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Biomedical subjects

R Lieberman

Publications and source records attributed to R Lieberman.

At least 37 records · Page 2Linked to original sources
PubMed2000

Progress in cancer chemoprevention: development of diet-derived chemopreventive agents.

Because of their safety and the fact that they are not perceived as "medicine," food-derived products are highly interesting for development as chemopreventive agents that may find widespread, long-term use in populations at normal risk. Numerous diet-derived agents are included among the >40 promising agents and agent combinations that are being evaluated clinically as chemopreventive agents for major cancer targets including breast, prostate, colon and lung. Examples include green and black tea polyphenols, soy isoflavones, Bowman-Birk soy protease inhibitor, curcumin, phenethyl isothiocyanate, sulforaphane, lycopene, indole-3-carbinol, perillyl alcohol, vitamin D, vitamin E, selenium and calcium. Many food-derived agents are extracts, containing multiple compounds or classes of compounds. For developing such agents, the National Cancer Institute (NCI) has advocated codevelopment of a single or a few putative active compounds that are contained in the food-derived agent. The active compounds provide mechanistic and pharmacologic data that may be used to characterize the chemopreventive potential of the extract, and these compounds may find use as chemopreventives in higher risk subjects (patients with precancers or previous cancers). Other critical aspects to developing the food-derived products are careful analysis and definition of the extract to ensure reproducibility (e.g., growth conditions, chromatographic characteristics or composition), and basic science studies to confirm epidemiologic findings associating the food product with cancer prevention.

Biomarkers↗
PubMed2000

Novel translational model for breast cancer chemoprevention study: accrual to a presurgical intervention with tamoxifen and N-[4-hydroxyphenyl] retinamide.

Surrogate end point biomarkers for risk assessment and efficacy of potential chemopreventive agents are needed to improve the efficiency and reduce the cost of chemoprevention trials. It is imperative to develop the best clinical breast model for translational surrogate end point biomarker studies, especially with respect to accrual feasibility. We have initiated a prospective study to develop biomarkers for tamoxifen and N-[4-hydroxyphenyl] retinamide by administering either a placebo or both drugs for 2-4 weeks to women with ductal carcinoma in situ or early invasive cancers in the interval between the initial diagnostic core biopsy and definitive surgery. The principle end point is pretreatment versus posttreatment tumor levels of Ki-67; a number of other exploratory markers will also be examined. The planned target sample size is 100 patients. Between February 1997 and February 2000, 4514 women who had either an abnormal mammogram or a diagnosed breast cancer were screened for the study. Of these 4514 screened patients, 52 (1%) were registered on the study. Major factors of nonparticipation in the remaining 4462 women were as follows: (a) no evidence of malignancy (2081 patients; 46%); (b) ineligible per protocol criteria (575 patients; 13%); (c) preoperative chemotherapy/tamoxifen (520 patients; 11%); (d) surgery scheduling conflict (360 patients; 8%); (e) outside needle biopsy (221 patients; 5%); (f) no residual disease after excisional biopsy (345 patients; 8%); and (g) second opinion only (123 patients; 3%). Other nonparticipation factors included fine needle aspiration only, refusal, tumor size > 2 cm, and estrogen replacement therapy (35 patients each; 2% each). The protocol was amended in midstudy to allow outside needle biopsy, tumor > 2 cm, and estrogen replacement therapy. Accrual to biomarker (nontherapeutic) protocols with delay in definitive cancer surgery is challenging but feasible. Although some accrual problems remain, we have nonetheless succeeded in recruiting 50% of our target sample size in a 3-year period.

Adult↗
PubMed1999

Bayesian monitoring of phase II trials in cancer chemoprevention.

Early randomized Phase II cancer chemoprevention trials which assess short-term biological activity are critical to the decision process to advance to late Phase II/Phase III trials. We have adapted published Bayesian interim analysis methods (Spiegelhalter et al., J. R. Statist. Soc A, 1994; 157: 357-416) which give greater flexibility and simplicity of inference to the monitoring of randomized controlled Phase II trials using intermediate endpoints. The Bayesian stopping rule is designed to stop the trial more quickly when the evidence suggests ineffectiveness rather than when it suggests biological activity, thus allowing resources to be concentrated on those agents that show the most promise in this early stage of testing. We investigate frequentist performance characteristics of the proposed method through simulation of randomized placebo controlled trials with a growth factor intermediate end-point using mean and variance values derived from the literature. Simulation results show expected error rates and trial size similar to other commonly used group sequential methods for this setting. These results suggest that the Bayesian approach to interim analysis is well suited for monitoring small randomized controlled Phase II chemoprevention trials for early detection of either inactive or promising agents.

