 4) differences in the pharmacology and recommendations for the use of the epipodophyllotoxin etoposide in patients with excretory organ dysfunction; and 5) the clinical feasibility of reversing multidrug resistance by using calcium channel blockers, the potential utility of other classes of agents to modulate multidrug resistance in the clinic, and new insights on resistance to bleomycin.

Antibiotics, Antineoplastic↗
PubMed1991

Sequences of taxol and cisplatin: a phase I and pharmacologic study.

Untreated and minimally pretreated solid tumor patients received alternating sequences of taxol and cisplatin. Sequential dose escalation of each agent using taxol doses of 110 or 135 mg/m2 and cisplatin doses of 50 or 75 mg/m2 resulted in four dosage permutations that induced grades 3 and 4 neutropenia in 72% to 84% and 50% to 53% of courses, respectively. Neutropenia was brief, and hospitalization for neutropenia and fever was required in 13% to 24% of courses. However, further escalation of taxol to 170 or 200 mg/m2 induced grade 4 neutropenia in 79% to 82% of courses. At the highest taxol-cisplatin dose level (200 mg/m2 to 75 mg/m2), the mean neutrophil count nadir was 98/microL, and hospitalization for neutropenia and fever was required in 64% of courses. The sequence of cisplatin before taxol, which has less antitumor activity in vitro, induced more profound neutropenia than the alternate sequence. Pharmacologic studies indicated that this difference was probably due to 25% lower taxol clearance rates when cisplatin preceded taxol. Although neurotoxicity was initially thought to be a potentially serious effect of the combination, mild to modest neurotoxicity occurred in only 27% of patients. Adverse effects also included myalgias, alopecia, vomiting, diarrhea, bradycardia, and asymptomatic ventricular tachycardia. Objective responses were noted in melanoma, as well as non-small-cell lung, ovarian, breast, head and neck, colon, and pancreatic carcinomas. Based on these results, the sequence of taxol before cisplatin at doses of 135 and 75 mg/m2, respectively, is recommended for phase II/III trials, with escalation of taxol to 170 mg/m2 if treatment is well tolerated.

Adult↗
PubMed1991

Cardiac disturbances during the administration of taxol.

The clinical development of taxol, a new antimicrotubule agent with a unique mechanism of cytotoxic action, has proceeded slowly due to serious hypersensitivity reactions (HSRs) and shortages in its supply. Nevertheless, large-scale phase II trials have been initiated as taxol has recently demonstrated impressive activity in advanced and cisplatin-refractory ovarian carcinoma. Furthermore, the incidence of HSRs has been reduced substantially with premedications and modifications in the administration schedule. However, various manifestations of potential cardiotoxicity have been observed in several patients who participated in four phase I and II studies of taxol. Asymptomatic bradycardia has occurred in a high proportion of patients, including 29% of ovarian cancer patients who were treated with maximally tolerated doses of taxol in a phase II study. More profound cardiac disturbances, including a range of atrioventricular conduction blocks, left bundle branch block, ventricular tachycardia (VT), and manifestations of cardiac ischemia, have been observed in seven of 140 patients (5%) who received taxol. Descriptions of these events are presented in this report to alert investigators to the potential for these adverse effects. Although these disturbances did not result in serious sequelae in most patients, investigators should continue to maintain a high degree of caution until precise risk factors, frequency, and clinical significance of these adverse cardiac effects are determined.

Aged↗
PubMed1990

Effects of the differentiating agent hexamethylene bisacetamide on normal and myelodysplastic hematopoietic progenitors.

