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Supplementary Data from A Phase II Randomized Trial of Chemoradiation with or without Metformin in Locally Advanced Cervical Cancer

Purpose:Tumor hypoxia is associated with poor response to radiation (RT). We previously discovered a novel mechanism of metformin: enhancing tumor RT response by decreasing tumor hypoxia. We hypothesized that metformin would decrease tumor hypoxia and improve cervical cancer response to RT.Patients and Methods:A window-of-opportunity, phase II randomized trial was performed in stage IB–IVA cervical cancer. Patients underwent screening positron emission tomography (PET) imaging with hypoxia tracer fluoroazomycin arabinoside (FAZA). Only patients with FAZA uptake (hypoxic tumor) were included and randomized 2:1 to receive metformin in combination with chemoRT or chemoRT alone. A second FAZA-PET/CT scan was performed after 1 week of metformin or no intervention (control). The primary endpoint was a change in fractional hypoxic volume (FHV) between FAZA-PET scans, compared using the Wilcoxon signed-rank test. The study was closed early due to FAZA availability and the COVID-19 pandemic.Results:Of the 20 consented patients, 6 were excluded due to no FAZA uptake and 1 withdrew. FHV of 10 patients in the metformin arm decreased by an average of 10.2% (44.4%–34.2%) ± SD 16.9% after 1 week of metformin, compared with an average increase of 4.7% (29.1%–33.8%) ± 11.5% for the 3 controls (P = 0.027). Those with FHV reduction after metformin had significantly lower MATE2 expression. With a median follow-up of 2.8 years, the 2-year disease-free survival was 67% for the metformin arm versus 33% for controls (P = 0.09).Conclusions:Metformin decreased cervical tumor hypoxia in this trial that selected for patients with hypoxic tumor.See related commentary by Lyng et al., p. 5233

Purpose: Tumor hypoxia is associated with poor response to radiation (RT). We previously discovered a novel mechanism of metformin: enhancing tumor RT response by decreasing tumor hypoxia. We hypothesized that metformin would decrease tumor hypoxia and improve cervical cancer response to RT. Patients and Methods: A window-of-opportunity, phase II randomized trial was performed in stage IB–IVA cervical cancer. Patients underwent screening positron emission tomography (PET) imaging with hypoxia tracer fluoroazomycin arabinoside (FAZA). Only patients with FAZA uptake (hypoxic tumor) were included and randomized 2:1 to receive metformin in combination with chemoRT or chemoRT alone. A second FAZA-PET/CT scan was performed after 1 week of metformin or no intervention (control). The primary endpoint was a change in fractional hypoxic volume (FHV) between FAZA-PET scans, compared using the Wilcoxon signed-rank test. The study was closed early due to FAZA availability and the COVID-19 pandemic. Results: Of the 20 consented patients, 6 were excluded due to no FAZA uptake and 1 withdrew. FHV of 10 patients in the metformin arm decreased by an average of 10.2% (44.4%–34.2%) ± SD 16.9% after 1 week of metformin, compared with an average increase of 4.7% (29.1%–33.8%) ± 11.5% for the 3 controls (P = 0.027). Those with FHV reduction after metformin had significantly lower MATE2 expression. With a median follow-up of 2.8 years, the 2-year disease-free survival was 67% for the metformin arm versus 33% for controls (P = 0.09). Conclusions: Metformin decreased cervical tumor hypoxia in this trial that selected for patients with hypoxic tumor. See related commentary by Lyng et al., p. 5233

