Robust control for convection suppression in a fluid layer: The effects of boundary properties, actuator lag, and major parameter uncertainties.

The robustness of control is a requirement to maintain a fluid layer at conductive equilibrium heated to a highly supercritical condition. Robustness determines how much uncertainties, or design parameter mismatches, can be tolerated. Both linear stability analysis and three-dimensional fully nonlinear simulations are used for the study of the linear quadratic Gaussian (LQG) controller. The parameter mismatches from the nominal conditions are introduced into the plant model, while the LQG compensator assumes nominal conditions. The mismatches arise from boundary properties, actuator lag, sensor level uncertainty, and wall thickness, as well as from the major parameters such as Prandtl number, Rayleigh number, wave number, and truncation number in the reduced-order model. The results suggest that the LQG compensator action can preserve closed-loop stability at over ten times the critical Rayleigh number, provided that the mismatches in the sensor level and wall thickness are small. Mismatches in the Prandtl number and wall material properties have little impact. Mismatches in Rayleigh number and wave number are relatively benign compared with the sensor and thickness parameters. Techniques for measuring the plant output temperature at multiple levels with sufficient accuracy may be an implementation challenge.

Gain-scheduled controller for the suppression of convection at high Rayleigh number.

Recent studies in the feedback control of Rayleigh-Bénard convection indicate that one can sustain the no-motion state at a moderate supercritical Rayleigh number (Ra) using only proportional compensation. However, stabilization occurs at a much higher Rayleigh number using linear-quadratic-Gaussian (LQG) control synthesis. The restriction is that the convection model is linear. In this paper, we show that a comparable degree of stabilization is achievable for a fully nonlinear convection state. The process is demonstrated in two stages using a fully nonlinear, 3D Boussinseq model, compensated by a reduced-order LOQ controller and a gain-schedule table. In the first stage a fully-developed convective state is suppressed through the control action at a moderate supercritical Ra. After the residual convection decays to a sufficiently small amplitude, in the second stage, we increase the Ra by a large step and switch the compensator gains using the gain-schedule table. During this change the control action is in place. Our nonlinear simulation results suggest that the nonlinear system can be stabilized to the limit predicted by the linear analysis. The simulation shows that the large Ra jump induces a large transient temperature in the conductive component, which appears to have very small impact on the stabilization.

Expression of cell cycle regulators p57(KIP2), cyclin D1, and cyclin E in epithelial ovarian tumors and survival.

The search for new prognostic indicators is especially important in the diagnosis and treatment of ovarian cancer because clinicopathologic criteria currently used to predict survival are largely inadequate. We examined 2 groups of patients with epithelial ovarian cancer, 1 group of long-term survivors (>5 years), and 1 group of short-term survivors (<2 years) for levels of expression of the cell cycle regulators p57(KIP2), cyclin D1, and cyclin E and their relationship with survival. Our findings show that p57(KIP2) is not associated with prognosis, in contrast to p27(KIP1) expression, which is previously shown to be positively associated with long-term survival in univariate analysis (P =.001). Cyclin E expression, in contrast to cyclin D1 expression, is marginally associated with short-term survival in univariate analysis for a group of 53 women. Among the short-term survivors, 15 (65%) of 23 were positive for cyclin E expression, compared with only 11 (37%) of 30 long-term survivors (P = 0.054). This association remained significant (P =.04) in a logistic regression analysis adjusted simultaneously for performance status and extent of residual disease, the 2 strongest predictors of survival in our study. We also found a significant difference in the frequency of the cyclin E staining pattern between nonserous and serous ovarian tumor subtypes (P =.0002). Immunostaining for levels of cyclin E and p27(KIP1) expression may have potential as prognostic markers in the management of ovarian cancer.

A phase II double-blind randomized study of the simultaneous administration of recombinant human interleukin-6 and recombinant human granulocyte colony-stimulating factor following paclitaxel and carboplatin chemotherapy in patients with advanced epithelial ovarian cancer.

