Search PubMed⌕ Search

Biomedical subjects

M J Ratain

Publications and source records attributed to M J Ratain.

At least 127 records · Page 7Linked to original sources
PubMed1993

Phase I trial of granulocyte-macrophage colony-stimulating factor plus high-dose cyclophosphamide given every 2 weeks: a Cancer and Leukemia Group B study.

BACKGROUND: Chemotherapy-induced myelosuppression often limits escalation of cancer chemotherapy doses. Cyclophosphamide, an alkylating agent, is an ideal candidate for dose escalation: A log-linear relationship between cell kill and dose has been demonstrated, and the drug spares hematopoietic stem cells. In addition, studies suggest that granulocyte-macrophage colony-stimulating factor (GM-CSF) can enhance the ability to achieve optimal dose intensity as well as ameliorating chemotherapy-induced myelosuppression. PURPOSE: The purpose of this study was to determine the maximum tolerated dose and the toxic effects of cyclophosphamide administered every 2 weeks with GM-CSF support. METHODS: For this trial by the Cancer and Leukemia Group B (CALGB), cohorts of patients were treated with cyclophosphamide as a 1-hour intravenous infusion every 14 days; GM-CSF was given subcutaneously on days 3-10. Four dose levels of cyclophosphamide (1.5, 3.0, 4.5, and 6.0 g/m2) and three dose levels of GM-CSF (2.5, 5.0, and 10.0 micrograms/kg per day) were evaluated. There was no dose escalation in individual patients. Fifty-one patients with solid tumors who had CALGB performance status 0 or 1 and minimal prior radiotherapy were eligible for analysis. Drug clearance and area under the curve for plasma drug concentration x time (AUC) were estimated at completion of the infusion and at 4 and 24 hours after the start of the infusion. RESULTS: Ninety-five courses of therapy were analyzed. Treatment with cyclophosphamide at 3.0 g/m2 or more resulted in neutropenia (absolute neutrophil counts < 100/microL) in all cycles of therapy. At those doses, blood cell count recovery adequate for re-treatment occurred in 67%-85% of cycles (median, 16 days). Doses of 6.0 g/m2 were associated with the greatest degree of myelosuppression and frequent hospitalization (88% of cycles); requirements for blood transfusion prohibited further dose escalation. Nonhematologic toxic effects were tolerable, with two episodes of reversible cardiotoxicity and four episodes of hemorrhagic cystitis that precluded further therapy. Degree of myelosuppression was not correlated with cyclophosphamide AUC or clearance. CONCLUSIONS: The recommended phase II dose of cyclophosphamide is 4.5 g/m2 administered every 2 weeks with GM-CSF given at 5.0 micrograms/kg per day of GM-CSF. Our results suggest that, with GM-CSF support, high cumulative doses of cyclophosphamide can be given to achieve optimal dose intensity, with reproducible blood cell count recovery and without the need for autologous bone marrow transplantation. IMPLICATIONS: Phase II studies of this intensive regimen in malignant diseases sensitive to alkylating agents are currently being done in CALGB.

Adult↗
PubMed1993

Phase I study of amonafide dosing based on acetylator phenotype.

Amonafide is extensively metabolized, including N-acetylation to an active metabolite. Prior studies have demonstrated that patients who are fast acetylators of amonafide (and other drugs) have increased toxicity at standard doses of amonafide. The primary objective of this study was to define the recommended phase II dose of amonafide separately for slow and fast acetylators. Twenty-six patients with advanced cancer underwent acetylator phenotyping with caffeine and were assigned to a dose level. Slow acetylators were treated at 375 mg/m2 (daily for 5 days) and had a median WBC nadir of 1600/microliters. Fast acetylators were treated at both 200 and 250 mg/m2, resulting in median WBC nadirs of 5300 and 2000/microliter, respectively. Two patients were not typeable, and two patients appear to have been misphenotyped, one in each phenotype category. Pharmacodynamic analysis yielded a model for nadir WBC including acetylator phenotype, 24-h N-acetyl-amonafide plasma concentration, gender, and pretreatment WBC. We recommend doses of 250 and 375 mg/m2 (for 5 days) for further phase II testing of amonafide in fast and slow acetylators, respectively.

