Abstract CT213: A multicenter phase 1a/b study of NG-350A, a tumor-selective anti-CD40-antibody expressing adenoviral vector, and pembrolizumab in patients with metastatic or advanced epithelial tumors (FORTIFY)

Background: The efficacy of immune checkpoint inhibitors is often limited by immunosuppressive tumor microenvironments (TME) and novel combination therapies are required to overcome resistance. NG-350A is a novel T-SIGn (Tumor-Specific Immuno Gene) adenoviral vector that expresses a fully human agonistic IgG anti-CD40 antibody to promote innate and adaptive immune responses. Additionally, NG-350A selectively replicates in tumor cells, allowing IV dosing to be coupled with local transgene expression in the TME, thereby targeting all tumor lesions while limiting systemic exposure. Through these immunostimulatory effects the vector is designed to re-program ‘cold’ TMEs to allow functional anti-cancer immune responses. Data from an ongoing study with IV NG-350A monotherapy have shown promising tolerability, as well as prominent and sustained elevations in inflammatory cytokines (IL-2, IFNγ, IL-17A, IL-2 and IFNα2) consistent with the mechanism of action of anti-CD40 in stimulating TME re-programming [Naing 2021]. Based on these promising initial data, we designed a study to further assess the safety, tolerability and preliminary efficacy of NG-350A + pembrolizumab.

Methods: FORTIFY (NCT05165433) is an open-label, dose-escalating, phase 1a/b study of NG-350A + pembrolizumab. Eligible patients have advanced/metastatic epithelial tumors that have progressed after ≥1 line of systemic therapy and are incurable by local therapy. Patients eligible for phase 1a must have experienced failure of prior PD-1/PD-L1 inhibition as part of any prior line of therapy; patients eligible for phase 1b must have primary resistance to PD-1/PD-L1 inhibition. During phase 1a, up to 30 patients will receive escalating doses of IV NG-350A (Bayesian Optimal Interval design) to a maximum of 1 × 1012 viral particles (vp) on Day 1 and 1 × 1013 vp on Days 3 and 5 (1 cycle). Patients will receive a fixed-dose of pembrolizumab (200 mg IV) on Day 15 and then every 3 weeks thereafter for up to 35 cycles. Phase 1b will further investigate the efficacy/safety of the selected regimen in up to 3 tumor-specific cohorts using a Simon 2-stage design. Co-primary objectives are to characterize the safety and tolerability of NG-350A + pembrolizumab and to identify a recommended dose. Preliminary efficacy and immunogenicity are secondary endpoints. Pharmacodynamic outcomes will be assessed using tumor tissues and blood. Analyses of tumor tissue (serial biopsies at baseline and Day 15 of cycles 1-3 [cycles 1-2 only in Phase 1b]) will explore virus replication, transgene expression and immune/inflammatory responses. Analyses of serial blood samples will explore cytokine production and changes in peripheral immune cell subsets. Recruitment is expected to begin in Q1 2022.

Citation Format: Tom Lillie, Mark O'Hara, Christian Ottensmeier, Eileen Parkes, Lee Rosen, David Krige, Marya Chaney, Jo Carter, Vladimir Evilevitch, Matthew Thomas, Aung Naing. A multicenter phase 1a/b study of NG-350A, a tumor-selective anti-CD40-antibody expressing adenoviral vector, and pembrolizumab in patients with metastatic or advanced epithelial tumors (FORTIFY) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT213.

