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Biomedical subjects

M R Cooper

Publications and source records attributed to M R Cooper.

At least 37 records · Page 2Linked to original sources
PubMed1998

Phase II study of suramin plus aminoglutethimide in two cohorts of patients with androgen-independent prostate cancer: simultaneous antiandrogen withdrawal and prior antiandrogen withdrawal.

Management of prostate cancer progression after failure of initial hormonal therapy is controversial. Recently, the activity of the simple discontinuation of antiandrogen therapy has been established by several groups, as well as the enhanced activity when combined with adrenal suppression (i.e., aminoglutethimide and hydrocortisone). Furthermore, suramin has generated considerable interest following reports of response rates ranging from 17 to 70%. More recently, suramin response rates of 18 and 22% have been reported when the potential confounding variables of flutamide withdrawal and hydrocortisone were prospectively controlled. On the basis of the activity of combining aminoglutethimide with flutamide withdrawal, we designed a protocol in which suramin was combined with aminoglutethimide in two cohorts of patients (those with simultaneous antiandrogen withdrawal compared to those who had previously discontinued antiandrogen therapy). Eighty-one evaluable patients were enrolled in this study between June 1992 and November 1994. Patients were a priori divided into two cohorts, those receiving prior antiandrogen withdrawal (n = 56) and those receiving simultaneous antiandrogen withdrawal (n = 25) at the time the patients were enrolled into the trial. For the group that discontinued antiandrogen prior to enrolling in therapy, the partial response rate (> 50% decline in PSA for > 4 weeks) was 14.2%, whereas the partial response was 44% for those patients who discontinued their antiandrogen at the time of starting suramin and aminoglutethimide. The median time to progression was 3.9 months in patients failing prior antiandrogen withdrawal and 5.5 months in those patients having concomitant antiandrogen withdrawal (P = 0.36 for the overall difference). The progression-free survival estimate at 1 year for patients having prior antiandrogen withdrawal was 19.8% [95% confidence interval (CI), 11-32.9%]. For those patients who experienced antiandrogen withdrawal simultaneous with the treatment, the progression-free survival estimates at 1 and 2 years were 27.1 (95% CI, 13.2-47.6%) and 4.5% (95% CI, 0.8-21.6%). The median survival time for those patients having prior antiandrogen withdrawal was 14.2 months, whereas the median survival was 21.9 months for those having concomitant antiandrogen withdrawal (P = 0.029 for the overall difference). In conclusion, the partial response rate of 44% for those who had concomitant flutamide withdrawal with adrenal suppression was consistent with that of other reports using a similar maneuver. Although this study was not randomized and thus we should not over-interpret the results, flutamide withdrawal plus adrenal suppression appears to have greater activity than flutamide withdrawal alone. Furthermore, these data suggest that suramin adds little to the response rate observed for other adrenal suppressive agents in the presence of antiandrogen withdrawal. This interpretation is in agreement with those studies controlling for adrenal suppression and flutamide withdrawal prior to suramin administration, which noted modest activity of short duration. Given that antiandrogen withdrawal is now accepted as an active maneuver for a subset of patients progressing after maximum androgen blockade, we propose that future trials attempting to maximize response rates incorporate this maneuver whenever possible into prospectively designed regimens.

Adult↗
PubMed1997

Phase II trial of docetaxel in non-Hodgkin's lymphomas: a study of the Cancer and Leukemia Group B.