Acetylation↗
PubMed1993

A phase I study of subcutaneous recombinant interleukin-2 and interferon alfa-2a.

BACKGROUND: Both recombinant interferon alfa and interleukin-2 (IL-2) have been shown to have some activity as single agents in metastatic renal cell cancer (RCC), although their activity is minimal in more common solid tumors. Recent preclinical studies have suggested that the combination of these two agents is especially promising. METHODS: Subcutaneous recombinant interferon alfa-2a and IL-2 were administered at one of five dose levels to 33 patients with refractory solid tumors, including 21 patients with RCC. A constant ratio of 5:1 of interferon alfa-2a to IL-2 was used. Interferon alfa-2a and IL-2 were administered three and five times weekly, respectively, for a total of 4 weeks, followed by a rest of 1-3 weeks between cycles. RESULTS: The dose-limiting toxic effects included hypotension, nephrotoxicity, and fatigue. At the recommended Phase II dose of 7.5 million units (MU)/m2 of interferon alfa-2a and 1.5 MU/m2 of IL-2, 12 patients were treated. Ten of 12 completed the 4-week cycle without modification. Four patients at that dose level had Grade 3-4 toxic effects. Partial responses were observed in 4 of 16 assessable patients with RCC. CONCLUSIONS: Subcutaneous interferon alfa-2a and IL-2 can be self-administered safely on an outpatient basis. At tolerable doses, responses can be achieved in metastatic RCC.

Adult↗
PubMed1993

Phase I clinical and pharmacological study of iododeoxyuridine and bleomycin in patients with advanced cancer.

Studies previously performed in our laboratory demonstrated synergistic cytotoxicity and DNA strand break formation in human tumor cells following exposure to a combination of bromodeoxyuridine and bleomycin. Synergy was evident when bromodeoxyuridine was administered prior to or simultaneously with bleomycin and occurred over a wide range of concentration ratios. We therefore undertook a phase I clinical trial of the combination of iododeoxyuridine (IdUrd) and bleomycin to determine the maximally tolerated dose of IdUrd that could be administered with a standard dose of bleomycin and to determine the toxicities of the combination. Eligible patients were those with advanced cancer refractory to standard therapy who had a performance status of 0-2, measurable or evaluable disease, and adequate organ function. IdUrd was administered as a 5-day continuous i.v. infusion beginning at a dose of 250 mg/m2/day with escalation in cohorts of 3-6 patients according to a modified Fibonacci scheme. Bleomycin was administered at a dose of 15 mg/m2/day as a continuous i.v. infusion during the last 3 days of the IdUrd infusion. Cycles of therapy were repeated every 28 days. Plasma levels of IdUrd and iodouracil were determined by high performance liquid chromatography. Thirty patients received a total of 79 cycles of IdUrd/bleomycin. Dose-limiting toxicity was bone marrow suppression. At the maximally tolerated IdUrd dose of 2780 mg/m2/day, the median neutrophil nadir after the first cycle of therapy was 805/microliters and the median platelet nadir was 48,000/microliters. Other toxic effects included mucositis, fatigue, nausea, diarrhea, fever, and skin toxicity. Plasma steady-state concentrations of IdUrd increased proportionally to administered IdUrd dose. IdUrd clearance varied from 0.253 liters/min/m2 to 0.503 liters/min/m2 and did not correlate with IdUrd dose. IdUrd dose and concentration correlated significantly with granulocyte and platelet nadirs, and a pharmacodynamic model for white blood cell count nadir could be defined by pretreatment white blood cell count, IdUrd dose, and gender. The recommended IdUrd dose for phase II testing of this combination is 2140 mg/m2/day. Phase II studies will be of particular interest in those diseases, such as carcinomas of the head, neck, and esophagus, where bleomycin has documented activity as a single agent.

Adult↗
PubMed1993

Model-guided determination of maximum tolerated dose in phase I clinical trials: evidence for increased precision.

