Modified ADM1 structure for modelling municipal primary sludge hydrolysis

This study elaborates the rate-limiting steps of particle disintegration/hydrolysis of primary sludge using methane production rate (MPR) curves from multiple batch experiments. Anaerobic batch degradation of fresh primary sludge showed a complex MPR curve marked with two well-defined temporal peaks. The first immediate peak was associated with the degradation of relatively readily hydrolysable substrates, while the second delayed peak was associated with the degradation of large-sized particles. For simulating the second delayed peak, it was necessary to consider a more elaborate particle disintegration/hydrolysis model. Based on the anaerobic respirograms of 17 runs in four datasets and using a substrate characterisation approach similar to activated sludge models (ASMs), the primary sludge was classified into three biodegradable fractions having different kinetics. These are (1) a hydrolysable substrate (X(Settle-I)) showing a degradation typical to slowly biodegradable compounds, (2) a substrate fraction (X(Settle-II)) having a degradation similar to lysis of biomass fraction and (3) a substrate requiring disintegration before hydrolysis (X(Settle-III)) representing the large-sized particles in primary sludge. Based on these results, modifications in the model structure of anaerobic digestion model no. 1 (ADM1) are proposed to improve the modelling of primary sludge solid degradation in anaerobic digesters.

Encouraging results from a phase I study of capecitabine (X), irinotecan (I) and oxaliplatin (O) as first-line therapy in patients (pts) with metastatic colorectal cancer (MCRC)

4086

Background: First-line treatment with I, O and infusional 5-FU/Leucovorin (LV) triplets is associated with high response rates and long survival in MCRC. The oral fluoropyrimidine X is better tolerated and shows improved response rates vs. 5- FU/LV in MCRC. This dose-escalation study aims to establish dose-limiting toxicity (DLT), maximum tolerated dose (MTD) and recommended phase II doses (RPIID) of I, O and X and to evaluate efficacy and safety in first-line. Methods: Starting doses were: I (180mg/m2 i.v. d1), O (85mg/m2 i.v. d1), × (850mg/m2 bid orally d2–15). Dose escalations are based on toxicity observed at previous dose level (DL), until DLT, MTD and RPIID are reached. Results: We have enrolled 27 pts (21 men, 6 women), median age 59 years (range 25–74), at 6 DLs. ECOG PS was 0 or 1 in 25 pts, and 2 in 2 pts. Pts received a median of 10 cycles (range 1–23). All pts are evaluable for toxicity (24 for efficacy). Most common grade 3/4 hematological adverse events (AEs) during dose escalation: granulocytopenia (41%), anemia (7%), and thrombocytopenia (15%). Most common grade 3 non-hematological AEs: late-onset diarrhea (11%), fever (14%), and fatigue (4%). DLTs at each dose level: DL1 (1 febrile neutropenia with bowel perforation); DL2 (1 grade 3 diarrhea); DL3 (1 febrile neutropenia with grade 2 edema); DL4 (1 severe febrile neutropenia in cycles 2&3, pt deceased due to sepsis); no DLTs were reported at DL5 & 6. MTD has not yet been reached. Overall response rate is 79% (95% CI, 62–97%), including 2 CRs and 17 PRs (3 still unconfirmed). Disease control rate is 92%. Two pts had subsequent curative liver resection and 4 pts are under consideration for curative procedures. Median progression-free survival is 15 months (95% CI, 8–22). Conclusions: XIO is well tolerated and highly effective as first-line treatment for MCRC. Severe neutropenia was significant but of short duration and manageable; it is likely to be the main DLT. MTD has not yet been identified but is expected shortly. A phase II study to confirm the efficacy and safety of XIO, possibly in combination with targeted agents, will follow. Supported by Roche, Sanofi-Aventis, and Pfizer Canada.

No significant financial relationships to disclose.

Are doctors themselves responsible for delay in cancer management?

17027

Background: In developing countries poor results of cancer management are believed to be due to late presentation of patients because of poverty, illiteracy and lack of cancer awareness. But the scenario changed little despite regular cancer awareness campaigns in last few decades. Methods: 1,006 cancer patients were assessed for time of onset of symptoms, time of presentation to physician, time taken in diagnosis & initiation of anticancer treatment to identify the level of delay in cancer management and factors responsible. Results: 81.3% of the patients belonged to low socioeconomic group. 61.9% were illiterate & 43.7% were laborers. Literacy level of 84.5% of patients was under metric level and 50.3% had no awareness about cancer. 55.4% patients presented to qualified medical practitioners, 38.9% to non-qualified medical practitioners & 5.5% to qualified non-medical practitioners working as primary care physicians. Almost 80% of patients had delay in cancer management at various levels, the maximum being at diagnosis level. 67.3% patients presented to primary care physician within a month of onset of symptoms without delay. In 68.6% patients the diagnosis of cancer was delayed by more than one month once they presented, the physicians being responsible for this delay in 60.4 % cases. Though non-qualified physicians almost never diagnosed cancer but even 58% of the qualified medical physicians delayed the diagnosis of cancer in the symptomatic patients. In 77.1% patients, physicians did not suspect cancer and disposed off the patients on symptomatic treatment. Literacy of the patients affects awareness and has bearing on the pattern of consultation whereby most of the literates consulted qualified physicians while most of the illiterates consulted non-qualified physicians resulting in delay. Conclusions: Presentation of the cancer patient depends upon reaction to the symptom and therefore despite illiteracy and poverty, majority of symptomatic patients present without delay to their primary care physicians. Delay occurs at diagnosis level in most of the patients and physician is the most common factor responsible for this delay. Tendency to treat the symptoms rather than making diagnosis of the patient and poor oncology knowledge to differentiate symptoms of cancer may be the reasons for this.

No significant financial relationships to disclose.