PURPOSE: To evaluate the new anticancer agent, docetaxel, with a novel mechanism of action in patients with non-Hodgkin's lymphoma International Working Formulation (IWF) A through H, to determine the response rate by histologic group and the toxicities of this agent in this population. PATIENTS AND METHODS: Sixty-eight patients previously treated for non-Hodgkin's lymphoma with two prior cytotoxic regimens for low-grade and one prior regimen for intermediate-grade lymphoma were entered onto this phase II trial. Central pathologic review was required. Twenty-four IWF A to C and 31 IWF D to H patients with normal hepatic and renal function, performance status (PS) 0 to 2, and adequate hematologic function were eligible. Patients received docetaxel 100 mg/m2 intravenously over 1 hour without corticosteroid premedications every 3 weeks with weekly hematologic monitoring, and tumor assessment every 3 weeks. For grade 3 or 4 hematologic toxicity, the docetaxel dosage was lowered to 75 mg/m2. Patients received a maximum of six cycles of therapy. RESULTS: The major response rate was 13% (95% confidence limits, 3% to 32%) for IWF A to C and 16% (95% confidence limits, 5% to 34%) for IWF D to H; response durations ranged from 1.4 to 20 months. Time to response ranged from 1.3 to 2.8 months. Patients refractory to previous chemotherapy were less apt to respond to docetaxel, but the differences were not statistically different in this small sample size. Twelve percent of IWF A to C and 6% of IWF D to H patients discontinued treatment because of toxicity. The major toxicity was granulocytopenia (grade 3 to 4), which occurred in virtually all patients during the first course of therapy. CONCLUSION: This study confirms that docetaxel has limited but definite activity in patients with non-Hodgkin's lymphoma and suggests that the previously reported responses with taxanes can not be attributed solely to the use of corticosteroid premedications.

Adult↗
PubMed1997

Phase II trial of suramin, leuprolide, and flutamide in previously untreated metastatic prostate cancer.

PURPOSE: To assess the efficacy and toxicity of suramin, hydrocortisone, leuprolide, and flutamide in previously untreated metastatic prostate cancer. PATIENTS AND METHODS: Patients with stage D2 and poor-prognosis stage D1 prostate cancer were given suramin on a pharmacokinetically derived dosing schedule to maintain suramin concentrations between 175 and 300 micrograms/mL. Additionally, all patients received flutamide 250 mg orally three times daily, initiated on day 1 and continued until disease progression; depot leuprolide 7.5 mg intramuscularly begun on day 5 and repeated every 4 weeks indefinitely; and replacement doses of hydrocortisone. RESULTS: Fifty patients were entered onto the study: 48 with stage D2 and two with stage D1 disease. The median age was 59 years (range, 42 to 79) and 31 patients had a Karnofsky performance status (KPS) of 100%. Forty-five patients had bone metastases and 25 had measurable soft tissue disease. Forty-one (82%) had severe disease. The overall response rate in 49 assessable patients was three complete responses (CRs) and 30 partial responses (PRs) for an overall response rate of 67%. Eighteen patients have died. The median survival time has not been reached, with a median potential follow-up duration of 44 months. Grade 3 to 4 toxicity was seen in 38% of patients and was predominantly hematologic and reversible. CONCLUSION: The high response rate and prolonged survival in a poor-prognosis group of patients with metastatic prostate cancer warrant a phase III randomized comparison of this regimen versus hormonal therapy alone. Toxicity was moderate and reversible.

Adult↗
PubMed1997

9-Aminocamptothecin: a topoisomerase I inhibitor with preclinical activity in prostate cancer.

9-Aminocamptothecin (9-AC) is a topoisomerase I inhibitor currently being developed as an antineoplastic agent. The aim of these preclinical studies was to assess the activity of 9-AC against prostate cancer, a malignancy notoriously insensitive to most cytotoxic agents in the clinic. The activity of 9-AC was first tested in vitro against one hormone-sensitive (LNCaP) and three hormone-resistant (PC-3, PC-3M, and DU145) human prostate cancer cell lines. After 96 h of drug exposure, concentrations required to inhibit cell viability to 50% of control values (IC50s) were 34.1, 10, 6.5, and 8.9 nm for PC-3, PC-3M, DU145, and LNCaP, respectively. Because 9-AC is known to undergo rapid hydrolysis, we assayed lactone levels in tissue culture medium over 24 h and found that the half-life was 20 min, with only 15%of the drug remaining as lactone at steady state. Consequently, the IC50s calculated from a single dose of the drug may represent overestimates. Subsequently, we tested the activity of a colloidal dispersion formulation of 9-AC against PC-3 implanted into flanks of nude mice. 9-AC was given for a total of 3 weeks by daily oral gavage (excluding weekends) or by twice weekly s.c. injections. 9-AC inhibited tumor growth at the lowest oral dose (0.35 mg/kg/day), whereas higher oral doses (0.75 and 1 mg/kg/day) and s.c. administration (4 mg/kg/week) caused tumor regression. 9-AC was well tolerated at all doses, with no toxic death or weight loss of more than 10% observed in any group. Finally, we considered that the activity of 9-AC seen in the mouse xenograft model might be explained, in part, by the relatively acidic tumor microenvironment, which would favor the formation of the more potent lactone. Simultaneous determination of plasma and tumor 9-AC lactone concentrations confirmed this hypothesis. Taken together, these studies suggest that 9-AC should be submitted for clinical trials in patients with prostate cancer.

