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Biomedical subjects

A A Miller

Publications and source records attributed to A A Miller.

At least 37 records · Page 2Linked to original sources
PubMed1996

Phase I and pharmacologic study of 7- and 21-day continuous etoposide infusion in patients with advanced cancer.

PURPOSE: This phase I study was undertaken to evaluate the safety and tolerability of prolonged infusional etoposide, and to evaluate its pharmacokinetic/pharmacodynamic profile in patients with advanced cancer. METHODS: A group of 17 patients received a 7-day infusion of etoposide (schedule A) every 21 days at doses from 30 to 75 mg/m2 per day, and a second group of 37 patients a 21-day infusion (schedule B) every 28 days at doses from 18 to 40 mg/m2 per day. Patients had a median Karnofsky performance status (PS) of 80%, and 34 patients had no prior chemotherapy. Etoposide concentrations at steady state (Css) and other pharmacokinetic parameters (plasma clearance, CLp; area under the curve, AUC) were determined during the first treatment cycle. Correlation coefficients were calculated to measure the relationship between variables. RESULTS: Myelosuppression was the major toxicity, and was associated with three deaths. The maximum tolerated dose due to neutropenia was 75 mg/m2 per day for schedule A and 40 mg/m2 per day for schedule B. There was significant interpatient pharmacokinetic variability in both infusional schedules. Even though etoposide dose levels did not significantly correlate with plasma levels, the Css was > or = 1 microgram/ml in the majority of the patients. A significant correlation between AUC and neutrophil absolute decrease was noted only in schedule B (r = 0.56, P = 0.003). There were several marginal relationships in schedule B: PS versus Css (r = 0.31, P = 0.058), PS versus AUC (r = -0.38; P = 0.058) and age versus CLp (r = -0.31, P = 0.057). CONCLUSION: Overall, significant correlations were found for several hematologic variables and etoposide dose levels, but not with the Css values. One major problem with the application of pharmacodynamic models to predict hematologic toxicity in clinical practice is the presence of significant interpatient variability.

Adult↗
PubMed1996

Prolonged infusion of etoposide in patients with advanced non-small cell lung cancer.

We assessed the efficacy and toxicity of two etoposide infusional schedules in patients with advanced non-small cell lung cancer (NSCLC). Twenty-six patients were treated with a 21-day infusion every 28 days at a dose of 25-40 mg/m2/d, and six patients with a 7-day infusion every 21 days at a dose of 45-75 mg/m2/d. Sixty-three percent of patients had a Karnofsky status of 80% or better, and only five (15%) patients had prior chemotherapy. Plasma etoposide concentrations were determined in 26 patients. Sixty-nine treatment cycles were administered. Two patients (6.3%; 90% confidence interval, 1.1-18.4%) had partial responses; with response durations of 2 and 7 months, respectively. The median survival was 4 months. Grade 3 or 4 neutropenia occurred in 13 of 69 cycles (19%) and was associated with three toxic deaths. Ten patients required RBC transfusions. Nausea was common, but was associated with vomiting in only 7% of all cycles. The interpatient variability of etoposide concentrations at steady state was significant. We conclude that the antitumor activity of prolonged infusion of etoposide is not superior to standard dose and schedule in advanced NSCLC.

Adult↗
PubMed1995

A phase I study of etoposide phosphate administered as a daily 30-minute infusion for 5 days.