Phase III trial of capecitabine + oxaliplatin (XELOX) vs. 5-fluorouracil (5-FU), leucovorin (LV), and oxaliplatin (FOLFOX4) as 2nd-line treatment for patients with metastatic colorectal cancer (MCRC)

4031

Background: Capecitabine is an oral fluoropyrimidine that has demonstrated similar efficacy to 5-FU/LV in the 1st-line treatment of MCRC. Most patients now receive multi-agent chemotherapy and FOLFOX4 has become a popular regimen in this setting. We conducted a phase III study comparing XELOX with FOLFOX4 in patients who had received prior treatment with irinotecan in combination with bolus and/or infusional 5-FU/LV for MCRC. The primary endpoint of the study was time-to-tumor progression (TTP). With 610 patients, this study had 80% power to detect non-inferiority of the XELOX vs. FOLFOX, defined by a progression hazard ratio (HR) of <1.3. Methods: Patients were treated with XELOX (oxaliplatin 130mg/m2 i.v., capecitabine 1,000mg/m2 bid oral x 14 days, q3w) or FOLFOX4 (as described previously). Results: The study recruited 627 patients (the intent-to-treat - ITT - group). Baseline characteristics were well balanced. The primary objective of the study was met with a progression HR of 0.97 for the XELOX group (95% CI, 0.83–1.14). Median TTP was 4.8 months for XELOX- and 4.7 months for FOLFOX4-treated patients. Overall survival was also similar between the groups with a death HR of 1.03 for the XELOX group (95% CI, 0.87–1.23). Median survival was 11.9 months for XELOX- and 12.6 months for FOLFOX4-treated patients. Grade 3/4 toxicities occurred in 60.1% of XELOX- and 72.4% of FOLFOX4-treated patients. The most common treatment-related grade 3/4 adverse events (XELOX vs. FOLFOX4) were: diarrhea (20 vs. 5%), neutropenia (5 vs. 35%), fatigue (5 vs. 8%), paresthesia (9 vs. 8%), nausea/vomiting (6 vs. 5%). The rate of grade 3 hand-foot syndrome was 3.5% with XELOX and 0.6% with FOLFOX4. The 60-day all cause mortality was 3.9% in XELOX- and 4.2% in FOLFOX4-treated patients. Conclusions: These results demonstrate that second-line treatment with XELOX is non-inferior to FOLFOX4 in terms of PFS. Results for overall survival and response rates were also similar between the two groups. The safety profile was similar to previous studies, with no unexpected toxicities. Study supported by Hoffmann-La Roche.

No significant financial relationships to disclose.

Management of Calculi in A Donor Kidney

INTRODUCTION

We evaluated the safety and efficacy of ex vivo ureteroscopy (ExURS) and extracorporeal shock wave lithotripsy (ESWL) as means of rendering a donated kidney stone-free in living related and deceased donor renal transplantation.

MATERIAL AND METHODS

Three cases with calculi in donor kidneys were managed; 1 was from a living related donor and 2 were from deceased donors. Immediately after cold perfusion, ExURS was performed with iced saline solution in 2 cases. Access to the collecting system was via the ureteral stump. Calculi were fragmented with pneumatic intracorporeal lithotripsy and fragments were removed with forceps. Posttransplantation ESWL was given to 1 patient for migration of a small lower caliceal calculus in the upper ureter in 1 allograft of a dual-kidney transplantation.

RESULTS

Access to the renal collecting system and stone fragmentation was technically successful in both cases. Indwelling ureteral stents were kept during transplantation in all cases. There were no intraoperative or postoperative ureteral complications. Following ESWL, stone was fragmented and cleared on its own within a week. At mean follow up of 2.2 years no new stone formed in any recipient or donor.

CONCLUSIONS

ExURS was technically feasible to render a stone-bearing kidney stone- free without compromising ureteral integrity or renal allograft function. ESWL could be performed at a later date.

Phase I study of Aplidine in a dailyx5 one-hour infusion every 3 weeks in patients with solid tumors refractory to standard therapy. A National Cancer Institute of Canada Clinical Trials Group study: NCIC CTG IND 115

BACKGROUND

Aplidine is a cyclic depsipeptide isolated from the marine tunicate Aplidium albicans.

METHODS

This phase I study of Aplidine given as a 1-hour i.v. infusion daily for 5 days every 3 weeks was conducted in patients with refractory solid tumors. Objectives were to define the dose limiting toxicities, the maximal tolerated dose, and the recommended phase II dose.

RESULTS

Thirty-seven patients were accrued on study. Doses ranged from 80 microg/m(2) to 1500 microg/m(2)/day. Eleven patients received more than three cycles of Aplidine. Dose-limiting toxicities occurred at 1500 microg/m(2) and 1350 microg/m(2)/day and consisted of nausea, vomiting, myalgia, fatigue, skin rash and diarrhea. Mild to moderate muscular pain and weakness was noted in patients treated with multiple cycles with no significant drug related neurotoxicity. Bone marrow toxicity was not observed. The recommended dose for phase II studies was 1200 microg/m(2) daily for 5 days, every 3 weeks. Pharmacokinetic studies performed during the first cycle demonstrated that therapeutic plasma levels of Aplidine are reachable well below the recommended dose. Nine patients with progressive disease at study entry had stable disease and two had minor responses, one in non-small cell lung cancer and one in colorectal cancer.

CONCLUSIONS

Aplidine given at a dose of 1200 microg/m(2) daily for 5 days, every 3 weeks is well tolerated with few severe adverse events. This schedule of Aplidine is under evaluation in phase II studies in hematological malignancies and solid tumors.

Final clinical and pharmacokinetic (PK) results from a phase 1 study of the novel N-cadherin (N-cad) antagonist, Exherin (ADH-1), in patients with refractory solid tumors stratified according to N-cad expression

3016

Background: Malignant transformation and invasiveness correlate with upregulation of N-cad, a cell adhesion molecule expressed on tumor cells and vascular endothelium. N-cad antagonism by ADH-1, a cyclic pentapeptide (CHAVC), causes rapid tumor vascular disruption and apoptosis in preclinical models. We report the final clinical and PK results from the first human study (AHX-01–001). Methods: 46 subjects with incurable solid tumors stratified according to tumor N-cad expression were enrolled. 99 doses of ADH-1 were given by IV bolus or short infusion (31 in a Special Access Program). Doses ranged from 50–1000 mg/m2, with 3–6 subjects/cohort. Blood and urine were collected for PK on Day 1, assayed by LC/MS/MS, and a 2 compartment analysis was performed. Results: ADH-1 was generally well tolerated and the maximum tolerated dose was not defined. The most commonly reported adverse events were grade 1–2 fatigue (59%), nausea (32%), dysgeusia (25%), and flushing (20%). 4 subjects in the N-cad positive group (n=28, including 3 N-cad unknown) demonstrated anti-tumor activity; a PR of 6 month duration in refractory esophageal carcinoma; a minor response in lung metastases from an unknown primary following a single dose; and >7 months SD in refractory adrenocortical and colorectal carcinoma. No anti-tumor activity was noted in the N-cad negative group (n=18). The mean initial ADH-1 half-life (t½) was 20 min and the mean terminal phase t½ was 2.2 hr. Mean systemic clearance (CL) was 6.5 L/hr/m2. Both t½ and CL were independent of dose. Cmax increased dose proportionally, ranging from 7 to148 μg/mL, and AUC0-∞ tended to increase dose proportionally. The volume of distribution at steady-state (Vss) averaged 14.3 L/m2, indicating modest tissue distribution. Approximately 30% of the dose was excreted unchanged in the urine. Conclusions: ADH-1 was generally well tolerated and demonstrated evidence of anti-tumor activity in subjects with N-cad positive tumors. The PK profile was biphasic and the t½ averaged 2.2 hr. Cmax and AUC0-∞ increased dose proportionally, and CL was independent of dose.