Animals↗
PubMed1996

A phase I/II study of continuous infusion suramin in patients with hormone-refractory prostate cancer: toxicity and response.

INTRODUCTION: Suramin is a synthetic polysulfonated naphthylurea which has been used for the treatment of African trypanosomiasis and onchocerciasis, but since the mid-1980s has received attention as a possible antiretroviral and antineoplastic agent. OBJECTIVE: This clinical trial of suramin was undertaken as a phase I/II study in patients with hormone-refractory prostate cancer, with the hypothesis that the intensity of therapy with suramin could be increased significantly if measures were undertaken to maintain the plasma concentrations of the drug under 300 microg/ml. METHODS: We report the clinical results of this trial, wherein patients were treated at three different targeted plasma suramin concentrations (275, 215 and 175 microg/ml) for varying periods of time (2, 4 or 8 weeks), with delivery of the drug by continuous intravenous infusion. RESULTS: The major toxicity observed in this trial was neurologic, consisting of a motor and sensory peripheral neuropathy that resulted in both paresis and paralysis of the limbs. Nearly all of this severe (CTEP grade III, IV) neurologic toxicity was observed in the patients treated at a plasma suramin concentration of 275 microg/ml for 4 or more weeks. A single patient treated at 215 microg/ml for 8 weeks developed moderate (CTEP grade III) proximal lower extremity weakness, and no patient treated at 175 microg/ml developed this toxicity. The second most common toxicity observed was infection of the central venous catheter. The overall response rate for all of the evaluable patients was 17% (13 of 75 patients). In addition, prostate-specific antigen (PSA)-defined responses were observed in six patients receiving therapy at 175 microg/ml, but these responses were confounded by cessation of therapy with flutamide during suramin treatment. CONCLUSIONS: In summary, although plasma suramin concentrations were maintained below 300 microg/ml, neurologic toxicity nonetheless occurred with high frequency in patients treated at 275 microg/ml for 4 or more weeks. Therapy at 215 and 175 microg/ml was in general well tolerated, but central venous catheter-related infection, as well as the inconvenience and expense of continuous infusional therapy, make this method of drug delivery impractical. Only moderate antitumor activity was observed during this trial, but it is possible that both continuation of flutamide and flutamide withdrawal during suramin therapy confounded the assessment of suramin's activity in hormone-refractory prostate cancer.

Aged↗
PubMed1996

A phase I study of pentosan polysulfate sodium in patients with advanced malignancies.