BACKGROUND: A widely used phase I design in clinical trials of chemotherapy for cancer and for AIDS (acquired immunodeficiency syndrome) allows for dose escalation in cohorts of three to six patients. Escalation continues until a predefined percentage of patients experience unacceptable toxic effects at a given dose level. A safe and maximum tolerated dose (MTD) for phase II study is then determined. This standard phase I study design has serious inadequacies. MTD is not a model-based estimate of the true dose that would yield the targeted dose-limiting toxicity rate. Moreover, this simplistic study design allows some patients in the phase I study to be treated at doses unlikely to have therapeutic efficacy. PURPOSE: We constructed a novel quantitative assessment design that repetitively evaluates accumulating dose-toxicity data by repeatedly fitting and updating a pharmacodynamic model after small cohorts of patients are treated. The goal was to more accurately estimate the MTD. METHODS: One hundred phase I studies were simulated by both the standard and quantitative assessment phase I designs. We compared determination of MTD, frequency of grade 0 leukopenia (no toxicity), and study size in the studies simulated using the standard design with those in the studies simulated using the quantitative assessment design. RESULTS: The median MTD determined from the 100 studies was nearly identical for the two designs: 100 and 95 mg/m2 per day for standard and quantitative assessment designs, respectively. However, the interstudy variation in the MTD was decreased in the quantitative assessment design. Moreover, the study size was significantly reduced (P < .0001), and the median percentage of patients treated at subtoxic doses (no leukopenia) was significantly lower for the quantitative assessment design (44% versus 48%; P < .0001). CONCLUSION: Our results show clear evidence that a phase I study design using dose and toxicity data in a repetitive and quantitative manner can identify the MTD with more accuracy than the standard design. IMPLICATIONS: New approaches must be explored to improve our ability to identify the optimal dose for phase II studies of chemotherapy for cancer and for AIDS. There is evidence that the quantitative assessment design will identify the MTD with fewer patients, more precision, and fewer patients exposed to suboptimal doses.

Clinical Trials, Phase I as Topic↗
PubMed1993

Phase I clinical and pharmacology study of 502U83 given as a 24-h continuous intravenous infusion.

502U83 is an arylmethylaminopropanediol that displays significant antitumor activity in a number of murine and human tumor-model systems. In the present phase I study, a 24-h continuous intravenous infusion of this agent was given every 28 days to patients with advanced or refractory solid tumors. In all, 46 patients received a total of 96 cycles of 502U83 at doses ranging from 25 to 8,000 mg/m2. No significant hematologic, gastrointestinal, or neurologic toxicity was observed. At doses of 2,000 mg/m2 and higher, prolongation of the corrected QT interval on ECG was evident in most patients but was completely reversible, was not associated with arrhythmias, and was not dose-limiting. Dose-limiting pulmonary toxicity characterized by acute onset of dyspnea, severe hypoxemia, interstitial pulmonary edema, and death occurred in three patients treated at the highest dose levels. Plasma concentrations of 502U83 and its metabolites were measured by high-performance liquid chromatography. The 502U83 maximal concentration (Cmax) and area under the concentration-time curve (AUC) were proportional to the delivered dose; however, substantial interpatient variability in total body clearance was noted at all dose levels. Significant conversion of 502U83 to two glucuronide metabolites was detected. Metabolite concentrations were highest in the three patients who succumbed to pulmonary toxicity, although the precise contribution of these metabolites to the observed toxic effects is unknown. In view of the unfavorable clinical profile of QTc prolongation and pulmonary toxicity produced by 502U83, further clinical development of this agent has been suspended.

Adult↗
PubMed1993

Statistical approaches to pharmacodynamic modeling: motivations, methods, and misperceptions.

We have attempted to outline the fundamental statistical aspects of pharmacodynamic modeling. Unexpected yet substantial variability in effect in a group of similarly treated patients is the key motivation for pharmacodynamic investigations. Pharmacokinetic and/or pharmacodynamic factors may influence this variability. Residual variability in effect that persists after accounting for drug exposure indicates that further statistical modeling with pharmacodynamic factors is warranted. Factors that significantly predict interpatient variability in effect may then be employed to individualize the drug dose. In this paper we have emphasized the need to understand the properties of the effect measure and explanatory variables in terms of scale, distribution, and statistical relationship. The assumptions that underlie many types of statistical models have been discussed. The role of residual analysis has been stressed as a useful method to verify assumptions. We have described transformations and alternative regression methods that are employed when these assumptions are found to be in violation. Sequential selection procedures for the construction of multivariate models have been presented. The importance of assessing model performance has been underscored, most notably in terms of bias and precision. In summary, pharmacodynamic analyses are now commonly performed and reported in the oncologic literature. The content and format of these analyses has been variable. The goals of such analyses are to identify and describe pharmacodynamic relationships and, in many cases, to propose a statistical model. However, the appropriateness and performance of the proposed model are often difficult to judge. Table 1 displays suggestions (in a checklist format) for structuring the presentation of pharmacodynamic analyses, which reflect the topics reviewed in this paper.

