Immune checkpoint inhibitors: new strategies to checkmate cancer.

Immune checkpoint inhibitors (ICIs) targeting cytotoxic T lymphocyte-associated protein-4 (CTLA-4) or programmed cell death protein 1 (PD-1) receptors have demonstrated remarkable efficacy in subsets of patients with malignant disease. This emerging treatment modality holds great promise for future cancer treatment and has engaged pharmaceutical research interests in tumour immunology. While ICIs can induce rapid and durable responses in some patients, identifying predictive factors for effective clinical responses has proved challenging. This review summarizes the mechanisms of action of ICIs and outlines important preclinical work that contributed to their development. We explore clinical data that has led to disease-specific drug licensing, and highlight key clinical trials that have revealed ICI efficacy across a range of malignancies. We describe how ICIs have been used as part of combination therapies, and explore their future prospects in this area. We conclude by discussing the incorporation of these new immunotherapeutics into precision approaches to cancer therapy.

Phase 2 placebo-controlled, double-blind trial of dasatinib added to gemcitabine for patients with locally-advanced pancreatic cancer.

Background: Pancreatic ductal adenocarcinoma (PDAC) has a high mortality rate with limited treatment options. Gemcitabine provides a marginal survival benefit for patients with advanced PDAC. Dasatinib is a competitive inhibitor of Src kinase, which is overexpressed in PDAC tumors. Dasatinib and gemcitabine were combined in a phase 1 clinical trial where stable disease was achieved in two of eight patients with gemcitabine-refractory PDAC. Patients and methods: This placebo-controlled, randomized, double-blind, phase II study compared the combination of gemcitabine plus dasatinib to gemcitabine plus placebo in patients with locally advanced, non-metastatic PDAC. Patients received gemcitabine 1000 mg/m2 (30-min IV infusion) on days 1, 8, 15 of a 28-day cycle combined with either 100 mg oral dasatinib or placebo tablets daily. The primary objective was overall survival (OS), with safety and progression-free survival (PFS) as secondary objectives. Exploratory endpoints included overall response rate, freedom from distant metastasis, pain and fatigue progression and response rate, and CA19-9 response rate. Results: There was no statistically significant difference in OS between the two treatment groups (HR = 1.16; 95% confidence interval [CI]: 0.81-1.65; P = 0.5656). Secondary and exploratory endpoint analyses also showed no statistically significant differences. The burden of toxicity was higher in the dasatinib arm. Conclusions: Dasatinib failed to show increased OS or PFS in patients with locally advanced PDAC. Alternative combinations or trial designs may show a role for src inhibition in PDAC treatment.

A phase I, pharmacokinetic and pharmacodynamic study of GSK2256098, a focal adhesion kinase inhibitor, in patients with advanced solid tumors.

BACKGROUND: Focal adhesion kinase (FAK) is important in cancer growth, survival, invasion, and migration. The purpose of this study was to determine the maximum tolerated dose (MTD), safety, pharmacokinetics (PK), and pharmacodynamics (PD) of the FAK inhibitor, GSK2256098, in cancer patients. PATIENTS AND METHODS: The dose of GSK2256098 was escalated, in cohorts of patients with advanced cancer, from 80 to 1500 mg, oral twice daily (BID), until the MTD was determined. Serial blood samples were obtained from all patients, and the PK was determined. Paired tumor biopsies were obtained in select patients, and the level of phospho-FAK (pFAK) was determined. RESULTS: Sixty-two patients (39 males, 23 females; median age 61 y.o., range 21-84) received GSK2256098. Dose-limiting toxicities of grade 2 proteinuria (1000 mg BID), grade 2 fatigue, nausea, vomiting (1250 mg BID), and grade 3 asthenia and grade 2 fatigue (1500 mg BID) were reported with the MTD identified as 1000 mg BID. The most frequent adverse events (AEs) were nausea (76%), diarrhea (65%), vomiting (58%), and decreased appetite (47%) with the majority of AEs being grades 1-2. The PK was generally dose proportional with a geometric mean elimination half-life range of 4-9 h. At the 750, 1000, and 1500 mg BID dose levels evaluated, the pFAK, Y397 autophosphorylation site, was reduced by ∼80% from baseline. Minor responses were observed in a patient with melanoma (-26%) and three patients with mesothelioma (-13%, -15%, and -17%). In the 29 patients with recurrent mesothelioma, the median progression-free survival was 12 weeks with 95% CI 9.1, 23.4 weeks (23.4 weeks merlin negative, n = 14; 11.4 weeks merlin positive, n = 9; 10.9 weeks merlin status unknown, n = 6). CONCLUSIONS: GSK2256098 has an acceptable safety profile, has evidence of target engagement at doses at or below the MTD, and has clinical activity in patients with mesothelioma, particularly those with merlin loss.