Antineoplastic Agents↗
PubMed1999

Strategies for chemoprevention of prostate cancer.

Because prostate cancer has a long latency and high incidence, it is a good target for chemoprevention by agents such as retinoids, antiandrogens, antiestrogens, and vitamin D analogs. Phase II chemoprevention trials are frequently conducted on cohorts of patients with previous cancers or premalignant lesions who are scheduled for prostate cancer surgery; such trials are currently in progress with several agents. Prostatic intraepithelial neoplasia (PIN) can be used as a surrogate endpoint biomarker for prostate cancer incidence. Studies of men with high-grade PIN (HGPIN) are particularly useful in that they require a much smaller cohort of 200-400 patients instead of the 18 000 patients required for typical Phase III trials. Even with a smaller sample size, statistically significant evidence of cancer prevention is achieved due to the high probability of HGPIN progressing to cancer (35-55%). A Bayesian sequential monitoring system allows interim analysis of biomarker modulation as early as the completion of 30 patients. Putting all these strategies together will help inhibit, delay, or modulate the natural history of prostate carcinogenesis.

Journal Article↗
PubMed1999

Progress in cancer chemoprevention.

More than 40 promising agents and agent combinations are being evaluated clinically as chemopreventive drugs for major cancer targets. A few have been in vanguard, large-scale intervention trials--for example, the studies of tamoxifen and fenretinide in breast, 13-cis-retinoic acid in head and neck, vitamin E and selenium in prostate, and calcium in colon. These and other agents are currently in phase II chemoprevention trials to establish the scope of their chemopreventive efficacy and to develop intermediate biomarkers as surrogate end points for cancer incidence in future studies. In this group are fenretinide, 2-difluoromethylornithine, and oltipraz. Nonsteroidal anti-inflammatories (NSAID) are also in this group because of their colon cancer chemopreventive effects in clinical intervention, epidemiological, and animal studies. New agents are continually considered for development as chemopreventive drugs. Preventive strategies with antiandrogens are evolving for prostate cancer. Anti-inflammatories that selectively inhibit inducible cyclooxygenase (COX)-2 are being investigated in colon as alternatives to the NSAID, which inhibit both COX-1 and COX-2 and derive their toxicity from COX-1 inhibition. Newer retinoids with reduced toxicity, increased efficacy, or both (e.g., 9-cis-retinoic acid) are being investigated. Promising chemopreventive drugs are also being developed from dietary substances (e.g., green and black tea polyphenols, soy isoflavones, curcumin, phenethyl isothiocyanate, sulforaphane, lycopene, indole-3-carbinol, perillyl alcohol). Basic and translational research necessary to progress in chemopreventive agent development includes, for example, (1) molecular and genomic biomarkers that can be used for risk assessment and as surrogate end points in clinical studies, (2) animal carcinogenesis models that mimic human disease (including transgenic and gene knockout mice), and (3) novel agent treatment regimens (e.g., local delivery to cancer targets, agent combinations, and pharmacodynamically guided dosing).

Animals↗
PubMed1999

Evaluation of biomarker modulation by fenretinide in prostate cancer patients.