BackgroundSitravatinib, a tyrosine kinase inhibitor that targets TYRO3, AXL, MERTK and the VEGF receptor family, is predicted to increase the M1 to M2-polarized tumor-associated macrophages ratio in the tumor microenvironment and have synergistic antitumor activity in combination with anti-programmed death-1/ligand-1 agents. SNOW is a window-of-opportunity study designed to evaluate the immune and molecular effects of preoperative sitravatinib and nivolumab in patients with oral cavity squamous cell carcinoma.MethodsPatients with newly-diagnosed untreated T2-4a, N0-2 or T1 >1 cm-N2 oral cavity carcinomas were eligible. All patients received sitravatinib 120 mg daily from day 1 up to 48 hours pre-surgery and one dose of nivolumab 240 mg on day 15. Surgery was planned between day 23 and 30. Standard of care adjuvant radiotherapy was given based on clinical stage. Tumor photographs, fresh tumor biopsies and blood samples were collected at baseline, at day 15 after sitravatinib alone, and at surgery after sitravatinib–nivolumab combination. Tumor flow cytometry, multiplex immunofluorescence staining and single-cell RNA sequencing (scRNAseq) were performed on tumor biopsies to study changes in immune-cell populations. Tumor whole-exome sequencing and circulating tumor DNA and cell-free DNA were evaluated at each time point.ResultsTen patients were included. Grade 3 toxicity occurred in one patient (hypertension); one patient required sitravatinib dose reduction, and one patient required discontinuation and surgery delay due to G2 thrombocytopenia. Nine patients had clinical-to-pathological downstaging, with one complete response. Independent pathological treatment response (PTR) assessment confirmed a complete PTR and two major PTRs. With a median follow-up of 21 months, all patients are alive with no recurrence. Circulating tumor DNA and cell-free DNA dynamics correlated with clinical and pathological response and distinguished two patient groups with different tumor biological behavior after sitravatinib alone (1A) versus sitravatinib–nivolumab (1B). Tumor immunophenotyping and scRNAseq analyses revealed differential changes in the expression of immune cell populations and sitravatinib-targeted and hypoxia-related genes in group 1A vs 1B patients.ConclusionsThe SNOW study shows sitravatinib plus nivolumab is safe and leads to deep clinical and pathological responses in oral cavity carcinomas. Multi-omic biomarker analyses dissect the differential molecular effects of sitravatinib versus the sitravatinib–nivolumab and revealed patients with distinct tumor biology behavior.Trial registration numberNCT03575598.

Purpose/Objective(s) Tumor hypoxia is associated with poor response to radiation (RT) and chemotherapy, and worse treatment outcome. We previously discovered a novel mechanism of metformin in a xenograft model: enhancing tumor RT response by inhibiting tumor cell oxygen consumption. Our population-based study showed that cumulative dose of metformin after cervical cancer diagnosis was independently associated with a decreased risk of cervical cancer-specific mortality in diabetic women. Based on the pre-clinical and retrospective data, we hypothesized that metformin would decrease tumor hypoxia and improve tumor response to RT in locally advanced cervical cancer. Materials/Methods A window-of-opportunity, phase II randomized trial was performed in women with stage IB-IVA cervical adenocarcinoma, squamous cell or adenosquamous carcinoma. Patients underwent screening positron emission tomography (PET) imaging with hypoxia tracer fluoroazomycin arabinoside (FAZA). Those with non-hypoxic tumor (no FAZA uptake) were excluded. Patients with FAZA uptake were randomized centrally in a 2:1 ratio (in favor of metformin) to receive either metformin in combination with standard chemoRT or standard chemoRT alone. Metformin was started at 850mg once daily x 3 days, followed by 850mg twice daily throughout the entire duration of external radiotherapy. A second FAZA-PET/CT scan was performed after 1 week of metformin or no intervention in control group, just before start of chemoRT. The hypoxic volume was defined as all voxels within a tumor with standardized uptake values (SUVs) greater than 3 standard deviations (SD) from the mean gluteus maximus muscle SUV value. The hypoxic fraction (HF) was defined as the ratio of the number of hypoxic voxels to the total number of tumor voxels. The primary endpoint was absolute mean change in HF between the two FAZA-PET scans, compared using the Wilcoxon sign rank test. Disease-free survival (DFS) was defined as the duration of time from randomization to the time of relapse or death and compared using the log-rank test. Target accrual was 48 patients; the study was closed early to accrual due to FAZA availability and the COVID-19 pandemic. Results Of the twenty patients who consented, 6 were excluded due to no FAZA uptake and 1 withdrew. The median age of the 13 enrolled patients was 52; 8 (62%) had squamous cell carcinoma and 8 had stage IIB disease. HF of the 10 patients in the metformin arm decreased by an average of 10.2% (from 44.4% to 34.2%) ± SD 16.9% after 1 week of metformin, compared to an average increase of 4.7% (from 29.1% to 33.8%) ± 11.5% for the 3 patients in the control arm (P = 0.027). With a median follow-up of 2.8 years, the 2-year DFS was 67% for the metformin arm vs 33% for control (P = 0.09). Conclusion Metformin decreases cervical tumor hypoxia with a trend towards improved DFS in this trial. A larger confirmatory trial is warranted.