A phase I, dose escalation, pharmacodynamic, pharmacokinetic, and food-effect study of α2 integrin inhibitor E7820 in patients with advanced solid tumors.

UNLABELLED: Introduction E7820 is an orally administered sulfonamide that inhibits alfa-2-integrin mRNA expression. Pre-clinically E7820 showed tumor anti-angiogenic effects in various tumor cell lines and xenograft mouse models. Human daily dosing of 100 mg QD had previously been shown to be safe and tolerable. Methods The study consisted of two parts: Part A (food effect) and Part B (determination of maximum tolerated dose (MTD) for bi-daily (BID) dosing). E7820 dosing started at 50 mg BID with planned escalation to 60, 80 and 100 mg BID every 28 days. Results Fifteen patients were enrolled in Part A and 26 in Part B. The most frequent adverse events of all grades were constipation, diarrhea, nausea, and fatigue while anemia, neutropenia, and fatigue were most frequent grade ≥3 toxicities. At dose-level 60 mg BID, two patients experienced dose-limiting toxicities (grade 3 neutropenic sepsis and grade 4 neutropenia). Therefore the recommended dose (RD) was 50 mg BID. Food had no effect on E7820 exposure. E7820 exposure following twice daily administration was dose-proportional. Expression of platelet integrin-α2 measured as a response biomarker in Part B, generally decreased by a median 7.7 % from baseline following treatment with 50 mg BID E7820. Reduction was most pronounced within 1-week post treatment. The median duration of treatment was median 54, range 20-111 days. The best overall response in any treatment group was stable disease (SD): 23.1 % in Part A (100 mg QD); at the RD 66.7 % (12 of 18 patients) and 40 % in the 60 mg BID group in Part B. CONCLUSIONS: Food had no effect on E7820 exposure. A dose of 50 mg BID was considered the MTD. Treatment with E7820 is safe and tolerable with 2/3 of patients (66.7 %) at MTD having SD as their best response.

A phase II study of capecitabine and oxaliplatin combination chemotherapy in patients with inoperable adenocarcinoma of the gall bladder or biliary tract.

BACKGROUND: Advanced biliary tract carcinomas are associated with a poor prognosis, and palliative chemotherapy has only modest benefit. This multi-centre phase II study was conducted to determine the efficacy of capecitabine in combination with oxaliplatin in patients with inoperable gall bladder or biliary tract cancer. METHODS: This was a Phase II, non-randomised, two-stage Simon design, multi-centre study. Ethics approval was sought and obtained by the North West MREC, and then locally by the West Glasgow Hospitals Research Ethics Committee. Eligible patients with inoperable locally advanced or metastatic adenocarcinoma of the gall bladder or biliary tract and with adequate performance status, haematologic, renal, and hepatic function were treated with capecitabine (1000 mg/m(2) po, twice daily, days 1-14) and oxaliplatin (130 mg/m(2) i.v., day 1) every 3 weeks for up to six cycles. The primary objective of the study was to determine the objective tumour response rates (complete and partial). The secondary objectives included assessment of toxicity, progression-free survival, and overall survival. RESULTS: Forty-three patients were recruited between July 2003 and December 2005. The regimen was well tolerated with no grade 3/4 neutropenia or thrombocytopenia. Grade 3/4 sensory neuropathy was observed in six patients. Two-thirds of patients received their chemotherapy without any dose delays. Overall response rate was 23.8% (95% CI 12.05-39.5%). Stable disease was observed in a further 13 patients (31%) and progressive disease observed in 12 (28.6%) of patients. The median progression-free survival was 4.6 months (95% CI 2.8-6.4 months; Fig. 1) and the median overall survival 7.9 months (95% CI 5.3-10.4 months; Fig. 2). Fig. 1 Progression-free survival Fig. 2 Overall survival CONCLUSION: Capecitabine combined with oxaliplatin has a lower disease control and shorter overall survival than the combination of cisplatin with gemcitabine which has subsequently become the standard of care in this disease. However, capecitabine in combination with oxaliplatin does have modest activity in this disease, and can be considered as an alternative treatment option for patients in whom cisplatin and/or gemcitabine are contra-indicated.

