Final analysis of the randomized trial on imatinib as an adjuvant in localized gastrointestinal stromal tumors (GIST) from the EORTC Soft Tissue and Bone Sarcoma Group (STBSG), the Australasian Gastro-Intestinal Trials Group (AGITG), UNICANCER, French Sarcoma Group (FSG), Italian Sarcoma Group (ISG), and Spanish Group for Research on Sarcomas (GEIS)☆.

BACKGROUND: In 2004, we started an intergroup randomized trial of adjuvant imatinib versus no further therapy after R0-R1 surgery in localized, high/intermediate-risk gastrointestinal stromal tumors (GIST) patients. Interim analysis results were published in 2015 upon recommendation from an independent data review committee. We report the final outcome of the study. PATIENTS AND METHODS: This was a randomized, open-label, multicenter phase III trial carried out at 112 hospitals in 12 countries. Patients were randomized to 2 years of imatinib, 400 mg daily, or no further therapy after surgery. The primary endpoint was imatinib failure-free survival (IFFS), while relapse-free survival (RFS), relapse-free interval (RFI), overall survival (OS) and toxicity were secondary endpoints. Adjusting for the interim analyses, results on IFFS were assessed on a 4.3% significance level; for the other endpoints, 5% was used. RESULTS: Nine hundred and eight patients were randomized between January 2005 and October 2008: 454 to imatinib and 454 to observation; 835 patients were eligible. With a median follow-up of 9.1 years, 5 (10)-year IFFS was 87% (75%) in the imatinib arm versus 83% (74%) in the control arm [hazard ratio (HR) = 0.87, 95.7% confidence interval (CI) (0.65; 1.15), P = 0.31]; RFS was 70% versus 63% at 5 years and 63% versus 61% at 10 years, [HR = 0.71, 95% CI (0.57; 0.89), P = 0.002]; OS was 93% versus 92% at 5 years and 80% versus 78% at 10 years [HR = 0.88, 95% CI (0.65; 1.21), P = 0.43]. Among 526 patients with high-risk GIST by local pathology, 10-year IFFS and RFS were 69% versus 61%, and 48% versus 43%, respectively. CONCLUSIONS: With 9.1 years of follow-up, a trend toward better long-term IFFS in imatinib-treated patients was observed in the high-risk subgroup. Although the difference was not statistically significant and the surrogacy value of such an endpoint is not validated, this may be seen as supporting the results reported by the Scandinavian/German trial, showing a sustained small but significant long-term OS benefit in high-risk GIST patients treated with 3 years of adjuvant imatinib.

Preoperative cisplatin, fluorouracil, and docetaxel with or without radiotherapy after poor early response to cisplatin and fluorouracil for resectable oesophageal adenocarcinoma (AGITG DOCTOR): results from a multicentre, randomised controlled phase II trial.

BACKGROUND: Patients with oesophageal/gastro-oesophageal junction adenocarcinoma (EAC) not showing early metabolic response (EMR) to chemotherapy have poorer survival and histological response rates <5%. We investigated whether tailoring neoadjuvant therapy can improve outcomes in these patients. PATIENTS AND METHODS: Patients with resectable EAC were enrolled and randomised into two single-arm, multicentre phase II trials. After induction cisplatin and 5-fluorouracil (CF), all were assessed by day 15 positron emission tomography (PET). Patients with an EMR [maximum standardised uptake values (SUVmax) ≥35% reduction from baseline to day 15 PET] received a second CF cycle then oesophagectomy. Non-responders were randomised 1 : 1 to two cycles of CF and docetaxel (DCF, n = 31) or DCF + 45 Gy radiotherapy (DCFRT, n = 35) then oesophagectomy. The primary end point was major histological response (<10% residual tumour) in the oesophagectomy specimen; secondary end points were overall survival (OS), progression-free survival (PFS), and locoregional recurrence (LR). RESULTS: Of 124 patients recruited, major histological response was achieved in 3/45 (7%) with EMR, 6/30 (20%) DCF, and 22/35 (63%) DCFRT patients. Grade 3/4 toxicities occurred in 12/45 (27%) EMR (CF), 13/31 (42%) DCF, and 25/35 (71%) DCFRT patients. No treatment-related deaths occurred. LR by 3 years was seen in 5/45 (11%) EMR, 10/31 (32%) DCF, and 4/35 (11%) DCFRT patients. PFS [95% confidence interval (CI)] at 36 months was 47% (31% to 61%) for EMR, 29% (15% to 45%) for DCF, and 46% (29% to 61%) for DCFRT patients. OS (95% CI) at 60 months was 53% (37% to 67%) for EMR, 31% (16% to 48%) for DCF, and 46% (29% to 61%) for DCFRT patients. CONCLUSIONS: EMR is associated with favourable OS, PFS, and low LR. For non-responders, the addition of docetaxel augmented histological response rates, but OS, PFS, and LR remained inferior compared with responders. DCFRT improved histological response and PFS/LR outcomes, matching the EMR group. Early PET/CT has the potential to tailor therapy for patients not showing an early response to chemotherapy. TRIAL REGISTRATION: ACTRN12609000665235.