Hexamethylene bisacetamide (HMBA; NSC 95580) is a potent polar-planar differentiating agent of leukemia and solid tumor cell lines in vitro at clinically achievable concentrations. HMBA is currently being studied in patients with myelodysplastic syndrome. Previous phase I trials have demonstrated that HMBA produces hematologic toxicity in morphologically normal bone marrows of patients with solid tumors. Because of concern that HMBA may produce more severe myelotoxicity in patients with myelodysplastic syndrome since these patients have limited hematopoietic reserves, we studied the effects of HMBA on myelodysplastic and normal hematopoietic progenitors in vitro. HMBA concentrations that are optimal for differentiation in vitro (2 to 5 mmol/L) and HMBA concentrations that are being achieved in clinical trials (1 to 2 mmol/L) inhibited the growth of granulocyte-macrophage colony-forming units and erythroid burst-forming units from all 15 patients with myelodysplastic syndrome and all 4 normal subjects, HMBA did not induce proliferation of myelodysplastic or normal progenitors at any concentration; rather, it produced nearly identical inhibition of normal and myelodysplastic hematopoietic progenitors. HMBA also produced quantitatively similar inhibition of clonogenic leukemic growth of two myeloid leukemia cell lines. For a differentiating agent to be effective, it will likely have to either produce both differentiation and proliferation of abnormal hematopoietic progenitors or show selective inhibitory effects on abnormal as compared with normal progenitors. Although the mechanisms responsible for the antiproliferative effects of HMBA cannot be determined from this study, similar inhibitory effects of HMBA on normal and abnormal hematopoietic progenitors suggest that HMBA may be of limited utility in producing and sustaining elevations of peripheral blood cell counts in patients with myelodysplastic syndrome.

Acetamides↗
PubMed1990

Taxol: a novel investigational antimicrotubule agent.

Microtubules are among the most strategic subcellular targets of anticancer chemotherapeutics. Despite this fact, new antimicrotubule agents that possess unique mechanisms of cytotoxic action and have broader antineoplastic spectra than the vinca alkaloids have not been introduced over the last several decades--until the recent development of taxol. Unlike classical antimicrotubule agents like colchicine and the vinca alkaloids, which induce depolymerization of microtubules, taxol induces tubulin polymerization and forms extremely stable and nonfunctional microtubules. Taxol has demonstrated broad activity in preclinical screening studies, and antineoplastic activity has been observed in several classically refractory tumors. These tumors include cisplatin-resistant ovarian carcinoma in phase II trials and malignant melanoma and non-small cell lung carcinoma in phase I studies. Taxol's structural complexity has hampered the development of feasible processes for synthesis, and its extreme scarcity has limited the use of a conventional, broad-scale screening approach for evaluation of clinical antitumor activity. However, taxol's unique mechanism of action, its spectrum of preclinical antitumor activity, and tumor responses in early clinical trials have generated renewed interest in pursuing its development.

Alkaloids↗
PubMed1990

Phase I and pharmacokinetic study of brequinar sodium (NSC 368390).

Brequinar sodium is a quinoline carboxylic acid derivative that has shown antitumor activity in a number of in vivo murine and human tumor xenograft models. Its mechanism of action is blockade of de novo pyrimidine biosynthesis by inhibition of dihydroorotic acid dehydrogenase. In vitro and in vivo studies demonstrate the superiority of prolonged drug exposure in achieving tumor growth inhibition. This phase I study evaluated the administration of brequinar sodium by short, daily i.v. infusion for 5 days repeated every 4 weeks. Fifty-four subjects were enrolled in the study and received drug in doses ranging from 36-300 mg/m2. The dose-limiting toxicities were mucositis and diffuse skin rash. Other toxicities included myelosuppression, nausea, vomiting, malaise, and burning at the infusion site. The maximum tolerated dose on the "daily times 5" schedule was 300 mg/m2. The recommended phase II dose is 250 mg/m2. Pharmacokinetic analysis of the day 1 drug clearance curves in 51 subjects showed slight nonlinearity in the relationship between dose and area under the clearance curve (AUC). The dose versus AUC relationship was well described using a Michaelis-Menten model of brequinar elimination kinetics with Vmax = 45 (micrograms/ml)/h and Km = 123 micrograms. Analysis of the day 5 drug clearance curves revealed a diminution in Vmax to 30 (micrograms/ml)/h. As a consequence of the reduction in Vmax brequinar plasma concentrations on day 5 were higher than predicted from day 1 drug kinetics. Pharmacodynamic analysis of the day 1 kinetic parameters and the toxicities occurring during the first cycle of drug therapy revealed significant correlations between mucositis and dose, AUC, and peak brequinar concentration; between leukopenia and AUC and peak drug concentration; and between thrombocytopenia and beta elimination rate.

