Nivolumab and Ipilimumab as Maintenance Therapy in Extensive-Disease Small-Cell Lung Cancer: CheckMate 451.

PURPOSE: In extensive-disease small-cell lung cancer (ED-SCLC), response rates to first-line platinum-based chemotherapy are robust, but responses lack durability. CheckMate 451, a double-blind phase III trial, evaluated nivolumab plus ipilimumab and nivolumab monotherapy as maintenance therapy following first-line chemotherapy for ED-SCLC. METHODS: Patients with ED-SCLC, Eastern Cooperative Oncology Group performance status 0-1, and no progression after ≤ 4 cycles of first-line chemotherapy were randomly assigned (1:1:1) to nivolumab 1 mg/kg plus ipilimumab 3 mg/kg once every 3 weeks for 12 weeks followed by nivolumab 240 mg once every 2 weeks, nivolumab 240 mg once every 2 weeks, or placebo for ≤ 2 years or until progression or unacceptable toxicity. Primary end point was overall survival (OS) with nivolumab plus ipilimumab versus placebo. Secondary end points were hierarchically tested. RESULTS: Overall, 834 patients were randomly assigned. The minimum follow-up was 8.9 months. OS was not significantly prolonged with nivolumab plus ipilimumab versus placebo (hazard ratio [HR], 0.92; 95% CI, 0.75 to 1.12; P = .37; median, 9.2 v 9.6 months). The HR for OS with nivolumab versus placebo was 0.84 (95% CI, 0.69 to 1.02); the median OS for nivolumab was 10.4 months. Progression-free survival HRs versus placebo were 0.72 for nivolumab plus ipilimumab (95% CI, 0.60 to 0.87) and 0.67 for nivolumab (95% CI, 0.56 to 0.81). A trend toward OS benefit with nivolumab plus ipilimumab was observed in patients with tumor mutational burden ≥ 13 mutations per megabase. Rates of grade 3-4 treatment-related adverse events were nivolumab plus ipilimumab (52.2%), nivolumab (11.5%), and placebo (8.4%). CONCLUSION: Maintenance therapy with nivolumab plus ipilimumab did not prolong OS for patients with ED-SCLC who did not progress on first-line chemotherapy. There were no new safety signals.

Clinical Benefit-Risk Assessment of Nivolumab 240 mg Every 2 Weeks in Chinese Patients With Advanced and Metastatic Solid Tumors.

Nivolumab 240 mg every 2 weeks is approved in China by the National Medical Product Agency for squamous cell carcinoma of the head and neck and gastric cancer, based on population pharmacokinetic (PPK) analyses and benefit-risk assessment of safety/efficacy in solid tumors, including Chinese and global populations. The aim of this assessment was to investigate exposure and risk for adverse events (AEs) with flat dosing compared with weight-based dosing. Nivolumab 240-mg and 3-mg/kg every-2-week exposures in Chinese patients were simulated using PPK modeling, and AEs in Chinese and pooled global populations were compared by dosing regimen, exposure, and weight. The 10-mg/kg every-2-week regimen was included because it is known to be well tolerated. Predicted nivolumab exposure in Chinese patients receiving 240 mg every 2 weeks was ∼25% higher versus 3 mg/kg every 2 weeks, but ∼60% lower versus 10 mg/kg every 2 weeks. Grade 3/4 AE incidence in Chinese patients receiving nivolumab 3 mg/kg every 2 weeks was similar with 240-mg every-2-week dosing and with patients from global populations treated with 3 or 10 mg/kg every 2 weeks. There was no trend toward increased AE incidence with high versus low nivolumab exposure or in global patients of varying body weight receiving 3 or 10 mg/kg every 2 weeks. Objective response rates were similar in Chinese and global patients with squamous and nonsquamous NSCLC. Results showed that benefit-risk profiles with nivolumab 240 mg every 2 weeks were similar to those of the 3-mg/kg every-2-week regimen in Chinese patients and global populations, providing an alternative treatment option to Chinese patients.

First-line nivolumab plus ipilimumab in unresectable malignant pleural mesothelioma (CheckMate 743): a multicentre, randomised, open-label, phase 3 trial.