Oxaliplatin and 5-FU/folinic acid (modified FOLFOX6) with or without aflibercept in first-line treatment of patients with metastatic colorectal cancer: the AFFIRM study.

BACKGROUND: The combination of aflibercept with FOLFIRI has been shown to significantly prolong overall survival in patients with metastatic colorectal cancer (mCRC) after progression on oxaliplatin-based therapy. This trial evaluated the addition of aflibercept to oxaliplatin-based first-line treatment of patients with mCRC. PATIENTS AND METHODS: Patients with mCRC were randomized to receive first-line therapy with mFOLFOX6 plus aflibercept (4 mg/kg) or mFOLFOX6 alone. The primary end point of this phase II study was the progression-free survival (PFS) rate at 12 months in each arm. The analysis of efficacy between the arms was a pre-planned secondary analysis. RESULTS: Of 236 randomized patients, 227 and 235 patients were evaluable for the primary efficacy analysis and safety, respectively. The probabilities of being progression-free at 12 months were 25.8% [95% confidence interval (CI) 17.2-34.4] for the aflibercept/mFOLFOX6 arm and 21.2% (95% CI 12.2-30.3) for the mFOLFOX6 arm. The median PFS was 8.48 months (95% CI 7.89-9.92) for the aflibercept/mFOLFOX6 arm and 8.77 months (95% CI 7.62-9.27) for the mFOLFOX6 arm; the hazard ratio of aflibercept/mFOLFOX6 versus mFOLFOX6 was 1.00 (95% CI 0.74-1.36). The response rates were 49.1% (95% CI 39.7-58.6) and 45.9% (95% CI 36.4-55.7) for patients treated with and without aflibercept, respectively. The most frequent treatment-emergent grade 3/4 adverse events (AEs) excluding laboratory abnormalities reported for aflibercept/mFOLFOX6 versus mFOLFOX6 were neuropathy (16.8% versus 17.2%) and diarrhea (13.4% versus 5.2%). Neutropenia grade 3/4 occurred in 36.1% versus 29.3%. The most common vascular endothelial growth factor inhibition class-effect grade 3/4 AEs for aflibercept/mFOLFOX6 versus mFOLFOX6 were hypertension (35.3% versus 1.7%), proteinuria (9.2% versus 0%), deep vein thrombosis (5.9% versus 0.9%) and pulmonary embolism (5.9% versus 5.2%). CONCLUSION: No difference in PFS rate was observed between treatment groups. Adding aflibercept to first-line mFOLFOX6 did not increase efficacy but was associated with higher toxicity. CLINICAL TRIAL NUMBER: NCT00851084, www.clinicaltrials.gov, EudraCT 2008-004178-41.

Epiregulin gene expression as a biomarker of benefit from cetuximab in the treatment of advanced colorectal cancer.