Data Interpretation, Statistical↗
PubMed1993

Five-day infusional fluorodeoxyuridine with oral leucovorin and escalating doses of interferon alpha-2b: a phase I study.

In a previous phase I study we identified the maximally tolerated dose (MTD) of a continuous intravenous infusion of fluorodeoxyuridine (FUdR) to be 0.3 mg/kg daily for 5 days when combined with oral leucovorin (LV) given at 100 mg q4h. In an attempt to modulate FUdR further, we added escalating doses of interferon alpha-2b (IFN) to FUdR/LV in a phase I cohort study. A total of 36 patients with refractory solid tumor were treated at two dose levels of FUdR and five dose levels of IFN. Although the initial patient cohort was treated with a dose of FUdR lower than that previously identified as the MTD [FUdR at 0.2 mg/kg daily with LV at 100 mg q4h and IFN at 2 million units (MU)/m2 daily], three of six patients developed grade 3 mucositis, indicating that the toxicity of FUdR/LV was increased in the presence of low doses of IFN. After decreasing the FUdR dose to 0.1 mg/kg daily, we could increase the dose of IFN from 2 to 30 MU/m2 daily in five additional cohorts of patients. With increasing IFN doses, no increase in mucositis or dermatitis was observed, indicating no further potentiation of FUdR/LV toxicity with higher IFN doses. However, known toxicities of IFN, including transient myelosuppression and hepatic transaminase elevation, were observed more frequently at IFN doses of 15 and 30 MU/m2 daily, where they became dose-limiting. We conclude that IFN modulates FUdR/LV at low doses, resulting in increased FUdR toxicity. When the dose of IFN is increased, this FUdR/LV toxicity does not appear to be potentiated further and IFN-related toxicities become dose-limiting.

Administration, Oral↗
PubMed1993

Modulation of vinblastine resistance with cyclosporine: a phase I study.

OBJECTIVE: Tumor cell resistance is a major cause of failure to cure advanced malignancies. Multidrug resistance is thought to be an important mechanism of such resistance. Our aims were to identify doses of cyclosporine that would achieve blood levels effective in modulating multidrug resistance to vinblastine and to evaluate the toxicities and maximum tolerated dose of cyclosporine when administered in conjunction with vinblastine. METHODS: We conducted a phase I trial of vinblastine and escalating doses of cyclosporine. Cyclosporine was given by continuous intravenous infusion over 120 hours and vinblastine was administered by continuous infusion from hour 12 to hour 108. Sixty-two patients entered the trial, of whom 60 were evaluable. RESULTS: Cyclosporine was escalated from 1 to 15.6 mg/kg/day. Vinblastine doses were reduced to 1.6 and then 1.2 mg/m2/day because of increasing vinblastine toxicity at higher cyclosporine doses. The maximum tolerated dose of cyclosporine at 1.2 mg/m2/day vinblastine was 12.5 mg/kg/day; at this dose level, mean blood cyclosporine level was 1.25 +/- 0.41 mumol/L. Significant nephrotoxicity was observed at higher cyclosporine doses in two of four patients. Nephrotoxicity was not significant at doses at or lower than this maximum tolerated dose and was not cyclosporine dose dependent. Myelosuppression, neurotoxicity, and transient hyperbilirubinemia were observed and were cyclosporine dose dependent. CONCLUSIONS. Cyclosporine by continuous infusion may be safely given in high doses concurrently with continuous-infusion vinblastine. Plasma levels of cyclosporine > or = 1 mumol/L can be sustained during vinblastine administration. No sustained effect on T-cell subsets was observed. Vinblastine toxicity is enhanced by cyclosporine in a dose-dependent fashion and correlates with cyclosporine-induced hyperbilirubinemia.