No significant financial relationships to disclose.

A phase I/II study of capecitabine (X), irinotecan (I) and oxaliplatin (O) as first-line therapy in patients (pts) with advanced or metastatic colorectal cancer (MCRC)

13540

Background: Triplets of I, O and infusional 5-FU/Leucovorin (LV) are associated with high response rates and long survival in first-line MCRC [Falcone et al. JCO 2002;20:4006–14]. The oral fluoropyrimidine X has proved higher response rates and improved safety vs. 5-FU/LV in MCRC. Methods: This ongoing dose-escalation study aims to establish dose-limiting toxicity (DLT), maximum tolerated dose (MTD) and recommended phase II doses (RPIID) of I and O in combination with X as first-line therapy for MCRC and to assess the efficacy and safety of this XIO combination. Starting doses were: I (180mg/m2 i.v. on day 1), O (85mg/m2 i.v. on day 1), and X (850mg/m2 bid orally on days 2–15). Dose escalations are based on toxicity observed at the previous dose level (DL), until DLT, MTD and RPIID are documented, at which time a phase II component begins. Results: We enrolled 18 pts (13 men, 5 women), median age 61 (range 44–74) at 4 DLs. ECOG PS was 0 or 1 in 17 pts, and 2 in 1 pt. Pts received a median of 7 cycles (range 1–15) of XIO. All pts are evaluable for toxicity and 14 for response. The most common adverse events were: neutropenia (83% all grades (G) with 4 G3, 4 G4), diarrhea (67%, 4 G3, one of which was a DLT). Nausea (78%) and vomiting (56%) were mild and controlled with anti-emetics. Fatigue occurred in 50% pts, with 1 G3. The DLT was febrile neutropenia (3 pts at DLs 1, 3, & 4 respectively). One pt at DL4 developed severe neutropenia and sepsis during cycle 3, had aspiration pneumonia and died in hospital from respiratory and cardiac complications. MTD has not yet been reached. Responses were observed at all DLs: 11 partial responses with 2 still unconfirmed (79%, 95% CI 54–100), and 2 stable disease (14%). Progression-free survival and overall survival have not been reached. Conclusions: XIO is well tolerated and demonstrated significant efficacy as first-line treatment in MCRC. Severe neutropenia was significant but was of short duration and manageable. It is likely to be the main DLT. MTD has not yet been identified but is expected in the next few pts. A phase II study to confirm the efficacy and safety of the XIO combination will follow. Supported by Roche, Sanofi Aventis, and Pfizer Canada Inc.

[Table: see text]

A phase I, first in man study of OSI-7836 in patients with advanced refractory solid tumors: IND.147, a study of the Investigational New Drug Program of the National Cancer Institute of Canada Clinical Trials Group

PURPOSE

To determine the maximum tolerated dose (MTD), recommended phase II dose (RP2D), safety, tolerability, toxicity profile, dose-limiting toxicities (DLTs), anti-tumor activity and pharmacokinetics of OSI-7836 given IV on day 1 and day 8 every 3 weeks in patients with advanced incurable cancer.

METHODS

Twenty-seven previously treated patients with advanced or metastatic solid tumors were enrolled in this phase I study conducted by the National Cancer Institute of Canada Clinical Trial Group (NCIC CTG). OSI-7836 was administered IV on day 1 and day 8 every 3 weeks. The dose was initially escalated from 100 to 600 mg/m2 and finally de-escalated to 200 mg/m2 in seven cohorts of patients. Patients were evaluated every other cycle of treatment for radiological response. Pharmacokinetics were performed on day 1 and day 8 of cycle 1 for all patients.

RESULTS

Twenty-six patients were evaluable for toxicity. All patients experienced reversible Grade 3 lymphopenia beginning at cycle 1. The maximal delivered dose was 600 mg/m2. MTD was reached at 400 mg/m2. DLTs included fever, fatigue, rash, herpes simplex infection, nausea and vomiting. The RP2D was 200 mg/m2. No objective responses were seen in 21 evaluable patients. Pharmacokinetics were dose proportional, with a mean half-life of 46.0 min and a clearance of 34 l/(h.m2).

CONCLUSION

OSI-7836 given at 200 mg/m2 on day 1 and day 8 every 3 weekly is associated with manageable toxicity and is recommended for further study. While no objective responses were seen, the significant treatment related lymphopenia suggests that hematologic malignancies may warrant further investigation.

A National Cancer Institute of Canada Clinical Trials Group Study – IND.135: Phase I/II study of irinotecan (camptosar), oxaliplatin and raltitrexed (tomudex) (COT) in patients with advanced colorectal cancer

Thirty-one patients with metastatic colorectal cancer were enrolled in this phase I/II trial of a triple combination of camptosar (C), oxaliplatin (O) and tomudex (T), all given on day one of a convenient three-week schedule. Patients received 257 cycles (1-18) in five cohorts. Toxicity was manageable and haematological toxicity was mild to moderate. Diarrhoea was the main dose-limiting toxicity; nausea and vomiting were common. Fatigue was frequent, moderate in severity and a reason for discontinuation in some patients. The recommended phase II doses were (C) 220 mg/m(2), (O) 100mg/m(2), (T) 2.75 mg/m(2). A 50% response rate in 30 evaluable patients was confirmed by an independent radiology review board; progression-free survival and overall median survival were 7.3 months and 16.6 months, respectively. Of the 16 patients treated at the recommended dose, 9 (56.3%) experienced partial response. Further evaluation in a randomized study compared to sequential doublets is warranted. Triple combinations could be relevant in curative settings for high-risk patients.

An approach for substrate mapping between ASM and ADM1 for sludge digestion

Kinetic modelling of the hydrolysis stage of municipal activated sludge, which is presumed to be the rate-limiting step in the anaerobic sludge digestion process, was studied by measuring methane production rate (MPR) in anaerobic batch tests. The MPR curves revealed that the degradable organic components in municipal sludge could be classified into two fractions having different kinetics. The first fraction (XS1) constituted about 55% of the sludge COD and degraded with first-order kinetics. The second fraction (XS2), which degraded during the initial phase, accounted for about 21% of sludge COD. The degradation kinetics for XS2 was expressed by Contois-type equation with respect to concentration of substrate in the fed sludge and that of active biomass in the mixture. Simultaneous batch aerobic respirometric tests showed that the activated sludge was composed of 53% heterotrophic biomass (XH-Aerobe) COD and 20% of slowly biodegradable COD (XS), that had same kinetic expressions as observed in the batch anaerobic tests. The observed correlation between substrate fractions suggests XS1 and XS2 could be directly mapped to the aerobic state variables of XH-Aerobe and Xs respectively. The degradation of XS1 seems to be anaerobic decay of XH-Aerobe while XS2 is thought to be hydrolysis of XS by microcosm of the sludge.