PURPOSE: To determine the maximum tolerated dose, toxicities, kinetics, and disposition of etoposide phosphate when administered as a daily 30-minute infusion for 5 days. PATIENTS AND METHODS: Twenty-eight patients were enrolled in this phase I dose-escalation trial. Cohorts of patients received etoposide phosphate in etoposide equivalent doses of 50, 75, 100 and 125 mg/m2 intravenously for 30 minutes each day for 5 days. Pharmacokinetic sampling of both blood and urine was performed and concentrations of etoposide and etoposide phosphate were determined on day 1 of study for each patient and on day 4 of study for three patients receiving the 100 mg/m2 dose. RESULTS: The dose-limiting toxicity was reversible myelosuppression as evidenced by leukopenia and neutropenia. Toxicities seen were comparable to those expected from etoposide administration. With this schedule, the 100 mg/m2 dose was the maximum tolerated dose. Nonhematologic toxicities were generally mild. Two patients had major responses and three others had minor responses. Pharmacokinetic analyses revealed rapid (< 15 minutes) extensive conversion of etoposide phosphate to etoposide. Peak plasma etoposide concentrations and etoposide areas under the curve were proportional to the dose of etoposide phosphate administered. Etoposide kinetics were similar to those expected after a comparable dose of etoposide. CONCLUSIONS: Etoposide phosphate is a water-soluble pro-drug of etoposide that is rapidly converted to etoposide in vivo with a toxicity profile similar to etoposide. Etoposide generated from etoposide phosphate exhibits linear kinetics over a dose range of 50 to 125 mg/m2. When administered as a daily 30-minute infusion for 5 days, the dose-limiting toxicity is myelosuppression and 100 mg/m2 daily is the maximum tolerated dose.

Adult↗
PubMed1995

Phase II study of prolonged oral etoposide in combination with intravenous cisplatin in advanced non-small cell lung cancer.

The objectives of the study were to evaluate the combination of cisplatin and prolonged oral etoposide for response rate, survival, and toxicity. The treatment regimen consisted of etoposide (50 mg/m2/day) p.o. for 21 consecutive days and cisplatin (100 mg/m2) i.v. on day 1 every 28 days for up to six courses. Patients with Stage IIIB or IV non-small cell lung cancer who had not received prior chemotherapy and had an ECOG performance status of 0-2 were eligible if they had normal bone marrow, liver and renal functions. Patients were followed weekly for toxicity including complete blood counts. The total number of patients entered in the study was 60, of whom 56 were male and four female, 40 white and 20 African Americans. Median age was 64 years (range, 39-77). Performance status 0, 1, and 2 was present in five, 39, and 16 patients, respectively. Fourteen patients had Stage IIIB and 46 Stage IV disease. A total of 142 treatment courses were administered (median 2, range 1-6). Three patients had a complete response and 19 patients had a partial response for an objective response rate of 37% (95% confidence interval, 31-43%). Median survival was 5 months (range, 1-39+). Neutropenia was the major toxicity with Grade 4 occurring in 25 patients after the first course. The following percent of patients experienced severe or life-threatening hematologic toxicity (Grade 3 and 4 combined) over all courses: leukopenia, 73%; neutropenia, 73%; anemia, 42%; and thrombocytopenia, 37%. Three patients died of neutropenic sepsis.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1995

Schedule dependency of 21-day oral versus 3-day intravenous etoposide in combination with intravenous cisplatin in extensive-stage small-cell lung cancer: a randomized phase III study of the Cancer and Leukemia Group B.

