Validated machine learning tools to distinguish immune checkpoint inhibitor, radiotherapy, COVID-19 and other infective pneumonitis

BACKGROUND

Pneumonitis is a well-described, potentially disabling, or fatal adverse effect associated with both immune checkpoint inhibitors (ICI) and thoracic radiotherapy. Accurate differentiation between checkpoint inhibitor pneumonitis (CIP) radiation pneumonitis (RP), and infective pneumonitis (IP) is crucial for swift, appropriate, and tailored management to achieve optimal patient outcomes. However, correct diagnosis is often challenging, owing to overlapping clinical presentations and radiological patterns.

METHODS

In this multi-centre study of 455 patients, we used machine learning with radiomic features extracted from chest CT imaging to develop and validate five models to distinguish CIP and RP from COVID-19, non-COVID-19 infective pneumonitis, and each other. Model performance was compared to that of two radiologists.

RESULTS

Models to distinguish RP from COVID-19, CIP from COVID-19 and CIP from non-COVID-19 IP out-performed radiologists (test set AUCs of 0.92 vs 0.8 and 0.8; 0.68 vs 0.43 and 0.4; 0.71 vs 0.55 and 0.63 respectively). Models to distinguish RP from non-COVID-19 IP and CIP from RP were not superior to radiologists but demonstrated modest performance, with test set AUCs of 0.81 and 0.8 respectively. The CIP vs RP model performed less well on patients with prior exposure to both ICI and radiotherapy (AUC 0.54), though the radiologists also had difficulty distinguishing this test cohort (AUC values 0.6 and 0.6).

CONCLUSION

Our results demonstrate the potential utility of such tools as a second or concurrent reader to support oncologists, radiologists, and chest physicians in cases of diagnostic uncertainty. Further research is required for patients with exposure to both ICI and thoracic radiotherapy.

Computed tomography-based radiomic markers are independent prognosticators of survival in advanced laryngeal cancer: a pilot study

OBJECTIVE

Advanced laryngeal cancers are clinically complex; there is a paucity of modern decision-making models to guide tumour-specific management. This pilot study aims to identify computed tomography-based radiomic features that may predict survival and enhance prognostication.

METHODS

Pre-biopsy, contrast-enhanced computed tomography scans were assembled from a retrospective cohort (n = 72) with advanced laryngeal cancers (T3 and T4). The LIFEx software was used for radiomic feature extraction. Two features: shape compacity (irregularity of tumour volume) and grey-level zone length matrix - grey-level non-uniformity (tumour heterogeneity) were selected via least absolute shrinkage and selection operator-based Cox regression and explored for prognostic potential.

RESULTS

A greater shape compacity (hazard ratio 2.89) and grey-level zone length matrix - grey-level non-uniformity (hazard ratio 1.64) were significantly associated with worse 5-year disease-specific survival (p < 0.05). Cox regression models yielded a superior C-index when incorporating radiomic features (0.759) versus clinicopathological variables alone (0.655).

CONCLUSIONS

Two radiomic features were identified as independent prognostic biomarkers. A multi-centre prospective study is necessary for further exploration. Integrated radiomic models may refine the treatment of advanced laryngeal cancers.

Study protocol of LANTana: a phase Ib study to investigate epigenetic modification of somatostatin receptor-2 with ASTX727 to improve therapeutic outcome with [177Lu]Lu-DOTA-TATE in patients with metastatic neuroendocrine tumours, UK

INTRODUCTION

Suitability for peptide receptor radionuclide therapy (PRRT) for neuroendocrine neoplasia (NENs) depends on presence of somatostatin receptor-2 (SSTR2) determined by [68Ga]Ga-DOTA-peptide-positron emission tomography (PET). Some patients have low or no uptake on [68Ga]Ga-DOTA-peptide-PET, precluding PRRT. The upstream promoter region of SSRT2 is methylated, with percentage of methylation correlating with SSTR2 expression. Demethylating agents increase uptake on PET imaging in vivo such that tumours previously negative on PET become positive, correlating with a dose dependent increase in tumorous SSTR2 expression. LANTana will determine whether treatment with the demethylating agent, ASTX727, results in re-expression of SSTR2 using [68Ga]Ga-DOTA-peptide-PET to image epigenetic modification of the SSTR2 locus, allowing subsequent PRRT.

METHODS AND ANALYSIS

27 participants with a histological diagnosis of NEN (Ki67<55%) with no or low uptake on baseline [68Ga]Ga-DOTA-TATE-PET/CT will be recruited. Patients will receive 5 days of ASTX727 (fixed dose 35 mg decitabine+100 mg cedazuridine). [68Ga]Ga-DOTA-peptide-PET/CT will be repeated day 8±2; where there is significant uptake greater than liver in most lesions, PRRT will be administered. Primary objective is to determine re-expression of SSTR2 on PET imaging. Tolerability, progression-free survival, overall response and quality of life will be assessed. Methylation in peripheral blood mononuclear cells and tumorous methylation will be evaluated.

ETHICS AND DISSEMINATION

LANTana has ethical approval from Leeds West Research Ethics Committee (REC Reference: 21/YH/0247).Sponsored by Imperial College London and funded by Advanced Accelerator Applications pharmaceuticals. Results will be presented at conferences and submitted to peer-reviewed journals for publication and will be available on ClinicalTrials.gov.

TRIAL REGISTRATION NUMBERS

EUDRACT number: 2020-003800-15, NCT05178693.