Abstract CT214: A multicenter phase 1a/b study of NG-641, a tumor-selective transgene-expressing adenoviral vector, and nivolumab in patients with metastatic or advanced epithelial tumors (NEBULA)

Background: T-SIGn (Tumor-Specific Immuno Gene Therapy) vectors are transgene-expressing variants of the blood-stable adenovirus enadenotucirev. Through a novel multimodal combination of immunostimulatory effects the vectors are designed to re-program ‘cold’ tumor microenvironments (TME) to allow functional anti-cancer immune responses. T-SIGn vectors selectively replicate in tumor cells, allowing IV delivery to be coupled with local transgene expression in the TME, thereby targeting all tumor lesions while limiting systemic exposure. NG-641 is a T-SIGn vector that expresses a fibroblast activation protein-directed bi-specific T-cell activator antibody to target cancer-associated fibroblasts (CAFs) and an immune-enhancer module (CXCL9/CXCL10/IFNα2) to recruit and activate immune cells. In an ongoing study (NCT04053283), NG-641 monotherapy has been successfully dose-escalated to 1 × 1012 viral particles (vp) on Day 1 and 3 × 1012 vp on Days 3 and 5; initial results from this study have shown a manageable tolerability profile and elevations in serum cytokines indicative of T-cell activation. Based on these promising initial data with NG-641 monotherapy, we designed a new study to assess NG-641 + nivolumab.

Methods: NEBULA (NCT05043714) is an open-label, dose-escalating, phase 1a/b study of NG-641 + nivolumab. Eligible patients (pts) have advanced/metastatic epithelial tumors that have progressed after ≥1 line of systemic therapy and are incurable by local therapy. Pts eligible for phase 1a must have received prior PD-1/PD-L1 inhibition as part of any line of therapy; pts eligible for phase 1b must have primary resistance to PD-1/PD-L1 inhibition. During phase 1a, up to 30 pts will receive escalating doses of IV NG-641 (Bayesian Optimal Interval design) to a maximum dose of 1 × 1012 viral particles (vp) on Day 1 and 1 × 1013 vp on Days 3 and 5 (1 cycle). Pts will receive a fixed-dose of nivolumab (480 mg IV) on Day 15 and then every 4 weeks thereafter for up to 8 cycles. Phase 1b will further investigate the selected dose regimen in up to 3 tumor-specific cohorts (Cohorts A, B and C) using a Simon 2-stage design. Co-primary objectives are to characterize the safety and tolerability of NG-641 + nivolumab and to identify a recommended dose. Preliminary efficacy and immunogenicity are secondary endpoints. Pharmacodynamic outcomes will be assessed using tumor tissues and blood. Analyses of tumor tissue (serial biopsies at baseline and Day 15 of cycles 1-3 [cycles 1-2 only in Phase 1b]) will explore virus replication, transgene expression, immune/inflammatory responses and effects on CAFs by immunohistochemistry and gene expression analysis. Analyses of serial blood samples will explore cytokine production and changes in peripheral immune cell subsets. Enrollment to the first dose-escalation cohort is ongoing.

Citation Format: Tom Lillie, Eileen Parkes, Christian Ottensmeier, David Krige, Behnaz Ravanfar, Vladimir Evilevitch, Matthew Thomas, Lee Rosen. A multicenter phase 1a/b study of NG-641, a tumor-selective transgene-expressing adenoviral vector, and nivolumab in patients with metastatic or advanced epithelial tumors (NEBULA) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT214.

NEBULA: A multicenter phase 1a/b study of a tumor-selective transgene-expressing adenoviral vector, NG-641, and nivolumab in patients with metastatic or advanced epithelial tumors