BACKGROUND: Pentosan polysulfate (xylanopolyhydrogensulfate) is a semi-synthetic sulfated heparinoid polysaccharide which has been used as an anticoagulant for nearly thirty years in Europe. It antagonizes the binding of bFGF to cell surface receptors and has thus been evaluated for antitumor activity in several animal models and human tumor cell lines. In two angiogenic models pentosan has been shown to inhibit bFGF stimulation of angiogenesis. Previous clinical studies have determined the coagulation effects of pentosan to be the dose-limiting toxicity. PATIENTS AND METHODS: We conducted a phase I study designed to define the duration-limiting toxicity associated with progressive prolongation of a continuous intravenous infusion (three, five, and eight weeks). This study was not designed to escalate the dose of pentosan beyond that required to maintain the activated partial thromboplastin time (aPTT) between 1.8 and 2.2 times the baseline value. RESULTS: Thirteen patients with advanced stage metastatic cancer were enrolled (median age 50 years, range 34 to 61 years). Four patients were treated in cohort #1 (three weeks of infusional therapy), five patients were treated in cohort #2 (five weeks of therapy), and four patients in cohort #3 (eight weeks of therapy). All patients experienced a progressive prolongation of their aPTT and PT. Furthermore, all patients experienced at least grade I thrombocytopenia. Other complications were, in general, mild. One patient developed grade III liver abnormalities while receiving the eight-week infusion and another patient developed grade IV thrombocytopenia while receiving the same regimen. One patient with colon cancer had stable disease for 24 weeks, while the remaining 12 patients had no objective evidence of response. CONCLUSION: Pentosan was well tolerated when doses were adjusted for aPTT prolongations and a five-week cycle appeared to be the maximum tolerated duration of infusion (initially 4 mg/kg/day). One patient had stable disease, but there was no objective tumor response noted in the remaining 12 patients.

Adult↗
PubMed1996

Clinical and experimental evidence of inhibition of testosterone production by suramin.

The effect of suramin on testosterone production was evaluated in cancer patients, adult male rats, rat Leydig cells, and NCI-H295 human adrenal cancer cells. Testosterone plasma levels markedly decreased in 14 patients receiving suramin as a therapy for refractory cancer, and in 8 of them, the plasma LH and/or FSH levels increased beyond the normal range. The hCG stimulation test (5000 IU, im) was performed in 8 patients and induced an average 2.1-fold increase in testosterone levels over baseline values. Testicular histology after suramin treatment was available in 1 patient who died of progressive disease; this revealed atrophy of seminiferous tubules and reduced Leydig cells in the interstitium. A significant reduction in plasma testosterone was also observed in rats given 18 mg/kg suramin, ip, twice weekly for 8 weeks, whereas plasma LH and FSH levels did not change significantly. Cytohistochemistry of testes from suramin-treated rats showed a reduced number of 3 beta-hydroxysteroid dehydrogenase-positive cells within the interstitium compared to controls, and light microscopy revealed severe impairment of spermatogenesis. Suramin inhibited the production of testosterone by isolated rat Leydig cells as well as the conversion of pregnenolone to progesterone by the 3 beta-hydroxysteroid dehydrogenase enzyme extracted from rat testes, with 50% inhibitory concentrations (IC50 values) of 108.2 and 87.5 micrograms/mL, respectively. Furthermore, suramin reduced the release of testosterone into the culture medium of NCI-H295 adrenal cancer cells with IC50 values of 91.2 and 83.9 micrograms/mL after 6 and 12 days, respectively. These data provide the first evidence in patients that suramin treatment produces a marked reduction in the circulating levels of testosterone, a result that was also obtained in experimental models.

3-Hydroxysteroid Dehydrogenases↗
PubMed1996

Vincristine degradation by serum from leukemic patients: role of myeloperoxidase.

Myeloperoxidase (MPO) has been shown to catalyze the in vitro degradation of vincristine (VCR). Given that MPO is a lysosomal enzyme that can be released into the circulation by both normal activated and leukemic myeloid cells, we investigated the possibility that sera from patients with acute myeloblastic leukemia (AML) might exhibit an increased capacity to degrade VCR. 31 serum samples (23 from patients with acute myeloblastic leukemia and 8 from patients with other conditions) were analyzed after incubation with ((3)H)VCR by using HPLC. Sera from patients with AML demonstrated an increased ability to breakdown VCR when compared to either normal sera or to sera from patients with lymphoid leukemias. VCR degradation was significantly increased by adding hydrogen peroxide, an electron donor for MPO, to the sera and was almost completely inhibited by adding 1 mM acetaminophen, an inhibitor of MPO. VCR peroxidation in the presence of hydrogen peroxide correlated both with the number of leukemic blasts in the circulation at the time the sera were obtained and with serum MPO concentrations determined by an immunoassay. These data suggest that the inactivity of VCR in AML may be due in part to its rapid peroxidation to inactive species by the MPO of leukemic myeloblasts.