BACKGROUND: Anti-EGFR antibody, cetuximab, improves overall survival (OS) in K-ras wild-type chemotherapy-refractory colorectal cancer. Epidermal growth factor receptor ligand epiregulin (EREG) gene expression may further predict cetuximab benefit. METHODS: Tumour samples from a phase III clinical trial of cetuximab plus best supportive care (BSC) vs BSC alone (CO.17) were analysed for EREG mRNA gene expression. Predictive effects of high vs low EREG on OS and progression-free survival (PFS) were examined for treatment-biomarker interaction. RESULTS: Both EREG and K-ras status were ascertained in 385 (193 cetuximab, 192 BSC) tumour samples. Within the high EREG and K-ras wild-type status ('co-biomarker')-positive group (n=139, 36%), median PFS was 5.4 vs 1.9 months (hazard ratio (HR) 0.31; P<0.0001), and median OS was 9.8 vs 5.1 months (HR 0.43; P<0.001) for cetuximab vs BSC, respectively. In the rest (n=246, 64%), PFS (HR 0.82; P=0.12) and OS (HR 0.90; P=0.45) were not significantly different. Test for treatment interaction showed a larger cetuximab effect on OS (HR 0.52; P=0.007) and PFS (HR 0.49; P=0.001) in the co-biomarker-positive group. CONCLUSION: In pre-treated K-ras wild-type status colorectal cancer, patients with high EREG gene expression appear to benefit more from cetuximab therapy compared with low expression. Epiregulin as a selective biomarker requires further evaluation.

Association of hypomagnesemia with inferior survival in a phase III, randomized study of cetuximab plus best supportive care versus best supportive care alone: NCIC CTG/AGITG CO.17.

BACKGROUND: Cetuximab-induced hypomagnesemia has been associated with improved clinical outcomes in advanced colorectal cancer (CRC). We explored this relationship from a randomized clinical trial of cetuximab plus best supportive care (BSC) versus BSC alone in patients with pretreated advanced CRC. PATIENTS AND METHODS: Day 28 hypomagnesemia grade (0 versus ≥1) and percent reduction (<20% versus ≥20%) of Mg from baseline was correlated with outcome. RESULTS: The median percentage Mg reduction at day 28 was 10% (-42.4% to 63.0%) for cetuximab (N = 260) versus 0% (-21.1% to 25%) for BSC (N = 251) [P < 0.0001]. Grade ≥1 hypomagnesemia and ≥20% reduction from baseline at day 28 were associated with worse overall survival (OS) [hazard ratio, HR 1.61 (95% CI 1.12-2.33), P = 0.01 and 2.08 (95% CI 1.32-3.29), P = 0.002, respectively] in multivariate analysis including grade of rash (0-1 versus 2+). Dyspnea (grade ≥3) was more common in patients with ≥20% versus < 20% Mg reduction (68% versus 45%; P = 0.02) and grade 3/4 anorexia were higher in patients with grade ≥1 hypomagnesemia (81% versus 63%; P = 0.02). CONCLUSIONS: In contrast to prior reports, cetuximab-induced hypomagnesemia was associated with poor OS, even after adjustment for grade of rash.

Phase I trial of docetaxel, cisplatin and concurrent radical radiotherapy in locally advanced oesophageal cancer.

BACKGROUND: Locally advanced oesophageal cancer (LAEC) is associated with poor survival and more effective treatments are needed. The aim of this phase I trial was to assess the maximum tolerated dose (MTD) of a novel weekly docetaxel and cisplatin regimen concurrent with radical radiotherapy. METHODS: Patients with unresectable, non-metastatic LAEC were eligible. Treatment comprised docetaxel 15-30 mg m(-2) per week and cisplatin 15-30 mg m(-2) per week in six planned dose levels (DLs) in 3-6 patient cohorts with 50 Gy radiotherapy in 25 fractions. Maximum tolerated dose was based on defined dose-limiting toxicities (DLTs) during therapy and 2 weeks post therapy. RESULTS: A total of 24 patients were enrolled. There were two DLTs: grade 3 fever in DL1 (docetaxel 15 mg m(-2), cisplatin 15 mg m(-2)) and grade 3 nausea in DL2 (20 mg m(-2), 15 mg m(-2)). These DLs were each expanded to six patients without further DLTs. The most common acute toxicity was grade 3 radiation oesophagitis (37.5%). There were no grade 4 toxicities, and haematologic toxicity was minimal. Cisplatin and docetaxel dose intensity was 100% at the highest dose level (DL6). A MTD was not reached in this trial. Tumour overall response rate was 50% (33% complete, 17% partial). CONCLUSION: Cisplatin and docetaxel each 30 mg m(-2) per week concurrent with 50 Gy radiotherapy is recommended for use in phase II clinical trials in oesophageal cancer.