TPS2682

Background: Tumor-Specific Immuno Gene Therapy (T-SIGn) vectors are next-generation transgene-armed variants of the adenoviral vector enadenotucirev that selectively replicate in epithelial tumor cells. T-SIGn vectors are blood-stable, allowing IV delivery to be coupled with local transgene expression in the tumor microenvironment (TME), thereby targeting all lesions while limiting systemic exposure. The T-SIGn vector NG-641 encodes four immunostimulatory transgenes: fibroblast activation protein-directed bi-specific T-cell activator antibody to target cancer-associated fibroblasts (CAFs), IFNα2 to promote innate and adaptive immune responses, and CXCL9/10 to induce T-cell infiltration. Through this novel multimodal combination of immunostimulatory effects NG-641 is designed to re-program the TME to allow functional anti-cancer immune responses. In the ongoing STAR study (NCT04053283), NG-641 has been successfully dose-escalated to 1 × 1012 viral particles (vp) on Day 1 and 3 × 1012 vp on Days 3 and 5, with promising preliminary safety/tolerability and pharmacodynamic results. Based on these encouraging preliminary data with NG-641 monotherapy, we designed a new study to assess NG-641 + nivolumab. Methods: NEBULA (NCT05043714) is an open-label, dose-escalating, phase 1a/b study of NG-641 + nivolumab in patients (pts) with advanced/metastatic epithelial tumors that have progressed after ≥1 line of systemic therapy and are incurable by local therapy. Pts are eligible for phase 1a if they have received prior PD-1/PD-L1 inhibition as part of any line of therapy. During phase 1a, up to 30 pts will receive escalating doses of IV NG-641 to a maximum dose of 1 × 1012 viral particles (vp) on Day 1 and 1 × 1013 vp on Days 3 and 5 (1 cycle; Bayesian Optimal Interval design). Pts will receive a fixed-dose of nivolumab (480 mg IV) on Day 15 and then every 4 weeks thereafter for up to 8 cycles. In phase 1b, the recommended dose regimen will be further studied in patients with primary resistance to PD-1/PD-L1 inhibition; patients will be enrolled in up to 3 tumor-specific cohorts (Cohorts A-C; Simon 2-stage design). Co-primary objectives are to characterize the safety and tolerability of NG-641 + nivolumab and to identify a recommended dose. Preliminary efficacy and immunogenicity are secondary endpoints. Pharmacodynamic outcomes will also be assessed. Viral replication, transgene expression, immune/inflammatory responses and effects on CAFs by IHC and gene expression analysis will be analyzed using tumor tissue from serial biopsies (taken at baseline and Day 15 of cycles 1-3 [cycles 1-2 only in Phase 1b]). Serial blood samples will be analyzed to study cytokine production and changes in peripheral immune cell subsets. Enrollment to the first dose-escalation cohort is ongoing. Clinical trial information: NCT05043714.

FORTITUDE: Results of a phase 1a study of the novel transgene-armed and tumor-selective vector NG-350A with and without pembrolizumab (pembro)

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Background: Stimulating CD40 may support anti-cancer immune responses; however, on-target toxicity limits systemic dosing. NG-350A is a tumor-selective and blood stable adenoviral T-SIGn vector expressing a potent fully human IgG agonistic anti-CD40 antibody (mAb). NG-350A was designed to selectively deliver anti-CD40 to multiple tumor sites via IV delivery, driving immunological tumor re-engineering while avoiding systemic toxicity. We report results from a first-in-human trial after completion of enrollment. Methods: FORTITUDE (NCT03852511) is a phase 1 study of NG-350A ± pembro in patients (pts) with metastatic/advanced epithelial tumors. NG-350A monotherapy (mTx) was dose-escalated in separate intratumoral (IT; increasing numbers of doses) or IV (one cycle; three increasing dose levels) cohorts. IV NG-350A + pembro (200 mg Q3W for ≤8 cycles) was then assessed. Results: As of Jan 2022, 28 heavily pre-treated pts had received NG-350A, either as IT mTx (n=9; two dose levels), IV mTx (n=16; IV dose levels 1, 3 & 4) or IV + pembro (n=3; IV dose level 2). The MTD of NG-350A ± pembro was not reached, with no DLTs at the highest IT and IV dose levels. The safety profile of NG-350A was consistent with acute reactions to viral particles and asymptomatic aPTT prolongations (Table). No systemic CD40 transgene protein was detected at any dose level and the only SAE to occur in >1 pt was pneumonia. No objective responses were observed; however, 3/6 patients treated with NG-350A mTx at IV dose level 4 achieved stable disease (dose not yet tested with pembro). Dose-dependent specific increases in serum IL-12, IFNγ and IL-17a were detected in pts treated with IV NG-350A mTx from ̃Wk 2. Increases were sustained at ≥5x baseline levels 7 wks after dosing in the majority of evaluable pts treated at higher IV dose levels. These responses did not occur with IT dosing (or in prior studies with an unarmed vector); further follow-up is ongoing for NG-350A + pembro. IV NG-350A also led to the expansion of T cell clones in blood; most of these were newly detected. Conclusions: NG-350A ± pembro was well-tolerated, with no evidence of CD40-related toxicity. NG-350A IV mTx led to specific and sustained cytokine responses consistent with the MoA of the encoded anti-CD40 Ab. Peak cytokine elevations were typically higher than reported with systemic anti-CD40 Abs, suggesting NG-350A can drive local immunological tumor changes while avoiding systemic toxicity. A further trial (FORTIFY, NCT05165433) will continue dose-escalation of NG-350A + pembro to identify a dose level for efficacy assessments. Clinical trial information: NCT03852511. [Table: see text]