Abstract 455: Development of an antibody-drug conjugate panel targeting high grade serous ovarian cancer

Antibody drug conjugate (ADC) is a novel class of therapeutic agent which recently showed great success in both solid tumour and blood cancer. ADCs deliver potent cytotoxic payloads to tumour via cancer specific monoclonal antibodies. A few ADCs are currently evaluated in clinical trials for high grade serous ovarian cancer (HGSOC). However, most of them target FOLR1-alpha, a conventional HGSOC target which also expresses in vital organs including lungs. Thus, it is desirable to discover more specific antigen targets, and these new targets will be the foundation for the next-generation ADC for HGSOC.We propose that ovarian tumour specificity of an ADC target could contributed by three factors: 1. Lineage (e.g. fallopian tube marker FOLR1); 2. DNA amplification (e.g. ERBB2); 3. Other carcinogenesis process including epigenetic reprogramming. Then, by combining the GTEX, TCGA dataset with our own WES, long-reads RNA-sequencing and Mass spectrometry-based proteomics cohort, an array of differentially expressed genes in HGSOC tumours are identified. Out of over 50 candidates, two most promising targets are chosen for monoclonal antibodies (mAbs) production and subsequent ADC development. First, the affinity and specificity of the mAbs were confirmed by ELISA, flow cytometry and immunofluorescence. The cellular internalisation characteristics of these antibodies are confirmed by a fluorescence-based assay. Then, ADCs for these two targets are produced by conjugating monomethyl auristatin E payload to the mAbs via a cleavable linker. Finally, both ADCs show highly target-specific and sub-nanomolar cytotoxicity in model ovarian cancer cell lines. In conclusion, we identify a panel of HGSOC-specific ADC targets and develop two ADCs candidates for further pre-clinical and clinical investigations.

Citation Format: Ruisi Fu, Hantao Lou, Ning Wang, Dongnan Yan, Clara Tresserras-Segura, Haonan Lu, Eric Aboagye. Development of an antibody-drug conjugate panel targeting high grade serous ovarian cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 455.

Development of machine learning support for reading whole body diffusion-weighted MRI (WB-MRI) in myeloma for the detection and quantification of the extent of disease before and after treatment (MALIMAR): protocol for a cross-sectional diagnostic test accuracy study

INTRODUCTION

Whole-body MRI (WB-MRI) is recommended by the National Institute of Clinical Excellence as the first-line imaging tool for diagnosis of multiple myeloma. Reporting WB-MRI scans requires expertise to interpret and can be challenging for radiologists who need to meet rapid turn-around requirements. Automated computational tools based on machine learning (ML) could assist the radiologist in terms of sensitivity and reading speed and would facilitate improved accuracy, productivity and cost-effectiveness. The MALIMAR study aims to develop and validate a ML algorithm to increase the diagnostic accuracy and reading speed of radiological interpretation of WB-MRI compared with standard methods.

METHODS AND ANALYSIS

This phase II/III imaging trial will perform retrospective analysis of previously obtained clinical radiology MRI scans and scans from healthy volunteers obtained prospectively to implement training and validation of an ML algorithm. The study will comprise three project phases using approximately 633 scans to (1) train the ML algorithm to identify active disease, (2) clinically validate the ML algorithm and (3) determine change in disease status following treatment via a quantification of burden of disease in patients with myeloma. Phase 1 will primarily train the ML algorithm to detect active myeloma against an expert assessment ('reference standard'). Phase 2 will use the ML output in the setting of radiology reader study to assess the difference in sensitivity when using ML-assisted reading or human-alone reading. Phase 3 will assess the agreement between experienced readers (with and without ML) and the reference standard in scoring both overall burden of disease before and after treatment, and response.

ETHICS AND DISSEMINATION

MALIMAR has ethical approval from South Central-Oxford C Research Ethics Committee (REC Reference: 17/SC/0630). IRAS Project ID: 233501. CPMS Portfolio adoption (CPMS ID: 36766). Participants gave informed consent to participate in the study before taking part. MALIMAR is funded by National Institute for Healthcare Research Efficacy and Mechanism Evaluation funding (NIHR EME Project ID: 16/68/34). Findings will be made available through peer-reviewed publications and conference dissemination.

TRIAL REGISTRATION NUMBER

NCT03574454.

Abstract 5398: Apelinergic signalling in hepatocellular carcinoma (HCC): A new therapeutic treatment option

HCC is the third most frequent cancer-related death worldwide and incidence continues to rise. Most patients presenting with advanced stage disease where their treatment goal is palliation, emphasizing the requirement for new treatment options. HCC is characterized by arterialization of its blood supply deemed pathognomonic for its development. We investigated the neoangiogenic peptide apelin as a driver of carcinogenesis in HCC followed by the efficacy of novel apelin antagonists as a therapeutic strategy in-vitro. Firstly, meta-analysis conducted through the TCGA database showed that apelin is significantly upregulated in liver cancer compared to healthy tissue and this correlated with a worse mean overall survival. Additionally, enzyme-linked immunosorbent assay (ELISA) of patient serum samples corroborated that apelin concentration significantly increases from healthy liver to cirrhosis and then further through tumorigenesis. In-vitro studies across multiple hepatocyte cell lines in media conditioned with elevated serum apelin levels were then performed to investigate the effects of increased apelin. All cell-lines demonstrated an increase in migration and proliferative properties with naturally higher basal apelin expressing cell lines showing the most significant changes. Using knockdown models, we elucidated hypoxia a well-known driver of angiogenesis, up-regulates apelin expression through a HIF-1α dependent mechanism. Furthermore, increased apelin expression resulted in upregulation of its G-protein coupled receptor, APJ which initiates its downstream signaling pathways, together referred to as apelinergic signaling, demonstrating an autocrine loop. Co-culture of hepatocytes with hepatic stellate cells (HSCs), activated in cirrhosis, further elucidated a paracrine signaling loop whereby secreted chemokines from HSCs, which including apelin, enhanced hepatocyte proliferation and migration. Assessing apelin as a therapeutic target, several novel antagonists were designed in-silico and investigated across multiple hepatocyte cell lines. MM315 showed the most promise with significant cytostatic properties at nanomolar levels coupled with a high binding affinity to APJ at picomolar levels demonstrated through blocking studies. As HCC is a highly vascularized cancer, we explored the likely effects of these antagonists on endothelial cells, cultured in the presence of IC50 concentrations of each antagonist. MM315 treatment resulted in a significant reduction of abnormal blood vessel formation. Overall, our results suggest inhibiting apelinergic signaling is a promising therapeutic treatment for HCC, with MM315 being a lead compound. In-vivo work which will be presented.