PURPOSE: This was a randomized phase III study to test the schedule dependency of etoposide given as a conventional 3-day intravenous (IV) regimen versus a prolonged 21-day oral regimen for extensive-stage small-cell lung cancer (SCLC). Both regimens contained IV cisplatin. The objectives were to compare survival (primary end point) and to establish response rates, failure-free survival, and toxicity (secondary end points). PATIENTS AND METHODS: Patients with untreated measurable or assessable disease and normal organ function were eligible. Randomization was stratified according to performance status 0 versus 1 or 2. Treatment consisted of etoposide 130 mg/m2/d IV for 3 days and cisplatin 25 mg/m2/d IV for 3 days every 21 days for eight courses (schedule 1) versus etoposide 50 mg/m2/d orally for 21 days and cisplatin 33 mg/m2/d IV for 3 days every 28 days for six courses (schedule 2). In 1990, bioavailability of oral etoposide was assumed to be 50%, and the study was designed to deliver the same total doses of etoposide and cisplatin on both regimens over 24 weeks without the use of growth factors. RESULTS: Between December 1990 and October 1993, 306 eligible patients were entered. Of these, 69% were male and 66% were > or = 60 years of age; 21% had a performance status of 0, 47% a performance status of 1, and 32% a performance status of 2; 156 were randomized to receive schedule 1 and 150 to receive schedule 2. Overall median survival estimates were 9.5 and 9.9 months (difference not significant) for schedule 1 and schedule 2, respectively. The 95% confidence interval (CI) for overall survival, 8 to 11 months, was the same for both schedules, with 126 and 117 deaths on schedule 1 and 2, respectively. Both schedules also resulted in the same median failure-free survival estimate of 7 months (95% CI, 6 to 8 months on either schedule). Complete and partial responses were observed in 15% and 42% of patients on schedule 1 and 14% and 47% on schedule 2, respectively. The overall maximal hematologic toxicities grade 3 and 4 for leukocytes, neutrophils, platelets, and hemoglobin were, respectively, as follows: schedule 1, 62%, 85%, 32%, and 32%; schedule 2, 83%, 83%, 52%, and 53%. Lethal toxicity due to neutropenia and infection occurred in 4% of patients on schedule 1 and 10% on schedule 2 (difference not statistically significant). CONCLUSION: The two schedules of etoposide in combination with cisplatin did not result in differences in treatment outcome with respect to tumor response and survival. However, a significantly greater rate of severe or life-threatening hematologic toxicity was noted on the 21-day oral etoposide treatment schedule.

Administration, Oral↗
PubMed1995

Phase I study of paclitaxel and topotecan in patients with advanced tumors: a cancer and leukemia group B study.

PURPOSE: To define the dose-limiting toxicities (DLTs) and the recommended phase II doses of paclitaxel combined with topotecan, without and with filgrastim support. PATIENTS AND METHODS: Patients with advanced solid tumors and a maximum of one prior chemotherapy regimen for metastatic disease were eligible if they had a performance status of 0 to 1 and normal renal, hepatic, and bone marrow function. Prior treatment with taxanes or comptothecin analogs, and prior pelvic irradiation were not allowed. Patients with a history of cardiac disease or on medications known to affect cardiac conduction were excluded. The dose of topotecan was fixed at 1.0 mg/m2/d for 5 days. The dose of paclitaxel was escalated until the maximum-tolerated dose (MTD), without and with filgrastim 5 micrograms/kg subcutaneously (SC) on days 6 to 14, was reached. Paclitaxel was administered over 3 hours on day 1 before topotecan. Treatment cycles were repeated every 21 days. RESULTS: Of 46 patients entered, 45 were assessable for toxicity and 34 for response. The principal toxicity was neutropenia. Without filgrastim, the MTD of paclitaxel was 80 mg/m2 on day 1 in combination with topotecan 1.0 mg/m2/d for 5 days. With filgrastim, the dose of paclitaxel was escalated to 230 mg/m2 in combination with the same dose of topotecan. At this dose level, one patient had hematologic DLT and a second patient developed neuromuscular DLT. Three patients had a partial response (PR): one with head and neck cancer, a second with non-small-cell lung cancer, and the third with colon cancer. CONCLUSION: We conclude that paclitaxel can be given at clinically relevant doses in combination with topotecan and filgrastim. The recommended dose for phase II studies is paclitaxel 230 mg/m2 on day 1 and topotecan 1.0 mg/m2/day for 5 days with filgrastim 5 micrograms/kg on days 6 to 14.

Adult↗
PubMed1995

Dosing of oral etoposide normalized for body surface area.