A first-in-human phase I and pharmacokinetic study of CP-4126 (CO-101), a nucleoside analogue, in patients with advanced solid tumours.

BACKGROUND: CP-4126 (gemcitabine elaidate, previously CO-101) is a lipid-drug conjugate of gemcitabine designed to circumvent human equilibrative nucleoside transporter1-related resistance to gemcitabine. The purpose of this study was to determine the maximum tolerated dose (MTD) and the recommended phase II dose (RP2D) of CP-4126, and to describe its pharmacokinetic profile. METHODS: Eligible patients with advanced refractory solid tumours, and adequate performance status, haematological, renal and hepatic function, were treated with one of escalating doses of CP-4126 administered by a 30-min intravenous infusion on days 1, 8 and 15 of a 28-day cycle. Blood and urine samples were collected to determine the pharmacokinetics (PKs) of CP-4126. RESULTS: Forty-three patients, median age 59 years (range 18-76; male = 27, female = 16), received one of ten dose levels (30-1600 mg/m(2)). Dose-limiting toxicities included grade 3 anaemia, grade 3 fatigue and grade 3 elevation of transaminases. The MTD and RP2D were 1250 mg/m(2) on basis of the toxicity and PK data. CP-4126 followed dose-dependent kinetics and maximum plasma concentrations occurred at the end of CP-4126 infusion. Seven patients achieved stable disease sustained for ≥3 months, including two patients with pancreatic cancer who had progressed on or after gemcitabine exposure. CONCLUSIONS: CP-4126 was well tolerated with comparable toxicity profile to gemcitabine. Future studies are required to determine its anti-tumour efficacy, either alone or in combination with other cytotoxic chemotherapy regimens.

Outcome of patients with sarcoma and other mesenchymal tumours participating in phase I trials: a subset analysis of a European Phase I database.

BACKGROUND: Although sarcomas account for only 1% of all solid tumours, patients with sarcomas comprise a larger proportion of patients entering phase I trials, due to the limited number of registered or active drugs for these diseases. To help in patient selection, we evaluated the utility of the predictive Royal Marsden Score which had been derived in carcinoma patients. In addition, we analysed efficacy and toxicity regarding the sarcoma population enrolled in phase I trials. PATIENTS AND METHODS: We used data from a European Database comprising 2182 patients treated in phase I trials in 14 European institutions between 2005 and 2007. RESULTS: One hundred and seventy-eight patients diagnosed with advanced sarcoma or other mesenchymal tumours were identified and accounted for 217 phase I trial participations during the study period. Histological type, class of drug, number of metastatic sites, high serum lactate dehydrogenase activity (LDH), low albumin and high white blood cell count were independent prognostic factors. Poor performance status (PS), liver metastases and high leucocyte count were associated with increased risk of early death. The class of drug used was the strongest predictor of progression-free survival (PFS) duration, inhibitors of angiogenesis and histone deacetylase giving the best results. Poor PS, high serum LDH and low lymphocyte count correlated with shorter PFS. In this heterogeneous population, PFS with investigational agents appeared comparable with that previously published for patients receiving standard treatments beyond first line. CONCLUSION: Prognostic factors in sarcoma patients do not differ from a broader phase I population. Efficacy measures suggest that some patients with sarcoma derive benefit from therapy in this setting which could therefore be considered for patients with no remaining standard therapeutic option.