BACKGROUND: Approved systemic treatments for malignant pleural mesothelioma (MPM) have been limited to chemotherapy regimens that have moderate survival benefit with poor outcomes. Nivolumab plus ipilimumab has shown clinical benefit in other tumour types, including first-line non-small-cell lung cancer. We hypothesised that this regimen would improve overall survival in MPM. METHODS: This open-label, randomised, phase 3 study (CheckMate 743) was run at 103 hospitals across 21 countries. Eligible individuals were aged 18 years and older, with previously untreated, histologically confirmed unresectable MPM, and an Eastern Cooperative Oncology Group performance status of 0 or 1. Eligible participants were randomly assigned (1:1) to nivolumab (3 mg/kg intravenously once every 2 weeks) plus ipilimumab (1 mg/kg intravenously once every 6 weeks) for up to 2 years, or platinum plus pemetrexed chemotherapy (pemetrexed [500 mg/m2 intravenously] plus cisplatin [75 mg/m2 intravenously] or carboplatin [area under the concentration-time curve 5 mg/mL per min intravenously]) once every 3 weeks for up to six cycles. The primary endpoint was overall survival among all participants randomly assigned to treatment, and safety was assessed in all participants who received at least one dose of study treatment. This study is registered with ClinicalTrials.gov, NCT02899299, and is closed to accrual. FINDINGS: Between Nov 29, 2016, and April 28, 2018, 713 patients were enrolled, of whom 605 were randomly assigned to either nivolumab plus ipilimumab (n=303) or chemotherapy (n=302). 467 (77%) of 605 participants were male and median age was 69 years (IQR 64-75). At the prespecified interim analysis (database lock April 3, 2020; median follow-up of 29·7 months [IQR 26·7-32·9]), nivolumab plus ipilimumab significantly extended overall survival versus chemotherapy (median overall survival 18·1 months [95% CI 16·8-21·4] vs 14·1 months [12·4-16·2]; hazard ratio 0·74 [96·6% CI 0·60-0·91]; p=0·0020). 2-year overall survival rates were 41% (95% CI 35·1-46·5) in the nivolumab plus ipilimumab group and 27% (21·9-32·4) in the chemotherapy group. Grade 3-4 treatment-related adverse events were reported in 91 (30%) of 300 patients treated with nivolumab plus ipilimumab and 91 (32%) of 284 treated with chemotherapy. Three (1%) treatment-related deaths occurred in the nivolumab plus ipilimumab group (pneumonitis, encephalitis, and heart failure) and one (<1%) in the chemotherapy group (myelosuppression). INTERPRETATION: Nivolumab plus ipilimumab provided significant and clinically meaningful improvements in overall survival versus standard-of-care chemotherapy, supporting the use of this first-in-class regimen that has been approved in the USA as of October, 2020, for previously untreated unresectable MPM. FUNDING: Bristol Myers Squibb.

Nivolumab Versus Docetaxel in a Predominantly Chinese Patient Population With Previously Treated Advanced NSCLC: CheckMate 078 Randomized Phase III Clinical Trial.

INTRODUCTION: Data on immuno-oncology agents in Chinese patients are limited despite a need for new therapies. We evaluated the efficacy and safety of nivolumab in a predominantly Chinese patient population with previously treated NSCLC. METHODS: CheckMate 078 was a randomized, open-label, phase III clinical trial in patients from China, Russia, and Singapore with squamous or nonsquamous NSCLC that had progressed during/after platinum-based doublet chemotherapy (ClinicalTrials.gov: NCT02613507). Patients with EGFR/ALK alterations were excluded. Patients (N = 504) were randomized 2:1 to nivolumab (3 mg/kg every 2 weeks) or docetaxel (75 mg/m2 every 3 weeks), stratified by performance status, tumor histology, and tumor programmed death ligand 1 expression. The primary endpoint was overall survival (OS); secondary endpoints included objective response rate, progression-free survival, and safety. RESULTS: OS was significantly improved with nivolumab (n = 338) versus docetaxel (n = 166); median OS (95% confidence interval): 12.0 (10.4-14.0) versus 9.6 (7.6-11.2) months, respectively; hazard ratio (97.7% confidence interval): 0.68 (0.52-0.90); p = 0.0006. Objective response rate was 17% with nivolumab versus 4% with docetaxel; median duration of response was not reached versus 5.3 months. Minimum follow-up was 8.8 months. The frequency of grade 3 or greater treatment-related adverse events was 10% with nivolumab and 48% with docetaxel. CONCLUSIONS: This is the first phase III study in a predominantly Chinese population reporting results with a programmed death 1 inhibitor. In this population with previously treated advanced NSCLC, nivolumab improved OS versus docetaxel. Results were consistent with global CheckMate 017 and 057 studies.

Nivolumab versus Docetaxel in Advanced Squamous-Cell Non-Small-Cell Lung Cancer.