An NCIC-CTG phase I dose escalation pharmacokinetic study of the matrix metalloproteinase inhibitor BAY 12-9566 in combination with doxorubicin

BACKGROUND

This phase I study was performed to evaluate the safety, tolerability, and efficacy of the oral matrix metalloproteinase inhibitor BAY 12-9566 in combination with doxorubicin in patients with advanced solid tumours, and to identify the maximum tolerated dose of these agents in combination and the dose for use in subsequent studies.

PATIENTS AND METHODS

14 patients were entered onto 3 dose levels consisting of escalating doses of doxorubicin (50 mg/m(2), 60 mg/m(2) and 70 mg/m(2)) with 800 mg po bid BAY 12-9566. At all three dose levels, patients received doxorubicin alone in cycle one on day 1. Daily oral dosing with BAY 12-9566 was started on day 8 of cycle 1, and thus doxorubicin was given concurrently with BAY 12-9566 in cycle 2. Patients were continued on treatment until a dose limiting toxicity or tumour progression occurred.

RESULTS

Pharmacokinetic studies from cycles 1 and 2 from the patients treated in the first three dose levels demonstrated that the addition of BAY 12-9566 increased the AUC(0-12h) levels of doxorubicin by a median of 48%. No effects were seen on the BAY 12-9566 pharmacokinetic values. Two dose limiting toxicities were seen at the third dose level. One patient experienced grade 3 stomatitis in cycle 2, and another patient experienced grade 4 granulocytopenia in cycle 1 and grade 4 thrombocytopenia in cycle 2. Thus the maximum tolerated dose of 60 mg/m(2) was declared. These toxicities were those that would have been expected from doxorubicin alone.

CONCLUSIONS

BAY 12-9566 can be safely administered with full doses of doxorubicin without evidence of clinical interaction. The recommended dose of doxorubicin to be combined with BAY 12-9566 800 mg po b.i.d is 60 mg/m(2), however, further development of BAY 12-9566 has been abandoned.

An NCIC CTG phase I/pharmacokinetic study of the matrix metalloproteinase and angiogenesis inhibitor BAY 12-9566 in combination with 5-fluorouracil/leucovorin

BACKGROUND

This phase I study was performed to evaluate the safety, tolerability, and efficacy of the oral matrix metalloproteinase inhibitor BAY 12-9566 in combination with 5-fluorouracil/leucovorin in patients with advanced solid tumours, and to identify the maximum tolerated dose and the dose for use in future studies.

PATIENTS AND METHODS

BAY 12-9566 and 5-fluorouracil/leucovorin were administered to 17 patients in 3 cohorts. Each patient served as his/her own control, with 5-fluorouracil being given alone on days 1-5 of cycle 1. In cohort 1, BAY 12-9566 at 800 mg p.o. b.i.d. was given with 350 mg/m2 5-fluorouracil/20 mg/m2 leucovorin x 5 days q28 days. In cohort 2, the BAY 12-9566 dose was reduced to 400 mg p.o. b.i.d., with the 5-fluorouracil/leucovorin doses remaining unchanged. Finally, in cohort 3, BAY 12-9566 400 mg bid was given with 5-fluorouracil 400 mg/m2/day. Patients were continued on therapy until unacceptable toxicity or tumour progression occurred. Pharmacokinetic analyses for both BAY 12-9566 and 5-fluorouracil were performed.

RESULTS

The maximum tolerated dose was 400 mg p.o. b.i.d. BAY 12-9566 plus 5-fluorouracil/leucovorin at 400 mg/m2/day and 20 mg/m2/day, respectively. Thrombocytopenia necessitated a decrease of the dose of BAY 12-9566 by 50% from cohort 1 to cohort 2. Two dose-limiting toxicities occurred in cohort 3 consisting of neutropenic fever, and ileitis, causing severe diarrhea. Of 17 patients treated on study, 7 of 14 patients evaluable for response achieved stable disease. Pharmacokinetic analysis suggested there was no interaction between BAY 12-9566 and 5-fluorouracil.

CONCLUSIONS

BAY 12-9566 400 mg bid and 5-fluorouracil 350 mg/m2 plus leucovorin 20 mg/m2 can be co-administered. Although there is some evidence of a clinical interaction, there is no apparent pharmacokinetic interaction. Future studies with these 2 types of agents administered in combination are warranted.

Full-scale application of anaerobic digestion process with partial ozonation of digested sludge

For improving sludge digestion and biogas recovery, a new anaerobic digestion process combined with ozonation was tested at a full-scale unit for 2 years and its performance was compared with a simultaneously operated conventional anaerobic digestion process. The new process requires two essential modifications, which includes ozonation for enhancing the biological degradability of sludge organics and concentrating of solids in the digester through a solid/liquid separation for extension of SRT. These modifications resulted in high VSS degradation efficiency of ca. 88%, as much as 1.3 times of methane production and more than 70% reduction in dewatered sludge cake production. Owing to accumulation of inorganic solids in the digested sludge, water content of the dewatered sludge cake also reduced from 80% to 68%. An energy analysis suggested that no supplemental fuel was necessary for the subsequent incineration of the cake from the new process scheme. The process is suitable to apply to a low-loaded anaerobic digestion tank, where power production is used.

Minimization of greenhouse gas emission by application of anaerobic digestion process with biogas utilization

To assess the impact on greenhouse gas emission, different process schemes for municipal sludge treatment were evaluated based on the data from pilot-scale experiments and review of annual operation reports. A modified anaerobic digestion process with partial ozonation of digested sludge to improve biological degradability and the conventional anaerobic digestion process were compared with respect to the energy demand in each process schemes. Options for beneficial use of biogas included (1) application of biogas for power production and (2) recovery as an alternative to natural gas utilization. The analysis indicated that the partial ozonation process with power production led to minimal greenhouse gas emission because the extra energy production from this scheme was expected to cover all of the energy demand for the plant operation. Moreover, the final amount of dewatered sludge cake was only 40% of that expected from the conventional process, this significantly minimizes the potential for greenhouse gas emission in the subsequent sludge incineration processes.

Fatal renal failure as the first manifestation of sarcoidosis diagnosed on necropsy in a young man: a case report

Renal involvement as the first manifestation of sarcoidosis is rare and has never been reported in India. This report describes a 35 year old man who was admitted to the emergency department with a clinical diagnosis of acute on chronic renal failure, secondary to obstructive uropathy. Postmortem examination unexpectedly revealed disseminated sarcoidosis.