PURPOSE: Recombinant human interleukin-6 (rhuIL-6) is a glycosylated cytokine with hematopoietic stimulatory effects. In particular, preclinical studies suggest the agent can stimulate thrombopoiesis, even in conjunction with chemotherapy. We attempted to determine whether higher dose chemotherapy for ovarian cancer was possible given the pharmacologic use of this important growth factor. METHODS: We conducted a randomized, double-blind phase II study of IL-6 plus granulocyte colony-stimulating factor (G-CSF) versus placebo plus G-CSF in combination with a standard chemotherapy regimen. Patients with epithelial ovarian cancer, stages Ic to IV, were eligible. All patients were previously untreated with chemotherapy and had Karnofsky performance status >/=60. rhuIL-6 (Escherichia coli, SDZ ILS 969) 1.0 micrograms/kg or placebo was given subcutaneously on days 2-8 every cycle together with G-CSF 5.0 micrograms/kg subcutaneously days 2-15, following administration of paclitaxel 175 mg/m2 as a 3-h infusion and carboplatin given to a desired AUC of 7.5 on day 1 every 21 days. RESULTS: Fifty patients were entered in this study, although the study was temporarily suspended by the FDA in midstudy over manufacturing concerns. Therefore, 37 patients were evaluable for efficacy of growth factor; 19 patients received placebo plus G-CSF and 18 rhIL-6 plus G-CSF. There was no difference in prognostic variables between these two groups. Platelet nadirs were lower in the first cycle for the placebo group (P = 0.004, Wilcoxon sum-rank test) but not in other cycles. There was no statistically significant difference in cycle treatment delays, carboplatin dose delivered, number of patients with grade 4 thrombocytopenia, or platelet transfusion. Nonetheless, the trend of the data favored IL-6 in all cases. CONCLUSIONS: This study demonstrated a minimal effect (statistically significant in the first cycle only) on thrombopoiesis in women undergoing paclitaxel and carboplatin therapy of ovarian cancer. No clinically significant effect on actual chemotherapy delivery was demonstrated, however. Future studies, if warranted, to ameliorate thrombocytopenia should be carried out with regimens producing even greater thrombocytopenia than the current regimen in the control arm.

Expression of the cell cycle inhibitor p27KIP1 is a new prognostic marker associated with survival in epithelial ovarian tumors.

This case-control study was designed to identify factors associated with long-term survival. We examined two groups of patients with epithelial ovarian cancer, one group of long-term survivors (> 5 years) and one group of short-term survivors (< 2 years), for levels of expression of p53 and p27KIP1 proteins (as both proteins have been shown to be independent prognostic markers in tumors other than ovary) and the relationship with patient survival. Our findings show that p27KIP1 expression, in contrast to p53 expression, is positively associated with long-term survival in univariate analysis (P = 0.001), in analyses stratified by residual disease (P = 0.02) or performance status (P = 0.02), the two strongest prognostic factors for ovarian cancer, as well as multivariate analysis (P = 0.002) adjusting simultaneously for age, tumor stage, residual disease, performance status, and grade of differentiation. Therefore, immunostaining for levels of p27KIP1 expression may have potential as a new prognostic factor in the management of ovarian cancer.

Phase I/II study of PIXY321 in combination with cyclophosphamide and carboplatin in the treatment of ovarian cancer.

OBJECTIVE: Our purpose was to evaluate the safety and biologic effects of PIXY321 after chemotherapy in patients with ovarian carcinoma. STUDY DESIGN: A multicenter, nonrandomized, phase I/II study of subcutaneously administered PIXY321 after the second cycle of chemotherapy in cohorts of three or more patients at 50, 125, 250, 500, 750, or 100 micrograms/m2 per day. RESULTS: Cyclophosphamide (600 mg/m2) and carboplatin (400 mg/m2) were administered every 28 days to 34 patients. At doses > or = 500 mg/m2 per day, the median nadir platelet and median nadir absolute neutrophil counts in cycle 2 (with PIXY321) compared with cycle 1 (control) were both higher in 13 of 26 (50%) patients. Twenty-one patients were withdrawn from the study. A total of 17 of 21 (81%) were removed for myelosuppression (n = 15) or PIXY321 toxicity (n = 2). A total of 28 of 34 (82%) patients had injection site reactions. Thirty-seven nonhematologic grade 3 events occurred. CONCLUSIONS: At these doses and schedules PIXY321 can be safely administered. Aggressive dosing of cyclophosphamide and carboplatin could not be maintained for six cycles in the majority (62%) of patients.

A phase I trial of cyclosphosphamide and carboplatinum combined with interleukin-3 in women with advanced-stage ovarian cancer.