The objective of this clinical and pharmacological study was to determine whether any pretreatment parameters were associated with pharmacological or toxicity parameters after prolonged oral etoposide. Therefore, the relationships between patient characteristics and etoposide concentrations and hematological toxicity were evaluated. Sixty patients with advanced non-small cell lung cancer were treated with etoposide 50 mg/m2/day p.o. for 21 consecutive days and cisplatin 100 mg/m2 i.v. on day 1. Complete blood counts and etoposide plasma concentrations were obtained weekly. Etoposide was measured by high-performance liquid chromatography. The input variables were age, gender, race, weight, weight0.66, weight0.75, height, body surface area, performance status, albumin concentration; and total etoposide dose. The outcome measures were etoposide concentration; nadir values (white blood cells, neutrophils, hemoglobin, and platelets); the absolute decrease, relative decrease, and survival fraction of blood cells; and graded toxicity. No significant correlations were found in 49 fully evaluable patients between any of the input and outcome variables. Among the outcome variables, significant correlations were found between etoposide concentration and the logarithmic transformation of the nadir blood counts. If any of the input variables were significantly correlated to etoposide concentrations or toxicity variables, it would be possible to suggest another predictor variable besides body surface area. As long as treatment is not modified for etoposide concentrations, dosing of oral etoposide must still rely on estimates of body surface area.

Administration, Oral↗
PubMed1994

Intravenous pamidronate disodium treatment of bone metastases in patients with breast cancer. A dose-seeking study.

BACKGROUND: Treatment of the symptoms of bone metastases currently involves the use of narcotic medication, radiation therapy, or hormonal therapy. Pamidronate disodium, a bisphosphonate, may prove helpful in the palliative treatment of bone metastases in patients with breast cancer as demonstrated in this multicenter, dose-ranging trial. METHODS: Ambulatory female patients age 18 years or older with breast cancer metastatic to bone and a life expectancy of at least 3 months were eligible for the study. Bone metastases were confirmed by bone scan or bone survey within 6 months of enrollment. Sixty-one patients were treated as outpatients and were randomized to receive one of four intravenous pamidronate regimens for 12 weeks: 30 mg administered every 2 weeks, 60 mg every 4 weeks, 60 mg every 2 weeks, or 90 mg every 4 weeks. The primary efficacy parameter for this study was pain score. The change from baseline in pain score was determined for each patient at each study visit and at endpoint, defined as the last postbaseline evaluation for each patient before or at week 12. Secondary efficacy variables included narcotic scores, urinary calcium/creatinine and hydroxyproline/creatinine ratios, serum osteocalcin and bone alkaline phosphatase concentrations, and bone lesion (radiologic) response. RESULTS: At 3 months, the regimens of 60 mg every 4 weeks, 60 mg every 2 weeks, and 90 mg every 4 weeks resulted in significant reduction in bone pain beginning by week 6 of treatment. The regimen of 30 mg every 2 weeks was not effective. Narcotic use, as reflected by narcotic scores, did not parallel the pain scores, because there was little evidence of any effect for any of the treatment groups. Reduction in bone pain was accompanied by decreases in urinary calcium/creatinine and hydroxyproline/creatinine ratios, and bone alkaline phosphatase concentrations. Side effects of pamidronate were mild and transient. Radiographic changes consistent with healing of lytic lesions were observed in 15 patients (25%). CONCLUSION: Intravenous pamidronate is a well tolerated treatment that produced significant relief of bone pain in the majority of patients with metastatic breast cancer at the three highest doses tested.

Adolescent↗
PubMed1994

Predictive performance of a pharmacodynamic model for oral etoposide.

The objective of this work was to prospectively validate a pharmacodynamic model for 21-day oral etoposide. The model had been developed in 27 untreated patients with stage IIIB or IV non-small cell lung cancer. Treatment consisted of 50 mg/m2/day, p.o., etoposide for 21 days in combination with 100 mg/m2, i.v., cisplatin on day 1 every 28 days for up to 6 courses. Weekly evaluations included etoposide plasma concentrations (Ec, microgram/ml) before the daily dose and WBC and neutrophil counts (ANC, 10(3)/microliters). The relationship between Ec and the pretreatment (WBCp, ANCp) and nadir counts (WBCn, ANCn) in the first course was described as follows: WBCn = 0.35 (1 + WBCp x e-1.12 x Ec)) ANCn = 0.32 (1 + ANCp x e-2.47 x Ec) The same study criteria were used to enter 26 additional patients, and 21 were evaluable for pharmacodynamics (5 had incomplete data). Predicted nadir counts were not significantly different from observed nadir counts (paired t test, P > 0.4). There were 12 and 7 patients correctly predicted to be above and below, respectively, the clinically important ANCn of 0.5 x 10(3)/microliters. The model performed reliably, and therapeutic drug monitoring appears warranted in future studies.