Citation Format: Jamie Beaumont, Eric Aboagye, Beata Wojciak-Stothard, Gilberto Serrano-De-Almeida, Robert Glen, Rohini Sharma. Apelinergic signalling in hepatocellular carcinoma (HCC): A new therapeutic treatment option [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 5398.

195 The Application of Radiomics in Laryngeal Cancer: The Forgotten Cohort

Background

Radiomics is a novel method of extracting data from medical images that is difficult to visualise through the naked eye. This technique transforms digital images that hold information on pathology into high-dimensional-data for analysis. Radiomics has the potential to enhance laryngeal cancer care and to date, has shown promise in various other specialties.

Aim

The aim of this review is to summarise the applications of this technique to laryngeal cancer and potential future benefits.

Method

A comprehensive systematic review-informed search of the MEDLINE and EMBASE online databases was undertaken. Keywords ‘laryngeal cancer’ OR ‘larynx’ OR ‘larynx cancer’ OR ‘head and neck cancer’ were combined with ‘radiomic’ OR ‘signature’ OR ‘machine learning’ OR ‘artificial intelligence’. Additional articles were obtained from bibliographies using the ‘snowball method’.

Results

Seventeen articles were identified that evaluated the role of radiomics in laryngeal cancer. Two studies affirmed the value of radiomics in improving the accuracy of staging, whilst fifteen studies highlighted the potential prognostic value of radiomics in laryngeal cancer. Twelve (of thirteen) studies incorporated an array of different head and neck cancers in the analysis and only one study assessed laryngeal cancer exclusively.

Conclusions

Literature to date has various limitations including, small and heterogeneous cohorts incorporating patients with head and neck cancers of distinct anatomical subsites and stages. The lack of uniform data on solely laryngeal cancer and radiomics means drawing conclusions is difficult, although these studies have affirmed its value. Further large prospective studies exclusively in laryngeal cancer are required to unlock its true potential.

The application of radiomics in laryngeal cancer

OBJECTIVES

Radiomics is the conversion of medical images into quantitative high-dimensional data. Laryngeal cancer, one of the most common head and neck cancers, has risen globally by 58.7%. CT, MRI and PET are acquired during the diagnostic process providing potential data for radiomic analysis and correlation with outcomes.This review aims to examine the applications of this technique to laryngeal cancer and the future considerations for translation into clinical practice.

METHODS

A comprehensive systematic review-informed search of the MEDLINE and EMBASE databases was undertaken. Keywords "laryngeal cancer" OR "larynx" OR "larynx cancer" OR "head and neck cancer" were combined with "radiomic" OR "signature" OR "machine learning" OR "artificial intelligence". Additional articles were obtained from bibliographies using the "snowball method".

RESULTS

The included studies (n = 15) demonstrated that radiomic features are significantly associated with various clinical outcomes (including stage, overall survival, treatment response, progression-free survival) and that predictive models incorporating radiomic features are superior to those that do not. Two studies demonstrated radiomics could improve laryngeal cancer staging whilst 12 studies affirmed its predictive capability for clinical outcomes.

CONCLUSIONS

Radiomics has potential for improving multiple aspects of laryngeal cancer care; however, the heterogeneous cohorts and lack of data on laryngeal cancer exclusively inhibits firm conclusions. Large prospective well-designed studies in laryngeal cancer are required to progress this field. Furthermore, to implement radiomics into clinical practice, a unified research effort is required to standardise radiomics practice.

ADVANCES IN KNOWLEDGE

This review has highlighted the value of radiomics in enhancing laryngeal cancer care (including staging, prognosis and predicting treatment response).

Radiological assessment of Peritoneal Cancer Index on preoperative CT in ovarian cancer is related to surgical outcome and survival

PURPOSE

To evaluate whether Peritoneal Cancer Index (PCI) assessed on preoperative CT (CT-PCI) can be used as non-invasive preoperative tool to predict surgical outcome, disease-free survival (DFS) and overall survival (OS).

MATERIALS AND METHODS

This is a retrospective, observational cohort study performed in a single institution. We considered all patients with diagnosis of ovarian cancer and preoperative CT, who had undergone upfront cytoreductive surgery between 2008 and 2010 and had post-operative clinical follow-up to December 2015. Two radiologists reviewed CT scans and assessed CT-PCI using Sugarbaker's diagram. We assessed the discriminatory capacity of the CT-PCI score on the surgical outcome by ROC curve analysis. DFS and OS were assessed by Kaplan-Meier nonparametric curves and by multivariable Cox-regression analysis.

RESULTS

A total of 297 patients were included in the present analysis. CT-PCI was positively correlated with post-operative residual disease [odds ratio (OR) 1.04, 95% CI 1.01-1.07, p = 0.003]. ROC curve analysis returned AUC = 0.64 for the prediction of total macroscopic tumour clearance. In multivariable analysis, patients with no peritoneal disease seen on CT had a significantly longer DFS [Hazard ratio (HR) 2.28, p = 0.007]. Radiological serosal small bowel involvement was an independent predictor for shorter OS (HR 3.01, p = 0.002).

