Continuous Infusion Of Doxorubicin Research Articles

A precise pharmacodynamic study showing the advantage of a marked reduction in cardiotoxicity in continuous infusion of doxorubicin

We have already shown that the antileukemic activity of daunorubicin that had been reported to be dependent on the area under the concentration – time curve (AUC) was actually peak concentration (Cmax) dependent. The antitumor activity of doxorubicin (DXR) has also been reported to be dependent on AUC, whereas its cumulative cardiotoxicity has been reported to be Cmax dependent. In this study, we evaluated whether the antileukemic and cardiotoxic effects of DXR were AUC or Cmax dependent, and compared their cytotoxic effects, utilizing the computer-controlled in vitro pharmacokinetic simulation system or a conventional culture system for a leukemic cell line and measuring the intracellular ATP amount or the proportion of beating cells for the cardiotoxicity. In leukemic cells, the cytotoxic rate decreased as the simulated infusion time or exposure time increased with the same AUC value in the simulation and conventional culture system (P < 0.05 and <0.01, respectively). The intracellular ATP and proportion of beating cells also increased with prolonged DXR exposure time with the same constant concentration – time product value (P < 0.05 and <0.0001, respectively) in heart cells. These results indicated that both the antileukemic effects and the cardiotoxicity were Cmax dependent. However, a comparison of the two showed that cardiotoxicity was more Cmax dependent than the antileukemic effect. These results suggested that the continuous infusion treatment schedule of DXR may have the clinical advantage of reducing cardiotoxicity more markedly than the antileukemic effect.

Pegylated Liposomal Doxorubicin (PLD), Vincristine and Reduced-Dose Dexamethasone (DVd) in the Treatment of a Predominantly African American Population with Multiple Myeloma.

Recently there has been an important recognition of potentially different responses to pharmaceuticals based on genetic predisposition, with the first FDA advisory panel recommending approval of a heart failure drug for African Americans alone. Liposomal doxorubicin (DOXIL; PLD) is a microscopic pegylated phospholipid vesicle with a core containing conventional doxorubicin. The pegylated coat protects the liposomes from detection by mononuclear phagocytes increasing blood circulation time (t½ = 55 hours). Due to its prolonged half-life, PLD provides a similar effect to using continuous infusion doxorubicin, but administered over 1-hour, transforming the regimen into an outpatient treatment. PLD has also been shown to have a significantly better cardiac safety profile than conventional doxorubicin. A phase II trial using DVd was started in October 2000 and is still enrolling (PLD 40 mg/m2, vincristine 2 mg IVP, and dexamethasone 40 mg PO 1–4 d every 4-weeks). Twenty-seven patients have been enrolled (11 males/16 females; mean age 56 years [range 41–75]). The majority of patients enrolled in this study are African American (74%), a patient population not commonly studied. Patients presented with relatively advanced disease (stages II – III). Baseline mean serum albumin level was 3.5 mg/dL (range 1.4 to 4.4), beta-2 microglobulin 3.38 (range 1.0 – 8.97), fourteen patients had IgG Kappa, three patients has IgG Lambda, six patients with IgA, and four patients with light chain disease. Eighteen patients completed six cycles of therapy, with two patients completing five cycles. Six patients underwent autologous bone marrow transplant following their response to DVd.CR, and nCR was achieved in nine patients, partial responses were achieved in seven patients, minor response in two patients, and progressive disease in five patients, based on Blade Response Assessment. Median follow up is twenty-four months (range 3 months – 5 years). Overall medium time to progression is approximately 1 year. Twenty patients are still alive, one patient has been lost to follow up, and six deaths have occurred. Four early deaths were due to disease progression and sepsis. Two died after one year of therapy due to progressive refractory disease. One died after the second cycle because of sudden cardiac death with sepsis. Three of the early deaths had amyloidosis. No episodes of cardiac dysfunction were observed.Conclusion: African Americans have a 3-fold higher risk of cardiac toxicity with conventional doxorubicin. The use of DVd in this predominantly African American patient population was cardiac safe and provided an easy administered outpatient option, with an overall response rate of ~66% in stage II–III patients.