Adult↗
PubMed1993

5-Fluorouracil, hydroxyurea and escalating doses of iododeoxyuridine with concomitant radiotherapy for malignant gliomas: a clinical and pharmacologic analysis.

BACKGROUND: Iododeoxyuridine (IUdR) is a known radiation enhancer, and interacts biochemically with 5-fluorouracil (5-FU) and hydroxyurea (HU). PATIENTS AND METHODS: IUdR was added to the previously studied regimen of continuous infusion 5-FU at 300 mg/m2/day for 5 days, HU 500 mg every 12 hours for 11 doses and radiotherapy 200 cGy/day for 5 days, all administered for 7 consecutive weeks to patients with malignant glioma. IUdR was administered as 5-day continuous intravenous infusion during weeks 1 and 4. The IUdR dose was changed in cohorts of patients. IUdR plasma concentrations were determined during weeks 1 and 4, and IUdR incorporation into the DNA of granulocytes was measured on weeks 2 and 5. RESULTS: Two patients treated at the initial IUdR dose of 500 mg/m2/day developed grade 3 or 4 myelosuppression and mucositis. Additional dose levels of IUdR tested were 250 mg/m2/day and 125 mg/m2/day; at the latter dose, severe or life-threatening toxicity was seen in only 3 of 8 patients treated. IUdR incorporation into DNA of granulocytes was 10.5(+/- 2.3)% at an IUdR dose of 500 mg/m2/day but decreased to 0.76(+/- 0.3)% at 125 mg/m2/day. Similarly, IUdR plasma concentrations decreased from 436 (+/- 114) ng/ml to 99 (+/- 29) ng/ml. CONCLUSIONS: The addition of IUdR to 5-FU and HU results in significant systemic toxicity necessitating limitation of the IUdR dose to 125 mg/m2/day. There is a significant biochemical interaction between IUdR, 5-FU and HU leading to increased IUdR incorporation into DNA and to substantial clinical toxicity. Further clinical studies to exploit this interaction at more feasible schedules may be useful.

Adult↗
PubMed1993

Cisplatin, fluorouracil, and leucovorin augmented by interferon alfa-2b in head and neck cancer: a clinical and pharmacologic analysis.

PURPOSE: To increase the activity of cisplatin, fluorouracil (5-FU), and leucovorin (PFL) through further biochemical modulation and study the pharmacologic interaction of 5-FU and interferon alfa-2b (IFN). PATIENTS AND METHODS: Escalating doses of IFN (0.5 to 4.0 x 10(6) U/m2/d x 6) were added to cisplatin 100 mg/m2, continuous infusion 5-FU 800 or 640 mg/m2/d x 5, and leucovorin 100 mg orally every 4 hours. Forty-eight previously untreated patients with locoregionally advanced head and neck cancer received up to three cycles of PFL-IFN. RESULTS: Twenty-one patients were treated during a phase I cohort study. Dose-limiting mucositis was seen with 800 mg/m2/d of 5-FU and 0.5 x 10(6) U/m2/d of IFN. After decreasing the 5-FU dose to 640 mg/m2/d, the maximally tolerated dose (MTD) of IFN was 2.0 x 10(6) U/m2/d. Mucositis and myelosuppression were dose-limiting. Of 34 patients treated at this MTD, 56% (95% confidence interval, 39% to 73%) had a complete remission. There was no correlation between 5-FU clearance and IFN dose. Pharmacodynamic analyses at the MTD showed that older age, female sex, and higher 5-FU area under the time versus concentration curve (AUC) were associated with lower nadir counts and/or increased mucositis. Seven patients with diabetes mellitus had significantly increased myelosuppression, serum creatinine, hypocalcemia, higher 5-FU concentrations, and lower 5-FU clearance compared with nondiabetics. CONCLUSION: The recommended doses for PFL-IFN are 640 mg/m2/d for 5-FU and 2.0 x 10(6) U/m2/d for IFN. Sex, age, 5-FU AUC, and diabetes mellitus may have an impact on the pharmacodynamics of this regimen.