Acetaminophen↗
PubMed1996

The polyp prevention trial I: rationale, design, recruitment, and baseline participant characteristics.

The Polyp Prevention Trial (PPT) is a multicenter randomized controlled trial examining the effect of a low-fat (20% of total energy intake), high-fiber (18 g/1000 kcal), high-vegetable and -fruit (5-8 daily servings) dietary pattern on the recurrence of adenomatous polyps of the large bowel, precursors of most colorectal malignancies. Eligibility criteria include one or more adenomas removed within 6 months of randomization; complete nonsurgical polyp removal and complete colonic examination to the cecum at the qualifying colonoscopy: age 35 years of more; no history of colorectal cancer, inflammatory bowel disease, or large bowel resection; and satisfactory completion of a food frequency questionnaire and 4-day food record. Of approximately 38,277 potential participants with one or more polyps recently resected, investigators at eight clinical centers randomized 2,079 (5.4%; 1,037 in the intervention and 1,042 in the control arm) between June 1991 and January 1994, making the PPT the largest adenoma recurrence trial ever conducted. Of PPT participants, 35% are women and 10% are minorities. At study entry, participants averaged 61.4 years of age; 14% of them smoked, and 22% used aspirin. At the baseline colonoscopy, 35% of participants had two or more adenomas, and 29% had at least one large (> of = 1 cm) adenoma. Demographic, behavioral, dietary, and clinical characteristics are comparable across the two study arms. Participants have repeat colonoscopies after 1 (T(1)) and 4 (T(4)) years of follow-up. The primary end point is adenoma recurrence; secondary end points include number, size, location, and histology of adenomas. All resected lesions are reviewed centrally by gastrointestinal pathologists. The trial provides 90% power to detect a reduction of 24% in the annual adenoma recurrence rate. The primary analytic period, on which sample size calculations were based is 3 years (T(1) to T(4)), which permits a 1-year lag time for the intervention to work and allows a more definitive clearing of lesions at T(1), given that at least 10-15% of polyps may be missed at baseline. The final (T(4)) colonoscopies are expected to be completed in early 1998.

Adenoma↗
PubMed1996

Phase I study of lovastatin, an inhibitor of the mevalonate pathway, in patients with cancer.

Lovastatin, an inhibitor of the enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase (the major regulatory enzyme of the mevalonate pathway of cholesterol synthesis), displays antitumor activity in experimental models. We therefore conducted a Phase I trial to characterize the tolerability of lovastatin administered at progressively higher doses to cancer patients. From January 1992 to July 1994, 88 patients with solid tumors (median age, 57 +/- 14 years) were treated p.o. with 7-day courses of lovastatin given monthly at doses ranging from 2 to 45 mg/kg/day. The inhibitory effects of lovastatin were monitored through serum concentrations of cholesterol and ubiquinone, two end products of the mevalonate pathway. Concentrations of lovastatin and its active metabolites were also determined, by bioassay, in the serum of selected patients. Cyclical treatment with lovastatin markedly inhibited the mevalonate pathway, evidenced by reductions in both cholesterol and ubiquinone concentrations, by up to 43 and 49% of pretreatment values, respectively. The effect was transient, however, and its magnitude appeared to be dose independent. Drug concentrations reached up to 3.9 micrometer and were in the range associated with antiproliferative activity in vitro. Myopathy was the dose-limiting toxicity. Other toxicities included nausea, diarrhea, and fatigue. Treatment with ubiquinone was associated with reversal of lovastatin-induced myopathy, and its prophylactic administration prevented the development of this toxicity in a cohort of 56 patients. One minor response was documented in a patient with recurrent high-grade glioma. Lovastatin given p.o. at a dose of 25 mg/kg daily for 7 consecutive days is well tolerated. The occurrence of myopathy, the dose-limiting toxicity, can be prevented by ubiquinone supplementation. To improve on the transient inhibitory activity of this dosing regimen on the mevalonate pathway, alternative schedules based on uninterrupted administration of lovastatin should also be studied.