BACKGROUND: Patients with advanced squamous-cell non-small-cell lung cancer (NSCLC) who have disease progression during or after first-line chemotherapy have limited treatment options. This randomized, open-label, international, phase 3 study evaluated the efficacy and safety of nivolumab, a fully human IgG4 programmed death 1 (PD-1) immune-checkpoint-inhibitor antibody, as compared with docetaxel in this patient population. METHODS: We randomly assigned 272 patients to receive nivolumab, at a dose of 3 mg per kilogram of body weight every 2 weeks, or docetaxel, at a dose of 75 mg per square meter of body-surface area every 3 weeks. The primary end point was overall survival. RESULTS: The median overall survival was 9.2 months (95% confidence interval [CI], 7.3 to 13.3) with nivolumab versus 6.0 months (95% CI, 5.1 to 7.3) with docetaxel. The risk of death was 41% lower with nivolumab than with docetaxel (hazard ratio, 0.59; 95% CI, 0.44 to 0.79; P<0.001). At 1 year, the overall survival rate was 42% (95% CI, 34 to 50) with nivolumab versus 24% (95% CI, 17 to 31) with docetaxel. The response rate was 20% with nivolumab versus 9% with docetaxel (P=0.008). The median progression-free survival was 3.5 months with nivolumab versus 2.8 months with docetaxel (hazard ratio for death or disease progression, 0.62; 95% CI, 0.47 to 0.81; P<0.001). The expression of the PD-1 ligand (PD-L1) was neither prognostic nor predictive of benefit. Treatment-related adverse events of grade 3 or 4 were reported in 7% of the patients in the nivolumab group as compared with 55% of those in the docetaxel group. CONCLUSIONS: Among patients with advanced, previously treated squamous-cell NSCLC, overall survival, response rate, and progression-free survival were significantly better with nivolumab than with docetaxel, regardless of PD-L1 expression level. (Funded by Bristol-Myers Squibb; CheckMate 017 ClinicalTrials.gov number, NCT01642004.).

Activity and safety of nivolumab, an anti-PD-1 immune checkpoint inhibitor, for patients with advanced, refractory squamous non-small-cell lung cancer (CheckMate 063): a phase 2, single-arm trial.

BACKGROUND: Patients with squamous non-small-cell lung cancer that is refractory to multiple treatments have poor outcomes. We assessed the activity of nivolumab, a fully human IgG4 PD-1 immune checkpoint inhibitor antibody, for patients with advanced, refractory, squamous non-small-cell lung cancer. METHODS: We did this phase 2, single-arm trial at 27 sites (academic, hospital, and private cancer centres) in France, Germany, Italy, and USA. Patients who had received two or more previous treatments received intravenous nivolumab (3 mg/kg) every 2 weeks until progression or unacceptable toxic effects. The primary endpoint was the proportion of patients with a confirmed objective response as assessed by an independent radiology review committee. We included all treated patients in the analyses. This study is registered with ClinicalTrials.gov, number NCT01721759. FINDINGS: Between Nov 16, 2012, and July 22, 2013, we enrolled and treated 117 patients. 17 (14·5%, 95% CI 8·7-22·2) of 117 patients had an objective response as assessed by an independent radiology review committee. Median time to response was 3·3 months (IQR 2·2-4·8), and median duration of response was not reached (95% CI 8·31-not applicable); 13 (77%) of 17 of responses were ongoing at the time of analysis. 30 (26%) of 117 patients had stable disease (median duration 6·0 months, 95% CI 4·7-10·9). 20 (17%) of 117 patients reported grade 3-4 treatment-related adverse events, including: fatigue (five [4%] of 117 patients), pneumonitis (four [3%]), and diarrhoea (three [3%]). There were two treatment-associated deaths caused by pneumonia and ischaemic stroke that occurred in patients with multiple comorbidities in the setting of progressive disease. INTERPRETATION: Nivolumab has clinically meaningful activity and a manageable safety profile in previously treated patients with advanced, refractory, squamous non-small cell lung cancer. These data support the assessment of nivolumab in randomised, controlled, phase 3 studies of first-line and second-line treatment. FUNDING: Bristol-Myers Squibb.

Using Modified RECIST and Alpha-Fetoprotein Levels to Assess Treatment Benefit in Hepatocellular Carcinoma.