Antineoplastic Agents↗
PubMed1990

Phase I study and pharmacodynamics of piroxantrone (NSC 349174), a new anthrapyrazole.

Piroxantrone (PRX, NSC 349174) is one of the first of a new class of intercalating agents, the anthrapyrazoles, to undergo clinical evaluation. Additionally, it is the first drug trial to prospectively test a new pharmacology-based dose escalation schema proposed for Phase I trials of anticancer compounds. In this Phase I trial, PRX was administered as a 1-h infusion every 3 weeks to patients with advanced cancer. Forty-four evaluable patients received 116 courses at doses ranging from 7.5 to 190 mg/m2. The dose-limiting toxicity was myelosuppression with leukopenia predominating. Nonhematological toxicities were minimal and consisted of nausea and vomiting, alopecia, mucositis, and phlebitis. Based on this trial, the maximum tolerated and recommended Phase II doses for PRX administered on this schedule are 190 and 150 mg/m2, respectively. PRX plasma elimination was rapid and best fit by a two-compartment model for 17 of 24 patients receiving greater than or equal to 90 mg/m2. The plasma clearance rate was 1290 +/- 484 ml/min (720 +/- 210 ml/min/m2) and did not vary with dose. The t1/2 alpha was 2.9 +/- 5.3 (SD) min and the t1/2 beta was 18.7 +/- 36.5 min. Area under the concentration versus time curve (AUC) at the maximal tolerated dose (MTD) was 435 mumol.min/liter, 40% higher than the predicted AUC from preclinical testing. The percentage decrease in WBC and neutrophil count was correlated with the AUC. The potential advantage of pharmacology-based dose escalation was limited in this study by assay insensitivity, extremely rapid plasma elimination, and the proximity of the starting dose to the dose where the target AUC was achieved and standard dose escalations were to begin. Consequently, there was no reduction in the number of dose escalations required to define the maximum tolerated dose. However, the practical aspects of this approach have been established and its use is recommended for further trials where detailed preclinical pharmacological studies are available.

Adult↗
PubMed1990

Bryostatin 1, a unique biologic response modifier: anti-leukemic activity in vitro.

Bryostatin 1, a macrocyclic lactone isolated from the marine bryozoan Bugula neritina, has demonstrated both antineoplastic activity against the murine P388 leukemia line in vivo and stimulatory activity against mouse and human hematopoietic progenitors. We studied the effects of bryostatin 1 on the growth of human leukemias in vitro. Bryostatin 1 inhibited 1 to 4 logs of clonogenic leukemia cell growth from three of four leukemia cell lines. Bryostatin 1 also inhibited, by at least 1 log, the proliferation of clonogenic acute nonlymphocytic leukemia (ANLL) cells from 10 to 12 patients with newly diagnosed or relapsed ANLL. Maximal inhibition of leukemic growth occurred at 10(-9) to 10(-7) mol/L bryostatin 1. Interestingly, bryostatin 1 also inhibited the growth of hematopoietic progenitors from eight patients with myelodysplastic syndromes (MDS). Leukemia cells exposed to bryostatin 1 for up to 96 hours and then washed, demonstrated no substantial inhibition of clonogenic growth, indicating that the anti-leukemic effect of bryostatin 1 is cytostatic. The phorbol ester 12-0-tetradecanoylphorbol-13-acetate (TPA) produced more potent inhibition of clonogenic leukemia growth, and this inhibition was blocked by bryostatin 1. Thus, the anti-leukemic activity of bryostatin 1 may be mediated through activation of protein kinase C. Bryostatin 1 inhibits clonogenic leukemia cells at concentrations that stimulate normal hematopoietic progenitors. The differential effects of bryostatin 1 on normal and abnormal hematopoiesis suggest that bryostatin 1 may have value in the treatment of leukemias and MDS.