Phase I Trial of Preoperative Concurrent Doxorubicin and Radiation Therapy, Surgical Resection, and Intraoperative Electron-Beam Radiation Therapy for Patients With Localized Retroperitoneal Sarcoma

The primary objective of this phase I trial was to define the maximum-tolerated dose of external-beam radiation with concurrent fixed-dose continuous-infusion doxorubicin followed by surgical resection and electron-beam intraoperative radiation therapy (EB-IORT) for patients with localized, potentially resectable retroperitoneal sarcomas (RPS). Thirty-five patients with radiographically resectable primary or recurrent intermediate- or high-grade RPS were treated. Doxorubicin was administered each week for 4 or 5 weeks as an initial bolus (4 mg/m2) followed by a 4-day continuous infusion (4 mg/m2/d). Concurrent radiation therapy was administered in escalating doses of 18.0, 30.6, 36.0, 41.4, 46.8, or 50.4 Gy in 1.8-Gy fractions. Radiographic restaging was performed 4 to 8 weeks after chemoradiation, and patients with localized disease underwent surgical resection with EB-IORT (15 Gy). Chemoradiation was completed as outpatient therapy in 31 patients (89%); four patients required hospital admission during chemoradiation or in the postchemoradiation preoperative period. At the highest radiation dose of 50.4 Gy, two (18%) of 11 patients had grade 3 or 4 nausea. Twenty-nine patients (83%) underwent laparotomy; six patients had interval disease progression and did not undergo surgery. Grossly complete resection (R0 or R1) was performed in 26 (90%) of 29 patients who had surgery. EB-IORT was feasible and successfully administered to 22 patients who had R0 or R1 resections. Preoperative chemoradiation, surgical resection, and EB-IORT are feasible for patients with RPS. Preoperative external-beam radiation can be administered to a total dose of 50.4 Gy with continuous-infusion doxorubicin.

Salvage chemotherapy according to the ASHAP protocol: a single-center study of 24 patients with relapsed or refractory aggressive non-Hodgkin's lymphomas.

Numerous salvage protocols for relapsed or refractory aggressive non-Hodgkin's lymphomas have been described. The purpose of this retrospective study was to evaluate the efficacy and the toxicity of the ASHAP protocol, which combines a continuous infusion of doxorubicin and cisplatin with high-dose cytarabine and methylprednisolone. Twenty-four patients with relapsed or refractory aggressive non-Hodgkin's lymphomas were treated with a median of 3 cycles (range: 1-5) of ASHAP. Twelve patients achieved a complete and four a partial remission for an overall response rate of 67%. The 3-year overall and progression-free survival rates were 60% and 40%, respectively. Ten of the responding patients were consolidated by high-dose chemotherapy. After a median follow-up of 15.5 months, four patients are in continuous complete remission, while six patients suffered relapses (two fatal). For reasons of low risk profile [international prognostic index (IPI) score of 0, n=2] or age >60 years ( n=4), consolidation was limited to involved-field radiotherapy in six patients. All of these patients are alive after a median follow-up of 37 months, with two relapses. Factors predicting a poor response to salvage therapy were primary refractory disease, elevated lactate dehydrogenase activity, and an IPI score of >/=2. The principal toxicity was myelosuppression with grade III or IV neutropenia or thrombocytopenia occurring in 88% or 75%, respectively, of the patients. Nonhematological toxicity was generally mild. There were no treatment-related deaths. The ASHAP regimen is a highly active and well-tolerated salvage protocol for patients with relapsed aggressive non-Hodgkin's lymphomas which compares favorably with other established protocols.

A comparison of human G-Csf and human Gm-Csf given concurrently with anti-cancer chemotherapy

Granulocyte-colony-stimulating factor (G-Csf) and granulocyte-macrophagecolony-stimulating factor (GM-Csf) were each given concurrently with continuous infusion of doxorubicin, ifosphamide, or vinorelbine. Both cytokines enabled the dose intensity of these three anti-tumor agents to be substantially increased without an increase in drug toxicity. The effect of Gm-Csf as a stimulant of dendritic cell production and function was noted.

