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Biomedical subjects

R P Warrell

Publications and source records attributed to R P Warrell.

At least 109 records · Page 6Linked to original sources
PubMed1986

Gallium nitrate for acute treatment of cancer-related hypercalcemia: clinicopharmacological and dose response analysis.

Current treatment of cancer-related hypercalcemia is limited by agents of limited effectiveness or excessive toxicity. Gallium nitrate is a new drug which both inhibits bone resorption and increases calcium content of bone. We have now treated 39 episodes of hypercalcemia with gallium nitrate administered as a continuous i.v. infusion for 5-7 days at 3 daily dose levels (100 and 200 mg/m2, and 50 mg/m2 by brief infusion followed by 150 mg/m2). Nadir calcium values were significantly lower (9.2 +/- 1.5 mg/dl) for patients who received the highest dose relative to patients who received the lowest dose (10.5 +/- 1.6 mg/dl, P less than 0.001). While the actual percentage of patients who achieved normocalcemia was higher at the highest dose relative to the lowest dose (86 versus 60%), this difference was not statistically significant. Mean serum concentration of inorganic phosphorous declined significantly for all patients from 2.9 +/- 0.86 mg/dl at base line to 1.8 +/- 0.66 mg/dl (P less than 0.001). Pharmacokinetic studies suggested that a threshold plasma gallium concentration of approximately 1 microgram/ml must be attained to achieve acute normalization of elevated serum calcium levels. Steady-state plasma gallium levels were attained after 48 h; there was no evidence of drug accumulation in plasma after 2 days. Effects on serum creatinine concentration were negligible, and there were no other toxic reactions. These data confirm preclinical experiments which suggested that inhibition of bone resorption by gallium nitrate is dependent upon the dose and duration of drug exposure. We conclude that gallium nitrate is effective treatment for cancer-related hypercalcemia. The drug is now being evaluated against standard treatment in a randomized, double-blind trial.

Adult↗
PubMed1985

Homoharringtonine: an effective new drug for remission induction in refractory nonlymphoblastic leukemia.

Homoharringtonine (HHT) is a new plant alkaloid originally isolated in the People's Republic of China. Preliminary studies have suggested antitumor activity in several neoplastic diseases. We treated 49 patients with relapsed or resistant acute leukemia with escalating doses of homoharringtonine administered by continuous infusion. Three dose levels were examined: 5 mg/m2 for seven days, 7 mg/m2 for seven days, and 5 mg/m2 for nine days. Of 28 patients with acute nonlymphoblastic leukemia who received cumulative doses of 45 to 49 mg/m2, seven patients (25%) achieved complete remission. Four of these remissions occurred in a subset of ten patients previously resistant to two or more induction attempts with conventional chemotherapy. There were no remissions in three patients with secondary leukemia or in seven patients with acute lymphoblastic leukemia. Reversible hypotension, fluid retention, diarrhea, and tumor lysis syndrome were the major toxic effects of this treatment. Our results indicate that homoharringtonine is an effective new drug for the treatment of acute nonlymphoblastic leukemia and that this drug does not share cross-resistance with conventional antileukemic agents. The recommended dose is 5 mg/m2/d administered by continuous infusion for nine days.

Acute Disease↗
PubMed1985

Metabolic effects of gallium nitrate administered by prolonged infusion.

Gallium nitrate was recently found to be effective treatment for resistant cancer-related hypercalcemia. In vitro and in vivo experiments have suggested that the drug directly inhibits calcium resorption from bone; however, the overall effects of gallium nitrate on calcium balance were unknown. We have completed metabolic balance studies in four patients who received this drug by prolonged infusion. All patients were in positive calcium balance while receiving the drug. Each patient also showed a substantial decrease in urinary calcium excretion. Serum phosphorus decreased in all four patients. There was no change in phosphorus, sodium, chloride, or magnesium balance or in creatinine clearance. We conclude that prolonged infusions of gallium nitrate reduce urinary calcium excretion and that the hypocalcemic effect of this drug is primarily due to inhibition of calcium resorption from bone. Thus, the drug may prove useful in reducing accelerated bone resorption in patients with bone metastases or chronic cancer-related hypercalcemia.

Antineoplastic Agents↗
PubMed1984

Gallium nitrate inhibits calcium resorption from bone and is effective treatment for cancer-related hypercalcemia.

Approximately two-thirds of patients who receive the anticancer drug gallium nitrate develop mild hypocalcemia. To evaluate the mechanism of drug-induced hypocalcemia, we tested the effects of gallium nitrate upon in vitro release of 45Ca++ from explanted fetal rat bones. The drug significantly inhibited 45Ca++ release in response to stimulation with both parathyroid hormone and a lymphokine preparation with osteoclast activating factor activity. The inhibitory effects on bone resorption were both time- and dose-dependent. Later, in a pilot study, we treated 10 patients who had cancer-related hypercalcemia with gallium nitrate administered by continuous infusion. All patients responded by a reduction of total serum calcium to normal or subnormal concentrations (13.8 +/- 1.05 mg/dl, mean +/- SD pretreatment, to 8.03 +/- 1.03 mg/dl, mean posttreatment nadir). Our results indicate that gallium nitrate effectively treats cancer-related hypercalcemia and that it probably acts by inhibiting calcium release from bone.