Adolescent↗
PubMed1993

Pharmacodynamic-pharmacokinetic relationships and therapeutic drug monitoring.

Pharmacokinetic-pharmacodynamic studies are becoming increasingly important in the development of new anti-cancer drugs. The Hill maximal effect model describes a sigmoidal dose-response relationship and has been applied to analyses of both haematological and non-haematological toxicity. This review discusses several approaches to population pharmacodynamics, including the two stage, NONMEM, and non-parametric approaches. Pharmacodynamic models for the haematological toxicity of amonafide, carboplatin, doxorubicin, etoposide, HMBA and menogaril are discussed, as are models for non-haematological toxicity. Adaptive control methods and therapeutic drug monitoring are useful in dosing drugs with narrow therapeutic windows, but the indications for using such strategies should be carefully selected. Models for 5FU, HMBA, methotrexate, 6-mercaptopurine, carboplatin and etoposide are discussed. Limited sampling strategies can facilitate the completion of pharmacokinetic studies and should be developed during phase I testing of new compounds. A new area of future importance is the investigation of drugs with active metabolites, such as the anthracyclines and amonafide.

Antineoplastic Agents↗
PubMed1992

Phase I-II trial of erythropoietin in the treatment of cisplatin-associated anemia.

BACKGROUND: Cancer patients undergoing chemotherapy with cisplatin-containing regimens often develop anemia. Although the cause is multifactorial, erythropoietin deficiency appears to play an important role. Recombinant human erythropoietin (epoetin) has been reported to be effective in reversing cisplatin-associated anemia in animal studies but not in clinical trials. PURPOSE: This pahse I-II clinical trial was designed to assess the safety and efficacy of treatment with epoetin for anemia associated with cisplatin chemotherapy. METHODS: Twenty-one cancer patients treated with cisplatin and manifesting anemia (hemoglobin level less than 110 g/L) received epoetin at escalating doses (25, 50, 100, or 200 U/kg body weight) intravenously five times a week for 4 weeks. RESULTS: Epoetin was well tolerated, and a maximal tolerated dose was not reached. Two patients experienced hypertension, which responded to standard antihypertensive therapy. No dose-dependent severe toxic effects were seen. The increase in hemoglobin levels from baseline on day 1 of the study was statistically significant after 4 weeks of epoetin therapy in the groups receiving 100 U/kg (mean change +/- SD = 19 +/- 13 g/L; P = .03) or 200 U/kg (mean change = 24 +/- 17 g/L; P = .007). A clinical response--an increase in hemoglobin level greater than 10 g/L--was achieved in 12 patients after 4 weeks of treatment. For these responders, the mean increase in hemoglobin level was 25 +/- 3.3 g/L over the level observed at the same time in the chemotherapy cycle preceding epoetin treatment, and this increase was statistically significant (P = .0001). Neither serum erythropoietin level nor hemoglobin level predicted a patient's response to epoetin. CONCLUSIONS: These preliminary findings suggest that epoetin is effective and well tolerated for the reversal of cisplatin-associated anemia, with the 100-U/kg and 200-U/kg dose levels offering optimal clinical response. IMPLICATIONS: We are conducting a phase III trial to determine the effect of epoetin on transfusion requirements in patients undergoing chemotherapy.

Adult↗
PubMed1992

5-Fluorouracil, leucovorin, hydroxyurea, and escalating doses of continuous-infusion cisplatin with concomitant radiotherapy: a clinical and pharmacologic study.