UK national survey of prophylactic YAG iridotomy

PURPOSE

Acute angle-closure glaucoma is a common ophthalmic emergency and individuals with shallow anterior chambers and suspected narrow angles are increasingly referred to the hospital eye service for assessment. There appears to be variation in subsequent management, with no national consensus or college guidelines. This study ascertains the current use of prophylactic YAG iridotomy in patients with no known history of an acute angle-closure glaucoma attack, and also the methods used in patient selection.

MATERIALS AND METHODS

Questionnaire-based survey mailed to 650 UK consultant ophthalmologists with a covering letter in 2003.

RESULTS

A total of 546 questionnaires were returned. In all, 408 respondents (74.7%) confirmed they perform prophylactic YAG iridotomy and of these 347 (85.0%) use patient symptoms and 268 (65.6%) presenting IOP in patient selection, 394 (96.6%) perform gonioscopy and 97 (23.8%) use some form of provocative test first. A total of 135 (25.3%) stated they do not perform this procedure.

CONCLUSION

This study reveals current national practice among UK ophthalmologists, with variations in the assessment of patients with narrow angles but a high uptake of prophylactic YAG iridotomy.

Process performance and change in sludge characteristics during anaerobic digestion of sewage sludge with ozonation

A new process configuration combining anaerobic digestion with ozonation, and operated at long SRT, was studied with the objective of on-site reduction in sludge quantity and improving biogas recovery. The process performance with respect to solid reduction efficiency and other important process parameters like accumulation of inorganic solids, changes in sludge viscosity and dewatering characteristics were evaluated from the data of long term pilot scale continuous experiments conducted using a mixture of primary and secondary municipal sewage sludge. Due to sludge ozonation and long SRT, high VSS degradation efficiency of approximately 80% was achieved at a reactor solid concentration of 6.5%. A high fraction of inorganic solid (>50%) consisting mainly of acid insoluble and iron compounds was found to accumulate in the reactor. The high inorganic content accumulated in the digested sludge did not, however, contribute to the observed increase in sludge viscosity at high solid concentration. The sludge viscosity was largely found to depend on the organic solid concentration rather than the total solid content. Moreover, higher inorganic content in the digested sludge resulted in better sludge dewaterability. For a quick assessment of the economic feasibility of the new process, an economic index based on the unit cost of digested sludge disposal to unit electric cost is proposed.

Endoscopic removal of knotted urethral catheter: a point of technique

Urethral catheter knotting is a rare complication of the simple and widely practiced clean intermittent self-catheterization. We report the endoscopic retrieval of a retained knotted feeding tube in a 12-year-old child. Various factors leading to such a rare complication and a new minimal invasive technique are described. To the best of our knowledge this technique has not been previously reported in the medical literature.

Phase II study of troxacitabine (BCH-4556) in patients with advanced and/or metastatic renal cell carcinoma: a trial of the National Cancer Institute of Canada-Clinical Trials Group

PURPOSE

A multi-institution phase II study was undertaken by National Cancer Institute of Canada-Clinical Trials Group to evaluate the efficacy and toxicity of intravenous troxacitabine (Troxatyl; Shire Pharmaceuticals Plc, Laval, Quebec, Canada), in patients with renal cell carcinoma.

PATIENTS AND METHODS

Between June 1999 and March 2000, 35 patients (24 male) with a mean age of 60 years who had advanced and/or metastatic disease were treated with troxacitabine given as an intravenous infusion over 30 minutes at a dose of 10 mg/m2 intravenously, once every 3 weeks.

RESULTS

Of the 33 of 35 patients evaluable for response, there were two confirmed partial responses, 21 patients had stable disease (median duration, 4.4 months), and 10 patients had progressive disease. Eight patients remained stable for more than 6 months, of whom six remain free of progression. The most common drug-related nonhematologic toxicities observed were skin rash (77.1%), hand-foot syndrome (68.6%), alopecia (51.4%), fatigue (51.4%), and nausea (57.1%). Out of a total of 145 cycles of treatment, 98 were given without steroid premedication, whereas 47 cycles were given with steroid premedication. Without premedication, skin rash occurred in 37% of cycles compared with 26% when steroids were given prophylactically.

CONCLUSION

Troxacitabine given at a dose of 10 mg/m2 once every 3 weeks was well tolerated in patients with metastatic renal cell cancer, with common toxicities being a moderate to severe granulocytopenia and skin rash. Steroid premedication may reduce the frequency and severity of the skin rash. Our current study suggests that the nucleoside analog troxacitabine may have modest activity against renal cell carcinoma; however, larger studies are required to confirm this.

Optimal process configuration for anaerobic digestion with ozonation

Economical source minimization of excess sludge production is an attractive option to deal with the problem of sludge disposal under strict disposal standards. In this paper long-term operational results for two different process configurations that combine oxidative ozone treatment with anaerobic sludge digestion are described. In the first configuration ozone pretreatment was combined with chemostat anaerobic digestion while in the second configuration ozone pre/post-treatments were combined with an anaerobic digester operated without solid removal. From the results of chemostat experiments, the ozone pretreatment solubilized around 19% and 37% of the solids at 0.015 and 0.05 gO3/gTS ozone dose respectively. The ozone pretreatment resulted in improved TVS reduction efficiencies and the degradation efficiencies were observed to depend on the applied ozone dose and system SRT. The TVS degradation efficiency for pre-ozonated sludge at an ozone dose of 0.05 gO3/gTS was 59% as compared to 31% for the control reactor fed with un-ozonated sludge. Test results with the second configuration indicated that overall TVS removal efficiencies for a process scheme with post-ozonation could be improved up to 85% with a minimum ozone dose of 0.045 gO3/gTVS-fed. However, since no solids (except that for sampling) were withdrawn in this configuration, the accumulated total solids in the reactors increased to 28 g/l to 30 g/l at pseudosteady state. The average specific methane recoveries were observed to be 0.36 lCH4/gTVS fed which were slightly lower than theoretically expected. Based on the experimental results, important points in the choice of process configuration are discussed.

Anaerobic digestion of excess activated sludge with ozone pretreatment

Source minimization of excess sludge production by economical means can be considered an attractive option to deal with the problem of sludge disposal under strict disposal standards. In this paper long-term operational results for a process that combines the oxidative ozone pretreatment with anaerobic sludge digestion are described. The ozone pretreatment solubilized around 19% and 37% of the solids at 0.015 and 0.05 gO3/gTS ozone dose. The solubilization ratios during ozonation did not show any significant difference for the sludge concentrations ranging from 1.8-2.6%. The TVS concentrations after ozone treatment were observed to be about 3% lower than the feed sludge concentrations suggesting only partial mineralization during ozonation. The ozone pretreatment resulted in improved solid reduction efficiencies during anaerobic digestion leading to higher methane recovery. The TVS removal efficiencies during anaerobic digestion were observed to increase by a maximum of 35-90% depending on the applied ozone dose during ozone pretreatment. The improvement in TVS degradation efficiency at different applied ozone doses correlated well with the extent of solubilization during ozonation. Long-term data also suggested that biomass acclimation to ozonated sludge was necessary before higher degradation efficiencies could be achieved.