Safety and tolerability of T-SIGn vectors when administered using “flat” versus “low-high-high” (LHH) dosing regimens

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Background: Tumor-selective viruses, particularly those dosed systemically to deliver transgenes, are potentially powerful cancer therapies. However, acute cytokine reactions to viral particle (vp) infusion may affect vector tolerability [Small 2006], thereby limiting the maximum tolerated dose (MTD) and subsequent transgene delivery. T-SIGn vectors (e.g. NG-641 and NG-350A) are transgene-armed variants of the epithelial tumor-selective adenovirus enadenotucirev (EnAd). Acute serum cytokine increases post-dosing have been seen at the MTD of EnAd (“flat” dosing of 3 x 1012 vp on Days [D] 1, 3 and 5) [Machiels 2019]. Following supportive preclinical data [McElwaine-Johnn 2019], we explored if a LHH dosing regimen, in which a lower dose is given on D1 prior to two higher doses on D3 and 5, may improve vector safety/tolerability thereby allowing higher cumulative doses to be given. Methods: Data were pooled from three Phase 1 dose-escalation studies in advanced/metastatic epithelial cancer: SPICE (EnAd + pembrolizumab/nivolumab; NCT02636036), FORTITUDE (NG-350A ± pembrolizumab; NCT03852511) and STAR (NG-641; NCT04053283). Serum cytokines were measured using a 17-analyte Luminex assay. IL-6/MCP-1 data for D1, 3 and 5 (pre- and 6-10 hrs post-dose) were analyzed to examine acute cytokine changes. TNFα/IFNγ were examined due to their association with cytokine release syndrome (CRS). Samples analyzed from SPICE/FORTITUDE were taken before PD-1 inhibitor administration. Results: 84 patients (SPICE n=51; FORTITUDE n=18; STAR n=15) were included in these analyses; 79 had cytokine data. AEs and Gr≥3 AEs within 1 wk of first dose, and DLTs at any time, were less frequent with a LHH vs flat dosing regimen (Tbl). Importantly, a LHH dose of 1-6-6 (1 x 1012 vp on D1; 6 x 1012 vp on D3 and 5; greater than the previous flat MTD) was tolerated. Acute increases in TNFα/IFNγ were limited and no severe CRS was seen. Increases in IL-6/MCP-1 with 1 x 1011 or 1 x 1012 vp flat dosing were negligible, whereas acute increases in IL-6/MCP-1 were seen after the first dose of 3 x 1012 vp when given as a flat dose (negligible increases on D3/5). Notably, cytokine responses with 1-3-3 dosing (1 x 1012 vp on D1; 3 x 1012 vp on D3 and 5), including after the first 3 x 1012 vp dose on D3, were negligible. Cytokine responses after the first dose of 6 x 1012 vp in the 1-6-6 regimen were similar to those seen with the first dose of the flat 3 x 1012 vp regimen. Conclusions: LHH dosing appears to induce a desensitization mechanism allowing higher cumulative doses of T-SIGn vectors to be given without the associated acute reactions to viral infusions. This finding may have implications for optimizing safety-efficacy profiles of viral vectors in cancer. Clinical trial information: NCT02636036, NCT03852511 and NCT04053283. [Table: see text]