CONCLUSION

Radiological PCI assessed on preoperative CT is associated with the probability of residual disease after cytoreductive surgery; however, it has low performance as a triage test to reliably identify patients who are likely to have complete cytoreductive surgery. CT-PCI is positively correlated with both DFS and OS and may be used as an independent prognostic factor, for example in patients with high FIGO stages.

Reliability of DCE MRI data in primary brain tumours: a comparison of Tofts and Shutter Speed Models

The accuracy of quantitative measurements of perfusion parameters by DCE-MRI is crucial as it can significantly impact the clinical care of cancer patients. In this study, we provide a method to identify reliable DCE-MRI brain data for perfusion quantification with different pharmacokinetic models.

We analysed DCE-MRI data of 14 patients with primary brain tumours using the Tofts model (TM), the extended-Tofts model (ETM), the shutter speed model (SSM) and the extended shutter speed model (ESSM). Due to the presence of the blood brain barrier, which can block the leakage of the CA into the interstitium, we also implemented the no-exchange model (NEM). For each lesion, we produced a 3D model selection map with the evaluation of the Akaike Information Criteria. The variability of each pharmacokinetic parameter extracted from the fitting of the model of choice was assessed with a noise propagation procedure, resulting in distributions of the coefficient of variation (CV).

Results showed the NEM to be the most frequent model of choice (35.5%), followed by the ETM (32%), the TM (28.2%), the SSM (4.3%) and the ESSM (<0.1%). In analysing the reliability of Ktrans, when considering regions with a CV<20%, ≈25% of voxels were found to be stable. The remaining 75% of voxels were considered to be unreliable.

In conclusion, an appropriate model selection, considering tissue biology and its effects on BBB permeability and exchange conditions, together with an analysis on the reliability and stability of the calculated parameters, is critical in the identification of reliable brain DCE-MRI data.

Concurrent occurrence of a wandering spleen, organoaxial gastric volvulus, pancreatic volvulus, and cholestasis - A rare cause of an acute abdomen

The concurrence of wandering spleen, organoaxial gastric volvulus, and pancreatic volvulus is very rare. They have been associated with symptoms such as severe abdominal pain, abdominal distention, and vomiting. However, the diagnosis remains complicated and any delay can result in ischemia and necrosis of the organs involved. In this case presentation, we present a unique case involving a 14-year-old girl who presented initially with acute abdominal pain. Assessment with enhanced computed tomography scan led to the diagnosis of wandering spleen, organoaxial gastric volvulus, and pancreatic volvulus, in addition to cholestasis, making it the first study to report on the simultaneous occurrence of this triad and cholestasis.

[18F] Fluciclatide PET as a biomarker of clinical response to combination therapy of pazopanib and paclitaxel in patients with platinum-resistant or platinum-refractory advanced ovarian cancer: Results of a phase Ib study

3070

Background: Angiogenesis has been shown to be a driver of platinum resistance in ovarian cancer. We assessed the effect of combination pazopanib and paclitaxel followed by maintenance pazopanib in patients with platinum resistant/refractory ovarian cancer. Integrins αvβ3 and αvβ5 are both up-regulated in tumour-associated vasculature. [18F]Fluciclatide is a novel PET tracer that has high affinity for integrins αvβ3/5, and was used to assess the anti-angiogenic effect of pazopanib. Methods: We conducted an open-label, phase Ib study in patients with platinum resistant/refractory ovarian cancer. Patients received 1 week of single agent pazopanib (800mg daily) followed by combination therapy with weekly paclitaxel 80mg/m2. Following completion of 18 weeks of therapy, patients continued with single agent pazopanib until disease progression. Dynamic [18F]Fluciclatide-PET imaging was conducted at baseline and after 1 week of pazopanib. Response (RECIST 1.1), toxicities and survival outcomes were recorded. Circulating markers of angiogenesis were assessed with therapy. Results: Fourteen patients were included in the intention-to-treat analysis. Complete and partial response was seen in 7 patients (54%). Median progression free survival (PFS) was 7.97 months, and overall survival (OS) was 18.5 months. A reduction in [18F]fluciclatide uptake was observed following 1 week of pazopanib, and the reduction in uptake was predictive of long PFS. Elevated baseline circulating angiopoietin and FGF were predictive of greater reduction in SUV60,mean following pazopanib. Kinetic modelling indicated a reduction in K1 and Ki following pazopanib indicating reduced radiotracer delivery and retention. Conclusions: Combination therapy followed by maintenance pazopanib is effective and tolerable in patients with platinum resistant/refractory ovarian cancer. We have shown that [18F]fluciclatide-PET uptake parameters alter with pazopanib therapy indicating an anti-angiogenic response. Clinical trial information: NCT01608009.