Administration, Oral↗
PubMed1994

Phase I study of topotecan and cisplatin in patients with advanced solid tumors: a cancer and leukemia group B study.

PURPOSE: The objectives of this phase I trial were to determine the dose-limiting toxicities (DLTs) of the novel topoisomerase I inhibitor topotecan combined with cisplatin, to define the maximum-tolerated doses (MTDs) of the combination without and with the use of filgrastim, and to define recommended doses for phase II trials. PATIENTS AND METHODS: Patients with advanced solid tumors were eligible if they had normal bone marrow, renal, and hepatic function and had not previously been treated with platinum compounds. Topotecan was administered intravenously on days 1 through 5 and cisplatin was administered intravenously on day 1 of a 21-day cycle. The topotecan dose was fixed at 1.0 mg/m2/d on the first four dose levels, and cisplatin was escalated in 25-mg/m2 increments from 25 to 100 mg/m2 without filgrastim. After encountering DLT, the dose of cisplatin was decreased by one level and topotecan dose escalation was attempted. After defining the MTD without growth factor, the study proceeded with escalating cisplatin doses to define the MTD with filgrastim 5 micrograms/kg subcutaneously (SC) daily starting on day 6 of treatment. Priming with filgrastim 5 micrograms/kg SC on days -6 to -2 before the first course was explored last. RESULTS: Of 38 patients entered, 37 were eligible, 35 assessable for toxicity in the first course, and 28 assessable for response. The principal toxicity was grade 4 neutropenia, which had to last more than 7 days to be considered dose-limiting. No DLT was observed at the starting cisplatin dose of 25 mg/m2 (dose level 1). On level 2 (cisplatin 50 mg/m2, one patient had dose-limiting neutropenia and one patient had grade 3 renal toxicity. On level 3 (cisplatin 75 mg/m2), two patients had dose-limiting neutropenia. Therefore, cisplatin dose escalation was stopped. On dose level 5 (cisplatin 50 mg/m2 and topotecan 1.25 mg/m2/d), one patient had grade 4 neutropenia that lasted more than 7 days and one patient died of neutropenic sepsis. The remaining dose levels used topotecan 1.0 mg/m2/d plus cisplatin 75 mg/m2 (level 6) and 100 mg/m2 (levels 7 and 8) with filgrastim. No DLT was observed on level 6. On level 7, two patients had dose-limiting neutropenia and one patient had grade 3 hyperbilirubinemia. Priming with filgrastim on level 8 demonstrated no obvious advantage over level 7, and one patient had grade 4 thrombocytopenia that lasted more than 7 days. Three patients with non-small-cell lung cancer achieved a partial response and one patient with breast cancer had a complete response. CONCLUSION: Topotecan and cisplatin in combination cause more neutropenia than expected from either drug given alone at the same dosage. The recommended phase II doses are topotecan 1.0 mg/m2/d for 5 days in combination with cisplatin 50 mg/m2 on day 1 without filgrastim or cisplatin 75 mg/m2 on day 1 with filgrastim support.

Adult↗
PubMed1993

Miller-Dieker syndrome. Detection of a cryptic chromosome translocation using in situ hybridization in a family with multiple affected offspring.

