Tumor Doubling Time Research Articles

Abstract P3-07-03: Anti-tumor activity of a liposomal formulation of Eribulin compared with the same dose of Eribulin in patient-derived breast cancer xenografts

Abstract Backgrounds: A liposomal formulation of Eribulin, E7389-LF may allow increased access to tumor tissues and has been under development for breast cancer. In a phase 1, expansion cohort as a late line treatment, objective response rate was observed to be 35.7% (Her2-negative breast cancer), and 42.9% for hormone receptor-positive (HR+ve) patients (Masuda, European Journal of Cancer, 2022). However, survival benefit and its mode of action of E7389-LF remains unclear, although E7389-LF seems more effective than Eribulin in clinic. Methods: PDX#1 is a breast cancer patient-derived xenograft (PDX) from a patient with triple negative breast cancer who later received Eribulin for 7 cycles until progression in lung metastases. PDX#2 is also a breast cancer PDX from paclitaxel-resistant HR+ve/HER2-ve breast cancer, respectively. These two PDXs were provided by the National Cancer Center J-PDX library, Japan, and were bred in NOD/Shi-scid, IL-2Rγnull (NOG) mice and observed until the onset of a mammary tumor approximately 180 and 240 mm3 in volume (Day 0). PDX tumors were randomized and monitored with tumor growth measurements. Each group received either saline, 0.34mg/kg, or 0.67 mg/kg (clinically relevant dose of E7389-LF, estimated) of Eribulin or E7389-LF at Day 0 and 7 (Experiment 1). For short-term experiments, 9 PDX#1 or 12 PDX#2 tumors were removed one week after an injection of saline, 0.67 mg/kg of Eribulin, or 0.67 mg/kg of E7389-LF (n=3/group for PDX#1, n=4/group for PDX#2), and tumors were immunohistochemically stained with anti-CD31 antibody, an endothelial cell marker, to investigate microvessel density and RNA sequencing was additionally performed (Experiment 2). Results: Table 1 summarizes the results. In Experiment 1, both E7389-LF and Eribulin showed significant antitumor activity compared with saline in a dose-dependent manner with respect to tumor growth inhibition and survival benefit, extension of tumor doubling time (earlier day with relative tumor volume >200%), in PDX#1 and #2. Tumor shrinkage was seen in PDX#1, and E7389-LF at 0.34 mg/kg, or 0.67 mg/kg were more potent than the same doses of Eribulin at Day 21 in both PDXs (p < 0.05). E7389-LF at 0.67 mg/kg also showed relative tumor growth inhibition compared with the same dose of Eribulin in PDX#2 (p < 0.05). As for survival, PDX#1 with E7389-LF at 0.67 mg/kg demonstrated significantly longer survival (p=0.03) than Eribulin at 0.67 mg/kg, while PDX#2 with E7389-LF at 0.67 mg/kg did not (p=0.10). In Experiment 2, microvessel density increased in PDX#1 after receiving eribulin and E7389-LF compared with untreated ones, with a significant difference for E7389-LF (p=0.006), and showed an increasing tendency over Eribulin (p=0.06), while microvessel density in PDX#2 did not differ between groups. Conclusions: Pre-clinical data demonstrates that E7389-LF is more potent than the same dose of Eribulin in patient-derived breast cancer xenografts. Survival benefit was observed in a PDX with a tumor shrinkage and an increase in microvessel density. Table 1. Summary of the findings. p<0.05 vs Saline (at the indicated time point for tumor volume), *: p<0.05 E7389-LF vs Eribulin (at Day 21 for tumor volume) Citation Format: Maki Tanioka, Taro Semba, Tatsunori Shimoi, Yuki Niwa, Kan Yonemori. Anti-tumor activity of a liposomal formulation of Eribulin compared with the same dose of Eribulin in patient-derived breast cancer xenografts [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-07-03.