Doxorubicin Administration by Continuous Infusion Is Not Cardioprotective: The Dana-Farber 91-01 Acute Lymphoblastic Leukemia Protocol

PURPOSE: Acute doxorubicin-induced cardiotoxicity can be prevented in adults by continuous infusion of the drug, but mechanisms of cardiotoxicity are different in children. We compared cardiac outcomes in children receiving bolus or continuous infusion of doxorubicin. PATIENTS AND METHODS: In a randomized study, children with high-risk acute lymphoblastic leukemia received doxorubicin 360 mg/m2 in 30-mg/m2 doses every 3 weeks either by bolus (within 1 hour, n = 57) or by continuous infusion (over 48 hours, n = 64). Echocardiograms obtained before doxorubicin and at longest follow-up times were centrally remeasured, and z scores of cardiac measurements were calculated based on a healthy population. RESULTS: The groups were similar in age, sex distribution, doxorubicin dose, and duration of follow-up. Before treatment, measures of left ventricular (LV) structure and function did not reveal dilated cardiomyopathy and were not statistically different between bolus and continuous-infusion groups. The follow-up echocardiograms demonstrated no significant difference between the two groups for any cardiac characteristic, but both groups showed significant abnormalities of LV structure and function compared with normal and with baseline. For example, the mean LV fractional shortening fell by approximately two SD in both groups between the two echocardiograms. LV contractility was depressed in both groups (for bolus patients, median z score = −0.70 SD, P = .006; for continuous-infusion patients, median z score = −0.765, P = .005). Dilated cardiomyopathy and inadequate LV hypertrophy were noted in both groups. Clinical cardiac manifestations and event-free survival did not differ. CONCLUSION: Continuous doxorubicin infusion over 48 hours for childhood leukemia did not offer a cardioprotective advantage over bolus infusion. Both regimens were associated with progressive subclinical cardiotoxicity. Other cardioprotective strategies should be explored.

Phase II Study of 96-hr Continuous-Infusion Etoposide and Doxorubicin with Bolus Cyclophosphamide in Refractory Epithelial Ovarian Cancer

Effective salvage chemotherapy for patients with ovarian cancer who have failed platinum- and taxane-based regimens has not been identified. It has been reported that prolonged infusions of chemotherapy may be active in some malignancies which have become refractory to bolus treatments. We evaluated a regimen of 96-hr continuous-infusion doxorubicin (10 mg/m2/24 hr), etoposide (50 mg/m2/24 hr), and bolus cyclophosphamide (750 mg/m2) administered every 21 days to patients with ovarian cancer who had previously been treated with paclitaxel and a platinum compound. Nineteen women were treated, 15 of whom had platinum-refractory cancer. Six of the first 9 experienced a neutropenic fever after the first treatment cycle, and therefore all subsequent patients received prophylactic granulocyte-colony-stimulating factor. Other significant toxicities included hand and foot syndrome (1 patient) and mucositis (4 patients). There was one partial response in a patient with platinum-sensitive disease. We conclude that this regimen causes significant myelosuppression and does not have major activity in heavily pretreated patients with ovarian cancer.

Timing and magnitude of decline in alpha-fetoprotein levels in treated children with unresectable or metastatic hepatoblastoma are predictors of outcome: a report from the Children's Cancer Group.

We analyzed data on 31 children with primary unresectable or metastatic hepatoblastoma (HB) to investigate possible prognostic correlations between the serum level of alpha-fetoprotein (AFP), its changes during treatment, and outcome. Patients were treated according to the Children's Cancer Group (CCG) protocol 823F, which included an initial surgery before eight courses of chemotherapy that consisted of cisplatin immediately followed by a continuous infusion of doxorubicin. Four courses were given before and four after the second surgery. AFP levels were measured before treatment, before and after second surgery, and at the end of treatment. Twenty-four of 31 patients showed a decline of > or = 1 log in AFP levels before second surgery (early responders). By the end of treatment, there were 16 patients, all early responders, without clinical or radiographic evidence of tumor and with normal AFP levels. Fifteen of those 16 had a decline of > or = 2 logs in AFP before second surgery (large early response). Of the 15 patients who failed to respond to treatment, 10 died, among whom only one patient had a large early response. A large early response was the strongest independent predictor of outcome in a univariate and multivariate Cox regression model, and patients with such a response had the best survival (P < .0001). For children with unresectable or metastatic HB, early changes in AFP levels are a reliable predictor of outcome and can be used for identification of poor responders to treatment, ie, patients whose AFP level fails to decrease 2 logs before second surgery should be considered for alternative treatment.