BACKGROUND AND AIMS: Assessing treatment responses in hepatocellular carcinoma (HCC) is challenging, and alternative radiologic methods of measuring treatment response are required. Modified Response Evaluation Criteria in Solid Tumors (mRECIST) for HCC and alpha-fetoprotein (AFP) levels were assessed in a post hoc analysis of a phase II study of brivanib, a selective dual inhibitor of fibroblast growth factor and vascular endothelial growth factor signaling. METHODS: HCC patients were treated with first-line (cohort A; n = 55) or second-line (cohort B; n = 46) brivanib alaninate 800 mg once daily. Outcomes were compared between World Health Organization (WHO) criteria and (retrospectively by) mRECIST by independent review. The relationship between on-study AFP changes and outcome was analyzed in patients with elevated AFP at baseline. RESULTS: Response rates were higher with mRECIST versus WHO criteria in cohorts A (25.5% vs. 7.3%) and B (10.9% vs. 4.3%). Progressive disease (PD) as assessed by mRECIST was associated with a very short median overall survival (OS; cohort A, 2.8 months; cohort B, 5.3 months); PD as assessed by WHO criteria reflected a mixed population of patients with better outcomes. mRECIST responders tended to have a>50% AFP decrease during therapy. In cohorts A and B pooled, an early AFP response (>20%or >50% decline from baseline within the first 4 weeks) was not associated with longer median OS. CONCLUSIONS: Tumor response as assessed by mRECIST differed from that by WHO criteria, with mRECIST possibly identifying true nonresponders with a poor prognosis. Many patients had AFP decreases correlating with tumor shrinkage, yet an association with long-term benefit was unclear. mRECIST and on-treatment AFP levels are being explored further with brivanib in HCC.

Phase II, open-label study of brivanib as second-line therapy in patients with advanced hepatocellular carcinoma.

PURPOSE: Brivanib, a selective dual inhibitor of fibroblast growth factor and VEGF signaling, has recently been shown to have activity as first-line treatment for patients with advanced hepatocellular carcinoma (HCC). This phase II open-label study assessed brivanib as second-line therapy in patients with advanced HCC who had failed prior antiangiogenic treatment. EXPERIMENTAL DESIGN: Brivanib was administered orally at a dose of 800 mg once daily. The primary objectives were tumor response rate, time to response, duration of response, progression-free survival, overall survival (OS), disease control rate, time to progression (TTP), and safety and tolerability. RESULTS: Forty-six patients were treated. Best responses to treatment with brivanib (N = 46 patients) using modified World Health Organization criteria were partial responses for two patients (4.3%), stable disease for 19 patients (41.3%), and progressive disease for 19 patients (41.3%). The tumor response rate was 4.3%; the disease control rate was 45.7%. Median OS was 9.79 months. Median TTP as assessed by study investigators following second-line treatment with brivanib was 2.7 months. The most common adverse events were fatigue, decreased appetite, nausea, diarrhea, and hypertension. CONCLUSION: Brivanib had a manageable safety profile and is one of the first agents to show promising antitumor activity in advanced HCC patients treated with prior sorafenib.

A 40-week double-blind aripiprazole versus lithium follow-up of a 12-week acute phase study (total 52 weeks) in bipolar I disorder.

BACKGROUND: This study followed manic or mixed bipolar I subjects for an additional 40 weeks after initial randomization to 12 weeks of lithium versus aripiprazole monotherapy. This is the only long-term, double-blind study comparing lithium and aripiprazole. METHODS: Patients continued receiving either aripiprazole 15 or 30 mg/day, or lithium 900, 1200 or 1500 mg/day in a double-blind fashion for 40 weeks after completing a 12-week double-blind study (52 weeks total treatment). Efficacy endpoints included adjusted mean change from baseline to Week 52 in Young Mania Rating Scale (YMRS) total score and Montgomery-Åsberg Depression Rating Scale (MADRS) total scores (observed cases). Remission was defined as YMRS total score≤12. Safety and tolerability were also assessed. RESULTS: Of the 66 patients who entered the extension phase, only 20 patients (30.3%) completed the entire phase (aripiprazole n=7; lithium n=13). The significant improvement that occurred over the first 12 weeks was maintained over the 40 weeks of blinded continuation (from Week 12 through Week 52). The most common treatment-emergent adverse events in the extension phase for aripiprazole were akathisia, headache, somnolence, anxiety and nasopharyngitis (all 8%), and for lithium were insomnia (15.8%), headache (13.2%), diarrhea (13.2%) and vomiting (10.5%). Mean weight change was +2.71 kg for lithium and +5.66 kg for aripiprazole (p=0.46). LIMITATIONS: This trial was not powered to statistically compare active treatments, and long-term completion rates were low in both groups. CONCLUSIONS: Aripiprazole monotherapy appears to be equivalently useful to lithium for the extended treatment of mixed or manic bipolar disorder patients.

Phase II, open-label study of brivanib as first-line therapy in patients with advanced hepatocellular carcinoma.