Early progression of a pancreatic metastasis of synovial sarcoma after pancreatectomy

BackgroundSynovial sarcoma is a malignant tumor that constitutes up to 10% of all soft-tissue sarcomas. The most frequent metastatic sites of synovial sarcoma are the lungs, lymph nodes, and bone, whereas pancreatic metastasis is extremely rare. Here, we report a case of pancreatic metastasis of synovial sarcoma.Case presentationNine years before presentation, a 31-year-old woman underwent extensive resection of the primary tumor after chemotherapy for left upper extremity synovial sarcoma. Six months before presentation, interscapulothoracic amputation was performed for an enlarged mass in the left upper extremity; the patient was treated with pazopanib. Three months before presentation, chest computed tomography showed multiple lung metastases; during subsequent follow-up, abdominal computed tomography revealed a pancreatic metastasis of synovial sarcoma. The doubling time of the pancreatic tumor was 14 days, and it grew rapidly. Furthermore, treatment-resistant pancreatitis symptoms were detected; thus, we performed distal pancreatectomy and administered one course of a 70% dose of trabectedin. However, the patient died of rapid progression of lung metastasis and respiratory failure within 2 months after surgery.ConclusionsPancreatectomy may be carefully performed in cases of isolated pancreatic metastasis. However, the presence of other distant extrapancreatic metastases (e.g., uncontrolled lung metastases) may rule out pancreatectomy treatment.

Translated article] Tumor Doubling Time in Skin Cancer: Can It Be Estimated and Is It Useful?

Skin cancer, like other cancers, is characterized by the uncontrolled growth of transformed cells. Tumor growth has been studied for decades. We review different methods for measuring skin tumor growth and propose a new system for estimating tumor doubling time that could be useful in the management of skin cancer.

Primary Cardiac Burkitt’s Lymphoma- A Deadlock

Burkitt’s lymphoma is a high-grade, extremely aggressive form of B-cell non Hodgkin lymphoma with a very fast replication time (tumour doubling time of around 25 hours). The three forms of Burkitt’s lymphoma are documented which include endemic, sporadic, and immunodeficiency associated. It is enormously rare with less than 30 cases reported till date. Primary cardiac lymphoma is a rare cardiac neoplasm. The most common type is diffuse large B-cell lymphoma. Diagnosis is usually late and with poor prognosis. Primary cardiac lymphoma is more common in immunodeficient patients. This is a case of primary cardiac Burkitt’s lymphoma which was diagnosed in a 58-year-old immunocompetent male. The patient’s two-dimensional echocardiography and plain Computed Tomography (CT) scan of the chest revealed presence of massive pericardial effusion with mild to moderate bilateral pleural effusion. Cardiac Positron Emission Tomography (PET) CT revealed a soft tissue mass at atrioventricular groove which indicated either pericardial lymphoma or inflammatory serositis. The patient was opted for surgery, but the mass was noted involving the free wall of right ventricle including the diaphragmatic surface which extended onto atrioventricular groove and base of right atrial appendage. Thus, a decision to not proceed further with surgical repair was made. The histopathological and cytogenetic findings confirmed the presence of Burkitt's lymphoma. Later, it was discovered that the patient died within one month of diagnosis.

Efficacy of adoptively transferred allogeneic CIK cells on colorectal cancer: Augmentative antitumoral effects of GvHD.

A preclinical study was designed to evaluate the effects of adoptively transferred cytokine-induced killer (CIK) cells on colorectal adenocarcinoma. Forty NOG mice bearing HT-29 xenograft tumors were developed and equally divided into 2 groups of treatment and control. The mice in the treatment group received cumulatively 40-60×106 CIK cells in four divided doses. Median tumor doubling times for HT-29 xenograft tumors in the treatment and control groups were found to be 8.98 and 4.32days; respectively. The treatment resulted in tumor growth delay (TGD) of 52.5%. CIK cell-induced log cell kill (LCK) was found to be 0.67, which implies reduction of 78.6% of neoplastic colorectal cells. Median length of survival in the treated mice was significantly longer than controls (57 (41-63) vs 41 (31-57) days, P<0.001). Mice in the treatment group experienced graft-versus-host disease (GvHD) from median of day 13th after the cell therapy. LCK and TGD significantly increased after emergence of GvHD. After necropsy, tumors of the treatment group contained high levels of human-originated CD3+, CD4+ and CD8+ cells and showed significantly lower mitotic counts (P<0.001) and residual tumor scores (P=0.005) than the controls (entirely negative for the mentioned CD markers). Ninety percent of the treated mice were found to be responding. Adoptive transfer of allogeneic CIK cells may be an efficient antitumoral therapy for colorectal cancer. Allogeneic CIK cell-mediated GvHD may contribute to amplification of graft-versus-tumor effects of the cellular therapy.