Increased intracellular concentrations of doxorubicin in resistant lymphoma cells in vivo by concomitant therapy with verapamil and cyclosporin A

The tumor cell uptake of doxorubicin was studied in vivo in cells from 2 patients with clinically resistant leukemic lymphomas treated with continuous infusions of doxorubicin 9 mg/m2 and vincristine with oral dexamethasone. After 24 hours, intravenous or oral verapamil was added and in one treatment course intravenous cyclosporin A was given. Plasma and intracellular doxorubicin concentrations and plasma concentrations of verapamil and norverapamil were determined with HPLC. In the 1st patient the intracellular uptake rate of doxorubicin was increased from 0.007 to 0.013 nmol/mg protein/h after the start of verapamil infusion. In the first treatment course of patient number 2, the intracellular concentration of doxorubicin was increased by 280% during a 6-h infusion of verapamil. When this patient in the next treatment course was given oral verapamil, no significant effect on doxorubicin uptake was seen. However, when 100 mg of cyclosporin A was added in three intravenous injections at 8-h intervals, the doxorubicin concentration in the tumor cells increased from 0.027 to 0.086 nmol/mg protein. In conclusion, this study shows that the intracellular concentrations of doxorubicin can be increased also in vivo during patient therapy by the addition of verapamil or cyclosporin A.

Escalating dose of continuous infusion combination chemotherapy for refractory neuroblastoma.

This trial was undertaken to determine if a continuous infusion format with increased dose-intensity had antitumor activity with tolerable toxicity in patients with advanced neuroblastoma. Forty heavily pretreated patients with refractory or progressive neuroblastoma received continuous infusion doxorubicin, cisplatin, and etoposide along with bolus ifosfamide in a dose-escalation format. A total of 79 courses of chemotherapy were administered at five different dose levels. Fifteen of 35 assessable patients (43%) achieved either a partial response (PR) or complete response (CR), including five patients with a CR, three with a very good PR (VGPR), and seven with a PR. Hematologic toxicity was severe, but reversible, and other toxicities, although significant, were tolerable and much less than that accepted in a bone marrow transplantation (BMT) setting. This investigation illustrates that response is possible even in an extremely poor-prognosis group of patients, and it suggests that such a regimen may be effective if given before disease progression occurs.

Doxorubicin and doxorubicinol pharmacokinetics and tissue concentrations following bolus injection and continuous infusion of doxorubicin in the rabbit

Cumulative dose-related, chronic cardiotoxicity is a serious clinical complication of anthracycline therapy. Clinical and animal studies have demonstrated that continuous infusion, compared to bolus injection of doxorubicin, decreases the risk of cardiotoxicity. Continuous infusion of doxorubicin may result in decreased cardiac tissue concentrations of anthracyclines, including the primary metabolite doxorubicinol, which may also be an important contributor to cardiotoxicity. In this study, doxorubicin and doxorubicinol plasma pharmacokinetics and tissue concentrations were compared in New Zealand white rabbits following intravenous administration of doxorubicin (5 mg.kg-1) by bolus and continuous infusion. Blood samples were obtained over a 72-h period after doxorubicin administration to determine plasma doxorubicin and doxorubicinol concentrations. Rabbits were killed 7 days after the completion of doxorubicin administration and tissue concentrations of doxorubicin and doxorubicinol in heart, kidney, liver, and skeletal muscle were measured. In further experiments, rabbits were killed 1 h after bolus injection of doxorubicin and at the completion of a 24-h doxorubicin infusion (anticipated times of maximum heart anthracycline concentrations) to compare cardiac concentrations of doxorubicin and doxorubicinol following both methods of administration. Peak plasma concentrations of doxorubicin (1739 +/- 265 vs 100 +/- 10 ng.ml-1) and doxorubicinol (78 +/- 3 vs 16 +/- 3 ng.ml-1) were significantly higher following bolus than infusion dosing. In addition, elimination half-life of doxorubicinol was increased following infusion. However, other plasma pharmacokinetic parameters for doxorubicin and doxorubicinol, including AUC infinity, were similar following both methods of doxorubicin administration. Peak left ventricular tissue concentrations of doxorubicin (16.92 +/- 0.9 vs 3.59 +/- 0.72 micrograms.g-1 tissue; P < 0.001) and doxorubicinol (0.24 +/- 0.02 vs 0.09 +/- 0.01 micrograms.g-1 tissue; P < 0.01) following bolus injection of doxorubicin were significantly higher than those following infusion administration. Tissue concentrations of parent drug and metabolite in bolus and infusion groups were similar 7 days after dosing. The results suggest that cardioprotection following doxorubicin infusion may be related to attenuation of the peak plasma or cardiac concentrations of doxorubicin and/or doxorubicinol.