Antineoplastic Agents↗
PubMed1990

Development of polyploidization in taxol-resistant human leukemia cells in vitro.

The effects of taxol on antitubulin immunofluorescent staining patterns, cellular DNA content, and labeling with [3H]thymidine were measured for the taxol-sensitive HL60 and taxol-resistant K562 cell lines after exposures for 0, 4, 12, and 24 h. Taxol caused a relative increase in the fraction of 4C interphase and metaphase cells in both lines although the 4C interphase accumulation was greater for the resistant K562 line. Of the cells with S-phase DNA content, taxol-treated HL60 cells were less likely to incorporate [3H]thymidine than taxol-treated K562 cells. However, a decrease in percentage of S-phase labeling for both lines relative to control cells was seen. Finally, taxol induced the development of polyploid cells (cells with DNA contents greater than that of the 4C G2-M peak) in the relatively taxol-resistant K562 cells, an effect not seen in the relatively taxol-sensitive HL60 line. After 24 h of taxol exposure 70% of all K562 cells were polyploid while only 8% of the HL60 cells were polyploid. The capacity of K562 cells to generate polyploidy in response to taxol correlated with taxol resistance by previous assay and may be a useful indicator of drug resistance.

Alkaloids↗
PubMed1989

Taxol: a unique antineoplastic agent with significant activity in advanced ovarian epithelial neoplasms.

STUDY OBJECTIVE: To assess the activity of taxol in patients with advanced, progressive, and drug-refractory ovarian cancer and to delineate more clearly the toxicity of taxol in this patient population. DESIGN: Nonrandomized, prospective phase II trial. PATIENTS: Forty-seven patients with drug-refractory epithelial ovarian cancer who had one or more lesions measurable in perpendicular diameters. Of these patients, 45 were evaluable for toxicity and 40 were evaluable for response. INTERVENTIONS: PATIENTS were treated every 22 days with varying doses of taxol (110 to 250 mg/m2 body surface) given as a 24-hour infusion with subsequent doses based on adverse effects. A premedication regimen was used to avoid acute hypersensitivity reactions. MEASUREMENTS AND MAIN RESULTS: Twelve patients (30%; CI, 16% to 44%) responded to taxol for periods lasting from 3 to 15 months. The dose-limiting toxicity was myelosuppression with leukocytes affected more severely and commonly than thrombocytes or reticulocytes. Leukopenia was usually brief in duration but was associated with sepsis in 3 cases (2 fatal). Other adverse effects included myalgias, arthralgias, alopecia, diarrhea, nausea, vomiting, mucositis, and peripheral neuropathy. Rare cases of cardiac and central neurotoxicity were also noted. CONCLUSIONS: Taxol is an active agent in drug-refractory ovarian cancer and deserves further study in combination with other active drugs in previously untreated patients with advanced ovarian cancer.

Alkaloids↗
PubMed1989

Phase I and pharmacodynamic study of taxol in refractory acute leukemias.