PURPOSE: Brivanib, a selective dual inhibitor of fibroblast growth factor and VEGF signaling, has demonstrated encouraging antitumor activity in preclinical and phase I studies. We performed a phase II open-label study of brivanib as first-line therapy in patients with unresectable, locally advanced, or metastatic hepatocellular carcinoma. EXPERIMENTAL DESIGN: Brivanib was administered orally at a dose of 800 mg once daily. The primary objective was 6-month progression-free survival, progression-free survival rate; secondary objectives were tumor response rate, time to response, duration of response, median progression-free survival, median overall survival, disease control rate (complete response, partial response, or stable disease ≥ 42 days), and safety and tolerability. RESULTS: Between March 2007 and May 2009, 55 patients were treated and were evaluable for response. Patients were assessed using modified World Health Organization (mWHO) criteria. According to mWHO criteria and as assessed by Independent Response Review Committee, the six-month progression-free survival rate (95% CI) was 18.2% (9.1%-30.9%). Median progression-free survival (95% CI) was 2.7 months (1.4-3.0). One patient achieved a complete response and three achieved a partial response. Twenty-two had stable disease. Median overall survival (95% CI) was 10 (6.8-15.2) months. Brivanib was generally well tolerated; the most common adverse events included fatigue, hypertension, and diarrhea. CONCLUSION: Brivanib as first-line therapy demonstrates promising antitumor activity and a manageable safety profile in patients with advanced, unresectable HCC.

Assessment of safety, tolerability and effectiveness of adjunctive aripiprazole to lithium/valproate in bipolar mania: a 46-week, open-label extension following a 6-week double-blind study.

OBJECTIVE: This study evaluated the long-term tolerability and effectiveness of aripiprazole adjunctive to lithium or valproate in partial responders with bipolar mania. METHODS: Completers of a 6-week double-blind comparison of adjunctive aripiprazole versus placebo in bipolar mania partially responsive to lithium or valproate monotherapy could enter a 46-week extension treatment with open-label adjunctive aripiprazole plus lithium (ARI + LI) or valproate (ARI + VAL). Safety, efficacy and functioning were assessed. CLINICAL TRIAL REGISTRATION: CN138-134LT: Study of Aripiprazole in Patients With Bipolar I Disorder; ID number: NCT00257972; registry: www.clinicaltrials.gov. RESULTS: In total, 283 (ARI + LI n = 108; ARI + VAL n = 175) patients entered and 146 (ARI + LI n = 55; ARI + VAL n = 91) completed the 46-week, open-label extension. Frequently reported adverse events (AEs) that occurred with ARI + LI vs. ARI + VAL were: tremor (17.0% vs. 12.1%), akathisia (6.6% vs. 8.6%), headache (6.6% vs. 4.0%), insomnia (9.4% vs. 10.3%), depression (7.5% vs. 9.2%) and weight increase (11.3% vs. 8.6%). Extrapyramidal symptom-related AEs occurred in 24 (22.6%) ARI + LI- and 38 (21.8%) ARI + VAL-treated patients, with eight discontinuations. The majority of new-onset events of akathisia and insomnia occurred early. Mean (SE) weight change from double-blind endpoint to Week 46 (LOCF) was 2.3 (0.6) kg with ARI + LI and 2.0 (0.4) kg with ARI + VAL. Significant improvements from baseline over the 52 weeks (LOCF) occurred with ARI + LI and ARI + VAL on mean (95%CI) YMRS total score (-16.5 [-18.1; -14.8] and -17.6 [-18.9; -16.3], both p < 0.001 vs. baseline) and MADRS total score (-1.7 [-3.3; -0.1], p < 0.05 vs. baseline vs. -2.7 [-4.0; -1.4], p < 0.001 vs. baseline). Over the 46-week extension, continued aripiprazole provided continued YMRS improvement with ARI + LI (-2.9) and ARI + VAL (-3.3), while mean MADRS total changes were +1.1 and +1.0, respectively, and LIFE-RIFT changes were 0.2 and -0.5, respectively. CONCLUSIONS: Long-term aripiprazole adjunctive to lithium/valproate in bipolar mania was safe and well tolerated. Improvements in manic symptoms and functioning were maintained. Aripiprazole, adjunctive to either lithium or valproate, appeared to be equally safe and effective combinations for the treatment of bipolar disorder. LIMITATIONS: As an open-label extension study with a low completion rate, a conservative interpretation of the findings is warranted. Additionally, the study population was not randomly selected but chosen at the discretion of the investigator, and patients did not maintain therapeutic levels of their mood stabiliser consistently.

Caveolin-1 is critical for the maturation of tumor blood vessels through the regulation of both endothelial tube formation and mural cell recruitment.