A phase I trial of Capecitabine+Gemcitabine with radical radiation for locally advanced pancreatic cancer.

Standard chemoradiotherapy with infusional 5FU for locally advanced pancreatic cancer (LAPC) has limited efficacy in this disease. The combination of Capecitabine (Cap) and Gemcitabine (Gem) are synergistic and are potent radiosensitisers. The aim of this phase I trial was thus to determine the highest administered dose of the Cap plus Gem combination with radical radiotherapy (RT) for LAPC. Patients had LAPC, adequate organ function, ECOG PS 0-1. During RT, Gem was escalated from 20-50 mg m(-2) day(-1) (twice per week), and Cap 800-2000 mg m(-2) day(-1) (b.i.d, days 1-5 of each week). Radiotherapy 50.4 Gy/28 fractions/5.5 weeks, using 3D-conformal techniques. Three patients were entered to each dose level (DL). Dose-limiting toxicity(s) (DLTs) were based on treatment-related toxicities. Twenty patients were accrued. Dose level (DL) 1: Cap/Gem; 800/20 mg m(-2) day(-1) (3 patients), DL2: 1000/20 (12 patients), DL3: 1300/30 (5 patients). Dose-limiting toxicities were observed in DL3; grade 3 dehydration (1 patient) and grade 3 diarrhoea and dehydration (1 patient). Dose level 2 was the recommend phase 2 dose. Disease control rate was 75%: PR=15%, SD=60%. Median overall survival was 11.2 months. The addition of Cap and Gem to radical RT was feasible and active and achieved at relatively low doses.

Pancreatic cancer--is the wall crumbling?

In spite of advances made in the management of the other more common cancers of the gastrointestinal tract, significant progress in the treatment of pancreatic cancer remains elusive, more so with the recent negative results of several much anticipated randomized trials. Gemcitabine has been a standard treatment for advanced pancreatic cancer since it was shown a decade ago to result in a superior clinical benefit response and survival compared with bolus 5-fluorouracil (5-FU). Since then, clinical trials have explored the pharmacokinetic modulation of gemcitabine by fixed dose administration and the combination of gemcitabine with other cytotoxics or the biological 'targeted' agents. Against a background of numerous negative randomized trials of gemcitabine-based combination treatment, two trials have recently reported modest survival improvements with the use of combination treatment: the United Kingdom National Cancer Research GEMCAP trial of gemcitabine with the orally administered precursor of 5-FU-capecitabine and the National Cancer Institute of Canada Clinical Trials Group PA.3 trial in which the tyrosine kinase inhibitor erlotinib was used with gemcitabine. This review will summarize the results of several recent randomized trials of combination treatment in advanced pancreatic cancer and discuss their implications for clinical practice and for future research in this disease.

Tumor immunotherapy in the mouse with the use of 131I-labeled monoclonal antibodies.