Exploiting inflammation for therapeutic gain in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy associated with <5% 5-year survival, in which standard chemotherapeutics have limited benefit. The disease is associated with significant intra- and peritumoral inflammation and failure of protective immunosurveillance. Indeed, inflammatory signals are implicated in both tumour initiation and tumour progression. The major pathways regulating PDAC-associated inflammation are now being explored. Activation of leukocytes, and upregulation of cytokine and chemokine signalling pathways, both have been shown to modulate PDAC progression. Therefore, targeting inflammatory pathways may be of benefit as part of a multi-target approach to PDAC therapy. This review explores the pathways known to modulate inflammation at different stages of tumour development, drawing conclusions on their potential as therapeutic targets in PDAC.

Phase I evaluation of the effects of ketoconazole and rifampicin on cediranib pharmacokinetics in patients with solid tumours.

PURPOSE: To investigate any effect of a CYP3A4 inhibitor (ketoconazole) or inducer (rifampicin) on cediranib steady-state pharmacokinetics in patients with advanced solid tumours. METHODS: In two Phase I, open-label trials, patients received once-daily oral doses of cediranib alone [20 mg (ketoconazole study); 45 mg (rifampicin study)] for 7 days followed by cediranib at the same dose with ketoconazole 400 mg/day for 3 days or once-daily rifampicin 600 mg/day for 7 days, respectively. Patients then continued to receive once-daily cediranib. RESULTS: In the ketoconazole study, 46 patients were dosed; 38 were evaluable for C (ss,max), 36 for AUC(ss). gMean AUC(ss) and C (ss,max) for cediranib 20 mg increased by 21 % (94 % CI 9-35 %) and 26 % (94 % CI 10-43 %), respectively, in the presence of ketoconazole. In the rifampicin study, 64 patients were dosed; 44 were evaluable for C (ss,max) and 41 for AUC(ss). gMean AUC(ss) and C (ss,max) for cediranib 45 mg decreased by 39 % (90 % CI 34-43 %) and 23 % (90 % CI 16-30 %), respectively, in the presence of rifampicin. gMean ratios for AUC(ss) and C (ss,max) were >1 for ketoconazole and <1 for rifampicin and CIs were outside the pre-specified equivalence boundaries, indicating a statistically significant effect. Significant inter-patient variability in cediranib AUC(ss) and C (ss,max) was observed. The safety profile of cediranib was similar to that reported previously. CONCLUSIONS: Co-administration of ketoconazole or rifampicin had statistically significant effects on steady-state pharmacokinetics of cediranib in patients with advanced solid tumours. Therefore, caution is advised when administering cediranib with potent enzyme inhibitors or inducers.

A phase 1 study of OSI-930 in combination with erlotinib in patients with advanced solid tumours.

AIM: To determine the maximum tolerated dose (MTD) of OSI-930 that can be combined with erlotinib, and establish recommended phase 2 doses when both agents are administered daily in patients with advanced solid tumours. PATIENTS AND METHODS: Eligible patients with advanced solid tumours were enrolled into this standard "three+three" dose escalation study. Study treatment commenced on day 1 with OSI-930, and erlotinib was introduced on day 8. PK profiles of OSI-930, erlotinib and its active metabolite, OSI-420, were determined. Changes in sVEGFR2 as a pharmacodynamic biomarker of OSI-930 activity were assessed. RESULTS: Twenty one patients were enrolled to 1 of 3 cohorts: 200 mg OSI-930 BID+100 mg erlotinib QD; 200 mg OSI-930 BID+150 mg erlotinib QD; 300 mg OSI-930 BID+150 mg erlotinib QD. The most common adverse events were anorexia (85%), diarrhoea (75%), rash (70%) and lethargy (65%). The MTD was not reached but the onset of cumulative toxicity necessitating dose modification after the 28-d DLT assessment period was common at the highest dose level. A PK interaction was identified with co-administration of both agents resulting in a two-fold increase in OSI-930 exposure. Pharmacodynamic activity was observed with a decline in sVEGFR levels detected in all patients. Ten patients had disease stabilization (median duration 119 d). CONCLUSIONS: 200 mg OSI-930 BID+150 mg erlotinib QD were the recommended doses for further evaluation of this combination.