Taxol, a novel antimicrotubule agent that enhances tubulin polymerization and microtubule stability, was administered to adults with refractory leukemias as a 24-h i.v. infusion in a Phase I study. The primary objectives were to determine the maximum tolerated dose of taxol administered on this schedule to patients with acute leukemias and describe the nonhematological toxicities which became dose limiting. The starting dose, 200 mg/m2, was based on the maximum tolerated dose in solid tumor trials, in which myelosuppression precluded dose escalation. Seventeen patients received 28 evaluable courses at 200, 250, 315, and 390 mg/m2. Severe mucositis limited further dose escalation. Other nonhematological effects included peripheral neuropathy, alopecia, myalgias, arthralgias, nausea, vomiting, diarrhea, and an acute pulmonary reaction that was presumptively due to taxol's Cremophor vehicle. Mean peak taxol plasma concentrations at all dose levels were in the range of concentrations that were previously demonstrated to induce microtubule bundles, a morphological effect associated with cytotoxicity, in leukemia cells in vitro. Pretreatment blasts from 12 patients were incubated with taxol ex vivo. Taxol-induced microtubule bundles were apparent in the blasts of eight patients who also had cytoreduction of tumor, and sensitivity to bundle formation was related to the magnitude of antitumor activity. In contrast, taxol did not induce microtubule bundles ex vivo in the blasts of the other four total nonresponders. Based on this study, the maximum tolerated doses and recommended Phase II doses for taxol, limited by nonhematological toxicity and administered as a 24-h i.v. infusion to patients with refractory leukemias, are 390 and 315 mg/m2. Phase II trials at these myelosuppressive doses are required to determine taxol's activity in the treatment of leukemias. In addition, further evaluation of microtubule bundle formation ex vivo in Phase II studies is necessary to determine the ultimate utility of this assay in assessing tumor sensitivity to taxol.

Acute Disease↗
PubMed1989

Phase I trial of trimetrexate glucuronate on a five-day bolus schedule: clinical pharmacology and pharmacodynamics.

Trimetrexate glucuronate (TMTX), a nonclassical folate antagonist, has been evaluated clinically on several schedules. We have studied TMTX administered as an iv bolus for 5 consecutive days every 3 weeks in 35 patients with advanced solid tumors. Drug was given at doses ranging from 7.6 to 18.8 mg/m2. The maximal tolerated dose was 13.1 mg/m2 per day x 5 for patients without prior myelotoxic treatment and 7.6 mg/m2 per day x 5 for previously treated patients. Because of wide individual differences in drug tolerance, dose escalation in 25% increments is recommended for patients not experiencing toxic effects. The dose-limiting toxicity was neutropenia. Rash and mucositis were also significant. TMTX concentrations were measured 1 and 24 hours after each dose, and the data were fit by use of a one-compartment pharmacokinetic model. With this simplified sampling and modeling scheme, the mean total body clearance (+/- SD) of trimetrexate was 31 +/- 20 mL/min per m2 and the volume of distribution was 13 +/- 7 L/m2. Mean plasma concentrations 1 hour after a dose were 1.12, 2.43, 3.33, and 3.25 mumol/L at 7.6, 9.1, 10.9, and 13.1 mg/m2, respectively. The mean TMTX concentration (+/- SD) 24 hours after a dose was 114 +/- 87 nmol/L. The mean area under the concentration-versus-time curve at 13.1 mg/m2 was 2,266 mumol.min/L. The drug concentration 1 hour after the first dose and the area under the concentration-versus-time curve were highly correlated with leukopenia and thrombocytopenia (r = .6 and .65 and P = .0007 and .0001, respectively). The maximal tolerated dose on the daily x 5 schedule was 30% of the dose tolerated on an iv bolus schedule. The choice of drug schedule for clinical trials when murine and human pharmacokinetics differ is discussed. Phase II trials are under way with both the iv bolus and the daily x 5 schedules.

Adult↗
PubMed1989

Assessment of N-methylformamide (NMF) administered orally on a three times weekly schedule: a phase I study.