Depicting Changes in Tumor Biology in Response to Cetuximab Monotherapy or Combination Therapy by Apoptosis and Proliferation Imaging Using 18F-ICMT-11 and 18F-FLT PET

Imaging biomarkers must demonstrate their value in monitoring treatment. Two PET tracers, the caspase-3/7-specific isatin-5-sulfonamide 18F-ICMT-11 (18F-(S)-1-((1-(2-fluoroethyl)-1H-[1,2,3]-triazol-4-yl)methyl)-5-(2(2,4-difluoro-phenoxymethyl)-pyrrolidine-1-sulfonyl)isatin) and 18F-FLT (3'-deoxy-3'-18F-fluorothymidine), were used to detect early treatment-induced changes in tumor biology and determine whether any of these changes indicate a response to cetuximab, administered as monotherapy or combination therapy with gemcitabine. Methods: In mice bearing cetuximab-sensitive H1975 tumors (non-small lung cancer), the effects of single or repeated doses of the antiepidermal growth factor receptor antibody cetuximab (10 mg/kg on day 1 only or on days 1 and 2) or a single dose of gemcitabine (125 mg/kg on day 2) were investigated by 18F-ICMT-11 or 18F-FLT on day 3. Imaging was also performed after 2 doses of cetuximab (days 1 and 2) in mice bearing cetuximab-insensitive HCT116 tumors (colorectal cancer). For imaging-histology comparison, tumors were evaluated for proliferation (Ki-67 and thymidine kinase 1 [TK1]), cell death (cleaved caspase-3 and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling [TUNEL]), and target engagement (epidermal growth factor receptor expression) by immunohistochemistry, immunofluorescence, and immunoblotting, respectively. Tumor and plasma were analyzed for thymidine and gemcitabine metabolites by liquid chromatography-mass spectrometry. Results: Retention of both tracers was sensitive to cetuximab in H1975 tumors. 18F-ICMT-11 uptake and ex vivo cleaved caspase-3 staining notably increased in tumors treated with repeated doses of cetuximab (75%) and combination treatment (46%). Although a single dose of cetuximab was insufficient to induce apoptosis, it did affect proliferation. Significant reductions in tumor 18F-FLT uptake (44%-50%; P < 0.001) induced by cetuximab monotherapy and combination therapy were paralleled by a clear decrease in proliferation (Ki-67 decrease, 72%-95%; P < 0.0001), followed by a marked tumor growth delay. TK1 expression and tumor thymidine concentrations were profoundly reduced. Neither imaging tracer depicted the gemcitabine-induced tumor changes. However, cleaved caspase-3 and Ki-67 staining did not significantly differ after gemcitabine treatment whereas TK1 expression and thymidine concentrations increased. No cetuximab-induced modulation of the imaging tracers or other response markers was detected in the insensitive model of HCT116. Conclusion:18F-ICMT-11 and 18F-FLT are valuable tools to assess cetuximab sensitivity depicting distinct and time-variant aspects of treatment response.

Targeting autophagy sensitises lung cancer cells to Src family kinase inhibitors

Lung cancer is the main cancer killer in both men and women, mostly due to the rapid development of drug resistant metastatic disease. Here, we evaluate the potential involvement of SRC family kinases (SFK) in lung cancer biology and assess the possible benefits of their inhibition as a therapeutic approach. We demonstrated that various SRC family members, including LYN and LCK, normally expressed solely in hematopoietic cells and neural tissues, are overexpressed and activated in a panel of SCLC and NSCLC cell lines. This was clinically relevant as LYN and FYN are also overexpressed in lung cancer clinical specimens. Moreover, LYN overexpression correlated with decreased patient survival on univariate and multivariate analysis. Dasatinib (BMS-354825), a SRC/ABL inhibitor, effectively blocked SFK activation at nanomolar concentrations which correlated with a significant decrease in cell numbers of multiple lung cancer cell lines. This effect was matched by a decrease in DNA synthesis, but only moderate induction of apoptosis. Indeed, dasatinib as well as PP2, another SFK inhibitor, strongly induced autophagy that likely prevented apoptosis. However, inhibition of this autophagic response induced robust apoptosis and sensitised lung cancer cells to dasatinib in vitro and in vivo. Our results provide an explanation for why dasatinib failed in NSCLC clinical trials. Furthermore, our data suggest that combining SFK inhibitors with autophagy inhibitors could provide a novel therapeutic approach in this disease.

68Ga-DOTATATE PET/CT to predict response to peptide receptor radionuclide therapy (PRRT) in neuroendocrine tumours (NETs)

4093

Background: PRRT represents a step change in NET management, significantly improving survival. However, objective response to PRRT, approximately 20%, is poor. There are no predictive biomarkers of response. Uptake on 68Ga-DOTATATE PET/CT imaging is used to assess patient suitability for PRRT, highlighting the presence of somatostatin receptors (SSTR) to which PRRT selectively binds. We hypothesise that the density of SSTRs, as defined by a minimum SUV uptake, predicts for response to PRRT. Methods: 54 patients underwent PRRT. Modified PERCIST assessment was performed: up to 2 target lesions per organ were identified and volume of interest drawn. Maximum 5 targets were counted. Average SUV (SUVave) was calculated by dividing sum of SUVmax of target lesions by number of lesions. Response was determined by RECIST 1.1. Ki67 and SSTR2 expression were assessed on tumour samples and compared with SUVave. Results: Response to PRRT: partial response (PR) 26%, stable disease (SD) 40% progressive disease (PD) 12%. Response to PRRT predicted progression free survival (PFS) with patients experiencing PR having a PFS 2.5x that of those with SD, and almost 20x as long as PD. Using ROC curve analysis, SUVave of 21.6 predicted for tumour response with high sensitivity (0.74) and specificity (1.0), p = 0.15, 95% CI 0.71-3.96. No association between baseline SUVave and SSTR2 or Ki-67 was observed. SUVave > 21.6 was an independent predictor of clinical outcome. Conclusions: Objective response to PRRT defines a subset of patients with markedly improved PFS. SUVave 21.6 defines a threshold below which patients have a poor response to PRRT. This threshold should be taken forward into prospective study.

Validity and test-retest reliability of an at-work production loss instrument

BACKGROUND

Besides causing ill health, a poor work environment may contribute to production loss. Production loss assessment instruments emphasize health-related consequences but there is no instrument to measure reduced work performance related to the work environment.

AIMS

To examine convergent validity and test-retest reliability of health-related production loss (HRPL) and work environment-related production loss (WRPL) against a valid comparable instrument, the Health and Work Performance Questionnaire (HPQ).