In the normal microvasculature, caveolin-1, the structural protein of caveolae, modulates transcytosis and paracellular permeability. Here, we used caveolin-1-deficient mice (Cav(-/-)) to track the potential active roles of caveolin-1 down-modulation in the regulation of vascular permeability and morphogenesis in tumors. In B16 melanoma-bearing Cav(-/-) mice, we found that fibrinogen accumulated in early-stage tumors to a larger extent than in wild-type animals. These results were confirmed by the observations of a net elevation of the interstitial fluid pressure and a relative deficit in albumin extravasation in Cav(-/-) tumors (versus healthy tissues). Immunostaining analyses of Cav(-/-) tumor sections further revealed a higher density of CD31-positive vascular structures and a dramatic deficit in alpha-smooth muscle actin-stained mural cells. The increase in blood plasma volume in Cav(-/-) tumors was confirmed by dynamic contrast enhanced-magnetic resonance imaging and found to be associated with a more rapid tumor growth. Finally, an in vitro wound test and the aorta ring assay revealed that silencing caveolin expression could directly impair the migration and the outgrowth of smooth muscle cells/pericytes, particularly in response to platelet-derived growth factor. In conclusion, a decrease in caveolin abundance, by promoting angiogenesis and preventing its termination by mural cell recruitment, appears as an important control point for the formation of new tumor blood vessels. Caveolin-1 therefore has the potential to be a marker of tumor vasculature maturity that may help adjusting anticancer therapies.

Glucocorticoids modulate tumor radiation response through a decrease in tumor oxygen consumption.

PURPOSE: We hypothesized that glucocorticoids may enhance tumor radiosensitivity by increasing tumor oxygenation (pO(2)) through inhibition of mitochondrial respiration. EXPERIMENTAL DESIGN: The effect of three glucocorticoids (hydrocortisone, dexamethasone, and prednisolone) on pO(2) was studied in murine TLT liver tumors and FSaII fibrosarcomas. At the time of maximum pO(2) (t(max), 30 min after administration), perfusion, oxygen consumption, and radiation sensitivity were studied. Local pO(2) measurements were done using electron paramagnetic resonance. The oxygen consumption rate of tumor cells after in vivo glucocorticoid administration was measured using high-frequency electron paramagnetic resonance. Tumor perfusion and permeability measurements were assessed by dynamic contrast-enhanced magnetic resonance imaging. RESULTS: All glucocorticoids tested caused a rapid increase in pO(2). At t(max), tumor perfusion decreased, indicating that the increase in pO(2) was not caused by an increase in oxygen supply. Also at t(max), global oxygen consumption decreased. When irradiation (25 Gy) was applied at t(max), the tumor radiosensitivity was enhanced (regrowth delay increased by a factor of 1.7). CONCLUSION: These results show the potential usefulness of the administration of glucocorticoids before irradiation.

Mechanism of reoxygenation after antiangiogenic therapy using SU5416 and its importance for guiding combined antitumor therapy.

Emerging preclinical studies support the concept of a transient "normalization" of tumor vasculature during the early stage of antiangiogenic treatment, with possible beneficial effects on associated radiotherapy or chemotherapy. One key issue in this area of research is to determine whether this feature is common to all antiangiogenic drugs and whether the phenomenon occurs in all types of tumors. In the present study, we characterized the evolution of the tumor oxygenation (in transplantable liver tumor and FSAII tumor models) after administration of SU5416, an antagonist of the vascular endothelial growth factor receptor. SU5416 induced an early increase in tumor oxygenation [measured by electronic paramagnetic resonance (EPR)], which did not correlate with remodeling of the tumor vasculature (assessed by CD31 labeling using immunohistochemistry) or with tumor perfusion (measured by dynamic contrast enhanced-magnetic resonance imaging). Inhibition of mitochondrial respiration (measured by EPR) was responsible for this early reoxygenation. Consistent with these unique findings in the tumor microenvironment, we found that SU5416 potentiated tumor response to radiotherapy but not to chemotherapy. In addition to the fact that the characterization of the tumor oxygenation is essential to enable correct application of combined therapies, our results show that the long-term inhibition of oxygen consumption is a potential novel target in this class of compounds.

Determination of the maturity and functionality of tumor vasculature by MRI: correlation between BOLD-MRI and DCE-MRI using P792 in experimental fibrosarcoma tumors.