The hematopoietic growth factor, recombinant human interleukin-3 (rhu IL-3), stimulates production of both leukocytes and platelets, and thus potentially has greater utility than growth factors that solely stimulate leukocytes production when employed with dose-intensive chemotherapeutic regimens. To determine the optimal schedule for administration of rhu IL-3 in combination with cyclophosphamide and carboplatin, an aggressive regimen for the treatment of advanced ovarian cancer, a phase I trial was initiated by the New York Gynecologic Oncology Group. Following surgical debulking, all patients received cyclophosphamide and carboplatin for 6 cycles. rhu IL-3 was administered at 50, 250, or 500 microgram subcutaneously for 5 days either immediately prior to or after administration of chemotherapy. Cohorts of six patients were treated at each dose level (three pre- and three postchemotherapy). Eighteen patients received 91 cycles of treatment. The major toxicities attributable to rhu IL-3 included fevers, chills, malaise, nausea, and headache, but were not dose-limiting at the doses of rhu IL-3 employed. The major finding of this study was that rhu IL-3 administered after chemotherapy offered greater platelet protection than rhu IL-3 administered prior to chemotherapy as assessed by median platelet nadir and duration of platelet counts < 50,000/mm3. A second major finding was a dose-response relationship for rhu IL-3: the two higher doses employed, 250 and 500 micrograms, offered more effective platelet protection than the lower dose employed, 50 micrograms. rhu IL-3 had no significant effects on leukocyte nadirs or duration of nadirs at any schedule or dose employed. rhu IL-3 may reduced the thrombocytopenia associated with aggressive treatment with cyclophosphamide and carboplatin, although this remains to be confirmed in a randomized, placebo-controlled trial. The effects of rhu IL-3 are dose- and schedule-dependent.

Pharmacokinetics of the cardioprotector ADR-529 (ICRF-187) in escalating doses combined with fixed-dose doxorubicin.

BACKGROUND: Although doxorubicin is an anticancer agent with a wide spectrum of activity, therapy with this anthracycline must often be discontinued at a time of benefit to the patient because of the drug's cumulative cardiotoxicity. ICRF-187 (ADR-529, dexrazoxane) is a bisdioxopiperazine compound that protects against cardiac toxicity induced by doxorubicin. PURPOSE: Our objectives in this study were to determine the maximum tolerated dose of ADR-529 (which uses a different vehicle than ICRF-187) when given with a fixed doxorubicin dose and to determine whether ADR-529 alters doxorubicin pharmacokinetics. METHODS: Twenty-five patients were treated with doxorubicin (60 mg/m2) preceded by administration of ADR-529 in escalating dosages (i.e., 60, 300, 600, 750, and 900 mg/m2) to groups of three to nine patients. ADR-529 was administered over a 15-minute period beginning 30 minutes before doxorubicin treatment; the protocol was repeated every 3 weeks. Blood was sampled frequently for drug levels, which were determined by high-pressure liquid chromatography with fluorescence (doxorubicin) and electrochemical detection (ADR-529). RESULTS: Dose-limiting neutropenia occurred in four of six previously treated patients at an ADR-529 dose of 600 mg/m2; the dose ratio of ADR-529 to doxorubicin was 10:1. For three additional patients with better Eastern Cooperative Oncology Group performance status and a maximum of one prior chemotherapy regimen, 600 mg/m2 was tolerated, but grade 3 or 4 neutropenia occurred in four of six patients who received an ADR-529 dose of 900 mg/m2 and in three of four patients at a dose of 750 mg/m2. Doxorubicin's estimated terminal half-life was 39.5 +/- 18.3 (mean +/- SD) hours; the area under the curve for plasma concentration of drug x time (AUC) was 1.74 +/- 0.40 (micrograms/microL) x hour. Total-body clearance was 598 +/- 142 microL/m2 per minute (N = 20), and it did not vary with ADR-529 dose. Estimated distribution and elimination phase half-lives for plasma ADR-529 were 0.46 +/- 0.30 hours and 4.16 +/- 2.94 hours, respectively. Total-body clearance was 111 +/- 87 microL/m2 per minute (N = 18); AUC was linear (r2 = .92), and the clearance rate was constant (r2 = .18) from 60 to 900 mg/m2. CONCLUSIONS: Myelotoxicity was dose limiting for ADR-529 at 600-750 mg/m2 when given with a fixed dose of doxorubicin at 60 mg/m2 (dose ratios of ADR-529 to doxorubicin ranged from 10:1 to 12.5:1). When used in combination, ADR-529 did not perturb doxorubicin's distribution, metabolism, or excretion; therefore, other mechanisms of cardioprotection must be involved. IMPLICATIONS: We recommend that an ADR-529 dose of 600 mg/m2 be given with single-agent doxorubicin at a dose of 60 mg/m2 in future studies.