Low dose continuous infusion doxorubicin in children and young adults.

Ten patients (age range 3.2-26.3 yrs) with relapsed or resistant malignancies received a total of 20 courses of low dose continuous infusion doxorubicin (3 mg/m2/day for 28 days) delivered by portable Graseby infusion pumps via central venous catheters. Each patient received a median dose of 144 mg/m2 (range 87-261). Four patients responded to treatment (1 complete response (CR) and 3 partial response (PR)) and performance status improved in seven patients. Overall toxicity was minimal: WHO Grade 4 anaemia in 2/18 courses, Grade 4 neutropenia in 1/18, Grade 3-4 thrombocytopenia in 3/18, nausea and vomiting of Grades 2 and 4 in 4/20 and 1/20 respectively, and mucositis of Grades 2 and 4 in 2/20 courses each. Cardiac toxicity was assessed using echocardiography, and fractional shortening remained within normal limits in all patients. Low dose continuous infusion doxorubicin is a feasible, well tolerated, ambulatory therapy in children and may be an effective way of delivering doxorubicin with less toxicity, thus enabling the development of more dose intensive regimens.

Pediatric hepatic tumors: Clinical trials conducted in the United States

Hepatoblastomas (HBs) and hepatocellular carcinomas (HCCs) constitute the majority of hepatic tumors in children. Although most children who have HB or HCC present with unresectable disease, chemotherapy may reduce the size of the primary tumor and metastases, thus allowing subsequent successful removal. Clinical trials conducted over the past decade in the United States have demonstrated that chemotherapy regimens consisting of continuous-infusion doxorubicin and cisplatin or high-dose cisplatin alone effectively reduce tumor size. The prognosis of children with HB is better than that of those with HCC. Over half the patients who initially have unresectable HB can be rendered disease free with chemotherapy and subsequent surgery.

Effective treatment of unresectable or metastatic hepatoblastoma with cisplatin and continuous infusion doxorubicin chemotherapy: A report from the childrens cancer study group : J.A. Ortega, J.E. Krailo, D.R. Haas, et al. J Clin Oncol 9:2167–2176, (December), 1991

Effective treatment of unresectable or metastatic hepatoblastoma with cisplatin and continuous infusion doxorubicin chemotherapy: A report from the childrens cancer study group : J.A. Ortega, J.E. Krailo, D.R. Haas, et al. J Clin Oncol 9:2167–2176, (December), 1991

Effective treatment of unresectable or metastatic hepatoblastoma with cisplatin and continuous infusion doxorubicin chemotherapy: a report from the Childrens Cancer Study Group.