This phase I study was conducted to reevaluate the dose-limiting toxicities, maximum tolerated (MTD) and recommended phase II doses of oral NMF administered on a three times weekly schedule for 4 out of every 6 weeks. This schedule was based on the observation that prolonged administration of NMF was associated with the most efficacious antitumor activity in preclinical studies. Phase II trials that employed a starting dose of 800 mg/m2, determined in a previous phase I trial, were suspended because of frequent and severe toxicities. In the current study, a symptom complex characterized by nausea, vomiting, and malaise was the dose-limiting toxicity of oral NMF administered on this schedule. Other toxicities included hepatic enzyme elevations, mild myelosuppression, and worsening of preexistent toxic peripheral neuropathies. Of interest, three patients who were asymptomatic prior to treatment, rapidly developed symptoms of increased intracranial pressure after starting NMF; and, computerized tomographic brain scans revealed metastatic tumors with significant peritumoral edema. NMF was well tolerated at 600 mg/m2, however, an abrupt increase in toxicity resulted when the dose was increased to 700 mg/m2. Although NMF peak plasma concentrations (Cmax) and areas under the plasma disappearance curves (AUC) differed between the 600 and 700 mg/m2 dose levels, these differences were not striking, and similar NMF plasma concentrations and exposures were well tolerated during intravenous trials. Based on this study, the recommended phase II dose for oral NMF administered three times weekly for 4 of 6 weeks was 600 mg/m2.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1989

Demonstration of the cell cycle positions of taxol-induced "asters" and "bundles" by sequential measurements of tubulin immunofluorescence, DNA content, and autoradiographic labeling of taxol-sensitive and -resistant cells.

We used reliable and relatively inexpensive equipment to make sequential sets of measurements of antitubulin immunofluorescence, Feulgen staining, and autoradiography on the same cells. This was done to evaluate tubulin conformations, DNA content, and [3H]-thymidine incorporation in cell lines sensitive (HL60) and resistant (K562) to the novel anti-tubulin chemotherapeutic agent taxol. Numbers of cells with microtubule bundles have been found to correlate with sensitivity to taxol by clonogenic assay for several leukemic cell lines. We have found that cells with "asters" produced by taxol exposure are in mitosis and that cells with taxol-induced "bundles" are in G0/G1, S, and G2 phases. We further found that S-phase cells with microtubule bundles in both sensitive (HL60) and resistant (K562) cell lines were able to incorporate [3H]-thymidine after 4-hr exposure to taxol. As microtubule bundles and asters occur in cells of the same cell cycle phases in both lines, we conclude that the greater frequency of cells with microtubule bundles reported for sensitive cells after taxol treatment cannot result from drug exclusion nor from different effects of the drug on cell microtubules in these two leukemic lines.

Alkaloids↗
PubMed1988

Clinical and pharmacologic reappraisal of dichloromethotrexate.

Dichloromethotrexate (DCMTX) has been the subject of sporadic clinical development for the last 30 years. Although DCMTX was developed in hopes of discovering a more potent antifolate, the potential pharmacologic and toxicologic advantages of the analog have become of greater interest. This phase I and pharmacokinetic trial of DCMTX given on days 1, 8, and 15 every 28 days was undertaken to test these potential advantages. The maximally tolerated dose on this schedule was 980 mg/m2. Hepatic toxicity was dose limiting. Malaise, myelosuppression, and mucositis were also major toxic effects. The recommended dose for subsequent phase II studies of DCMTX administered on this schedule is 785 mg/m2 with a reduction to 625 mg/m2 for patients with a poor performance status or extensive prior therapy. Plasma disappearance curves for most patients were biphasic or triphasic, although several demonstrated more complex kinetic patterns that suggested significant enterohepatic circulation. The magnitude of the area under the plasma disappearance curve was related to the severity of DCMTX-induced hepatotoxicity. The elimination kinetics were linear, with a mean plasma clearance of 294 mL/min (range, 128-715). The pharmacokinetic behavior of DCMTX does not support its use over methotrexate in regional perfusion. DCMTX's primarily nonrenal elimination suggests that it may have an advantage over methotrexate when combined with nephrotoxic drugs such as cisplatin. However, there is little reason to commit major resources to further evaluation of DCMTX unless significant advantages in antineoplastic activity are identified.

Adult↗