Phase I study of TP300 in patients with advanced solid tumors with pharmacokinetic, pharmacogenetic and pharmacodynamic analyses.

BACKGROUND: A Phase I dose escalation first in man study assessed maximum tolerated dose (MTD), dose-limiting toxicity (DLT) and recommended Phase II dose of TP300, a water soluble prodrug of the Topo-1 inhibitor TP3076, and active metabolite, TP3011. METHODS: Eligible patients with refractory advanced solid tumors, adequate performance status, haematologic, renal, and hepatic function. TP300 was given as a 1-hour i.v. infusion 3-weekly and pharmacokinetic (PK) profiles of TP300, TP3076 and TP3011 were analysed. Polymorphisms in CYP2D6, AOX1 and UGT1A1 were studied and DNA strand-breaks measured in peripheral blood mononuclear cells (PBMCs). RESULTS: 32 patients received TP300 at 1, 2, 4, 6, 8, 10, 12 mg/m(2). MTD was 10 mg/m(2); DLTs at 12 (2/4 patients) and 10 mg/m(2) (3/12) included thrombocytopenia and febrile neutropenia; diarrhoea was uncommon. Six patients (five had received irinotecan), had stable disease for 1.5-5 months. TP3076 showed dose proportionality in AUC and Cmax from 1-10 mg/m(2). Genetic polymorphisms had no apparent influence on exposure. DNA strand-breaks were detected after TP300 infusion. CONCLUSIONS: TP300 had predictable hematologic toxicity, and diarrhoea was uncommon. AUC at MTD is substantially greater than for SN38. TP3076 and TP3011 are equi-potent with SN38, suggesting a PK advantage. TRIAL REGISTRATION: EU-CTR2006-001345-33.

A phase I and pharmacokinetic study of elisidepsin (PM02734) in patients with advanced solid tumors.

PURPOSE: To determine the maximum-tolerated dose (MTD), dose-limiting toxicity (DLT), and recommended phase II dose (RD) of elisidepsin. METHODS: Eligible patients with refractory, advanced solid tumors received elisidepsin as 24-h intravenous infusion every 3 weeks. Pharmacokinetic profiles were analyzed during cycles 1 and 2. RESULTS: Forty-two patients received elisidepsin at doses from 0.5 to 6.8 mg/m(2). The MTD was 6.8 mg/m(2), and the RD was 5.5 mg/m(2). Cohort expansion at the RD was done at a fixed dose (FD) of 10 mg, considered equivalent to 5.5 mg/m(2). DLTs (reversible grade 3 transaminase increases) occurred at 6.8 mg/m(2) (n = 2 patients), 5.5 mg/m(2) (n = 1), and 10 mg FD (n = 1). One patient with esophageal adenocarcinoma achieved complete response for >38 months, and 12 patients had disease stabilization (8 for ≥3 months). Median time-to-progression for these 12 patients was 4.8 months. Plasma elisidepsin concentrations increased with dose. No drug accumulation between cycles was found. No correlation was observed between body surface area (BSA) and plasma clearance; therefore, elisidepsin was given as flat dose (in mg) in the expansion cohort at the RD and in ongoing clinical trials. CONCLUSIONS: Elisidepsin is well tolerated with predictable reversible transaminase increases. Encouraging preliminary evidence of antitumor activity was observed.

A phase I study of E7080, a multitargeted tyrosine kinase inhibitor, in patients with advanced solid tumours.