Animals↗
PubMed1983

Intratumoral consumption of indium-111 labeled platelets in a patient with hemangiomatosis and intravascular coagulation (Kasabach-Merritt syndrome).

Previous studies regarding sites of platelet destruction in patients with the Kasabach-Merritt syndrome are conflicting. The authors recently studied an adult patient with multiple large hemangiomata, thrombocytopenia, and intravascular coagulation by external imaging following the injection of autologous Indium-111 labeled platelets. Sequential images showed prompt accumulation of platelet-associated radioactivity in areas within the right hemithorax which corresponded to certain tumors noted on the chest roentgenogram. Despite the presence of multiple other lesions in bone and soft tissues, platelet radioactivity was otherwise normally confined to liver and spleen. Using data obtained from serial images, it was shown that radioactivity within the thoracic masses actually increased over time. These data indicate that platelet consumption occurred as an active process and that localization was not a result of tumor vascularity. It is concluded that platelets are locally consumed within certain hemangiomata. However, within the same individual, there may exist considerable heterogeneity among these tumors with respect to platelet-trapping ability. In similar patients with multiple tumors, indium-platelet scanning might be used to direct local therapy to particular lesions in an effort to correct the thrombocytopenia.

Abdomen↗
PubMed1983

Treatment of patients with advanced malignant lymphoma using gallium nitrate administered as a seven-day continuous infusion.

Previous trials of gallium nitrate (NSC-15200) showed that bolus administration produced dose-limiting nephrotoxicity without substantial antitumor activity. As an effort to increase the therapeutic index of this compound and to establish a satisfactory out-patient schedule, the authors evaluated the effects of gallium nitrate administered as a continuous infusion in patients with advanced malignant lymphoma. In an initial Phase I trial, four dose levels which ranged from 200 to 400 mg/m2/day in 27 patients were studied. Nausea which impaired oral hydration was found to be dose-limiting. A dose of 300 mg/m2/day was chosen for extended Phase II evaluation and 37 additional patients were entered into the study at that dose level. Overall, 16 of 47 patients (34%) who had bi-dimensionally measurable parameters of disease achieved major antitumor responses (six of 15 with diffuse "histiocytic" lymphoma, five of ten with diffuse poorly-differentiated lymphocytic lymphoma, two of five with nodular poorly-differentiated lymphocytic lymphoma, and three of 17 with Hodgkin's disease). The median duration of response was 2.5 months. Only 8% of patients who received 300 mg/m2/day developed an increase in serum creatinine concentration greater than 1.1 mg/dl over baseline values. Hypocalcemia occurred in two-thirds of patients. Other toxic effects, including paresthesiae, diarrhea, and hearing loss, were noted in less than 5% of patients. There was minimal myelosuppression. The authors conclude that gallium nitrate administered as a continuous infusion for seven days at 300 mg/m2/day is well-tolerated and effective treatment for patients with advanced malignant lymphoma. Outpatient administration using portable infusion pumps is safe and practical. Further evaluation of the drug administered as a constant infusion is indicated in patients with other neoplastic diseases.

Adolescent↗
PubMed1983

Sequential inhibition of polyamine synthesis. A phase I trial of DFMO (alpha-difluoromethylornithine) and methyl-GAG [methylglyoxal-bis(guanylhydrazone)].

Both DFMO and methyl-GAG inhibit sequential enzymatic reactions in the pathway of polyamine biosynthesis. Since polyamines may be important factors in proliferation of cancer cells, we initiated a phase-I study of these agents in patients with advanced cancer. DFMO was given by mouth at a constant daily dose of 4 g/m2 starting on day 1 of the treatment protocol. The dose of methyl-GAG ranged from 200 to 700 mg/m2 administered IV every 2 weeks beginning on day 4. Twenty-two patients were entered into the protocol. Toxic reactions to this therapy were dose-related and included nausea, fatigue, diarrhea, and myelosuppression. One patient with colon cancer experienced a greater than 50% decrease in measurable disease but developed severe myelotoxicity. While DFMO was well tolerated, the combination of drugs appeared to cause substantially more hematologic and gastrointestinal toxicity than encountered during our recent experience with methyl-GAG used alone. We suggest that future studies of this drug combination carefully evaluate levels of polyamines and inhibition of enzymatic activity to minimize toxicity.

Adult↗
PubMed1983

Methylglyoxal-bis(guanylhydrazone) (Methyl-GAG): current status and future prospects.

Initial clinical trials of methyl-GAG (MGBG) showed that repetitive daily administration produced severe, occasionally fatal, toxic reactions. After two decades of neglect, recent studies have shown that doses of 500-600 mg/sq m administered every 7-14 days are very well tolerated. Moreover, current results indicate that MGBG has useful antitumor activity in patients with advanced malignant lymphoma and carcinomas of the head and neck, esophagus, and lung (non-small cell). The drug's mechanism of cytotoxic action and its toxic effects are not shared by most other cancer chemotherapeutic drugs. Furthermore, Phase II and Phase III evaluation are required to determine the therapeutic potential of this unique agent.