This report describes the use of 131I-labeled monoclonal antibodies in two experimental models for tumor immunotherapy. In vitro treatment of the radiation-induced murine thymoma ITT-1-75NS with radiolabeled anti-Ly-2.1 significantly impaired subsequent tumor growth in vivo. However, in vivo treatment of this tumor, which previously had been injected into C57BL/6 mice, was unsuccessful. By contrast, in vitro treatment of a human colorectal tumor cell line (COLO 205) with 131I-labeled 250-30.6--a monoclonal antibody directed against a secretory component of normal and malignant gastrointestinal epithelium--completely inhibited subsequent tumor growth in BALB/c nude (nu/nu) mice. Furthermore, in vivo treatment of preexisting human colorectal tumor xenografts significantly impaired progressive tumor growth. Although some tumor inhibition was also produced by unlabeled 250-30.6 antibody, this response was considerably amplified by treatment with [131I]-labeled 250-30.6 (P less than .05), suggesting that in vivo treatment of human tumors with the use of 131I-labeled monoclonal antibodies may be clinically beneficial. The antithyroid drug propylthiouracil was used to reduce dehalogenation of the radiolabeled immunoglobulins in an attempt to improve their therapeutic efficacy.

Localization of human colorectal tumor xenografts in the nude mouse with the use of radiolabeled monoclonal antibody.

For the evaluation of the clinical usefulness of monoclonal antibodies as diagnostic or therapeutic reagents, tumor localization must be clearly demonstrated in an experimental model. In this report, nude mice carrying two human tumor xenografts--a colon carcinoma (Colo 205) and a melanoma (Colo 239)--were given ip injections of radiolabeled monoclonal antibodies. Monoclonal antibody 250-30.6, which reacted specifically with the colon carcinoma but not with the melanoma, was labeled with 125I, while a second monoclonal antibody of similar immunoglobulin subclass, but unreactive with either cell type, was labeled with 131I. Both antibodies were injected simultaneously, and either the mice were scanned with a gamma camera or their tissues were removed and the localization of radiolabeled antibody was calculated with the use of localization index (LI)--the ratio of the tissue to blood distribution for each isotope. The studies showed that specific localization had occurred, there being a colon tumor LI of 6 at 2 days. Tumors of 150-300 mg (mean diameter, 6 mm) and with an LI as low as 1.5 could be successfully imaged after computer-assisted background subtraction. This study demonstrated that relatively small human tumor xenografts in the nude mouse can be specifically detected with the use of paired monoclonal antibodies, each labeled with a different isotope.

Combined use of cyclosporin A and verapamil in modulating multidrug resistance in human leukemia cell lines.

This study describes the synergistic interaction of two biochemical modulators, cyclosporin A (CyA) and verapamil (Vp), in multidrug-resistant cells, the highly resistant and moderately resistant variants (CEM/VLB 1000 and CEM/VLB 100) of the parental drug-sensitive T-cell leukemia cell line CEM/CCRF. In the absence of either modulator, the 50% inhibitory concentration for Adriamycin in these cell lines was 270 +/- 10.6 (SD) micrograms/ml, 96 +/- 8.5 micrograms/ml, and 1.5 +/- 0.1 micrograms/ml, respectively. CyA and Vp dramatically reduced multidrug resistance in CEM/VLB 100 and CEM/VLB 1000 in a dose-dependent manner but had no effect on the sensitivity of the parental line to Adriamycin. At a CyA concentration of 8.3 mumol (10 micrograms/ml), the 50% inhibitory concentration of Adriamycin of CEM/VLB 1000 and CEM/VLB 100 fell to 5.9 +/- 0.9 micrograms/ml and 3.3 +/- 0.6 micrograms/ml, respectively. Similarly at a Vp concentration of 10 mumol the 50% inhibitory concentration of Adriamycin of CEM/VLB 1000 and CEM/VLB 100 fell to 23.7 +/- 3.7 micrograms/ml and 5.7 +/- 0.2 micrograms/ml, respectively. More importantly, CyA and Vp showed significant synergism when tested in combination in the moderately resistant line at concentrations normally seen after the clinical administration of these modulators. Synergy was also present when both drugs were tested in the highly resistant variant. These data indicate the need for in vivo studies, given the potential clinical importance of these observations.

TACTIC: a multicentre, open-label, single-arm phase II trial of panitumumab, cisplatin, and gemcitabine in biliary tract cancer.