The Childrens Cancer Study Group (CCSG) undertook a study (CCG-823F) to test the feasibility of administering continuous infusion doxorubicin (CI DOX) and cisplatin (CDDP) in patients with unresectable or incompletely resected hepatoblastoma (HB) or hepatocellular carcinoma (HCC). Chemotherapy consisted of CI DOX 20 mg/m2/d for days 1 to 4 and CDDP 100 mg/m2 on day 1 followed by a 21-day rest period. Second-look surgery was performed after the administration of four chemotherapy courses. Forty-seven (47) assessable patients were entered on study, 33 with HB and 14 with HCC; of these, 34 (26 HB and eight HCC) completed the initial four courses of chemotherapy. Of the 26 HB patients, 25 were evaluated as responding to chemotherapy before the scheduled second-look procedure and were considered surgically resectable at that time. Surgery was performed on 22 patients; three patients refused the second-look surgery. Nine patients had no evidence of residual malignant disease, seven underwent surgical resection of remaining tumor, four were left with microscopic residual disease, one had a partial resection with gross tumor left behind, and one remained unresectable. Nine HCC patients completed four chemotherapy courses. Eight patients achieved a partial remission and second-look surgery was attempted on seven. Only two had all malignant disease removed at the second procedure. Data from 225 courses of chemotherapy were evaluated for toxicity. Neutropenia (absolute granulocyte count less than 500/mL) was observed in 68 courses, and five of these episodes were associated with sepsis. Severe mucositis was documented in 21 courses, and hypomagnesemia (magnesium less than 1.2 mg) was noted in 30 patients. Two patients developed decreased left ventricular shortening fraction, which resolved when chemotherapy was discontinued. In summary, CI DOX plus CDDP is a well-tolerated and effective regimen in inducing surgical resectability in HB patients who are unresectable at diagnosis and significantly improves survival for this group of patients to 66.6%.

A prospective randomized trial of adjuvant chemotherapy with bolus versus continuous infusion of doxorubicin in patients with high-grade extremity soft tissue sarcoma and an analysis of prognostic factors

A prospective randomized trial was conducted to compare the cardiotoxic and therapeutic effects of doxorubicin (60 mg/m2 every 3 to 4 weeks) administered by bolus or 72-hour continuous infusion as adjuvant chemotherapy in 82 eligible patients after resection of high-grade soft tissue sarcoma of the extremity or superficial trunk. Cardiac toxicity, defined as a 10% or greater decrease in left ventricular ejection fraction as assessed by radionuclide cineangiography, was evaluated in 69 patients. Cardiotoxicity was seen in 61% of patients in the bolus treatment arm with the median doxorubicin dose of 420 mg/m2. Among patients who received continuous infusion, 42% had cardiotoxicity with a median dose of 540 mg/m2. The rate of cardiotoxicity as a function of the cumulative dose of doxorubicin was significantly higher in the bolus treatment arm (P = 0.0017). Two patients in each group had clinical congestive heart failure, with one cardiac death occurring in each. There was a trend toward a lower rate of metastasis (P = 0.19) and a significantly lower rate of death of disease (P = 0.036) for patients treated with the bolus dose. Cox model analysis identified three unfavorable characteristics for the rate of developing a distant metastasis: blood transfusion within 24 hours of operation (P less than 0.00001), tumor deep to the fascia and 5 cm or more in size (P = 0.0043), and a histologic subtype other than liposarcoma (P = 0.0002). The unfavorable effect of continuous infusion was not selected in the model (P = 0.16). Adjuvant chemotherapy for patients with soft tissue sarcoma is investigational. Furthermore, the impact of perioperative blood transfusion merits further study.

The surgical management of children with incompletely resected hepatic cancer is facilitated by intensive chemotherapy

This prospective study was undertaken to evaluate the efficacy of continuous-infusion doxorubicin and cisplatin ( CI-DOX CPPD ) for the treatment of children with incompletely resected hepatic cancer. Of the 46 evaluable patients, 32 had hepatoblastoma (70%) and 14 had hepatocellular carcinoma. Ten children had stage II tumors (microscopic residual), 25 were defined as stage III (gross residual), and 11 had distant metastasis (stage IV). Twelve patients underwent initial incomplete resection of their hepatic lesions and in the 34 others tumor biopsy specimens were obtained. Chemotherapy was administered and the majority of the children (70%) had an excellent clinical response with a decrease in both α-fetoprotein levels and measured tumor dimensions. The combination of CI-DOX CPDD clearly facilitated surgical management, allowing for delayed hepatic resections in 20 of the 34 patients (59%) whose tumors were initially biopsied and considered to be unresectable. Overall survival in this study demonstrates a significant improvement in comparison to the historical controls. Twenty-one patients (46%) remain in complete clinical remission an average of 30 months following diagnosis (range, 17 to 40 months). The outcome of the children with hepatoblastoma was much better than those with hepatocellular carcinoma (63% v 17% survival). Survival of the 20 children who underwent delayed hepatic resections was not statistically different from the 12 patients whose hepatic tumors were removed at the initial laparotomy (41% v 58% survival). Although no obvious survival advantage was observed in those patients who underwent initial hepatic resections, there did appear to be an increased risk of postoperative complications in children whose tumors were resected following chemotherapy (8% v 25%).