An NCI-sponsored, phase II trial of N-(4-hydroxyphenyl)- retinamide (4-HPR) in patients with organ-confined prostate cancer in the period prior to radical prostatectomy was carried out. Thirty-seven men with the histologic diagnosis of prostate cancer planning to have radical prostatectomy entered the study after informed consent and were given 4-HPR (or matching placebo) as a single daily dose (two 100-mg capsules of 4-HPR or two capsules of placebo daily) for 3 weeks prior to surgery. Four men dropped out for unrelated reasons. Thirty-three men completed the study. At the time of surgery, repeat biopsies of the prostate were performed to study the effects of the drug on potential surrogate endpoint biomarkers (SEBs) of malignancy within the tissue. The panel of potential SEBs of malignancy include p53, cytomorphometric indices, ploidy, PNCA, erbB-2, erbB-3, EGF receptor, TGF-alpha tumor-associated glycoprotein-72, fatty acid synthetase and Lewis Y antigen. Twenty-three patients had matching pre- and posttherapy lesions and were considered informative. Results from the patients indicate significant differential expression of biomarkers in pretreatment specimens of uninvolved prostatic tissue (normal-appearing epithelia) prostatic intraepithelial neoplasia (PIN) and prostate cancer. The mean erbB-2 expression was 0.58 in uninvolved vs. 1.04 in PIN (p = 0.002); while the mean erbB-2 expression was 1.35 in prostate cancer (p = 0.0007, uninvolved vs. prostate cancer). A similar pattern of increased biomarker expression between uninvolved and PIN or prostate cancer tissues can be observed for EGF receptor (mean = 1.21, 1.87 and 1.76 for uninvolved, PIN and prostate cancer, respectively) and erbB-3 (mean = 0.81, 1.59 and 1.30 for uninvolved, PIN and prostate cancer, respectively). There were no statistically significant differences in biomarkers observed in the 4-HPR-treated patients when compared with placebo-treated control patients. There was a posttreatment up-regulation of biomarkers observed in both groups of patients. This observation is most likely explained by an effect due to the diagnostic sextant biopsy equally affecting both groups of patients. Results from this study do not demonstrate a chemoprevention effect of 4-HPR on tissue-based SEBs at the dose given.

Adenocarcinoma↗
PubMed1999

Chemoprevention of prostate cancer: concepts and strategies.

Chemoprevention is the administration of agents to prevent induction and inhibit or delay progression of cancers. For prostate, as for other cancer targets, successful chemopreventive strategies require well-characterized agents, suitable cohorts, and reliable intermediate biomarkers of cancer for evaluating chemopreventive efficacy. Agent requirements are experimental or epidemiological data showing chemopreventive efficacy, safety on chronic administration, and a mechanistic rationale for the observed chemopreventive activity. On this basis, promising chemopreventive drugs in prostate include retinoids, antiandrogens, antiestrogens, steroid aromatase inhibitors, 5alpha-reductase inhibitors, vitamins D and E, selenium, lycopene, and 2-difluoromethylornithine. Phase II trials are critical for evaluating chemopreventive efficacy. Cohorts in these trials should be suitable for measuring the chemopreventive activity of the agent and the intermediate biomarkers chosen as endpoints. Many cohorts proposed for phase II trials are patients with previous cancers or premalignant lesions. For such patients, trials should be conducted within the context of standard treatment. Two cohorts currently used in phase II prostate cancer chemoprevention trials are patients with PIN and patients scheduled for prostate cancer surgery. Biomarkers should fit expected biological mechanisms, be assayed reliably and quantitatively, measured easily, and correlate to decreased cancer incidence. Protocols for adequately sampling tissue are essential. Changes in PIN provide prostate biomarkers with the ability to be quantified and a high correlation to cancer. PIN measurements include nuclear polymorphism, nucleolar size and number of nucleoli/nuclei, and DNA ploidy. Other potentially useful biomarkers are associated with cellular proliferation kinetics (e.g. PCNA and apoptosis), differentiation (e.g. blood group antigens, vimentin), genetic damage (e.g. LOH on chromosome 8), signal transduction (e.g. TGFalpha, TGFbeta, IGF-I, c-erbB-2 expression), angiogenesis, and biochemical changes (e.g. PSA levels).

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

Pharmacokinetics of amifostine: effects of dose and method of administration.

Findings of pharmacokinetic studies of amifostine (Ethyol; Alza Pharmaceuticals, Palo Alto, CA/US Bioscience, West Conshohocken, PA) in animal models and in human cancer patients support the hypothesis that amifostine pharmacokinetics are nonlinear. The nonlinear pharmacokinetic behavior of amifostine suggests that administration of doses higher than 740 mg/m2 does not increase the amount of drug available due to urinary excretion of the excess parent drug and its metabolites. Although the intravenous formulation of amifostine is the only one currently used in the treatment of cancer patients, there is growing interest in the investigation of subcutaneous administration as a practical alternative. A pilot pharmacokinetic evaluation of subcutaneous administration of amifostine in 12 healthy male volunteers compared the relative bioavailability of 500 mg of amifostine administered subcutaneously with that of 200 mg/m2 given intravenously.

Administration, Oral↗
PubMed1998

The development of a risk-adjusted capitation payment system: the Maryland Medicaid model.