Management Strategies for Flu-Like Symptoms and Injection-Site Reactions Associated with Peginterferon Beta-1a: Obtaining Recommendations Using the Delphi Technique

BACKGROUND

Flu-like symptoms (FLSs) and injection-site reactions (ISRs) have been reported with interferon beta treatments for multiple sclerosis (MS). We sought to obtain consensus on the characteristics/management of FLSs/ISRs in patients with relapsing-remitting MS based on experiences from the randomized, placebo-controlled ADVANCE study of peginterferon beta-1a.

METHODS

ADVANCE investigators with a predefined number of enrolled patients were eligible to participate in a consensus-generating exercise using a modified Delphi method. An independent steering committee oversaw the development of two sequential Delphi questionnaires. An average rating (AR) of 2.7 or more was defined as consensus a priori.

RESULTS

Thirty and 29 investigators (ie, responders) completed questionnaires 1 and 2, respectively, representing 374 patients from ADVANCE. Responders reported that the incidence/duration of FLSs/ISRs in their typical patient generally declined after 3 months of treatment. Responders reached consensus that FLSs typically last up to 24 hours (AR = 3.17) and have mild/moderate effects on activities of daily living (AR = 3.34). Patients should initiate acetaminophen/nonsteroidal anti-inflammatory drug treatment on a scheduled basis (AR = 3.31) and change the timing of injection (AR = 3.28) to manage FLSs. Injection-site rotation/cooling and drug administration at room temperature (all AR ≥ 3.10) were recommended for managing ISRs. Patient education on FLSs/ISRs was advocated before treatment initiation.

CONCLUSIONS

Delphi responders agreed on the management strategies for FLSs/ISRs and agreed that patient education is critical to set treatment expectations and promote adherence.

FDG-PET/CT imaging predicts histopathologic treatment responses after the initial cycle of neoadjuvant chemotherapy in high-grade soft-tissue sarcomas

PURPOSE

In patients with soft-tissue sarcoma (STS), the early assessment of treatment responses is important. Using positron emission tomography/computed tomography (PET/CT) with [(18)F]fluorodeoxyglucose (FDG), we determined whether changes in tumor FDG uptake predict histopathologic treatment responses in high-grade STS after the initial cycle of neoadjuvant chemotherapy.

EXPERIMENTAL DESIGN

From February 2006 to March 2008, 50 patients with resectable high-grade STS scheduled for neoadjuvant therapy and subsequent tumor resection were enrolled prospectively. FDG-PET/CT before (baseline), after the first cycle (early follow-up), and after completion of neoadjuvant therapy (late follow-up) was done. Tumor FDG uptake and changes were measured by standardized uptake values. Histopathologic examination of the resected specimen provided an assessment of treatment response. Patients with > or = 95% pathologic necrosis were classified as treatment responders. FDG-PET/CT results were compared with histopathologic findings.

RESULTS

At early follow-up, FDG uptake decreased significantly more in 8 (16%) responders than in the 42 (84%) nonresponders (-55% versus -23%; P = 0.002). All responders and 14 of 42 nonresponders had a > or = 35% reduction in standardized uptake value between baseline and early follow-up. Using a > or = 35% reduction in FDG uptake as early metabolic response threshold resulted in a sensitivity and specificity of FDG-PET for histopathologic response of 100% and 67%, respectively. Applying a higher threshold at late follow-up improved specificity but not sensitivity. CT had no value at response prediction.