High-performance closed loop anaerobic digestion using pre/post sludge ozonation

To maximize the sludge degradation efficiencies during anaerobic digestion, pre-ozonation of raw activated sludge and/or post-ozonation of anaerobically digested sludge were used in combination with a reactor operated without solid withdrawal (closed loop operation scheme). Out of the two studied configurations, the configuration with the post-ozonation of digested sludge was found to be superior with respect to degradation efficiencies, lower accumulation of total volatile solid (TVS) and lower required ozone dose. The TVS concentration in the reactor with post ozonation was found to be around 26 +/- 2 g/l at an average TVS loading of 0.6 kgTVS/m3 x d. The maximum TVS removal efficiencies were observed to be around 85% with average specific gas recoveries of 0.36 l CH4/gTVS fed. The ozone dose of 3% on the recycle sludge was found to be sufficient as it was observed that the higher ozone doses of 6% neither improved the TVS reduction efficiency nor reduced the TVS concentration in the reactor. The ozone requirements were estimated at around 0.054 gO3/gTVS removed or 0.045 gO3/gTVS fed. The soluble COD concentrations from the reactor ranged from 500-875 mg/l with negligibly small amount of VFA. The average COD in the centrate of the digested sludge was around 3000 mg/l suggesting the presence of colloidal COD in the reactors.

The palliative benefit of irinotecan in 5-fluorouracil-refractory colorectal cancer: its prospective evaluation by a Multicenter Canadian Trial

Most patients with colorectal cancer (CRC) who have failed initial 5-fluorouracil (5-FU) chemotherapy have worsening of disease-related symptoms (DRS) and quality of life (QOL). Irinotecan has a reported response rate of 10%-20% in such patients. The aim of this phase II trial was to prospectively determine the palliative benefit of irinotecan utilizing DRS as primary endpoints of response. Patients had advanced CRC refractory to 5-FU with at least 1 DRS defined as (1) Karnofsky performance status (KPS) 60%-80%, (2) baseline analgesic use > or = 10 mg morphine/day (or equivalent), or (3) disease-related pain score > 1 cm on a 10-cm linear analogue self-assessment (LASA) scale. Patients received irinotecan 125 mg/m2 weekly for 4 weeks on an every-6-weeks schedule. The primary endpoint was palliative response defined as > or = 50% decrease in pain score or analgesic usage, or 10% increase in KPS, from baseline for 4 weeks. QOL was assessed by the European Organization for Research and Treatment of Cancer Quality-of-Life Questionnaire Core 30 (EORTC QLQ-C30) version 2 instrument. A total of 65 patients were entered onto the study. Median baseline parameters were KPS 70%, analgesic score 11 mg/day, and pain score 2.4 cm. A palliative response was achieved in 27 patients (42%), improvement in pain score predominated. LASA and EORTC QLQ-C30 instruments showed parallel changes in DRS. The radiological response rate was 11% (complete responses and partial responses, n = 46); 23 patients achieved stable disease. Median overall survival was 7.2 months. Irinotecan provides a rate of palliative benefit higher than the radiological response rate. Patients-oriented palliative endpoints can be useful in assessing the benefit of agents in early-phase clinical trials.

Incidence of schizophrenia in ethnic minorities in London: ecological study into interactions with environment

OBJECTIVE

To determine whether the incidence of schizophrenia among people from non-white ethnic minorities is greater in neighbourhoods where they constitute a smaller proportion of the total population.

DESIGN

Ecological design including retrospective study of case records to calculate the incidence of schizophrenia in the ethnic minority population across electoral wards and multi-level analysis to examine interaction between individuals and environment.

SETTING

15 electoral wards in Camberwell, South London.

PARTICIPANTS

All people aged 16 years and over who had contact with psychiatric services during 1988-97.

MAIN OUTCOME MEASURE

Incidence rates of schizophrenia according to Research Diagnostic Criteria.

RESULTS

The incidence of schizophrenia in non-white ethnic minorities increased significantly as the proportion of such minorities in the local population fell. The incidence rate ratio varied in a dose-response fashion from 2.38 (95% confidence interval 1.49 to 3.79) in the third of wards where non-white ethnic minorities formed the largest proportion (28-57%) of the local population to 4.4 (2.49 to 7.75) in the third of wards where they formed the smallest proportion (8-22%).

CONCLUSION

The incidence of schizophrenia in non-white ethnic minorities in London is greater when they comprise a smaller proportion of the local population.

Rapid extraction of DNA from diverse soils by guanidine thiocyanate method

Molecular methods are being frequently used for the study of soil microbial communities as majority of naturally occurring microbial populations are non-culturable. In the present study, we describe a protocol of DNA extraction from diverse soils using a combination of heat, enzyme (lysozyme) and guanidine thiocyanate. The efficacy of the procedure was evaluated in terms of yield, purity and duration of extraction. The protocol was effective for neutral, acidic as well as alkaline soils (pH range 4.5-8.5). The extracted soil DNA was observed with negligible shearing on agarose gel and the time taken for restriction digestion was very less. Further, the DNA extracted was almost completely devoid of contaminants and pure enough which could be used for PCR amplification and Southern hybridization.

Pseudoepitheliomatous hyperplasia secondary to cutaneous aspergillus

Cutaneous aspergillosis commonly occurs in immunocompromised hosts and may also complicate burn wounds. Pseudoepitheliomatous hyperplasia (PH) is a histologic reaction secondary to a wide range of stimuli, including fungal infection. We describe a case of an 18-year-old man, status-post burns over 70% of his total body surface area, with cutaneous aspergillosis of the axilla and secondary PH. A single case of PH secondary to primary aspergillosis has been described in the larynx but, to our knowledge, has never been described cutaneously. Histologic examination of the lesion reveals an irregularly acanthotic epidermis with deep invaginations within the dermis. There is an intense inflammatory reaction within the superficial and deep dermis. Numerous fungal forms are identified within the dermis. Special stains demonstrate septate hyphae with dichotomous branching, which is morphologically consistent with Aspergillus. Therefore, we conclude that cutaneous aspergillosis should be included in the differential diagnosis of causes of PH, especially in a patient population at risk for this infection.