Adult↗
PubMed1995

Antitumor activity of suramin in hormone-refractory prostate cancer controlling for hydrocortisone treatment and flutamide withdrawal as potentially confounding variables.

BACKGROUND: A prospective Phase II clinical trial was conducted to assess the clinical activity of a pharmacokinetically guided suramin regimen in patients who had documented progression of metastatic prostate cancer after hydrocortisone plus antecedent or simultaneous withdrawal of flutamide. METHODS: Fifty-four patients whose disease had progressed after castration and flutamide administration were enrolled on this trial. The study was divided into two parts. Initially, 52 patients received hydrocortisone (30 mg/day) and for those patients receiving flutamide, at study entry (34 patients) flutamide was simultaneously discontinued. Forty-three patients whose disease progressed on hydrocortisone received suramin for 6-8 weeks. Six patients who progressed on hydrocortisone became ineligible for suramin due to clinical deterioration, four patients are still responding to hydrocortisone at more than 1 year, and one patient elected to postpone initiation of suramin. Suramin was given as intermittent infusions at fixed doses on days 1-5 and thereafter dosing was guided by adaptive control with feedback to maintain plasma suramin concentrations between 300-175 micrograms/ml. Antitumor activity was assessed by prostate specific antigen (PSA) decline and soft-tissue disease response. RESULTS: Ten patients (19%; 95% CI, 9.6%-32.5%) responded to hydrocortisone therapy with either a 50% or greater PSA decline for at least 4 weeks (9 patients) and/or a partial response of measurable soft-tissue disease (2 patients). Five of these patients (10%) demonstrated a 80% or greater PSA decline. All responders to hydrocortisone had simultaneous flutamide withdrawal, and had been receiving flutamide as part of initial combined androgen blockade. Seven of 37 evaluable patients (19%; 95% CI, 8.0%-35.2%) responded to suramin with a 50% or greater decline in PSA for 4 weeks or longer. One patient (3%) had a 80% or greater decline in PSA. There were no soft-tissue disease responses to suramin. The median time to progression was 1.9 months for hydrocortisone therapy and 2.6 months for suramin therapy. The median survival for all patients was 14.6 months. CONCLUSION: Suramin has antitumor activity in metastatic prostate carcinoma independent of the therapeutic effect of hydrocortisone administration or flutamide withdrawal. The role of prior flutamide withdrawal and hydrocortisone replacement should be taken into account in future studies of suramin.

Aged↗
PubMed1995

Phase I study of phenylacetate administered twice daily to patients with cancer.

BACKGROUND: The growth-inhibiting and differentiating effects of sodium phenylacetate against hematopoietic and solid tumor cell lines has aroused clinical interest in its use as an anticancer drug. In an earlier Phase I trial of phenylacetate aimed at maintaining serum drug concentrations in the range that proved active in vitro (> 250 micrograms/ml) for 2 consecutive weeks, infusion rates approached the maximum velocity of drug elimination and commonly resulted in drug accumulation and reversible dose-limiting neurologic toxicity. In this study, the authors described the nonlinear pharmacokinetics, metabolism, toxicity, and clinical activity of phenylacetate. METHODS: The treatment regimen of this Phase I study was designed to expose patients intermittently to drug concentrations exceeding 250 micrograms/ml and to allow time for drug elimination to occur between doses to minimize accumulation. Sodium phenylacetate was administered as a 1-hour infusion twice daily (8 a.m., 5 p.m.) at two dose levels of 125 and 150 mg/kg for a 2-week period. Therapy was repeated at 4-week intervals for patients who did not experience dose-limiting toxicity or disease progression. RESULTS: Eighteen patients (4 of whom previously were treated with phenylacetate by continuous intravenous infusion) received 27 cycles of therapy. Detailed pharmacokinetic studies for eight patients indicated that phenylacetate induced its own clearance by a factor of 27% in a 2-week period. Dose-limiting toxicity, consisting of reversible central nervous system depression, was observed for three patients at the second dose level. One patient with refractory malignant glioma had a partial response, and one with hormone-independent prostate cancer achieved a 50% decline in prostate specific antigen level, which was maintained for 1 month. CONCLUSIONS: Phenylacetate administered at a dose of 125 mg/kg twice daily for 2 consecutive weeks is well tolerated. High grade gliomas and advanced prostate cancer are reasonable targets for Phase II clinical trials.