CONCLUSION

A 35% reduction in tumor FDG uptake at early follow-up is a sensitive predictor of histopathologic tumor response. Early treatment decisions such as discontinuation of chemotherapy in nonresponding patients could be based on FDG-PET criteria.

Reduction of glucose metabolic activity is more accurate than change in size at predicting histopathologic response to neoadjuvant therapy in high-grade soft-tissue sarcomas

PURPOSE

Change in tumor size as classified by Response Evaluation Criteria in Solid Tumors poorly correlates with histopathologic response to neoadjuvant therapy in patients with soft-tissue sarcomas. The aim of this study was to prospectively evaluate whether positron emission tomography with (18)F-fluorodeoxyglucose (FDG-PET) allows for a more accurate evaluation of histopathologic response.

EXPERIMENTAL DESIGN

From January 2005 to January 2007, 42 patients with resectable biopsy-proven high-grade soft-tissue sarcoma underwent a FDG-PET/computed tomography scan before and after neoadjuvant treatment. Relative changes in tumor FDG uptake and size from the baseline to the follow-up scan were calculated, and their accuracy for assessment of histopathologic response was compared by receiver operating characteristic curve analysis. Histopathologic response was defined as > or =95% tumor necrosis.

RESULTS

In histopathologic responders (n = 8; 19%), reduction in tumor FDG uptake was significantly greater than in nonresponders (P < 0.001), whereas no significant differences were found for tumor size (P = 0.24). The area under the receiver operating characteristic curve for metabolic changes was 0.93, but only 0.60 for size changes (P = 0.004). Using a 60% decrease in tumor FDG uptake as a threshold resulted in a sensitivity of 100% and a specificity of 71% for assessment of histopathologic response, whereas Response Evaluation Criteria in Solid Tumors showed a sensitivity of 25% and a specificity of 100%.

CONCLUSION

Quantitative FDG-PET was significantly more accurate than size-based criteria at assessing histopathologic response to neoadjuvant therapy. FDG-PET should be considered as a modality to monitor treatment response in patients with high-grade soft-tissue sarcoma.

Treatment monitoring by 18F-FDG PET/CT in patients with sarcomas: interobserver variability of quantitative parameters in treatment-induced changes in histopathologically responding and nonresponding tumors

Measurements of tumor glucose use by (18)F-FDG PET need to be standardized within and across institutions. Various parameters are used for measuring changes in tumor glucose metabolic activity with (18)F-FDG PET in response to cancer treatments. However, it is unknown which of these provide the lowest variability between observers. Knowledge of the interobserver variability of quantitative parameters is important in sarcomas as these tumors are frequently large and demonstrate heterogeneous (18)F-FDG uptake.

METHODS

A total of 33 patients (16 men, 17 women; mean age, 47 +/- 18 y) with high-grade sarcomas underwent (18)F-FDG PET/CT scans before and after neoadjuvant chemotherapy. Two independent investigators measured the following parameters on the pretreatment and posttreatment scans: maximum standardized uptake value (SUVmax), peak SUV (SUVpeak), mean SUV (SUVmean), SUVmean in an automatically defined volume (SUVauto), and tumor-to-background ratio (TBR). The variability of the different parameters was compared by concordance correlation coefficient (CCC), variability effect coefficient, and Bland-Altman plots.

RESULTS

Baseline SUVmax, SUVpeak, SUVmean, SUVauto, and TBR averaged 10.36, 7.78, 4.13, and 6.22 g/mL and 14.67, respectively. They decreased to 5.36, 3.80, 1.79, and 3.25 g/mL and 6.62, respectively, after treatment. SUVmax, SUVpeak, and SUVauto measurements and their changes were reproducible (CCC > or = 0.98). However, SUVauto poorly differentiated between responding and nonresponding tumors. The high intratumoral heterogeneity of (18)F-FDG resulted in frequent failure of the thresholding algorithm, which necessitated manual corrections that in turn resulted in a higher interobserver variability of SUVmean (CCCs for follow-up and change were 0.96 and 0.91, respectively; P < 0.005). TBRs also showed a significantly higher variability than did SUVpeak (CCCs for follow-up and change were 0.94 and 0.86, respectively; P < 0.005).