METHODS

Cross-sectional study of employees, not on sick leave, who were asked to self-rate their work performance and production losses. Using the Pearson correlation and Bland and Altman's Test of Agreement, convergent validity was examined. Subgroup analyses were performed for employees recording problem-specific reduced work performance. Consistency of pairs of HRPL and WRPL for samples responding to both assessments was expressed using Intraclass Correlation Coefficient (ICC) and tests of repeatability.

RESULTS

A total of 88 employees participated and 44 responded to both assessments. Test of agreement between measurements estimates a mean difference of 0.34 for HRPL and -0.03 for WRPL compared with work performance. This indicates that the production loss questions are valid and moderately associated with work performance for the total sample and subgroups. ICC for paired HRPL assessments was 0.90 and 0.91 for WRPL, i.e. the test-retest reliability was good and suggests stability in the instrument.

CONCLUSIONS

HRPL and WRPL can be used to measure production loss due to health-related and work environment-related problems. These results may have implications for advancing methods of assessing production loss, which represents an important cost to employers.

Choline Kinase Alpha (CHKα) as a Therapeutic Target in Pancreatic Ductal Adenocarcinoma: Expression, Predictive Value, and Sensitivity to Inhibitors

Choline kinase α (CHKα) plays a crucial role in the regulation of membrane phospholipid synthesis and has oncogenic properties in vitro. We have analyzed the expression of CHKα in cell lines derived from pancreatic ductal adenocarcinoma (PDAC) and have found increased CHKα expression, associated with differentiation. CHKα protein expression was directly correlated with sensitivity to MN58b, a CHKα inhibitor that reduced cell growth through the induction of apoptosis. Accordingly, CHKα knockdown led to reduced drug sensitivity. In addition, we found that gemcitabine-resistant PDAC cells displayed enhanced sensitivity to CHKα inhibition and, in vitro, MN58b had additive or synergistic effects with gemcitabine, 5-fluorouracil, and oxaliplatin, three active drugs in the treatment of PDAC. Using tissue microarrays, CHKα was found to be overexpressed in 90% of pancreatic tumors. While cytoplasmic CHKα did not relate to survival, nuclear CHKα distribution was observed in 43% of samples and was associated with longer survival, especially among patients with well/moderately differentiated tumors. To identify the mechanisms involved in resistance to CHKα inhibitors, we cultured IMIM-PC-2 cells with increasingly higher concentrations of MN58b and isolated a subline with a 30-fold higher IC50. RNA-Seq analysis identified upregulation of ABCB1 and ABCB4 multidrug resistance transporters, and functional studies confirmed that their upregulation is the main mechanism involved in resistance. Overall, our findings support the notion that CHKα inhibition merits further attention as a therapeutic option in patients with PDAC and that expression levels may predict response.

LARP1 post-transcriptionally regulates mTOR and contributes to cancer progression

RNA-binding proteins (RBPs) bind to and post-transcriptionally regulate the stability of mRNAs. La-related protein 1 (LARP1) is a conserved RBP that interacts with poly-A-binding protein and is known to regulate 5'-terminal oligopyrimidine tract (TOP) mRNA translation. Here, we show that LARP1 is complexed to 3000 mRNAs enriched for cancer pathways. A prominent member of the LARP1 interactome is mTOR whose mRNA transcript is stabilized by LARP1. At a functional level, we show that LARP1 promotes cell migration, invasion, anchorage-independent growth and in vivo tumorigenesis. Furthermore, we show that LARP1 expression is elevated in epithelial cancers such as cervical and non-small cell lung cancers, where its expression correlates with disease progression and adverse prognosis, respectively. We therefore conclude that, through the post-transcriptional regulation of genes such as mTOR within cancer pathways, LARP1 contributes to cancer progression.

Anti-nicastrin monoclonal antibodies elicit pleiotropic anti-tumour pharmacological effects in invasive breast cancer cells

The goal of targeted cancer therapies is to specifically block oncogenic signalling, thus maximising efficacy, while reducing side-effects to patients. The gamma-secretase (GS) complex is an attractive therapeutic target in haematological malignancies and solid tumours with major pharmaceutical activity to identify optimal inhibitors. Within GS, nicastrin (NCSTN) offers an opportunity for therapeutic intervention using blocking monoclonal antibodies (mAbs). Here we explore the role of anti-nicastrin monoclonal antibodies, which we have developed as specific, multi-faceted inhibitors of proliferation and invasive traits of triple-negative breast cancer cells. We use 3D in vitro proliferation and invasion assays as well as an orthotopic and tail vail injection triple-negative breast cancer in vivo xenograft model systems. RNAScope assessed nicastrin in patient samples. Anti-NCSTN mAb clone-2H6 demonstrated a superior anti-tumour efficacy than clone-10C11 and the RO4929097 small molecule GS inhibitor, acting by inhibiting GS enzymatic activity and Notch signalling in vitro and in vivo. Confirming clinical relevance of nicastrin as a target, we report evidence of increased NCSTN mRNA levels by RNA in situ hybridization (RNAScope) in a large cohort of oestrogen receptor negative breast cancers, conferring independent prognostic significance for disease-free survival, in multivariate analysis. We demonstrate here that targeting NCSTN using specific mAbs may represent a novel mode of treatment for invasive triple-negative breast cancer, for which there are few targeted therapeutic options. Furthermore, we propose that measuring NCSTN in patient samples using RNAScope technology may serve as companion diagnostic for anti-NCSTN therapy in the clinic.