PURPOSE: The phase II TACTIC trial prospectively selected patients with KRAS wild-type advanced biliary tract cancer for first-line treatment with panitumumab and combination chemotherapy. METHODS: Of 78 patients screened, 85 % had KRAS wild-type tumours and 48 were enrolled. Participants received cisplatin 25 mg/m(2) and gemcitabine 1000 mg/m(2) on day 1 and day 8 of each 21-day cycle and panitumumab 9 mg/kg on day 1 of each cycle. Treatment was continued until disease progression, unacceptable toxicity, or request to discontinue. The primary endpoint was the clinical benefit rate (CBR) at 12 weeks (complete response, partial response, or stable disease). CBR of 70 % was considered to be of clinical interest. Secondary outcomes were progression-free survival, time to treatment failure, overall survival, CA19.9 response and safety. RESULTS: Thirty-four patients had a clinical benefit at 12 weeks, an actuarial rate of 80 % (95 % CI 65-89 %). 46 % had a complete or partial response. Median progression-free survival was 8.0 months (95 % CI 5.1-9.9) and median overall survival 11.9 months (95 % CI 7.4-15.8). Infection accounted for 27 % of the grade 3 or 4 toxicity, with rash (13 %), fatigue (13 %), and hypomagnesemia (10 %) among the more common grade 3 or 4 non-haematological toxicities. CONCLUSION: A marker-driven approach to patient selection was feasible in advanced biliary tract cancer in an Australian population. The combination of panitumumab, gemcitabine, and cisplatin in KRAS wild-type cancers was generally well tolerated and showed promising clinical efficacy. Further exploration of anti-EGFR therapy in a more selected population is warranted.

Multiple atypical nevi: a cutaneous marker of germ cell tumors.

PURPOSE: This study assessed whether a specific association exists between atypical nevi and germ cell tumors (GCT). METHODS: A prospective comparison was performed on a cohort of 129 unselected patients with GCT and a series of 153 healthy men. Three or more of the following criteria were required for diagnosis of multiple atypical nevi: greater than 5 mm in diameter; variegated color, often speckled black/brown, with irregularly distributed pigmentation; irregular outline or indistinct border; and at least three such lesions. RESULTS: Prevalences for multiple atypical nevi in patients with GCT and in healthy controls were 37% and 15%, respectively (P < .01). Two patients with these lesions also had documented malignant melanoma. In contrast, 16% of patients with GCT had a history of testicular maldescent (the most common known risk factor), compared with 5% of healthy controls (P < .01). CONCLUSION: Multiple atypical nevi occur with a statistically significant increased prevalence in patients with GCT as compared with healthy controls, and constitute one of the most common known clinical associations with this malignancy. These data may be of relevance for our understanding of the biology of GCT and of malignant melanoma, in the design of screening programs for testis cancer, and in the follow-up evaluation of patients with each of these disorders.

ZD1694: A novel thymidylate synthase inhibitor with substantial activity in the treatment of patients with advanced colorectal cancer. Tomudex Colorectal Study Group.

PURPOSE: Tomudex (ZD1694; Zeneca Ltd, Macclesfield, United Kingdom) appears to have a favorable toxicity profile (defined in phase I studies) and antitumor activity in a broad range of epithelial tumors. We report here the results of a large phase II study of Tomudex in advanced colorectal cancer (CRC). PATIENTS AND METHODS: One hundred seventy-seven patients were entered onto the study between October 1992 and September 1993. Patients were required to have advanced CRC without prior chemotherapy (adjuvant chemotherapy was permissible) and at least one measurable lesion. Tomudex (ZD1694) was administered at a dose of 3 mg/m2 intravenously once every 3 weeks in the absence of toxicity or disease progression. Patients were assessed for objective response, progression, and survival. RESULTS: Of 177 patients entered onto the study, 5% had received prior adjuvant chemotherapy and 83% had liver metastases. Objective responses were seen in 26% of patients (95% confidence interval, 19% to 33%; four complete responses [CRs] and 41 partial responses [PRs]) while median time to progression was 4.2 months and median survival 9.6 months. All sites were audited, and responses were reviewed by an independent panel. Common toxicities included mild reversible transaminitis, nausea and vomiting, and asthenia or flu-like symptoms, and World Health Organization (WHO) grade 3 and 4 leukopenia and diarrhea were seen in 6% and 9.8% of patients, respectively. Stomatitis and alopecia were common. CONCLUSION: In this large multicenter phase II study of patients with advanced CRC, interesting activity was seen (objective response rate, 26%). In addition, Tomudex has an acceptable toxicity profile and a convenient dosing schedule (single intravenous injection every 3 weeks) and thus appears to offer real potential as a novel agent for the treatment of patients with advanced CRC.