CONCLUSION

SUVmax and SUVpeak provided the most robust measurements of tumor glucose metabolism in sarcomas. Delineation of the whole-tumor volume by semiautomatic thresholding did not decrease the variability of SUV measurements. TBRs were significantly more observer-dependent than were absolute SUVs. These findings should be considered for standardization of clinical (18)F-FDG PET/CT trials.

Change in quantitative FDG-PET was significantly more accurate than change in size at predicting histopathologic response to neoadjuvant therapy in high grade soft tissue sarcomas

10017

Background: Change in size by RECIST (Response Evaluation Criteria in Solid Tumors) has been the standard to assess response to therapy in non-GIST soft tissue sarcomas (STS). Although recent studies have demonstrated that Positron Emission Tomography with F18-fluorodeoxyglucose (FDG-PET) may be used to assess response, there has not been a direct comparison between these modalities. The aim of this study was to prospectively evaluate whether a change in quantitative FDG-PET or a change in size [computed tomography(CT)] was more accurate at predicting histopathologic response to neoadjuvant therapy in patients with high grade STS using a combined FDG-PET/CT scan. Methods: From 1/05 - 12/06 58 patients with resectable biopsy proven high grade STS scheduled to undergo neoadjuvant chemotherapy were prospectively enrolled in this study. Patients underwent FDG-PET/CT prior to and after neoadjuvant treatment (prior to surgery). Tumor FDG-uptake was quantified by standardized uptake values (SUV). Changes in tumor size were quantified according to RECIST. Following tumor resection, response was assessed histopathologically. Patients with = 10% viable tumor cells were classified as responders. To date, 36 patients have completed the study and are the subject of this analysis. Results: In histopathologic responders (n=10, 28%), reduction of tumor FDG-uptake was significantly greater (-64%) than in histopathologic non-responders (-37%), (p=0.005). Using a 50% decrease in tumor SUV as a threshold value resulted in a sensitivity of 90% and a specificity of 58% for assessment of histopathologic response (p=0.01). Response assessment per RECIST showed no significant correlation with histopathologic response (sensitivity 20%, specificity 89%, p=0.4). There was no correlation between changes in tumor size and histopathologic response (area under the ROC curve = 0.6, p=0.1). Conclusions: In patients with high grade STS, quantitative FDG-PET was significantly more accurate than size based criteria for assessment of histopathologic response to neoadjuvant therapy. FDG-PET should be considered as a modality to monitor treatment response is patients with high grade STS.

No significant financial relationships to disclose.

Modulation of the inflammatory response to histamine by terbutaline and sodium nitroprusside in guinea-pig skin

We measured the microvascular response (vasodilatation and plasma exudation) to skin prick provocations with histamine, terbutaline, sodium nitroprusside (SNP) and the combinations of terbutaline and histamine as well as SNP and histamine in guinea-pig skin. The response was measured by external detection of beta radiation from transferrin labelled with (113m)In. Histamine induced a moderate microvascular response. Terbutaline alone induced a smaller response, probably reflecting vasodilatation. When added to histamine, terbutaline significantly reduced the microvascular response to histamine. The response to histamine, SNP and the combination of histamine and SNP were all similar. We conclude that the anti-inflammatory effect of terbutaline can be readily measured with this technique. We found no indication of a pro-inflammatory effect of SNP when combined with histamine. Rather, the lack of additive effect may suggest an anti-inflammatory effect of SNP on the response to histamine.