Using hypercapnia and carbogen as functional markers of vessel maturation and function, we compared blood oxygen level-dependent (BOLD) contrast with standard dynamic contrast-enhanced (DCE)-MRI quantitative parameters in murine fibrosarcoma. Our results show that there was no correlation between vessel maturity and contrast-agent uptake rate (K(in) (Trans)) or contrast agent efflux rate (k(ep)). In addition, DCE-MRI provided higher estimates of the fraction of functional tumor compared to BOLD-MRI. The two putative markers of regional vascular density, i.e., the magnitude of BOLD signal change during carbogen challenge (VF) and the fractional plasma volume found by DCE-MRI (V(p)), were only weakly correlated (r(2) = 0.02-0.14). Furthermore, VF showed no correlation with K(in) (Trans). A positive correlation was observed (r(2) = 0.75) between mean tumor VF and k(ep), but only when averaged over the whole tumor (which includes tumor regions completely unperfused by the gadolinium (Gd) contrast agent). This would merely reveal a relationship between perfusion status and the capacity to respond to carbogen breathing. In conclusion, characterizations of tumor microvasculature imaging using BOLD-MRI and DCE-MRI appear to be largely complementary, given the weak correlations between their corresponding derived parameters.

Preclinical safety and antitumor efficacy of insulin combined with irradiation.

BACKGROUND AND PURPOSE: We have previously reported that insulin significantly enhances tumor oxygenation (pO(2)) and increases radiation-induced tumor regrowth delay in experimental models. Considering the large radiosensitizing effect, clinical trials might be envisioned. The aim of the present pre-clinical study was to obtain a more complete set of safety and efficacy data which would further justify the commencement of such clinical trials. MATERIAL AND METHODS: Toxicity on normal (early and late-responding) tissues was measured by the intestinal crypt regeneration assay and the late leg contracture assay. Efficacy in terms of enhancement of pO(2) (measured by in vivo EPR oximetry) and increase in radiation-induced tumor regrowth delay was evaluated with a dose-response study on mice bearing FSaII fibrosarcoma. RESULTS: The effect on regrowth delay was directly correlated with the effect on the tumor pO(2), with a maximal effect using 400 mU kg(-1) insulin. Importantly, there was no increase in the radiation toxicity for normal tissues. Finally, we found that the hypoglycaemia induced by insulin can be corrected by simultaneous glucose infusion without modification of efficacy. CONCLUSION: Insulin here demonstrated a therapeutic gain and a lack of toxicity to normal tissues. The results of this study fully justify further larger preclinical assays such as the use of fractionated irradiation and a tumor control dose assay, before determining the utility of insulin as a radiosensitizer for human patients in the clinic.

Complex relationship between changes in oxygenation status and changes in R*2: the case of insulin and NS-398, two inhibitors of oxygen consumption.

Insulin and NS-398 have been reported to inhibit oxygen consumption in experimental tumor models, thereby increasing oxygenation and radiosensitization. The aim of this work was to use MRI to study changes in murine FSaII tumor hemodynamics after administration of those oxygen consumption inhibitors. A multiple-echo gradient-echo (GRE) MRI sequence (4.7 T) was used to map changes in three factors: the GRE signal (at TE=20 ms), the parameter S0 (theoretical signal at TE=0 ms), and the relaxation rate R*2. Perfusion maps were obtained by dynamic contrast-enhanced (DCE) MRI. Insulin caused a significant decrease in the tumor blood oxygen level-dependent (BOLD) signal over time. factor This was likely the result of decreased blood flow, since both S0 and the percentage of perfused tumor decreased as well. Tumor R*2 did not change significantly in response to the treatments, which is surprising considering that other non-MRI techniques (electron paramagnetic resonance (EPR) oximetry and fiber-optic probes) have shown that tumor oxygenation increases after treatment. This suggests that metabolic changes associated with vasoactive challenges may have an unpredictable influence on blood saturation and R*2. In conclusion, this study further emphasizes the fact that changes in BOLD signal and R*2 in tumors do not depend uniquely on changes in oxygenation status.

Reversal of temporal and spatial heterogeneities in tumor perfusion identifies the tumor vascular tone as a tunable variable to improve drug delivery.

Maturation of tumor vasculature involves the recruitment of pericytes that protect the endothelial tubes from a variety of stresses, including antiangiogenic drugs. Mural cells also provide mature tumor blood vessels with the ability to either relax or contract in response to substances present in the tumor microenvironment. The observed cyclic alterations in tumor blood flow and the associated deficit in chemotherapeutic drug delivery could in part arise from this vasomodulatory influence. To test this hypothesis, we focused on endothelin-1 (ET-1), which, besides its autocrine effects on tumor cell growth, is a powerful vasoconstrictor. We first document that an ET(A) receptor antagonist induced relaxation of microdissected tumor arterioles and selectively and quantitatively increased tumor blood flow in experimental tumor models. We then combined dye staining of functional vessels, fluorescent microsphere-based mapping, and magnetic resonance imaging to identify heterogeneities in tumor blood flow and to examine the reversibility of such phenomena. Data from all these techniques concurred to show that administration of an ET(A) receptor antagonist could reduce the extent of underperfused tumor areas, proving the key role of vessel tone variations in tumor blood flow heterogeneity. We also provide evidence that ET(A) antagonist administration could, despite an increase in tumor interstitial fluid pressure, improve access of cyclophosphamide to the tumor compartment and significantly influence tumor growth. In conclusion, tumor endogenous ET-1 production participates largely in the temporal and spatial variations in tumor blood flow. ET(A) antagonist administration may wipe out such heterogeneities, thus representing an adjuvant strategy that could improve the delivery of conventional chemotherapy to tumors.