Intraperitoneal carboplatin: rationale and experience.

We conducted a phase I/II trial of intraperitoneal (IP) carboplatin in 27 patients with advanced gynecologic malignancies. This was based on the known activity of carboplatin in ovarian cancer and pharmacologic measurements that predict a favorable ratio of IP to plasma drug exposure when carboplatin is administered by the IP route. All patients had extensive prior therapy with cisplatin (mean dose, 554 mg/m2). Starting dose was 200 mg/m2, which was escalated to 500 mg/m2. Patients with compromised renal function (creatinine clearance 30 to 60 mL/min) had slower escalations than patients with creatinine clearances greater than 60 mL/min. Myelosuppression, especially thrombocytopenia, was the dose-limiting toxicity. In pretreated patients, we recommend a starting dose of 400 mg/m2. Patients with creatinine clearances of 30 to 60 mL/min should start at the lower dose of 200 mg/m2. This is in general agreement with the results of other trials of IP carboplatin. Measurements of IP carboplatin in preclinical studies predict less tissue penetration by carboplatin than the parent compound cisplatin. Nevertheless, in our series of heavily pretreated patients receiving IP carboplatin, eight patients remained free of disease progression for more than 2 years. Further trials of IP carboplatin are indicated.

Phase I study of doxorubicin, ICRF-187 and granulocyte/macrophage-colony-stimulating factor.

A group of 16 patients with advanced malignancy were entered on a phase I trial of escalating doses of doxorubicin with ICRF-187 for cardioprotection and granulocyte/macrophage-colony-stimulating factor (GMCSF) for bone marrow protection. Patients received intravenous ICRF-187 (dose ratio 20:1 ICRF-187:doxorubicin) 30 min prior to doxorubicin. GMCSF at a dose of 15 micrograms kg-1 day-1 was self-administered subcutaneously on days 3-14 of the cycle. Doxorubicin was administered every 21 days. Substantial hematological and non-hematological toxicity was seen. Fever, malaise, and pulmonary symptoms, thought to be due to GMCSF, were not eliminated by reduction in the GMCSF dose to 10 or 5 micrograms kg-1 day-1. Severe hematological toxicity was seen despite GMCSF administration and it was not possible to escalate the doxorubicin dose above 72 mg/m2 with this combination. Dose escalation of doxorubicin may be more feasible with the use of other growth factors or growth factor combinations.

ICRF-187 permits longer treatment with doxorubicin in women with breast cancer.

PURPOSE: To test potential protection by ICRF-187 against cumulative doxorubicin-dose-related cardiac toxicity, we conducted a randomized clinical trial in 150 women with advanced breast cancer. PATIENTS AND METHODS: Patients received fluorouracil (5FU) 500 mg/m2, doxorubicin 50 mg/m2, and cyclophosphamide 500 mg/m2 every 21 days intravenously (IV) (control regimen, 74 patients), or the same regimen preceded by ICRF-187 1,000 mg/m2 IV (experimental regimen, 76 patients). RESULTS: We previously reported that ICRF-187 in this dose and schedule provides cardiac protection and does not substantially alter the noncardiac toxicity or antitumor efficacy of the control regimen. In this updated analysis of the entire patient cohort, we provide additional support for these findings and demonstrate that patients in the ICRF-187 group received more cycles (median, 11) and higher cumulative doses (median, 500 mg/m2) of doxorubicin than patients in the control group (median, nine cycles, P less than .01; and 441 mg/m2, P less than .05). Twenty-six patients in the ICRF-187 group received doxorubicin doses of at least 700 mg/m2, and among them, 11 patients received 1,000 mg/m2 or more. Only three patients in the control group received doxorubicin doses of 700 mg/m2; the maximum dose administered to one patient in this group was 950 mg/m2. ICRF-187 cardiac protection was demonstrated by difference in incidence of clinical congestive heart failure (CHF; two patients in the ICRF-187 group v 20 in the control group; P less than .0001) and by differences in resting left ventricular ejection fraction (LVEF) determined by multigated radionuclide (MUGA) scan from baselines and that required patient removal from study (five patients in the ICRF-187 group had a decrease in LVEF to less than 0.45 or a decrease from the baseline LVEF of 0.20 or more v 32 in the control group; P less than .000001). Among the 30 patients who had an assessable endomyocardial biopsy at cumulative doxorubicin 450 mg/m2, none of 16 in the ICRF-187 group and six of 14 in the control group had a score of 2 (P less than .05). ICRF-187 cardiac protection was observed in patients with and without prior chest-wall radiation or other risk factors for developing doxorubicin cardiac toxicity. CONCLUSION: By protecting against cumulative doxorubicin-induced cardiac toxicity, ICRF-187 permits significantly greater doses of doxorubicin to be administered to patients with greater safety.