OBJECTIVE: To describe a family in whom fluorescence in situ hybridization allowed for accurate diagnosis of Miller-Dieker syndrome in an at-risk pregnancy and determination of parental carrier status. DESIGN: Retrospective case analysis and application of a new molecular tool to evaluate the family. SETTING: Health maintenance organization. The family was followed up by the Departments of Medical Genetics, Pediatrics, and Obstetrics and Gynecology, Kaiser Permanente Medical Center, Panorama City, Calif. PARTICIPANTS: Members of a single family. INTERVENTIONS: Clinical evaluation and neuroimaging studies of the proband. Prenatal diagnosis via ultrasonography and amniocentesis. Chromosomal evaluation of the couple and their offspring. In situ hybridization studies in both parents and an affected fetus. MEASUREMENTS/MAIN RESULTS: We describe a family in whom fluorescence in situ hybridization detected a submicroscopic deletion of the Miller-Dieker syndrome critical region 17p13.3 arising from a cryptic translocation in one of the parents. The proband was determined at birth owing to the presence of multiple congenital anomalies, including low birth weight, microcephaly, agenesis of the corpus callosum, lissencephaly, cerebral atrophy, unilateral ptosis, polydactyly, and omphalocele. High-resolution chromosome-banding analysis findings were normal in the parents and proband, who died at age 4 years. There were four subsequent pregnancies: two ended in first-trimester spontaneous abortion, and in the other two, large omphaloceles were detected in fetuses at 15 and 13 weeks' gestation. Both pregnancies were terminated. Fluorescence in situ hybridization probes for 17p13.3 had become available before the most recent pregnancy and were used to study parental and fetal cells. As a result, a balanced cryptic translocation between chromosome 17 and chromosome 19 was identified in the father: 46,XY,t(17;19)(p13.3q13.33). An unbalanced form of the translocation, involving a deletion of 17p13.3, was detected with fluorescence in situ hybridization in the fetus. This finding was in accordance with a clinical diagnosis of Miller-Dieker syndrome. CONCLUSIONS: Molecular cytogenetic technology should be used in cases of suspected Miller-Dieker syndrome when high-resolution cytogenetic analysis fails to detect del(17) (p13.3). Positive findings should be followed up with parental studies. In addition, omphalocele should be included among the list of malformations that make up the Miller-Dieker syndrome.

Adult↗
PubMed1993

Role of fetal breathing movements in control of fetal lung distension.

Our aim was to determine the role of fetal breathing movements (FBM) in the maintenance of fetal lung liquid volume. Experiments were performed in 14 chronically catheterized fetal sheep. FBM were selectively abolished for 48 h by the infusion of tetrodotoxin (TTX) onto the phrenic nerves of five fetuses. Lung liquid volumes and secretion rates were measured before each treatment, 46-48 h after the start of the TTX infusion, and 22-24 h after the end of the infusion. Blockade of the phrenic nerves reduced fetal lung liquid volumes from 27.6 +/- 1.9 to 21.8 +/- 2.6 ml/kg and increased lung liquid secretion rates from 3.8 +/- 0.6 to 6.2 +/- 1.1 ml.h-1.kg-1. Control experiments confirmed the lack of effect of TTX infused intravenously and saline infused intrapleurally on changes in fetal lung liquid volume and secretion rate. To measure the static relaxation volume of the fetal lung, in six fetuses we combined skeletal muscle paralysis with bypass of the upper airway for 48 h. This reduced fetal lung liquid volume from 39.1 +/- 3.1 to 23.0 +/- 2.5 ml/kg and increased lung liquid secretion rates from 4.1 +/- 0.7 to 5.8 +/- 0.9 ml.h-1.kg-1. This experiment demonstrates that the fetal lung is normally maintained at a level of expansion that is much greater than its static relaxation volume. We conclude that the volume of luminal liquid in the fetal lungs is dependent on the diaphragmatic contractions associated with FBM. Their effect is to resist the elastic recoil of the fetal lungs, thereby reducing the loss of liquid from the lungs via the trachea.

Animals↗
PubMed1993

Pharmacodynamics of prolonged oral etoposide in patients with advanced non-small-cell lung cancer.