A rapid reversed phase high performance liquid chromatographic method for determination of etoposide (VP-16) in human plasma

A rapid, simple and sensitive isocratic High Performance Liquid Chromatography (HPLC) method was developed to measure the concentration of etoposide in plasma samples with UV detection at 220 nm. The method uses a Bondapac C18 column at 60 degrees C. The mobile phase consists of Methanol: water (45:55 v/v) at a flow rate of 2.8 ml/min. Phenacetin was used as an internal standard. The plasma samples were extracted using ether with the organic layer evaporated under nitrogen. The residue was dissolved in 200 microl methanol with 20 microl injected into the HPLC column. The extraction method showed a recovery of 91.5+/-3% for etoposide. In this system, the retention time of phenacetin and etoposide were 3.3 and 4.4 min, respectively. The limit of detection of etoposide in plasma is 20 ng/ml and the limit of quantitation is 40 ng/ml. This analytical method has very good reproducibility (8.1% between-day variability at a concentration of 50 ng/ml). It is a fast, sensitive and economic method applicable for clinical and pharmacokinetic studies.

A phase I dose escalation study of the matrix metalloproteinase inhibitor BAY 12-9566 administered orally in patients with advanced solid tumours

BACKGROUND

This phase I study was performed to evaluate the safety, tolerability, and efficacy of the oral matrix metalloproteinase inhibitor BAY 12-9566 in patients with advanced solid tumours, and to identify the maximum tolerated dose and dose for use in subsequent studies.

PATIENTS AND METHODS

BAY 12-9566 was administered to 29 patients at doses ranging from 100 mg o.d. to 1600 mg (given either 400 mg q.i.d. or 800 mg b.i.d.). Blood samples for pharmacokinetic analyses were drawn on days 1-5, day 15 and days 29 and 30. Patients were continued on daily oral treatment of BAY 12-9566 until a dose limiting toxicity or tumour progression occurred.

RESULTS

A maximum tolerated dose was not defined because plasma levels of BAY 12-9566 could not be sufficiently increased, even with escalating doses of drug. Pharmacokinetic analysis suggested that absorption was saturable at higher doses. The predominant toxicities related to drug were asymptomatic reversible effects on platelets and transaminases and mild anemia. There were no significant musculoskeletal toxicities. No objective responses were seen at the doses tested, but stable disease was observed in some patients based on tumour measurements.

CONCLUSIONS

The recommended dose of BAY 12-9566 for further studies is 800 mg b.i.d. as this dose provides maximal plasma levels that can be achieved with a convenient dosing schedule for a chronically administered oral agent.

Liarozole fumarate (R85246): in the treatment of ER negative, tamoxifen refractory or chemotherapy resistant postmenopausal metastatic breast cancer

Three phase II studies were conducted to determine the efficacy and tolerability of liarozole fumarate (R85246; liarozole), a retinoic acid metabolism blocking agent (RAMBA) and aromatase inhibitor. Additionally, animal experiments in the MNU-induced rat mammary tumor model and in immature ovariectomized rats were conducted to further elucidate liarozole's mechanisms of action. Patients were postmenopausal with either: ER negative disease in first relapse (Group 1: 1n = 16); ER positive or unknown disease refractory to tamoxifen (Group 2; n = 16); ER positive, negative or unknown disease resistant or refractory to chemotherapy (Group 3; n = 27). Treatment was liarozole (150-300mg) twice daily orally until disease progression. Response rates were: 25% in group 1 (95% CI 11.0-52.3%: median duration (MD) 20 months; range 2-36.5); 25% in group 2 (95% CI 11.0-52.3%; MD 6.5 months: range 3.5-38): 11% in group 3 (95% CI 4.2-29.2%; MD 7 months; range 3-8.5). No significant improvement in quality of life scores (FLI-C) was noted. Toxicities observed were predominantly dermatological (skin disorders: 88%; dry mouth/eyes/lips: 69%). Plasma estradiol decreased from mean pre-treatment levels of 72.7 pM (9.1-1,839 pM) to below detection (9.2 pM) after 1 month. Liarozole, but not vorozole, partially inhibited estradiol induced uterine hypertrophy and demonstrated dose-dependent anti-tumor effects in the rats, only partially overcome by coadministration of estradiol. The clinical responses observed, together with our preclinical results, confirm liarozole's dual mechanism of action and provide a rationale for further evaluation of RAMBAs in the treatment of breast cancer.

Attenuation of changes in sarcoplasmic reticular gene expression in cardiac hypertrophy by propranolol and verapamil

The effects of propranolol and verapamil on contractile dysfunction, subcellular remodeling and changes in gene expression in cardiac hypertrophy due to pressure overload were examined. Rats were subjected to banding of the abdominal aorta and then treated with either propranolol (10 mg/kg daily), verapamil (5 mg/kg daily) or vehicle for 8 weeks after the surgery. Depression of the left ventricular function in the hypertrophied heart was associated with decreases in myofibrillar and myosin Ca2+ ATPase activities as well as Ca2+-pump and Ca2+-release activities of the sarcoplasmic reticulum (SR). The level of alpha-myosin heavy chain (alpha-MHC) mRNA was decreased while that of beta-MHC mRNA was increased in the pressure-overloaded heart. The level of SR Ca2+-pump ATPase (SERCA2) mRNA and protein content for SERCA2 were decreased in the pressure overloaded heart. Treatment of the hypertrophied animals with propranolol or verapamil resulted in preservation of the left ventricular function and prevention of the subcellular alterations. Shift in the alpha- and beta-MHC mRNA levels and changes in the expression in SERCA2 mRNA level and protein content were also attenuated by these treatments. The results suggest that blockade of beta-adrenoceptors or voltage-dependent calcium channels normalizes the cardiac gene expression, prevents subcellular remodeling and thus attenuates heart dysfunction in rats with cardiac hypertrophy. Furthermore, both cardiac beta-adrenoceptors and L-type Ca2+-channels may be involved in the genesis of cardiac hypertrophy due to pressure overload.