Cisplatin (CDDP), 5-fluorouracil (5-FU), and hydroxyurea (HU) have individually demonstrated activity against several solid tumors, act synergistically with each other in vitro, and may act as radiation sensitizers. Therefore, we designed a phase I study to determine the maximally tolerated dose of cisplatin as given in addition to our previously described combination of 5-FU, HU, and concomitant radiotherapy (XRT). Patients exhibiting advanced solid tumors requiring palliative XRT were eligible. The regimen consisted of 1 g HU given p.o.b.i.d. on days 1-5, 600 mg/m2 5-FU given i.v. daily by continuous infusion (c.i.) on days 1-5, escalating doses of cisplatin starting at 10 mg/m2 daily given by c.i. on days 1-5, and involved-field XRT carried out on days 1-5. The cycle was repeated every 14 days until the target XRT dose had been reached. In all, 19 patients were entered at the first dose level, and cumulative grade 3-4 myelosuppression was seen in 16 subjects. As no dose escalation was feasible, the chemotherapy was subsequently altered by using the above regimen for cycles 1, 3, 5, and 7 and substituting the less myelosuppressive regimen of 1 g HU given p.o.b.i.d. on days 1-5, 400 mg/m2 5-FU given i.v. daily by c.i., and 100 mg leucovorin given p.o.4 h on days 1-5 for cycles 2, 4, and 6. On this alternating program, 28 patients were treated with escalating doses of CDDP. The dose-limiting toxicity was again myelosuppression, which was prohibitive at a CDDP dose of 20 mg/m2 daily. In the final phase of the protocol, 30 subjects were treated with the above alternating-cycle regimen at a CDDP dose of 20 mg/m2 daily and a decreased HU dose of 500 mg p.o.b.i.d. in an attempt to circumvent the myelosuppression associated with this dose of CDDP. Although severe acute toxicity (cycles 1 and 2) was observed less frequently, cumulative toxicity (all cycles) remained pronounced. The other major toxicity encountered was mucositis, which was particularly pronounced in patients receiving radiation to the head and neck and following leucovorin-containing cycles. Plasma concentrations of free platinum did not correlate with the CDDP dose, possibly due to the narrow range of doses given. Pharmacodynamic modeling demonstrated that the CDDP dose and the HU dose were associated with leukopenia. Antitumor activity was demonstrated in a number of solid tumors particularly non-small-cell lung cancer and head and neck cancer.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1992

Therapy-related acute myeloid leukemia secondary to inhibitors of topoisomerase II: from the bedside to the target genes.

In the past five years, several groups have reported acute myeloid leukemia (AML) often monoblastic, as a complication of chemotherapy regimens including the epipodophyllotoxins, etoposide and teniposide. This syndrome is distinct clinically, pathologically and cytogenetically from classical therapy-related myelodysplasia and AML. There is also evidence that other topoisomerase II inhibitors, such as the intercalating agents (including doxorubicin, mitoxantrone, and actinomycin D) may be leukemogenic. Furthermore, there may be further interactions from concomitant topoisomerase II inhibitors and alkylating agents. Topoisomerase II inhibitors induce DNA cleavage and other chromosomal aberrations, including sister chromatid exchanges. These clastogenic abnormalities are not fully understood, and may be specific for each cytotoxic agent. Work is in progress to clone breakpoints such as the t(9;11) and t(8;21) and the use of the resultant DNA probes will enhance our understanding of the leukemogenic process. Given the potential diversity in patients with secondary leukemia, cytogenetic studies should be mandatory for both enhancing our knowledge base and guiding treatment in individual patients. Clinicians must also be wary of the leukemogenic potential of 'dose-intense' regimens including agents such as etoposide and doxorubicin.

Acute Disease↗
PubMed1992

Ethical issues in phase I oncology research: a comparison of investigators and institutional review board chairpersons.

PURPOSE: Phase I research trials assess the safety of agents never before administered to humans. In the field of oncology, this practice raises several important ethical questions. We examined the ethics of these trials by surveying phase I oncology investigators and institutional review board (IRB) chairpersons at major cancer research centers around the country. METHODS: Questionnaires were mailed to 78 investigators and 47 chairpersons to obtain their views on the ethical propriety of conducting phase I oncology research, and on institutional practice regarding these trials. The response rate was 68% in each group. RESULTS: The majority of each group reported that phase I oncology trials face no more scrutiny or resistance in their institution's IRB process than other research protocols. Nevertheless, IRB chairpersons were more likely than investigators to favor special procedural safeguards to protect subjects in phase I oncology trials. Nearly all respondents agreed that although actual medical benefit was very uncommon, most patients entered for a chance at a therapeutic effect. Investigators were more likely than chairpersons to report that patients obtained psychologic benefit from participation in phase I trials. CONCLUSION: Although individual IRB chairpersons and oncology investigators may have important differences of opinion concerning the ethics of phase I trials, these disagreements do not represent a widespread area of ethical conflict in clinical research.

Adult↗