Purpose To assess cervical tumor hypoxia using the hypoxia tracer 18F-fluoroazomycin arabinoside (18F-FAZA) and compare different reference tissues and thresholds for quantifying tumor hypoxia. Methods and Materials Twenty-seven patients with cervical cancer were studied prospectively by positron emission tomography (PET) imaging with 18F-FAZA before starting standard chemoradiation. The hypoxic volume was defined as all voxels within a tumor (T) with standardized uptake values (SUVs) greater than 3 standard deviations from the mean gluteus maximus muscle SUV value (M) or SUVs greater than 1 to 1.4 times the mean SUV value of the left ventricle, a blood (B) surrogate. The hypoxic fraction was defined as the ratio of the number of hypoxic voxels to the total number of tumor voxels. Results A 18F-FAZA-PET hypoxic volume could be identified in the majority of cervical tumors (89% when using T/M or T/B > 1.2 as threshold) on the 2-hour static scan. The hypoxic fraction ranged from 0% to 99% (median 31%) when defined using the T/M threshold and from 0% to 78% (median 32%) with the T/B > 1.2 threshold. Hypoxic volumes derived from the different thresholds were highly correlated (Spearman's correlation coefficient ρ between T/M and T/B > 1-1.4 were 0.82-0.91), as were hypoxic fractions (0.75-0.85). Compartmental analysis of the dynamic scans showed k3, the FAZA accumulation constant, to be strongly correlated with hypoxic fraction defined using the T/M (Spearman's ρ=0.72) and T/B > 1.2 thresholds (0.76). Conclusions Hypoxia was detected in the majority of cervical tumors on 18F-FAZA-PET imaging. The extent of hypoxia varied markedly between tumors but not significantly with different reference tissues/thresholds.

Previous literature has shown that 4D respiratory-gated positron emission tomography (PET) is beneficial for quantitative analysis and defining targets for boosting therapy. However the case for addition of a phase-matched 4D-computed tomography (CT) for attenuation correction (AC) is less clear. We seek to validate the use of 4D-CT for AC and investigate the impact of motion correction for low signal-to-background PET imaging of hypoxia using radiotracers such as FAZA and FMISO. A new insert for the Modus Medicals' QUASAR™ Programmable Respiratory Motion Phantom was developed in which a 3D-printed sphere was placed within the “lung” compartment while an additional compartment is added to simulate muscle/blood compartment required for hypoxia quantification. Experiments are performed at 4:1 or 2:1 signal-to-background ratio consistent with clinical FAZA and FMISO imaging. Motion blur was significant in terms of SUVmax, mean, and peak for motion ≥1 cm and could be significantly reduced (from 20% to 8% at 2-cm motion) for all 4D-PET-gated reconstructions. The effect of attenuation method on precision was significant (σ2 hCT-AC = 5.5%/4.7%/2.7% vs σ2 4D-CT-AC = 0.5%/0.6%/0.7% [max%/peak%/mean% variance]). The simulated hypoxic fraction also significantly decreased under conditions of 2-cm amplitude motion from 55% to 20% and was almost fully recovered (HF = 0.52 for phase-matched 4D-CT) using gated PET. 4D-gated PET is valuable under conditions of low radiotracer uptake found in hypoxia imaging. This work demonstrates the importance of using 4D-CT for AC when performing gated PET based on its significantly improved precision over helical CT.