This article describes the risk-adjusted payment methodology employed by the Maryland Medicaid program to pay managed care organizations. It also presents an empirical simulation analysis using claims data from 230,000 Maryland Medicaid recipients. This simulation suggests that the new payment model will help adjust for adverse or favorable selection. The article is intended for a wide audience, including state and national policy makers concerned with the design of managed care Medicaid programs and actuaries, analysts, and researchers involved in the design and implementation of risk-adjusted capitation payment systems.

Ambulatory Care↗
PubMed1998

Aromatase inhibitors as potential cancer chemopreventives.

Epidemiological and experimental evidence strongly supports a role for estrogens in the development and growth of breast tumors. A role for estrogen in prostate neoplasia has also been postulated. Therefore, one chemopreventive strategy for breast and prostate cancers is to decrease estrogen production. This can be accomplished by inhibiting aromatase, the enzyme that catalyzes the final, rate-limiting step in estrogen biosynthesis. The use of aromatase inhibitors is of clinical interest for cancer therapy, and selective, potent aromatase inhibitors have been developed. Several of these agents have demonstrated chemopreventive efficacy in animal models. The rationale for the use of aromatase inhibitors as chemopreventives and identification of inhibitors to serve as potential chemopreventive agents are the subjects of this review. After background information regarding aromatase is presented, the data for each inhibitor are summarized separately. The discussion focuses on those inhibitors that are clinically available or in clinical trials, including: aminoglutethimide (Cytadren), rogletimide, fadrozole hydrochloride, liarozole hydrochloride, anastrozole (Arimidex), letrozole, vorozole, formestane, exemestane, and atamestane. On the basis of results from preclinical studies, aromatase inhibitors may be promising agents for clinical trials in populations at high risk for developing estrogen-dependent cancers. Total suppression of aromatase may have adverse effects, as is evident in postmenopausal women (increased osteoporosis, cardiovascular disease, and urogenital atrophy). However, on the basis of preclinical studies of chemopreventive efficacy and chemotherapeutic applications of aromatase inhibitors showing dose-response efficacy, it may be possible to obtain chemopreventive effects without total suppression of aromatase and circulating estrogen levels. Suppressing local estrogen production may be an alternative strategy, as suggested by the discovery of a unique transcriptional promoter of aromatase gene expression, I.4, in breast adipose tissue. The development of drugs that target this promoter region may be possible.

Aromatase↗
PubMed1998

Development of new cancer chemoprevention agents: role of pharmacokinetic/pharmacodynamic and intermediate endpoint biomarker monitoring.

Recently, several promising strategies have been advanced for improving the efficiency of new agent development. These include pharmacokinetic/pharmacodynamic (PK/PD) and intermediate endpoint biomarker (IEB) monitoring. Here, we review their essential role as practical tools for guiding the evaluation of agents for cancer chemoprevention (CP) and provide examples of CP agents that utilize these approaches. Several important categories of IEBs are delineated, including histologically based (intraepithelial neoplasias and nuclear morphometry). The use of select IEBs combined with a Bayesian method for clinical trial monitoring for rapid identification of ineffective or promising agents is discussed. The similarities between IEB and TDM are described. Finally, we present future tools for enhanced monitoring of CP agents that will impact on laboratory medicine and are also applicable to many other drug classes, e.g., laser capture microdissection and cDNA chip microarrays that assess gene expression patterns of precancerous and cancerous lesions.

Anti-Inflammatory Agents↗
PubMed1997

Pharmacodynamics and pharmacokinetics of a 72-hour infusion of 9-aminocamptothecin in adult cancer patients.

PURPOSE: To investigate the pharmacokinetics and pharmacodynamics of 9-aminocamptothecin (9-AC) infused over 72 hours at doses of 5 to 74 micrograms/m2/h. PATIENTS AND METHODS: 9-AC lactone and total (lactone plus carboxylate) plasma concentrations were measured in 44 patients with solid tumors using a high-performance liquid chromatography (HPLC) assay. Fifteen patients underwent extended pharmacokinetic sampling to determine the distribution and elimination kinetics of 9-AC. RESULTS: At steady-state, 8.7% +/- 4.7% (mean +/- SD) of the total drug circulated in plasma as the active 9-AC lactone. Clearance of 9-AC lactone was uniform (24.5 +/- 7.3 L/h/m2) over the entire dose range examined; however, total 9-AC clearance was nonlinear and increased at higher dose levels. In 15 patients treated at dose levels > or = 47 micrograms/m2/h, the volume of distribution at steady-state for 9-AC lactone was 195 +/- 114 L/m2 and for total 9-AC it was 23.6 +/- 10.6 L/m2. The elimination half-life was 4.47 +/- 0.53 hours for 9-AC lactone and 8.38 +/- 2.10 hours for total 9-AC. In pharmacodynamic studies, dose-limiting neutropenia correlated with steady-state lactone concentrations (Css) R2 = .77) and drug dose (R2 = .71). CONCLUSION: Plasma 9-AC concentrations rapidly declined to low levels following the end of a 72-hour infusion and the mean fraction of total 9-AC circulating in plasma as the active lactone was less than 10%. The pharmacokinetics of 9-AC may have a great impact on its clinical activity and should be considered in the design of future clinical trials of this topoisomerase I inhibitor.