Brain and tumor penetration of carbon-11–labeled lapatinib ([11C]Lap) in patients (pts) with HER2-overexpressing metastatic breast cancer (MBC)

635

Background: About a third of HER2-overexpressing (HER2+) breast cancer pts will develop brain metastases in the course of their disease. Drug access to normal brain and brain metastases is therefore key to prevention and treatment of cerebral metastases. To provide direct evidence of Lap drug access and evaluate whether therapeutic doses of Lap act as a substrate for efflux transporters, thereby increasing Lap concentrations, we performed positron emission tomography (PET) studies with [11C]Lap. Methods: Pts with HER2+ MBC with an ECOG of <3 were grouped into 2 cohorts: with at least one 1-cm diameter brain metastasis or without brain metastases and underwent 90-minute dynamic cranial PET-CT scans after IV administration of a microdose (<1 mg) of [11C]Lap before and after 8 days of oral Lap (1500 mg once daily). Arterial blood samples were performed to assess [11C]Lap radioactivity contribution in blood and plasma, and the fraction of plasma [11C] radioactivity corresponding to metabolites. Tissue time-radioactivity curves (TACs) were generated and [11C]Lap exposure (AUC; area under TAC) derived for normal brain and brain metastases. Signal dissection of the total image activity was performed to remove the contribution of blood volume to the image and the actual tissue contribution due to [11C]Lap obtained. Results: 6 pts (3 with brain metastasis) were recruited. Arterial plasma analysis revealed that [11C]Lap contributed to >80% of activity in plasma at 60 minutes. Tissue data revealed [11C]Lap signal in normal brain was low with no appreciable uptake observed when corrected for blood volume contribution. [11C]Lap uptake was higher in brain metastases compared with normal brain and appreciable, even after correction for tissue blood volume contribution. Uptake was also observed in extra-cranial normal tissue. There was no difference in [11C]Lap uptake in normal brain and metastases between treatment-naïve and post-treatment scans. Conclusions: [11C]Lap uptake in brain metastases was higher than in normal brain. [11C]Lap drug access to brain metastases might therefore indicate possible efficacy against HER2+ brain metastases. Clinical trial information: NCT01290354.

Importance of quantification for the analysis of PET data in oncology: review of current methods and trends for the future

In oncology, positron emission tomography (PET) is an important tool for tumour diagnosis and staging, assessment of response to treatment and evaluation of the pharmacokinetic properties and efficacy of new drugs. Despite its quantitative potential, however, in daily clinical practice PET is used almost exclusively with 2-deoxy-2-[(18)F]fluoro-D-glucose ([(18)F]FDG) and, in addition, [(18)F]FDG data are normally assessed visually or using simple indices as the standardised uptake value (SUV). After explaining why more sophisticated quantification methods can be useful in oncology, the paper reviews the approaches that are commonly used and those available but not routinely employed. Particular emphasis is addressed to the SUV, for its importance in clinical practice. Issues specific to PET quantification in oncology and related examples are then discussed. Finally, some ideas for the development of new quantitative methods for analysing PET data in oncology and for the application of approaches already existing but not commonly employed are presented.

Imaging of cellular proliferation in liver metastasis by [18F]fluorothymidine positron emission tomography: effect of therapy

Although [(18)F]fluorothymidine positron emission tomography (FLT-PET) permits estimation of tumor thymidine kinase-1 expression, and thus, cell proliferation, high physiological uptake of tracer in liver tissue can limit its utility. We evaluated FLT-PET combined with a temporal-intensity information-based voxel-clustering approach termed kinetic spatial filtering (FLT-PET(KSF)) for detecting drug response in liver metastases. FLT-PET and computed tomography data were collected from patients with confirmed breast or colorectal liver metastases before, and two weeks after the first cycle of chemotherapy. Changes in tumor FLT-PET and FLT-PET(KSF) variables were determined. Visual distinction between tumor and normal liver was seen in FLT-PET(KSF) images. Of the 33 metastases from 20 patients studied, 26 were visible after kinetic filtering. The net irreversible retention of the tracer (Ki; from unfiltered data) in the tumor, correlated strongly with tracer uptake when the imaging variable was an unfiltered average or maximal standardized uptake value, 60 min post-injection (SUV(60,av): r = 0.9, SUV(60,max): r = 0.7; p < 0.0001 for both) and occurrence of high intensity voxels derived from FLT-PET(KSF) (r = 0.7, p < 0.0001). Overall, a significant reduction in the imaging variables was seen in responders compared to non-responders; however, the two week time point selected for imaging was too early to allow prediction of long term clinical benefit from chemotherapy. FLT-PET and FLT-PET(KSF) detected changes in proliferation in liver metastases.

18F-fluorothymidine (FLT) PET-CT for early response assessment in advanced pancreatic cancer

e21093

Background: Advanced pancreatic cancer has a poor prognosis with a median survival of 6-10 months. There is a need for early non-invasive assessment of treatment response. We evaluated FLT PET-CT combined with a kinetic spatial filtering method (FLT-PETKSF) for detecting response to gemcitabine-based chemotherapy in advanced pancreatic cancer. Methods: Dynamic FLT PET-CT data were collected from patients with confirmed locally advanced or metastatic pancreatic cancer before and 2 weeks after the first cycle of chemotherapy. Changes in tumor FLT-PET variables with treatment were determined. Standardized uptake value (SUV) reduction of 18% was taken as cut-off for response. Voxel quantification of each tumor volume was performed on the filtered data. Each voxel-intensity was normalised by injected dose, body weight and decay corrected to obtain the SUV for the voxel. Changes in high intensity voxels (HiVox: SUV ≥ 2) - were computed. Results: Results of the first 5 patients are discussed. There were 4 primary and 9 metastatic tumors. FLT-PETKSF improved tumor-to-background ratio and enabled visualisation of all the primary and metastatic tumors. The mean (± SD) average and maximum SUV at 60 min (SUV60, av & SUV60, max) of the primary lesions was 2.10 (±0.38) & 4.85 (±1.55) and that of the metastatic lesions was 3.74 (±1.49) & 6.90 (±2.05) respectively. The mean (± SD) percentage reduction in the SUV60, av & SUV60, max, HIVox was 26 (±44), 18 (±38) and 23 (±50) respectively. The changes in the voxel occurrences correlated strongly with the changes in both SUV60, av & SUV60, max (Pearson r-0.9, p=0.001) .Overall, there were 2 partial responders and 3 with stable disease. These responses concurred with response evaluation on mid-treatment CT scan. Conclusions: FLT-PET and FLT-PETKSF enables visualisation of the pancreatic tumors and the liver metastases, and could be used to monitor response to therapy.