¿Es la estimación del tiempo de duplicación tumoral posible y útil en el cáncer de piel?

Skin cancer, like other cancers, is characterized by the uncontrolled growth of transformed cells. Tumor growth has been studied for decades. We review different methods for measuring skin tumor growth and propose a new system for estimating tumor doubling time that could be useful in the management of skin cancer.

Synergistic effects of microbubble-mediated focused ultrasound and radiotherapy in a F98 glioma model

Combined microbubble-mediated focused ultrasound (FUS) and radiation therapy (RT) has been shown to improve outcomes in tumors outside the brain. Here, we study the effects of FUS + RT in a F98 glioma model. Tumor cells were implanted into the brains of 45 Fischer rats (n = 4–8 per group): Controls, FUS, RT (4,8,15-Gy), and FUS + RT (4,8,15-Gy). 9 days after implantation, tumors were targeted using FUS (1–2 W, 220 kHz, 5 ms bursts, 1 Hz PRF, 180 s, 20 μL/kg Definity microbubbles), followed by RT. Tumor progression was monitored using MRI. At 4Gy, FUS + RT increased tumor doubling time by 11% compared to RT only and Controls (P &amp;lt; 0.01). At higher doses, where RT alone had a significant effect, there were no significant differences in doubling time compared to RT alone. Tumor volumes were reduced by 21–57% (4Gy) and 20–48% (15Gy) compared with RT alone (P &amp;lt; 0.05). No significant benefit was observed at 8Gy. A moderate, but not significant, increase in median survival was observed: 28 versus 27days (4Gy), 30 versus 29days (8Gy), and 35 vs. 33 days (15Gy). However, at 4Gy, FUS + RT significantly improved survival by 6% compared to the control group (median survival = 27days), while RT only offered no improvement. This study indicates that FUS + RT may improve therapeutic outcomes in glioblastoma, particularly at low RT doses, where RT alone has no therapeutic benefit.

Tumor doubling time as preoperative predictor of malignancy and recurrence in newly diagnosed meningioma.

Most meningiomas are benign, and the indications for surgery are determined by size and symptoms, but some are malignant and have a high recurrence rate. Currently, no preoperative prognostic factors have been established. The purpose of this study was to investigate whether tumor doubling time (Td) is useful in predicting tumor prognosis. Patients who underwent surgery for newly diagnosed meningioma at our hospital between 2007 and 2021 with preoperative magnetic resonance (MR) imaging evaluation over a period of 6months were included in this study. We calculated the Td from the preoperative MR images and examined the correlation between Td and WHO grade, MIB-1 SI, and other conditions. A total of 269 newly diagnosed meningiomas were operated on during the study period, of which 62 met inclusion criteria. The median Td was 1082days (54-8579days), and MIB-1 SI was 2.45% (0.7-14.6%). Td and MIB-1 SI had a negative correlation (r = - 0.319, p = 0.0122). MIB-1 SI was higher in patients with Td < 3years than in those with Td ≥ 3 (p = 0.005), and the incidence of high WHO grade (grade2) was higher in patients with Td < 1year than in patients with Td ≥ 1 (p = 0.014). Meningiomas with Td < 3years had significantly higher MIB-1 SI, and tumors with Td < 1year had a higher likelihood of malignancy. Therefore, early treatment should be considered in patients with short Td meningioma even if asymptomatic, and further consideration could be given to radical resection at the time of surgery.

Upregulation of the oestrogen target gene SIX1 is associated with higher growth speed and decreased survival in HCV-positive women with hepatocellular carcinoma.