6569 Background: Sitravatinib (receptor TKI against TYRO3, AXL, MERTK and VEGF family of receptors) is predicted to increase M1-type tumor-associated macrophages (TAMs) and decrease MDSCs in the tumor microenvironment. SNOW is a window-of-opportunity study evaluating the immunogenic and antitumor effects of preoperative sitravatinib and nivolumab in patients (pts) with OCC. Early results demonstrated the combination was safe and active (Oliva et al, SITC 2019). Biomarker analyses and updated results are presented. Methods: Pts with untreated T2-4a, N0-2 or T1>1cm-N2 OCC are eligible. All pts receive oral sitravatinib 120mg daily from day (D) 1 up to 48h pre-surgery and 1 dose of Nivolumab 240mg on D15. Surgery planned between D23-D30. Standard of care adjuvant radiotherapy given based on clinical stage. Tumor pictures, fresh tumor biopsies, blood samples taken at baseline, D15 and pre-surgery. Tumor flow cytometry and multiplex immunofluorescence staining performed on all biopsies to study changes in immune-cell populations. Tumor whole-exome sequencing (WES) performed on baseline biopsies. Results: As of Jan 31st 2020, 10 out of 12 planned pts were enrolled. Study treatment was well-tolerated: only 1 pt had grade (G) >3 toxicity (hypertension) and 1 pt required surgery delay due to G2 thrombocytopenia. None had intraoperative complications. 1 pt had wound infection and tracheostomy bleeding 11 days post-surgery, possibly-related to study drugs. All pts had tumor reduction, 9/10 had pathological downstaging, including 1 complete response (Table). All had clear margins with no extranodal extension; none required adjuvant chemotherapy. All pts are alive with no recurrence (median follow-up= 69 weeks). Lower % of MDSCs and increased % of M1-TAMs and M1:M2 ratio trend was seen at D15 and pre-surgery, with stronger effect in major responders. Best responders (Pts S1-S2) had higher % of PD-L1+ TAMs at baseline. Tumor WES revealed an HRAS G12D mutation in pt S2 and a BLM mutation (DNA repair) in pt S6 (no downstaging). Conclusions: Pharmacodynamic analyses support the antitumor and immune effects of sitravatinib and nivolumab in OCC. Immune pathological response assessment and transcriptomics are on-going. Clinical trial information: NCT03575598 . [Table: see text]

To assess cervical tumor hypoxia using the hypoxia tracerTwenty-seven patients with cervical cancer were studied prospectively by positron emission tomography (PET) imaging withAHypoxia was detected in the majority of cervical tumors on

Development of perfusion imaging as a biomarker requires more robust methodologies for quantification of tumor physiology that allow assessment of volumetric tumor heterogeneity over time. This study proposes a parametric method for automatically analyzing perfused tissue from volumetric dynamic contrast-enhanced (DCE) computed tomography (CT) scans and assesses whether this 4-dimensional (4D) DCE approach is more robust and accurate than conventional, region-of-interest (ROI)-based CT methods in quantifying tumor perfusion with preliminary evaluation in metastatic brain cancer.Functional parameter reproducibility and analysis of sensitivity to imaging resolution and arterial input function were evaluated in image sets acquired from a 320-slice CT with a controlled flow phantom and patients with brain metastases, whose treatments were planned for stereotactic radiation surgery and who consented to a research ethics board-approved prospective imaging biomarker study. A voxel-based temporal dynamic analysis (TDA) methodology was used at baseline, at day 7, and at day 20 after treatment. The ability to detect changes in kinetic parameter maps in clinical data sets was investigated for both 4D TDA and conventional 2D ROI-based analysis methods.A total of 7 brain metastases in 3 patients were evaluated over the 3 time points. The 4D TDA method showed improved spatial efficacy and accuracy of perfusion parameters compared to ROI-based DCE analysis (P.005), with a reproducibility error of less than 2% when tested with DCE phantom data. Clinically, changes in transfer constant from the blood plasma into the extracellular extravascular space (Ktrans) were seen when using TDA, with substantially smaller errors than the 2D method on both day 7 post radiation surgery (±13%; P.05) and by day 20 (±12%; P.04). Standard methods showed a decrease in Ktrans but with large uncertainty (111.6 ± 150.5) %.Parametric voxel-based analysis of 4D DCE CT data resulted in greater accuracy and reliability in measuring changes in perfusion CT-based kinetic metrics, which have the potential to be used as biomarkers in patients with metastatic brain cancer.