Cyclosporin A and PSC 833 prevent up-regulation of MDR1 expression by anthracyclines in a human multidrug-resistant cell line.

We have previously demonstrated that within 24 h of exposure of the CEM/A7R cell line to epirubicin (EPI), MDR1 gene expression is induced. The aim of the current study was to investigate the role of cyclosporin A (CyA) and PSC 833, two biochemical modulators of the classical multidrug-resistant phenotype, in this model. CEM/A7R cells were exposed to EPI in the presence or absence of various concentrations of CyA or PSC 833. MDR1 expression was assessed using Northern blot analysis and quantitated using a phosphorimager. P-glycoprotein (P-gp) expression was analyzed by the determination of MRK16 binding using flow cytometry. P-gp function was measured in an assay of [3H]daunomycin accumulation. The coincubation of CyA or PSC 833 with EPI prevented the increase in MDR1 gene expression induced by EPI alone. This effect of the two modulators was dose dependent. Neither modulator alone had any significant effect on the expression of MDR1. In these experiments, changes in MDR1 expression correlated with changes in P-gp levels (based on MRK16 binding) and P-gp function. Thus, both PSC 833 and CyA appear to prevent the induction of MDR1 gene expression caused by the short-term exposure of CEM/A7R cells to EPI.

Altered methylation of the human MDR1 promoter is associated with acquired multidrug resistance.

One of the most important forms of drug resistance in acute myeloid leukemia is the multidrug resistance (MDR) phenotype, which is characterized by the expression of the MDR1 gene product, P-glycoprotein. Although a number of factors affect MDR1 gene expression, the genetic events that "switch on" the human MDR1 gene in tumor cells that were previously P-glycoprotein negative have remained elusive. Here, we report evidence that the methylation status of the human MDR1 promoter may serve as a basis for this "switch." Based on Southern analysis using methylation-sensitive and methylation-insensitive restriction enzymes, a tight correlation was found between MDR phenotype and demethylation of the 5' region of the MDR1 gene in a human T cell leukemia cell line. Similar results were obtained from the analysis of P-glycoprotein-positive and P-glycoprotein-negative samples of chronic lymphocytic leukemia. Treatment of the cell lines with the demethylating agent 5'-azadeoxycytidine altered the methylation pattern of the MDR1 promoter in P-glycoprotein-negative cells to resemble that of P-glycoprotein-positive cells and activated the promoter such that MDR1 mRNA was now detectable. Treatment also resulted in an increased resistance to epirubicin and decreased daunomycin accumulation, both of which were reversible by verapamil, a characteristic of the classical MDR phenotype in cells expressing P-glycoprotein. These results suggest that the MDR phenotype may be acquired as a result of changes in methylation of the MDR1 promoter.

Location of colon cancer (right-sided versus left-sided) as a prognostic factor and a predictor of benefit from cetuximab in NCIC CO.17.