Adult↗
PubMed1996

Teaching healthcare professionals about drug-induced disease: an innovative clinical therapeutic approach.

An innovative conference on the general principles of recognition and management of drug-induced disease was developed for healthcare professionals (particularly primary care). The full-day conference used a clinical therapeutic approach and was a cooperative effort of the United States Food and Drug Administration (FDA) Center for Drug Evaluation and Research (CDER) Staff College and Georgetown University Medical Center (GUMC). Linked with the FDA MedWatch postmarketing surveillance initiative, the conference used multiple formats, including didactic presentations, panel discussions, and case discussions led by faculty from various disciplines (e.g., internal and family medicine, psychiatry, clinical pharmacology, dentistry, clinical pharmacy, nursing, epidemiology). Conference topics included new drug approval, pharmacokinetic/pharmacodynamic considerations, and clinical assessment of adverse drug events. Tests were administered to participants before and after the conference, and participants completed a conference evaluation. Mean scores for the pre- and posttests were compared globally and by professional discipline. Conference evaluations were assessed for responses to eight standardized statements and elicited comments. After the conference, mean and median test scores were improved both globally and by discipline in comparison to protest results, with improvement on almost all individual test questions. Comparison of median scores for the pre- and posttests showed small differences between physicians and pharmacists. Evaluations showed markedly positive response to standardized statements, including enhancement of professional growth; elicited comments were supportive of conference effectiveness and attendee acceptance. This conference, which utilized a combination of educational formats, was designed to present material of an innovative nature. Results indicate that the conference was well-received and fulfilled specified learning objectives, including recognition of populations particularly vulnerable to adverse drug events and understanding of how individual providers can contribute to FDA postmarketing surveillance. Continuing educational efforts using this approach are encouraged.

Drug-Related Side Effects and Adverse Reactions↗
PubMed1996

Choroid plexus cysts: not associated with Down syndrome.

We sought to determine whether there is an association between choroid plexus cysts identified in the second-trimester fetus and trisomy 21. Over a 7-year period, fetuses scanned between 14 and 22 weeks were prospectively evaluated for the presence of choroid plexus cysts. Follow-up on fetuses with choroid plexus cysts was obtained by review of the medical records. Over the same time period, the scans and reports of all fetuses with trisomy 21 detected in our laboratory by mid-trimester amniocentesis were reviewed. The prevalence of choroid plexus cysts in fetuses with and without trisomy 21 were compared by means of X2 analysis. A total of 473 fetuses with choroid plexus cysts were identified among 32,053 second-trimester fetuses. Sixteen fetuses were lost to follow-up, three had structural defects and normal karyotypes and 21 had abnormal karyotypes, two of which were trisomy 21. Other abnormal karyotypes included trisomy 18, unbalanced translocation and triploidy, previously reported elsewhere. The remaining 433 fetuses either had normal karyotypes or were normal newborns. The prevalence of choroid plexus cysts (excluding fetuses with trisomy 18) was 1.38% in our general population. During the study period, 143 fetuses with trisomy 21 were karyotyped in our laboratory, and two of these (1.40%) had choroid plexus cysts. Both had other sonographic abnormalities suggesting trisomy 21. The difference in prevalence of fetuses with choroid plexus cysts and trisomy 21 vs. those without trisomy 21 was not statistically significant (X2 = 0.98; relative risk (RR) = 1.02; 95% CI = 0.26, 4.03). We conclude that choroid plexus cysts occur with similar frequency in fetuses with trisomy 21 to that in fetuses from the general population. The finding of choroid plexus cysts should not be used to increase the patient's calculated risk of having a fetus with trisomy 21.

Adult↗
PubMed1996

Role of pharmacokinetic-pharmacodynamic principles in rational and cost-effective drug development.