Vascular effects of anandamide and N-acylvanillylamines in the human forearm and skin microcirculation

The endocannabinoid anandamide is an emerging potential signalling molecule in the cardiovascular system. Anandamide causes vasodilatation, bradycardia and hypotension in animals and has been implicated in the pathophysiology of endotoxic, haemorrhagic and cardiogenic shock, but its vascular effects have not been studied in man. Human forearm blood flow and skin microcirculatory flow were recorded using venous occlusion plethysmography and laser-Doppler perfusion imaging (LDPI), respectively. Each test drug was infused into the brachial artery or applied topically on the skin followed by a standardized pin-prick to disrupt the epidermal barrier. Anandamide failed to affect forearm blood flow when administered intra-arterially at infusion rates of 0.3-300 nmol min(-1). The highest infusion rate led to an anandamide concentration of approximately 1 microM in venous blood as measured by mass spectrometry. Dermal application of anandamide significantly increased skin microcirculatory flow and coapplication of the transient receptor potential vanilloid 1 (TRPV1) antagonist capsazepine inhibited this effect. The TRPV1 agonists capsaicin, olvanil and arvanil all induced concentration-dependent increases in skin blood flow and burning pain when administered dermally. Coapplication of capsazepine inhibited blood flow and pain responses to all three TRPV1 agonists. This study shows that locally applied anandamide is a vasodilator in the human skin microcirculation. The results are consistent with this lipid being an activator of TRPV1 on primary sensory nerves, but do not support a role for anandamide as a circulating vasoactive hormone in the human forearm vascular bed.

Microvascular response in guinea pig skin to histamine challenge with and without application of skin window

We measured the microvascular response to histamine in guinea pig skin. Histamine (40 mg ml(-1)) was given either as a skin prick test or applied topically onto a skin window. The skin window was prepared by applying suction and gentle warming to the skin so that a blister was formed, and by removing the top of the blister. The microvascular response was measured as the accumulation of radiolabelled transferrin in the skin in vivo, reflecting a combination plasma exudation and vasodilatation. In the control (saline) challenge, the response was slightly greater in the skin window than after skin prick challenge and the scatter was larger. Histamine challenge resulted in a significant microvascular response with respect to the control situation when measured immediately after provocation for both challenge techniques. Ten minutes after challenge, a smaller response was measured, which was still significantly greater than control for the skin prick challenge, but not for topical provocation using the skin window technique. We conclude that the microvascular response to histamine after provocation with the skin prick technique is similar to that after topical provocation using the skin window technique. The skin window technique may have a lower sensitivity than the skin prick technique owing to a higher scatter in the control situation. This difference should be considered when performing and interpreting studies of the microvascular reaction in the skin.

Time course of the inflammatory response to histamine and allergen skin prick test in guinea-pigs

Plasma exudation and vasodilatation are key microvascular features of acute inflammation. Exudation and vasodilatation responses in the weal area after skin prick testing with histamine are essentially completed within 30 min. There is evidence to suggest that vasodilatation lasts considerably longer after provocation with allergen, but there is no information on the duration of plasma exudation. The purpose of this study was to measure the time course of the microvascular inflammatory response in the skin after histamine and allergen provocation. Skin prick tests were performed with histamine, allergen (ovalbumin) or saline (control) on guinea-pigs which were shaved on their backs. Radioactive 113mIn was used to label transferrin as a plasma tracer. Radioactivity was recorded from the superficial part of the skin by external detection of conversion electrons from the decay of 113mIn. The increase in count rate, corresponding to tracer accumulation by vasodilatation and/or plasma exudation, was used as a measure of the microvascular inflammatory response to skin prick test. The microvascular response was studied immediately and up to 30 min after provocation. The largest response to histamine and allergen occurred immediately after provocation. The exudative response then gradually declined to be absent after 25-30 min. Skin prick test with saline resulted in a small response of shorter duration. We conclude that the microvascular reaction to histamine as well as allergen provocation in guinea-pig skin has a rapid onset and a duration of approximately 30 min.