BACKGROUND: Right- and left-sided colon cancers (RC, LC) differ with respect to biology, pathology and epidemiology. Previous data suggest a mortality difference between RC and LC. We examined if primary tumour side also predicts for outcome in chemotherapy refractory, metastatic colon cancer (MCC). We also compared RC versus LC as a predictor of efficacy of epidermal growth factor receptor (EGFR) inhibition with cetuximab. METHODS: Reanalyzing NCIC CO.17 trial (cetuximab versus best supportive care [BSC]), we coded the primary tumour side as RC (caecum to transverse colon) or LC (splenic flexure to rectosigmoid). The association between tumour side and baseline characteristics was assessed. Cox regression models determined factors affecting overall survival (OS) and progression free survival (PFS). RESULTS: Patients with RC (150/399) had more poorly differentiated, mutant KRAS, mutated PIK3CA and wild-type BRAF tumours, fewer liver and lung metastases, and shorter interval between diagnosis and study entry. Among BSC patients, tumour side was not prognostic for PFS (hazard ratios (HR) 1.07 [0.79-1.44], p = 0.67) or OS (HR 0.96 [0.70-1.31], p = 0.78). Among wild-type KRAS patients, those with LC had significantly improved PFS when treated with cetuximab compared to BSC (median 5.4 versus 1.8 months, HR 0.28 [0.18-0.45], p < 0.0001), whereas those with RC did not (median 1.9 versus 1.9 months, HR 0.73 [0.42-1.27], p = 0.26), [interaction p = 0.002]. CONCLUSION: In refractory MCC, tumour location within the colon is not prognostic, but is strongly predictive of PFS benefit from cetuximab therapy. Additional research is needed to understand the molecular differences between RC and LC and their interaction with EGFR inhibition.

Effect of cyclosporin and verapamil on the cellular kinetics of daunorubicin.

Both cyclosporin and verapamil modulate the multidrug-resistant (MDR) phenotype in the classical MDR cell lines, CEM/VLB100 and CEM/VLB1000. Initial studies demonstrated a significant reduction in daunorubicin accumulation in the two resistant lines compared with the drug-sensitive parent line CEM/CCRF. Both cyclosporin and verapamil increased drug accumulation in the resistant lines. This effect was dose-dependent although a plateau occurred in CEM/VLB100 cells at concentrations of cyclosporin exceeding 4.2 mumol/l. Cyclosporin 4.2 mumol/l and verapamil 10 mumol/l significantly increased daunorubicin uptake and reduced drug efflux in the CEM/VLB100 and CEM/VLB1000 lines. At low clinical concentrations of cyclosporin (0.8-1.6 mumol/l and verapamil (1-2 mumol/l), there was a synergistic increase in drug accumulation in the two resistant cell lines (P less than 0.007). These data suggest that cyclosporin modulates the classical MDR phenotype by altering the cellular kinetics of daunorubicin. The in vitro synergistic action of cyclosporin and verapamil could be interesting clinically.

A phase I/II study of the intralesional injection of ricin-monoclonal antibody conjugates in patients with hepatic metastases.

A phase I/II study of the intralesional administration of ricin-labelled monoclonal antibodies was conducted in patients with hepatic metastases of gastrointestinal origin. The anti-carcinoembryonic antigen (CEA) antibody I-1 was conjugated to blocked ricin via a disulphide bridge. After a test dose of antibody, patients were injected with ricin-antibody conjugates under computed tomography (CT) guidance on two occasions 1 week apart. Patients with stable or responding disease would receive a third course. The dose of ricin relative to surface area was increased in a predefined manner in cohorts of 3 patients. A total of 27 patients with hepatic metastases were entered into this study. All patients had metastatic colorectal cancer (26 patients) or adenocarcinoma of unknown primary with elevated CEA levels (1 patient). The presence of malignancy was documented cytologically in 9 of 11 patients tested. Minor responses were seen in 7 patients. However, no major objective responses or changes in the growth rate of injected lesions were observed. Toxicity was generally mild, the most common being hepatic capsular pain 24-48 h after each injection. 6 patients experienced rigors. One patient had anaphylaxis. Human anti-mouse and anti-ricin antibody responses were observed. Although substantial amounts of ricin conjugated to monoclonal antibodies were delivered into single lesions, this therapeutic approach was unsuccessful. Future studies of ricin-labelled antibodies should incorporate the systemic administration of immunoconjugates.