BACKGROUND: The objectives of this phase I study were to assess the safety and tolerability of E7080 in patients with advanced, refractory solid tumours; to determine the maximum tolerated dose (MTD) and pharmacokinetics profile of E7080; and to explore preliminary evidence of its anti-tumour efficacy. METHODS: E7080 was administered orally in escalating doses on a once-daily continuous schedule in 28-day cycles to eligible patients. Samples for pharmacokinetic analyses were collected on days 1, 8, 15 and 22 of cycle 1 and day 1 of cycle 2. Anti-tumour efficacy was assessed every two cycles. RESULTS: Eighty-two patients received E7080 in dose cohorts from 0.2 to 32 mg. Dose-limiting toxicities were grade 3 proteinuria (two patients) at 32 mg, and the MTD was defined as 25 mg. The most frequently observed cumulative toxicities (all grades) were hypertension (40% of patients), diarrhoea (45%), nausea (37%), stomatitis (32%) and vomiting (23%). Seven patients (9%) had a partial response and 38 patients (46%) had stable disease as best response. E7080 has dose-linear kinetics with no drug accumulation after 4 weeks' administration. CONCLUSION: E7080 is well tolerated at doses up to 25 mg per day. Encouraging anti-tumour efficacy was observed in patients with melanoma and renal cell carcinoma.

Developing histone deacetylase inhibitors as anti-cancer therapeutics.

Post translational modification of histones and non-histone proteins by acetylation play a key role in tumourigenesis. Histone deacetylases (HDACs) are enzymes involved in remodelling of chromatin by deacetylating the lysine residues and play a pivotal role in epigenetic regulation of gene expression. An aberrant activity of HDACs has been documented in several types of cancers and HDACs have emerged as an attractive therapeutic target. HDAC inhibitors (HDACi) are a structurally diverse group of anti-cancer agents which have a potential role in regulation of gene expression and induction of cell death, cell cycle arrest, and differentiation by altering the acetylation status of histone and non-histone proteins. HDACi have pleiotropic effects on malignant cells and have demonstrated potent anti-cancer activity in pre-clinical studies. A number of clinical trials of HDACi as a monotherapy and/or in combination with conventional and novel chemotherapeutic drugs in solid and haematologic tumours have been published with variable efficacy.

Pharmacokinetic and pharmacodynamic properties of an oral formulation of the histone deacetylase inhibitor Belinostat (PXD101).

PURPOSE: The primary objective of this sub-study, undertaken as an extension to the previously reported phase-I study, was to explore the feasibility, tolerability and pharmacokinetics (PK) of belinostat when administered by the oral route. Preliminary pharmacodynamic (PD) studies were also performed to enable comparison of the biological effects of the oral and intravenous formulations. PATIENTS AND METHODS: Oral belinostat was administered in a range of doses and schedules (once, twice or thrice daily), on either day 1 or days 1-5, of the second or a subsequent treatment cycle in 15 patients who were included in the phase-I trial of intravenous belinostat. Serial blood samples were collected for PK and PD (histone acetylation) analyses, and the results compared with corresponding analyses following intravenous administration. RESULTS: A total mean daily AUC of 2,767 ± 1,453 ng h/ml (8.7 ± 4.6 µM h) resulted from a dose of 1,000 mg/m(2) once daily (qd). There was no clear evidence of drug accumulation on twice daily dosing (bid); however, a trend towards accumulation was apparent when belinostat was given three times daily (tid). Mean half-life (T½) of a single dose of 1,000 mg/m(2) was 1.5 h (± 0.3 h) and peak levels were reached in an average of 1.9 h (± 0.3 h). The half-life was found to be independent of dose, but a trend towards increasing half-life following multiple dosing was observed. Histone H4 hyperacetylation in PBMCs estimated after oral dosing was comparable to that achieved after intravenous administration. CONCLUSIONS: High doses of oral belinostat, up to 1,000 mg/m(2) bid for 5 consecutive days, have been tolerated in this small study. An oral formulation could lead to enhanced drug exposure and, more importantly, prolonged effects on the intended drug target. Future trials are required to establish the optimal dose and schedule of oral administration of belinostat.

Cytokeratin 18 in plasma of patients with gastrointestinal adenocarcinoma as a biomarker of tumour response.