Background and purpose We examined the utility of dynamic contrast-enhanced MRI (DCE-MRI), diffusion-weighted MRI (DWI), and FDG-PET imaging for brachytherapy target delineation in patients with locally advanced cervical cancer. Materials and methods Twenty-two patients had DWI, DCE-MRI, and FDG-PET/CT scans after brachytherapy applicator insertion, in addition to standard T2-weighted (T2w) 3T MRI. Gross tumor volume (GTV B ) and high-risk clinical target volume (HRCTV) were contoured first on T2w images, and then modified if indicated upon review of DWI/DCE-MRI/FDG-PET images by two observers. The primary endpoint was utility, determined by the number of patients whose volumes were modified, and interobserver variability. Results Eleven patients' T2w-GTV B were modified based on DWI/DCE-MRI/FDG-PET by observer 1, due to clearer demarcation (7) and residual disease not well visualized on T2w MRI (4). GTV B was modified in 17 patients by observer 2 (11 and 6, respectively). Incorporation of functional imaging improved the conformity index (CI) for GTV B from 0.54 (T2w alone) to 0.65 ( P =0.003). HRCTV was modified in 3 and 8 patients by observers 1 and 2, respectively, with a trend toward higher CI using functional imaging (0.71 to 0.76, P =0.06). Conclusions DWI/DCE-MRI/FDG-PET imaging as a supplement to T2w MRI decreased interobserver variability in GTV B delineation.

Purpose: Quantification of hypoxia from PET images is of considerable clinical interest. In the absence of dynamic PET imaging the hypoxic fraction (HF) of a tumor has to be estimated from voxel values of activity concentration of a radioactive hypoxia tracer. This work is part of an effort to standardize quantification of tumor hypoxic fraction from PET images. Methods: A simple hypoxia imaging model in the tumor was developed. The distribution of the tracer activity was described as the sum of two different probability distributions, one for the normoxic (and necrotic), the other for the hypoxic voxels. The widths of the distributions arise due to variability of the transport, tumor tissue inhomogeneity, tracer binding kinetics, and due to PET image noise. Quantification of HF was performed for various levels of variability using two different methodologies: a) classification thresholds between normoxic and hypoxic voxels based on a non-hypoxic surrogate (muscle), and b) estimation of the (posterior) probability distributions based on maximizing likelihood optimization that does not require a surrogate. Data from the hypoxia imaging model and from 27 cervical cancer patients enrolled in a FAZA PET study were analyzed. Results: In the model, where the true value of HF is known, thresholds usually underestimate the value for large variability. For the patients, a significant uncertainty of the HF values (an average intra-patient range of 17%) was caused by spatial non-uniformity of image noise which is a hallmark of all PET images. Maximum likelihood estimation (MLE) is able to directly optimize for the weights of both distributions, however, may suffer from poor optimization convergence. For some patients, MLE-based HF values showed significant differences to threshold-based HF-values. Conclusion: HF-values depend critically on the magnitude of the different sources of tracer uptake variability. A measure of confidence should also be reported.

TPS9089 Background: In melanoma, tumor hypoxia is associated with invasion, angiogenesis, and metastasis formation, as well as treatment resistance such as immune evasion. Evofosfamide (EVO, TH-302...