Botulinum toxin potentiates cancer radiotherapy and chemotherapy.

PURPOSE: Structural and functional abnormalities in the tumor vascular network are considered factors of resistance of solid tumors to cytotoxic treatments. To increase the efficacy of anticancer treatments, efforts must be made to find new strategies for transiently opening the tumor vascular bed to alleviate tumor hypoxia (source of resistance to radiotherapy) and improve the delivery of chemotherapeutic agents. We hypothesized that Botulinum neurotoxin type A (BoNT-A) could interfere with neurotransmitter release at the perivascular sympathetic varicosities, leading to inhibition of the neurogenic contractions of tumor vessels and therefore improving tumor perfusion and oxygenation. EXPERIMENTAL DESIGN: To test this hypothesis, BoNT-A was injected locally into mouse tumors (fibrosarcoma FSaII, hepatocarcinoma transplantable liver tumor), and electron paramagnetic resonance oximetry was used to monitor pO(2) in vivo repeatedly for 4 days. Additionally, contrast-enhanced magnetic resonance imaging was used to measure tumor perfusion in vivo. Finally, isolated arteries were mounted in wire myograph to monitor specifically the neurogenic tone developed by arterioles that were co-opted by the surrounding growing tumor cells. RESULTS: Using these tumor models, we showed that local administration of BoNT-A (two sites; dose, 29 units/kg) substantially increases tumor oxygenation and perfusion, leading to a substantial improvement in the tumor response to radiotherapy (20 Gy of 250-kV radiation) and chemotherapy (cyclophosphamide, 50 mg/kg). This observed therapeutic gain results from an opening of the tumor vascular bed by BoNT-A because we showed that BoNT-A could inhibit neurogenic tone in the tumor vasculature. CONCLUSIONS: The opening of the vascular bed induced by BoNT-A offers a way to significantly increase the response of tumors to radiotherapy and chemotherapy.

The role of vessel maturation and vessel functionality in spontaneous fluctuations of T2*-weighted GRE signal within tumors.

Acute hypoxia (transient cycles of hypoxia-reoxygenation) is known to occur in solid tumors and is generally believed to be caused by tumor blood flow instabilities. It was recently demonstrated that T2*-weighted (T2*w) gradient echo (GRE) MRI is a powerful non-invasive method for investigating periodic changes in tumor pO2 and blood flow associated with acute hypoxia. Here, the possible correlation between tumor vessel immaturity, vessel functionality and T2*w GRE signal fluctuations was investigated. Intramuscularly implanted FSa II fibrosarcoma-bearing mice were imaged at 4.7 T. Maps of spontaneous fluctuations of MR signal intensity in tumor tissue during air breathing were obtained using a T2*w GRE sequence. This same sequence was also employed during air-5% CO2 breathing (hypercapnia) and carbogen breathing (hypercapnic hyperoxia) to obtain parametric maps representing vessel maturation and vessel function, respectively. Vascular density, vessel maturation and vessel perfusion were also assessed histologically by using CD31 labeling, alpha-smooth muscle actin immunoreactivity and Hoechst 33242 labeling, respectively. About 50% of the tumor fluctuations occurred in functional tumor regions (responsive to carbogen) and 80% occurred in tumor regions with immature vessels (lack of response to hypercapnia). The proportion of hypercapnia-responsive voxels were found to be twice as great in fluctuating than in non-fluctuating tumor areas (P: 0.22 vs 0.13). Similarly, the proportion of functional voxels was somewhat greater in fluctuating tumor areas (P: 0.54 vs 0.43). The mean values of MR signal changes during hypercapnia (VD) and during carbogen breathing (VF) (significant voxels only) were also larger in fluctuating than in non-fluctuating tumor areas (P < 0.05). This study demonstrated that adequate vessel functionality and advanced vessel maturation could explain at least in part the occurrence of spontaneous T2*w GRE signal fluctuations. Functionality and maturation are not required for signal fluctuations, however, because a large fraction of fluctuations could still occur in non-perfused and/or immature vessels.