Effects of crocetin on pulmonary gas exchange in foxhounds during hypoxic exercise

The carotenoid compound crocetin has been hypothesized to enhance the diffusion of O(2) through plasma, and observations in the rat and rabbit have revealed improvement in arterial PO(2) when crocetin is given. To determine whether crocetin enhances diffusion of O(2) between alveolar gas and the red blood cell in the pulmonary capillary in vivo, five foxhounds, two previously subjected to sham and three to actual lobectomy or pneumonectomy, were studied while breathing 14% O(2) at rest and during moderate and heavy exercise before and within 10 min after injection of a single dose of crocetin as the trans isomer of sodium crocetinate (TSC) at 100 microg/kg iv. This dose is equivalent to that used in previous studies and would yield an initial plasma concentration of 0.7-1.0 microg/ml. Ventilation-perfusion inequality and pulmonary diffusion limitation were assessed by the multiple inert gas elimination technique in concert with conventional measurements of arterial and mixed venous O(2) and CO(2). TSC had no effect on ventilation, cardiac output, O(2) consumption, arterial PO(2)/saturation, or pulmonary O(2) diffusing capacity. There were minor reductions in ventilation-perfusion mismatching (logarithm of the standard deviation of perfusion fell from 0.48 to 0.43, P = 0.001) and in CO(2) output and respiratory exchange ratio (P = 0.05), which may have been due to TSC or to persisting effects of the first exercise bout. Spectrophotometry revealed that TSC disappeared from plasma with a half time of approximately 10 min. We conclude that, in this model of extensive pulmonary O(2) diffusion limitation, TSC as given has no effect on O(2) exchange or transport. Whether the original hypothesis is invalid, the dose of TSC was too low, or plasma diffusion of O(2) is not rate limiting without TSC cannot be discerned from the present study.

Immunohistochemical localization and correlation of p53 and PCNA expression in breast carcinoma

The object of the present study is to detect the p53 tumour suppressor gene and proliferation cell nuclear antigen (PCNA) expression in breast carcinoma by immunohistochemistry and correlate them with the prognostic parameters. Total 35 cases of primary breast carcinoma were studied and classified histologically. Paraffin sections were stained by using monoclonal antibody D07 for p53 protein and PC-10 for PCNA. Out of 35 cases, 16 (45.7%) were p53 positive and 25 (71.4%) were PCNA positive. The mean PCNA labelling index (PCNA LI +/- SD) was 58.97 +/- 22.72 in tumors positive for both p53+ and PCNA+ while cases negative for p53- and positive for PCNA+ has higher PCNA LI +/- SD (59.24 +/- 18.97). The difference in the two groups was not significant. Most cases were positive for both p53+ and PCNA+ in the age group < 30 with higher mean PCNA LI +/- SD (62.20 +/- 27.13) than in the group > 30 (57.88 +/- 18.47). In the pre-menopausal group 57.1% cases were positive for p53+ with higher PCNA LI +/- SD (59.94 +/- 24.22). Maximum p53 and PCNA positivity was observed in grade III tumors (63.2% and 84.2%). The mean PCNA LI +/- SD was also highest in grade III carcinomas (66.83 +/- 13.97). No significant correlation was found between p53 and PCNA status with morphological type and tumour size except that logistic regression showed a positive correlation with tumour grade. Therefore the present study suggests that both p53 expression and PCNA are markers of poor differentiation in breast cancer.

Liarozole fumarate (R85246): a novel imidazole in the treatment of receptor positive postmenopausal metastatic breast cancer

This phase II study of liarozole fumarate (R85246, liarozole), a novel imidazole with retinomimetic and aromatase inhibitory effects, was designed to determine the efficacy and tolerability in postmenopausal women with advanced breast cancer in progression, to correlate these effects with hormonal levels, and to evaluate quality of life. Twenty-nine women with ER-positive or unknown metastatic disease who received > or = 2 prior hormonal therapies were treated with 150-300 mg liarozole twice daily until disease progression. All patients were evaluable for toxicity and 25 for response. Four patients (16.0%, 95% CI 5.3-37.4%) had partial remission (PR) of their disease for a median of 7.4 months (range 1.2-12.9) and 7 (28%) had disease stabilization for a median of 4.8 months (1.6-16.0). Estradiol decreased from pre-treatment levels of 9.2-52 pM (mean 17.1) to below detection (9.2 pM, p = 0.0005) after 1 month. Similarly estrone levels fell from 14-307 pM (mean 92.7) to below detection (9.2 pM, p = 0.0001). The most common toxicity was dermatological (96.6%) with features compatible with hypervitaminosis A syndrome such as rash, pruritus, dry skin, and brittle nails. The majority of these were mild to moderate in severity. No significant improvement in quality of life scores (FLI-C) were noted. Liarozole is an active new treatment for breast cancer in patients heavily pre-treated with hormone therapies. Further studies are needed to confirm its relative efficacy in both receptor positive and negative postmenopausal breast cancer.

Concurrent use of multiple low dose chemotherapy agents with differing mechanisms of action as a strategy vs passive resistance: A pilot study

Resistance may be classified as active (or competitive) (due to excess amount of a factor) vs passive (or non-competitive) (due to a deficiency of a factor). Passive resistance may be important in human solid tumors. In passive resistance, the dose-response curve may be shallow, or may flatten at a relatively low dose. We hypothesized that, if passive resistance were important, it might be advantageous to use low doses of multiple concurrent chemotherapy agents with differing mechanisms of action, rather than using high doses of 2 or 3 drugs. We combined single day cisplatin 60 mg/m2, cyclophosphamide 250 mg/m2, epirubicin 40 mg/m2, paclitaxel 60 mg/m2, and vinblastine 2.5 mg/m2, with 5 days of 5-fluorouracil 200 mg/m2, folinic acid 20 mg/m2 and dexamethasone 4 mg orally q.i.d. every 3 weeks. In later cohorts, doses were escalated, and tamoxifen and verapamil were added. Twenty-three patients were entered. ECOG performance status was 1 in 15 patients and 2 in 8. Number of prior chemotherapy regimens was 0 in 4 patients, 1 in 4, 2 in 8, 3 in 4, 4 in 2, and 7 in 1. Sixteen patients had prior radiotherapy, and 3 had no prior therapy. Myelosuppression and febrile neutropenia were frequent, and 4 heavily pretreated patients died of pneumonia contracted while neutropenic. Diarrhea, nausea and vomiting, and fatigue were also prominent. Among 9 patients with non-small cell lung cancer, one had a partial remission, 4 had stable disease (including 3 with minor objective responses). Two additional non-small cell lung cancer patients also had objective tumor regression, but were coded as failures, since one had tumor progression in <6 weeks and the other died of respiratory failure (thought to be due to severe mucous plugging) one week after his first course of treatment. Among 14 patients with other tumor types, there was one partial response (esophageal carcinoma), 6 patients with stable disease for >6 weeks (including minor responses in one patient each with adenocarcinomas of kidney and breast), and 7 failures (including one patient with adenocarcinoma unknown primary who had minor tumor regression lasting 4 weeks). Despite the unacceptably high toxic death rate, median survival time was 24 weeks (range, 1 week to >104 weeks). This regimen is toxic, but survival duration is longer than would be expected in this heavily pre-treated population. Doses recommended for further study are those used in the first treatment cohort (as described above). Since myelosuppression is the major toxic effect, hemopoietic growth factors might prove helpful with this regimen.