BACKGROUND: Plasma biomarkers may be particularly useful as a predictor or early marker of clinical response to treatment in addition to radiological imaging. Cytokeratin 18 (CK18) is an epithelial-specific cytokeratin that undergoes cleavage by caspases during apoptosis. Measurement of caspase-cleaved (CK18-Asp396) or total cytokeratin 18 (CK18) from epithelial-derived tumours could be a simple, non-invasive way to monitor or predict responses to treatment. METHODS: Soluble plasma CK18-Asp396 and CK18 were measured by ELISA from 73 patients with advanced gastrointestinal adenocarcinomas before treatment and during chemotherapy, as well as 100 healthy volunteers. RESULTS: Both CK18-Asp396 and total CK18 plasma levels were significantly higher in patients compared with the healthy volunteers (P=0.015, P<0.001). The total CK18 baseline plasma levels before treatment were significantly higher (P=0.009) in patients who develop progressive disease than those who achieve partial response or stable disease and this correlation was confirmed in an independent validation set. The peak plasma levels of CK18 occurring in any cycle following treatment were also found to be associated with tumour response, but peak levels of CK18-Asp396 did not reach significance (P=0.01, and P=0.07, respectively). CONCLUSION: Plasma levels CK18 are a potential marker of tumour response in patients with advanced gastrointestinal malignancy.

A phase II study of pegylated-camptothecin (pegamotecan) in the treatment of locally advanced and metastatic gastric and gastro-oesophageal junction adenocarcinoma.

PURPOSE: Combination chemotherapy results in a significant survival advantage in patients with advanced gastric cancer compared to best supportive care. Nevertheless, the prognosis remains poor with a median survival of 8-10 months. Topoisomerase-I inhibitors such as irinotecan have activity in advanced gastric cancer. Pegamotecan may offer significant advantages over other topoisomerase-I inhibitors due to its prolonged circulating half-life, tolerability and passive tumour accumulation. PATIENTS AND METHODS: This was a non-randomised, multi-centre, two-step Fleming design phase II study. Eligible patients with locally advanced (inoperable) or metastatic gastric or gastro-oesophageal adenocarcinoma, with measurable disease, ECOG performance status < or =2, with adequate haematological, renal and hepatic function, who had received < or =1 prior chemotherapy regimen for advanced disease, were treated with 7,000 mg/m(2) of pegamotecan as a 1-h infusion every 21 days until disease progression or unacceptable toxicity. The primary efficacy measure was the objective response rate. RESULTS: Five of the 35 patients recruited into this study had a partial response (14.3%), with a median time to progression of 11.9 weeks (95% CI: 6.6, 13.1), and median overall survival of 38.1 weeks (95% CI: 29.0, 47.3). Grade 3/4 toxicities included neutropenia in 6 (17.1%) patients, thrombocytopenia in 4 (11.4%), fatigue in 8 (22.9%), nausea in 6 (17%), vomiting in 6 (17%) and anorexia in 4 (11.4%) patients. There were no episodes of febrile neutropenia and no toxic deaths. CONCLUSIONS: Pegamotecan has activity in this patient population and was generally well-tolerated. The favourable rate of haematological toxicities and diarrhoea compared with irinotecan in similar studies suggests that pegamotecan could be combined with other active agents in further studies in this disease.

High-resolution 3D isotropic MR imaging of mouse flank tumours obtained in vivo with solenoid RF micro-coil.

The investigation of mouse flank tumours by magnetic resonance imaging (MRI) is limited by the achievable spatial resolution, which is generally limited by the critical problem of signal-to-noise ratio. Sensitivity was improved by using an optimized solenoid RF micro-coil, built into the animal cradle. This simple design did not require extensive RF engineering expertise to construct, yet allowed high-resolution 3D isotropic imaging at 60 x 60 x 60 microm(3) for a flank tumour in vivo, revealing the heterogeneous internal structure of the tumour. It also allowed dynamic contrast enhanced (DCE) experiments and angiography (MRA) to be performed at 100 x 100 x 100 microm(3) resolution. The DCE experiments provided an excellent example of the diffusive spreading of contrast agent into less vascularized tumour tissue. This work is the first step in using high-resolution 3D isotropic MR to study transport in mouse flank tumours.

In vitro evaluation of cancer-specific NF-kappaB-CEA enhancer-promoter system for 5-fluorouracil prodrug gene therapy in colon cancer cell lines.