Adult↗
PubMed1995

A phase I study of the somatostatin analogue somatuline in patients with metastatic hormone-refractory prostate cancer.

BACKGROUND: Somatuline, a somatostatin analogue, has proven to be effective in several animal models of prostate cancer. Preliminary clinical studies also have suggested antitumor activity in patients with prostate cancer. The authors conducted a dose-escalation trial of 25 patients with metastatic hormone-refractory prostate cancer. METHODS: Dosages of 4, 7, 10, 13, 18, and 24 mg/day were administered by continuous intravenous infusion for at least 28 days. RESULTS: Plasma levels of insulin-like growth factor-I (IGF-I), but not those of IGF-II, declined modestly during therapy. Toxicities included grade I diarrhea, bloating, infection, nausea, and flatus. The gastrointestinal side effects were typically self-limiting and occurred during the initial portion of treatment cycles. In addition, three patients experienced grade II catheter-related infections. No clinical response was noted by either radiographic or tumor marker criteria. The maximally tolerated dose of somatuline was not determined. CONCLUSION: A continuous intravenous infusion of 24 mg/day of somatuline is well tolerated and could be evaluated in other types of cancer or possibly in less advanced prostate cancer, but no clinical activity was noted at this dose in patients with advanced metastatic hormone-refractory prostate cancer.

Aged↗
PubMed1995

Pharmacologic variables associated with the development of neurologic toxicity in patients treated with suramin.

PURPOSE: To describe pharmacologic variables correlated with the development of neurologic toxicity in patients treated with suramin. METHODS: Eighty-one patients were treated with suramin in a phase I study. The rate of drug infusion was continuously adjusted to maintain a preassigned plasma suramin concentration (175, 215, or 275 micrograms/mL) for a fixed duration (2 to 8 weeks). RESULTS: Eight patients developed grade III/IV neurologic motor impairment (predominantly motor axonal polyneuropathy). All were treated at the 275-micrograms/mL concentration. One patient treated at the 215-micrograms/mL concentration developed grade II motor dysfunction. In addition, seven of nine patients had sensory symptoms. Pharmacologic variables associated with the development of polyneuropathy included total cumulative suramin dose, duration of exposure to plasma concentrations greater than 200 micrograms/mL, and area under the curve (AUC) greater than 200 micrograms/mL. CONCLUSION: Significant neurologic toxicity can result from therapy with suramin, even when dosing is designed to avoid exposure to plasma concentrations greater than 350 micrograms/mL. Future clinical trials of suramin should be designed in such a way as to limit the total cumulative dose to < or = 157 mg/kg given over a period of > or = 8 weeks, limit the period of exposure to plasma suramin concentrations greater than 200 micrograms/mL to < or = 25 days, and limit the AUC greater than 200 micrograms/mL to < or = 48,000 mg.h/AL.

Adult↗
PubMed1995

Phase I study of continuous infusion 6-thioguanine in patients with acute leukemia.

6-Thioguanine (6-TG) was administered as a continuous i.v. infusion for 7 days to 24 patients with relapsed or refractory acute leukemia or in the blast phase of chronic granulocytic leukemia. The daily dose of 6-TG was escalated from 37.5 mg/m2 to 160 mg/m2. Stomatitis was dose-related and dose-limiting with a maximum tolerated dose of 120 mg/m2 daily. Cutaneous reactions were dose-related but not dose-limiting. The recommended dose for phase II trials in acute leukemia is 120 mg/m2 per day as a continuous infusion for 7 days. There were two complete and four partial remissions among all patients. At the suggested phase II dose of 120 mg/m2 there were two complete remissions and one partial remission in five evaluable patients.

Acute Disease↗