An important goal of drug development is to define dose and concentration-response relationships for new drugs and biologics. Such critical information from controlled clinical trials can provide primary evidence of efficacy and safety and an informative database for devising dosing instructions for clinical use. This article describes applications of pharmacologic principles [pharmacokinetic-pharmacodynamic (PK-PD)] and modeling methods for drugs in which the evaluation process is guided by and/or identifies significant PK and/or PD variability in drug response. In the case of the recently registered immunosuppressive agent, tacrolimus, preclinical PK-PD in model systems can be used to rationally design safe and effective immunomodulatory dosing regimens for phase 1 clinical studies. Furthermore, a study design based on concentration control guided by a novel artificial intelligence modeling system (AIMS) can be efficiently applied to conduct randomized clinical trials in auto-immunity and to implement cost-effective therapeutic drug monitoring of tacrolimus and cyclosporine in clinical transplantation. In the case of a cardioselective beta-adrenergic blocking agent, betaxolol, marketed for essential hypertension, population PD modeling can be shown to be a more efficient method for estimating dose response compared with standard statistical tests. Using a sigmoid Emax PD model, only a fraction (40 of 300) of the randomized patients was needed to demonstrate dose response. Therefore, two methods, i.e., PD modeling of dose response and AIMS-guided dosing, can achieve significant cost benefits for drug developers, patient care, and the health care system.

Artificial Intelligence↗
PubMed1996

Computer-guided randomized concentration-controlled trials of tacrolimus in autoimmunity: multiple sclerosis and primary biliary cirrhosis.

A randomized concentration-controlled clinical trial (RCCCT) is a trial design in which patients are randomized to predefined blood drug concentrations (low, medium, high). If the concentration ranges are sufficiently separated, this study design can reveal important blood concentration-response relations. Tacrolimus is a potent yet "infant" immunosuppressant for the treatment and prevention of graft rejection and has been shown to exhibit significant clinical activity in some immune-mediated disorders. A tacrolimus artificial intelligence modeling system (AIMS) was used to guide patient dosing to achieve target concentrations specified by the study protocols. In the Multiple Sclerosis study group, we were able to define a concentration range (0.3-0.7 ng/ml) that appeared to show efficacy and minimal tacrolimus toxicity. Patients randomized to the high zone (0.6-1.2 ng/ml) in the Primary Biliary Cirrhosis study group showed significant reduction (approximately 50%) in surrogate efficacy markers [aspartate aminotransferase (SGOT), alanine aminotransferase (SGPT)] compared with patients in the low zone (0.1-0.6 ng/ml). Therefore the RCCCT allowed the detection and delineation of clinically significant concentration-response relations in an ethical and efficient manner.

Artificial Intelligence↗
PubMed1996

Phase I and pharmacologic study of 9-aminocamptothecin given by 72-hour infusion in adult cancer patients.

PURPOSE: To conduct a phase I and pharmacologic study of the new topoisomerase I inhibitor, 9-aminocamptothecin (9-AC). PATIENTS AND MATERIALS: A 72-hour infusion of 9-AC was administered every 14 days to 48 solid-tumor patients at doses of 5 to 59 microg/m2/h without granulocyte colony-stimulating factor (G-CSF) and 47 to 74 microg/m2/h with G-CSF. RESULTS: Without G-CSF, two of eight patients who received 47 microg/m2/h had dose-limiting neutropenia in their initial cycle, as did both patients who received 59 microg/m2/h (with a platelet count < 25,000/microL in one). With G-CSF, zero of seven patients treated with 47 microg/m2/h had dose-limiting neutropenia in their first cycle, while dose-limiting neutropenia occurred in six of 14 patients (with platelet count < 25,000/microL in five) entered at 59 microg/m2/h. Among 39 patients entered at > or = 25 microg/m2/h 9-AC with or without G-CSF, fatigue, diarrhea, and nausea/vomiting of grade 2 severity ultimately occurred in 54%, 30%, and 38%, respectively, while grade 3 toxicities of each type occurred in 8% of patients. Steady-state 9-AC lactone concentration (Css) increased linearly from 0.89 to 10.6 nmol/L, and correlated strongly with leukopenia ( r = .85). CONCLUSION: The recommended phase II dose of 9-AC given by 72-hour infusion every 2 weeks is 35 microg/m2/h without G-CSF or 47 microg/m2/h with G-CSF support. Dose escalation in individual patients may be possible according to their tolerance.

Adult↗