Animals↗
PubMed1983

Administration of gallium nitrate by continuous infusion: lack of chronic nephrotoxicity confirmed by studies of enzymuria and beta 2-microglobulinuria.

Enzymuria and beta 2-microglobulinuria are sensitive markers of injury to renal tubular cells. We evaluated these markers in 41 patients with advanced malignant lymphoma who received gallium nitrate administered as a continuous infusion during a recent phase I-II study. In contrast to our findings with cisplatin, we observed no significant increase in enzyme excretion or beta 2-microglobulinuria in these patients even after long-term treatment. Our results indicate that gallium nitrate administered by infusion does not produce cumulative renal tubular toxicity.

Acetylglucosaminidase↗
PubMed1983

Phase I trial of 10-deaza-aminopterin in patients with advanced cancer.

The clinical effects of 10-deaza-aminopterin, an inhibitor of dihydrofolate reductase with a better therapeutic index against several murine tumors than that of methotrexate, were examined during the course of a phase I study in patients with advanced malignant neoplasms. Three escalating dose schedules were explored: single iv injections once daily, single iv injections twice weekly, and continuous infusion. The maximum tolerated doses were: single injections at a dose of 7 mg/m2/day for 5 days; single injections at a dose of 15 mg/m2 twice weekly for four to six doses; and continuous infusion at a dose of 3 mg/m2/day for 5-6 days in patients with solid tumors and until bone marrow hypoplasia in patients with leukemia. Mucositis was dose-limiting in all schedules. Occasionally, mild leukopenia, thrombocytopenia, and skin rash were noted. A minor antitumor response was seen in a patient with gallbladder carcinoma. Marked leukemic cell kill was observed in several patients with acute leukemia or blastic phase of chronic myelogenous leukemia. Disease-oriented phase II trials are planned at this Center for several tumor varieties.

Adult↗
PubMed1982

Phase I--II evaluation of a new anthracycline antibiotic, aclacinomycin A, in adults with refractory leukemia.

Aclacinomycin A (ACM) is a new anthracycline antibiotic that produces substantially less cardiotoxicity in animals than does doxorubicin. To define the effective dose for the treatment of patients with leukemia, we treated 43 patients with acute nonlymphoblastic leukemia (ANLL) or acute lymphoblastic leukemia (ALL) using ACM administered at three dose levels. All patients had previously received extensive treatment with other chemotherapy; their median cumulative dose of prior anthracycline was 340 mg/m2. An ACM dose of 100 mg/m2/day given for 2 days (total dose, 200 mg/m2) failed to produce significant bone marrow hypocellularity or remission in two patients. Total ACM doses of 300--360 mg/m2 (100 or 120 mg/m2/day x 3 days) produced marrow hypoplasia in 16 to 23 evaluable patients with ANLL. Overall, four of 32 patients with ANLL who received 300--360 mg/m2 of ACM achieved complete remission for duration of 1, 5+, 6 and 15+ months. Two of nine patients with ALL achieved partial remission. Toxic effects of this therapy included severe leukopenia and thrombocytopenia, nausea, mucositis, and diarrhea. ECG abnormalities were noted in 43% of patients who were carefully monitored; however, only one patient developed a significant decrease in left ventricular ejection fraction as measured by radionuclide cardiography. ACM produced only minimal alopecia and did not cause tissue necrosis following inadvertent subcutaneous infiltration. We conclude that 300--360 mg/m2 of ACM is an effective dose for the treatment of patients with ANLL and that further evaluation of this compound is indicated in patients who have received minimal prior therapy.

Aclarubicin↗
PubMed1982

Combination chemotherapy for patients with relapsed malignant lymphoma using methyl-GAG and teniposide (VM-26).

We treated 45 patients with advanced malignant lymphoma, using a combination of methyl-GAG and teniposide (VM-26). All patients had received extensive prior treatment with combination chemotherapy with or without irradiation. Both methyl-GAG (600 mg/m2) and VM-26 (100 mg/m2) were administered on Days 1 and 8 of the treatment protocol and, in responding patients, every 2 weeks thereafter. Partial responses occurred in six of 12 patients with Hodgkin's disease and in ten of 31 patients with non-Hodgkin's lymphoma. The median duration of response for all patients was 3 1/2 months (range, 1 1/2-11). There were moderate toxic effects, including nausea, myalgia, weakness, and myelosuppression. Relative to our recent experience with methyl-GAG as a single agent, the addition of VM-26 to methyl-GAG did not produce a superior rate or duration of response in similar, heavily pretreated patient populations with malignant lymphoma; however, the combination caused considerably more myelotoxicity. We conclude that the use of VM-26 with methyl-GAG in this dose schedule offers no advantage over single-agent therapy. Methyl-GAG, when administered on a biweekly schedule, is effective and well-tolerated. This agent should be considered for incorporation into chemotherapy protocols for the therapy of previously untreated patients with malignant lymphoma.

Clinical Trials as Topic↗