Lack of effect of cyclophosphamide on the immunogenicity of a melanoma antigen vaccine.

Melanoma antigen vaccines are a conceptually attractive approach to prevent or delay disease recurrence in patients with surgically resected malignant melanoma. However, the immunogenicity of current vaccines is relatively low. Cyclophosphamide, when given in low doses prior to antigen exposure, is an immunomodulator which has been shown to enhance both humoral and cellular antitumor responses in animals and humans. We conducted a prospective, randomized, clinical trial to study whether pretreatment with cyclophosphamide augments the immunogenicity of a polyvalent, allogeneic, melanoma antigen vaccine in patients with melanoma and low tumor burden. Forty-five patients with resected stage II melanoma (regional metastases) were randomly allocated to treatment with melanoma vaccine or melanoma vaccine plus cyclophosphamide. All patients received the same dose and schedule of vaccine immunizations; those randomized to cyclophosphamide received 300 mg/m2 i.v. 3 days prior to each vaccine immunization. Cellular immune responses were evaluated by delayed-type hypersensitivity (DTH) skin reactivity to a test dose of vaccine at baseline (prior to treatment) and following the fourth immunization. Humoral immune responses were measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiographic analysis of indirect immunoprecipitates of patients' sera at the same time points. Twenty-four patients were randomized to cyclophosphamide pretreatment and 21 to vaccine alone; 22 and 18 patients were evaluable in each group, respectively. Differences were statistically nonsignificant with respect to either cellular (DTH) or humoral (antibody) responses between the two groups. DTH responses were induced in 16 of 22 (73%) and 15 of 18 (83%) patients treated with cyclophosphamide plus vaccine and vaccine alone, respectively. The mean posttreatment augmentation in DTH response in the cyclophosphamide group was 9.5 mm, compared with 9.9 mm in the vaccine-only group. Eight of 12 (66%) cyclophosphamide-pretreated patients and 9 of 12 (75%) vaccine-only patients produced increased titers of antimelanoma antibodies following treatment. No differences were observed between the groups in disease-free or overall survival. In summary, low-dose cyclophosphamide pretreatment failed to augment the immunogenicity of a polyvalent, allogeneic, melanoma vaccine in patients with completely resected early-stage melanoma.

Phase I and pharmacologic evaluation of intraperitoneal 5-fluoro-2'-deoxyuridine.