P-glycoprotein expression in malignant lymphoma and reversal of clinical drug resistance with chemotherapy plus high-dose verapamil.

P-glycoprotein is a transmembrane protein thought to function as an efflux pump to detoxify cells. It is associated with multidrug resistance in laboratory systems and has recently been found in human tumors associated with in vitro and clinical drug resistance. We used an immunohistochemical method employing two monoclonal antibodies, JSB-1 and C-219, to detect expression of P-glycoprotein in lymphoma patients. One of 42 newly diagnosed and untreated lymphoma patients (2%) and seven of 11 previously treated and drug-resistant patients (64%) had detectable levels of P-glycoprotein (P less than .001). Based on prior reports suggesting that verapamil sensitizes drug-resistant cancer cells to chemotherapy by competitive inhibition of the P-glycoprotein, we tested the efficacy of verapamil as a chemosensitizer in 18 patients with drug-refractory disease. All patients had previously failed or relapsed within 3 months of a doxorubicin-vincristine-containing drug regimen. Patients received day-1 cyclophosphamide, and 4-day continuous infusion doxorubicin and vincristine and oral dexamethasone (CVAD). CVAD was combined with 5-day continuous infusion verapamil given at maximally tolerated dose. Overall, 13 of 18 patients (72%) responded to treatment including five complete remissions (CRs; 28%). The median duration of response was 200 days and median survival was 242 days. The dose-limiting toxicity of the verapamil infusion was temporary cardiac dysfunction including hypotension, congestive heart failure, and cardiac arrhythmia. We conclude that the P-glycoprotein is uncommonly expressed in untreated lymphomas and frequently expressed in clinically drug-resistant disease, and that chemotherapy using CVAD plus maximally tolerated doses of verapamil results in a high response rate in patients carefully selected for clinical drug resistance.

Pharmacokinetics and pharmacodynamics of long-term continuous-infusion doxorubicin.

Steady-state plasma levels of doxorubicin and doxorubicinol were analyzed in 32 patients with advanced cancer, each of whom was given doxorubicin by long-term continuous infusion at progressively increasing infusion rates. Patients received doxorubicin for 2 to 50 weeks at rates of 0.2 to 6.1 mg/m2/day. Dose-limiting stomatitis and leukopenia were observed. The mean maximum steady-state doxorubicin concentration was 6.04 ng/ml at a mean maximum infusion rate of 3.92 mg/m2/day. Clearance mechanisms did not appear to be saturated at the durations or infusion rates used in this study. The maximum steady-state doxorubicin level and the ln (initial WBC) were significant correlates of the ln (nadir WBC) (p = 0.002 and 0.02, respectively). A model was constructed according to these two parameters that significantly describes ln (nadir WBC) (p = 0.001). Neither age, infusion rate, nor doxorubicinol level correlated with nadir WBC. Stomatitis did not correlate with any of these parameters. The demonstration of this pharmacodynamic relationship highlights the potential importance of pharmacologic data collection in ongoing attempts to predict the clinical effects of anticancer drugs.

Continuous doxorubicin infusions. A pilot study in young patients

Eleven young patients with relapsed childhood malignancies received continuous infusions of 5-10 mg/m2/day doxorubicin. 30 infusions were given via a central venous access until signs of mucositis showed up (7-52 days). Other toxicity was low, both bone marrow depression and fever and neutropenia occurred in 7/30 and 5/30 courses of therapy, respectively. No signs of liver or cardiac toxicity were seen in these heavily pretreated patients. In 8/11 patients tumor regression was documented, though only two partial remission were noted. Continuous infusions of doxorubicin are an effective and relatively non-toxic treatment for relapsed childhood malignancies. Since this form of therapy enables good quality of life and medical care on ambulatory basis, a phase II-study of low-dose doxorubicin for relapsed tumors is justified.