Nuclear factor-kappa B (NF-kappaB) is a transcription factor with high transcriptional activity in cancer cells. In this study, we developed a novel enhancer-promoter system, kappaB4-CEA205, in which the basal carcinoembryonic antigen (CEA) promoter sequence (CEA205) was placed downstream of the four tandem-linked NF-kappaB DNA-binding sites (kappaB4). In combination with a kappaB4 enhancer, the transcriptional activity of the CEA promoter was significantly enhanced (three- to eight-fold) in cancer cell lines but not in normal cells. In cancer cell lines, the transcriptional activity of kappaB4-CEA205 was comparable with that of the SV40 promoter. We also constructed vectors in which the thymidine phosphorylase (TP) cDNA was under the control of CEA205, kappaB4, kappaB4-CEA205 and CMV promoters, respectively. TP protein and enzyme activity were detected at comparable levels in kappaB4-CEA205- and CMV-driven TP cDNA-transfected cancer cell lines (H630 and RKO). The kappaB4-TP and CEA205-TP-transfected cell lines, respectively, only demonstrated negligible and low levels of TP protein and enzyme activity. Both CMV- and kappaB4-CEA205-driven TP cDNA transiently transfected cells were 8- to 10-fold sensitised to 5-fluorouracil (5-FU) prodrug, 5'-deoxy-5-fluorouradine (5'-DFUR), in contrast to only 1.5- to 2-fold sensitised by the kappaB4- and CEA205-driven TP cDNA-transfected cells. The bystander killing effect of CMV- and kappaB4-CEA205-driven TP cDNA-transfected cells was comparable. This is the first report that indicates that the NF-kappaB DNA-binding site could be used as a novel cancer-specific enhancer to improve cancer-specific promoter activity in gene-directed enzyme prodrug therapy.

Phase II studies of BBR3464, a novel tri-nuclear platinum complex, in patients with gastric or gastro-oesophageal adenocarcinoma.

BBR3464, a novel tri-nuclear platinum complex, forms long-range DNA adducts and is highly potent when compared with cisplatin in vitro. Preclinical studies demonstrated activity in cisplatin-resistant tumours and tumours with mutated p53 status. Phase I & II clinical studies gave preliminary indications of activity in melanoma, pancreatic, lung and ovarian cancers. The aim of this study was to determine the efficacy and confirm the toxicity of BBR3464 when given either as first- or second-line treatment for advanced disease in patients with gastric and gastro-oesphageal adenocarcinoma. Two multicentre, open label, Gehan design studies were conducted; one study used BBR3464 as first-line and the other as second-line treatment for metastatic or locally advanced disease. Nineteen first-line and 26 second-line patients were enrolled receiving a total of 74 and 53 infusions, respectively. Initially, seven patients in the second-line study received BBR3464 using the planned schedule of 1.1 mg/m2 every 4 weeks; however, 5 of these patients experienced dose-limiting grade 3 or 4 febrile neutropenia; subsequent patients in both studies were treated using the modified schedule of 0.9 mg/m2, every 21 days. In 1 of 17 evaluable, previously untreated patients, regression of multiple skin lesions was noted with stabilisation of lung metastases and maxillary sinus mass, lasting 155 days. In the first-line study, the median time to progression was 85 days [95% Confidence Interval (CI): 42, 127] (2.8 months) and in the second-line study, the median time to progression was 71 days [95% CI: 42, 109] and 38 days [95% CI: 32, 73] in the 1.1 and 0.9 mg/m2 dose level groups, respectively. Toxicity data were available for 45 patients. Neutropenia was the main toxicity seen (G3: 40%, G4: 40%). Febrile neutropenia was observed in six patients (15%) treated with 0.9 mg/m2 compared with five patients (71%) treated with 1.1 mg/m2 BBR3464. Other drug-related toxicities (G3/4) included: anaemia, thrombocytopenia, nausea, vomiting, diarrhoea, mucositis and fatigue. Diarrhoea and nausea/ vomiting were adequately controlled by the use of loperamide and antiemetics, respectively. Recruitment to the second-line study was closed early due to the poor response rate (1/17 evaluable, 6%; 95% CI: 1%, 27%) and short time to progression noted in the first-line study. Further studies with BBR3464 in this tumour type are not recommended.