[(18)F]FLT: an imaging biomarker of tumour proliferation for assessment of tumour response to treatment

The paradigm of drug development is shifting towards early use of imaging biomarkers as surrogate end-points in clinical trials. Quantitative Imaging in Cancer: Connecting Cellular Processes (QuIC-ConCePT) is an initiative to qualify complementary imaging biomarkers (IB) of proliferation, cell death and tumour heterogeneity as possible tools in early phase clinical trials to help pharmaceutical developers in 'go, no-go' decisions early in the process of drug development. One of the IBs is [(18)F]3'-deoxy-3'-fluorothymidine with Positron Emission Tomography (FLT-PET). We review results of recent clinical trials using FLT-PET for monitoring tumour response to drug treatment and discuss the potential and the possible pitfalls of using this IB as a surrogate end-point in early phase clinical trials for assessing tumour response to drug treatment. From first human trial results it seems that the degree of FLT accumulation in tumours is governed not only by the tumour proliferation rate but also by other factors. Nevertheless FLT-PET could potentially be used as a negative predictor of tumour response to chemotherapy, and hence evaluation of this IB is granted in multi-centre clinical trials.

Development of radiotracers for oncology--the interface with pharmacology

There is an increasing role for positron emission tomography (PET) in oncology, particularly as a component of early phase clinical trials. As a non-invasive functional imaging modality, PET can be used to assess both pharmacokinetics and pharmacodynamics of novel therapeutics by utilizing radiolabelled compounds. These studies can provide crucial information early in the drug development process that may influence the further development of novel therapeutics. PET imaging probes can also be used as early biomarkers of clinical response and to predict clinical outcome prior to the administration of therapeutic agents. We discuss the role of PET imaging particularly as applied to phase 0 studies and discuss the regulations involved in the development and synthesis of novel radioligands. The review also discusses currently available tracers and their role in the assessment of pharmacokinetics and pharmacodynamics as applied to oncology.

Abstract 2608: HDAC-C1A: An irreversible HDAC inhibitor with significant anti-tumor activity

Histone deacetylase (HDAC) enzymes exert control over gene transcription and cell cycle progression and their inhibition has recently emerged as an efficacious strategy to treat cancer. However, current HDAC inhibitors have been linked to a shared undesirable toxicological profile that prompts the development of new entities. The present study evaluates the in vitro and in vivo PK/PD of a newly developed HDAC inhibitor, HDAC-C1A.

HDAC-C1A inhibited class I, II and sirtuins, with highest affinity for HDAC6 (IC50 = 63 ng/mL), an HDAC subtype thought to be associated with low toxicity; HDAC6 knockout does not lead to embryonic lethality. The drug irreversibly inhibited HDAC from HeLa cell extract; in HCT116 cells inhibition of enzyme activity as assessed by levels of acetyl-histone H3, H4 and acetyl-tubulin was maintained after washout demonstrating an irreversible mechanism. HDAC-C1A treatment was associated with a dose and time dependent increase of histone and non-histone targets that was maintained at 4 hours after washout; acetylation was lost by 4 h with clinically licensed HDAC inhibitor SAHA. HDAC-C1A inhibited the growth of a panel of 7 cancer cell lines with a mean GI50 of 1.6 ± 0.6 µg/mL. The drug was relatively stable after parenteral administration for 4 h. The Cmax and AUC0-4h following i.p. injection (160 mg/kg) were 20.4 µg/mL and 50 µg/mL*h, respectively.

Regarding efficacy, HDAC-C1A treatment was associated with a Tumor Growth Delay (TGD2x) of 5.7 ± 1.4 days and a Tumor Growth Inhibition (TGI) of 78% compared with vehicle when given i.p. at 20 mg/kg b.i.d. in a HCT116 human colon cancer xenograft model. This dose was non-toxic (no reduction in body weight). We also assessed the potential of [18F]fluorothymidine positron emission tomography ([18F]FLT-PET) to measure early response to HDAC-C1A treatment in HCT116 xenograft bearing mice. There was a 2-fold decrease in tumor [18F]FLT uptake compared to vehicle treated animals at 48 h post-treatment; the area under the normalized [18F]FLT time versus activity curve was 117 ± 6.9 at before treatment and decreased to 106 ± 5.5 (P = 0.02) at 24 hours and 54 ± 5 (P = 0.0001) at 48 h after initiating treatment.

In summary, HDAC-C1A combines irreversible HDAC inhibition with a favourable pharmacokinetic profile leading to significant anti-tumor activity in the HCT116 tumor model. Early response to the drug was detectable by [18F]FLT-PET. These preclinical data support further development of HDAC-C1A. This work was supported in part by Cancer Research U.K.-Engineering and Physical Sciences Research Council Grant C2536/A10337.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2608. doi:10.1158/1538-7445.AM2011-2608