PURPOSE: This study was undertaken to investigate the pharmacodynamic relationship between etoposide drug levels on 21-day oral treatment courses and hematologic toxicities in patients with advanced non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Thirty-two patients with stage IIIB or IV NSCLC were treated with oral etoposide 50 mg/m2/d for 21 consecutive days in combination with cisplatin 100 mg/m2 on day 1. Treatment was repeated every 28 days for up to six courses. Patients had not received previous chemotherapy and had a performance status of 0 to 2. Patients were monitored weekly while on treatment for compliance with oral etoposide and toxicity, including complete blood cell counts, and a blood sample before the daily etoposide dose (drug trough levels). Etoposide concentrations were measured in the plasma by high-performance liquid chromatography (HPLC). RESULTS: Three patients achieved a complete response (CR) and 10 patients a partial response for an objective response rate of 41% (95% confidence interval, 24% to 58%). The median survival was 4 months (range, 1 to 23). Neutropenia was dose-limiting, and two patients died of neutropenic sepsis. Pharmacodynamic correlations for drug concentrations and hematologic toxicities were available for 27 patients and a total of 76 treatment courses, and correlations were significant for graded hematologic toxicity and nadir counts of leukocytes, neutrophils, hemoglobin, and platelets. The grade of infection (77 courses) was also related to drug levels. Using data from 27 initial courses, a pharmacodynamic model was developed to estimate the nadir leukocyte or neutrophil count (WBCn, ANCn) based on the pretreatment count (WBCp, ANCp) and the etoposide concentration (Ec) as follows: WBCn = 0.35 (1 + WBCp x e-1.12 x Ec) and ANCn = 0.32 (1 + ANCp x e-2.47 x Ec). CONCLUSION: Etoposide concentrations are related to the resulting hematologic toxicities. It is possible to predict nadir counts in the first course by a pharmacodynamic model. The above equations need to be validated prospectively and may be useful in future studies of prolonged oral etoposide.

Administration, Oral↗
PubMed1992

Pharmacodynamics of three daily infusions of etoposide in patients with extensive-stage small-cell lung cancer.

The objectives of this study were to define the pharmacodynamics of etoposide and to develop potentially useful models (1) to estimate the plasma clearance using a limited number of samples and (2) to describe the relationship between clearance and the dose-limiting toxicity. A total of 17 patients with extensive-stage small-cell lung cancer were treated with 150 mg/m2 etoposide daily for 3 consecutive days and with 100 mg/m2 cisplatin on day 3 only. Both drugs were given intravenously over 1 h. Treatment was repeated every 21 days for up to six courses. All patients were newly diagnosed (no previous chemotherapy or irradiation) and had a performance status of 0-2. Six patients achieved a complete response as confirmed by repeat bronchoscopy and five patients showed a partial response, for an overall objective response rate of 65% (95% confidence interval, 38%-87%). The median survival was 8 months (range, 1-24+ months). The dose-limiting toxicity was neutropenia. Etoposide pharmacokinetics were measured during the first course and determinations were repeated during courses 3 or 4 and 6. Complete blood counts were obtained weekly. Correlations for etoposide clearance and hematologic toxicities were evaluated for 17 initial courses and for an overall number of 33 courses. Pharmacodynamic correlations were significant for graded hematologic toxicities, as well as nadirs of leukocytes, neutrophils, and platelets for the initial courses and for all courses. To reduce the requirement for numerous blood samples, a limited sampling model was developed to estimate the area under the concentration versus time curve (AUC) with the following equation: AUC = 15.45 + 3.86 x C2 + 7.10 x C4, where C2 and C4 represent the etoposide concentrations at 2 and 4 h, respectively. The total plasma clearance was calculated as the dose divided by the AUC; correlations with toxicity were better for clearance expressed in milliliters per minute than for that expressed in milliliters per minute per square meter of body surface area. The absolute neutrophil count at the nadir (ANCn) can be estimated by the following pharmacodynamic model, which is based on 33 courses: ANCn = -0.399 + 0.024 x Ecl, where Ecl represents the etoposide clearance expressed in milliliters per minute. Further studies are necessary to validate both models prospectively.

Adult↗