Intraperitoneal (i.p.) 5-fluoro-2'-deoxyuridine (Floxuridine, FUdR, FdUrd) was evaluated in a phase I study at a starting level of 500 mg given on 1 day in 2 I 1.5% dialysate. Escalations within patients were allowed every other cycle. A total of 23 patients (age, 32-78 years) received 108 treatment courses. Local tolerance at all dose levels was excellent, with no cases of drug-related peritonitis being observed. Nausea and vomiting increased in severity in relation to dose and was universal at greater than 3,000 mg x 3 days. One patient each developed grade 1 mucositis as well as diarrhea at a dose of 3,000 mg x 3 days and leukopenia and thrombocytopenia at 5,000 mg x 3 days. Peritoneal fluid (PF) and plasma (PL) FdUrd profiles were monitored by an HPLC method in 13 subjects, with 7 being studied serially at 2-4 increment doses for up to 6 h. Profiles that exhibited apparent linear pharmacokinetics gave PF drug levels 2-4 logs higher than the PL counterparts, with the latter essentially declining in parallel to the former, indicating that the disposition of FdUrd from the peritoneal compartment is rate-determining. The mean terminal half-life for PF FdUrd was found to be 115 min and mean peritoneal clearance was 25 ml/min. The vast differences in drug levels and AUC found between the PF and the PL profiles suggests a high systemic clearance of FdUrd, which was confirmed in two patients receiving 2 g FdUrd by short i.v. infusion. A disproportionate increase in the plasma FdUrd levels and the corresponding AUC values was found with increasing dose, suggesting a disproportionate increase in the systemic partitioning of FdUrd when doses were escalated within a patient. Substantial levels of peritoneal 5-fluorouracil (FUra) were also detected in most of the subjects. Thus, FdUrd was found to have several desirable properties for i.p. administration: (1) a 2- to 4-log pharmacologic advantage. (2) the absence of local toxicities, and (3) a favorable antitumor spectrum and some evidence of antitumor effects in this phase I and pharmacology study. A 3,000-mg dose given in 2 1 1.5% dialysate for 3 consecutive days exhibited antitumor activity and produced no systemic toxicity except nausea and vomiting, which was controlled by antiemetics. This dose schedule is therefore recommended for phase II trials directed against small-volume disease in the peritoneal cavity, such as may be found in some stages of ovarian and gastrointestinal cancers.(ABSTRACT TRUNCATED AT 400 WORDS)

Antimelanoma monoclonal antibody-ricin A chain immunoconjugate (XMMME-001-RTA) plus cyclophosphamide in the treatment of metastatic malignant melanoma: results of a phase II trial.

Prior studies with the XMMME-001-RTA immunoconjugate composed of an antimelanoma monoclonal antibody and ricin A chain demonstrated some antitumor activity. However, almost all patients studied developed human antimurine antibodies and antiricin antibodies. In an effort to abrogate these host anti-immunotoxin immune responses and thus enhance antitumor activity, we treated 20 patients with the immunoconjugate plus a single dose of intravenous cyclophosphamide. An overall response rate of 20% was observed-predominantly in pulmonary and soft tissue nodules. There was no diminution in antibody responses against either the murine antibody or the ricin moiety. Further studies to elucidate the role of cyclophosphamide in monoclonal antibody therapy are planned.

Intraperitoneal carboplatin: favorable results in women with minimal residual ovarian cancer after cisplatin therapy.

From August 1985 to November 1989 we conducted a trial of intraperitoneal (IP) carboplatin including a dose-escalation design in 25 women with advanced gynecologic malignancies. All had extensive prior therapy with cisplatin (median cumulative dose, 525 mg/m2). Carboplatin was administered IP in 2 L of 1.5% dextrose with a 4-hour dwell time every 4 weeks for six cycles at a starting dose of 200 mg/m2. Patients with reduced creatinine clearance (30 to 60 cc/min) were escalated more slowly than those with high (greater than 60 cc/min) clearance. Thrombocytopenia was dose-limiting and often more severe in patients with compromised renal function; there was no local drug toxicity. The median time of follow-up is 25 months. Complete responses (CRs) were documented in six of 23 assessable patients (26%) by repeat laparotomy, and an additional 11 patients (48%) had no disease evident by noninvasive restaging. Five of the CRs and six of the patients with no clinically evident disease have relapsed from 3 to 40 months after therapy. Six patients (26%) are alive and free of disease 8 to 47 (median, 20) months after therapy. IP carboplatin is effective against relapsed ovarian cancer, even after prior cisplatin therapy.

Phase II study of esorubicin (4'deoxydoxorubicin) in anthracycline naive patients with ovarian cancer.

Sixteen patients with metastatic ovarian cancer who had not previously been treated with anthracyclines were treated with 4'deoxydoxorubicin at a dose of 30 mg/m2 intravenously every 3 weeks. There were no clinical responses in this group of patients. Toxicities were infrequent with neutropenia and thrombocytopenia being dose limiting. Nausea and vomiting occurred in only 4 patients. We conclude that 4'deoxydoxorubicin is an inactive drug in this patient population and does not warrant further investigation in this disease.