The male/female ratio of patients with hepatocellular carcinoma (HCC) is often unbalanced towards the male sex, indicating a sex predisposition for HCC development. A possible explanation may be attributed to different hormonal statuses, including the pro-inflammatory action of androgens in men and the protective effects of oestrogen against excessive inflammation in women. Although several studies have studied gene expression in patients with HCC, very few have attempted to identify features that could be distinctive between male and female patients. The present study aimed to identify distinctive signalling mechanisms between men and women that may be associated with HCC progression. The present study analysed a detailed microarray database that was obtained from the prospective study of 78 patients with HCC to study gene expression according to sex. In addition, the present study aimed to evaluate whether the differentially expressed genes were known oestrogen targets. Moreover, RNAs from the HCC cohort were evaluated for microRNA (miRNA/miR) expression, and a relationship between miRNA and gene expression according to sex was investigated. One gene, sineoculis homeobox homolog 1 (SIX1), which is known to be an oestrogen target gene, was revealed to be highly upregulated in hepatitis virus C (HCV)-positive female patients with HCC but not in HCV-positive male patients. In addition, SIX1 upregulation had a significant relationship with tumour growth speed (assessed as tumour doubling time in two CTs performed 6 weeks apart) and survival (P=0.009 and P=0.042, respectively) in female patients only. Furthermore, SIX1 upregulation was related with miR-421 and miR-9-5p only in male patients; however, in female patients, SIX1 upregulation had a direct relationship with miR-181b, miR-503-5p and miR-125b (miRNAs with potential oncogenic capacity), and an inverse correlation with miR139-5p, miR-26b, let7c-3p and let7c-5p (putatively oncosuppressive microRNAs). These data suggested a distinctive model for liver carcinogenesis in HCV-positive women, with downregulation of protective mechanisms against tumour progression and the activation of potential oncogenes, in relation to the oestrogen target gene SIX1. (IRB10/08_CE_UniRer; ClinicalTrials ID: NCT01657695).

PARP targeted Auger emitter therapy with [125I]PARPi-01 for triple-negative breast cancer

BackgroundTriple-negative breast cancer (TNBC) lacks biomarkers for targeted therapy. Auger emitters display the best therapeutic effect, if delivered directly into the nucleus proximal to DNA. The nuclear protein Poly (ADP-ribose)-Polymerase 1 (PARP1) is a suitable target against which few inhibitors (PARPi) are clinically approved for treatment of breast cancer with germline BRCA mutation (BRCAmut). In this study, a theranostic approach was investigated in a TNBC xenografted mouse model by radiolabelling a close derivative of a PARPi Olaparib (termed PARPi-01) with the Auger emitters 123/125I.MethodsTNBC cell line MDA-MB-231 was subcutaneously implanted in female NOD/SCID mice. At a tumour size of ~ 500mm3, [123I]PARPi-01 was administered intravenously, and SPECT/CT images were obtained at 4 h or 24 h post injection (p.i). A therapy study was performed with [125I]PARPi-01 in 4 doses (10 MBq/dose, 10 days apart). Tumour growth was monitored by CT scans longitudinally once per week. Upon reaching study endpoint, tissues were harvested and stained with TUNEL assay for detection of apoptosis induction.ResultsSPECT/CT images showed rapid hepatobiliary tracer clearance at 4 h post injection (p.i.). Retention in thyroid at 24 h p.i. suggested tracer deiodination in vivo. The tumour and liver uptake were 0.2%ID/g and 2.5%ID/g, respectively. The tumour: blood ratio was 1.3. Endogenous therapy induced a significant delay in tumour growth (doubling time increased from 8.3 to 14.2 days), but no significant survival advantage. Significantly higher apoptosis ratio was observed in [125I]PARPi-01 treated tumour tissues. No radiotoxicity was detected in the liver and thyroid.ConclusionConsidering the radio-cytotoxic effect in the tumour tissue and a delay on tumour doubling time, [125I]PARPi-01 presents a potential radiotherapeutics for treatment of TNBC. Improvements to overcome the suboptimal pharmacokinetics are necessary for its potential clinical application.

Docetaxel targets aggressive methylation profiles and serves as a radiosensitizer in high-risk meningiomas.

Meningioma is the most common primary intracranial tumor in adults. A subset of these tumors recur and invade the brain, even after surgery and radiation, resulting in significant disability. There is currently no standard-of-care chemotherapy for meningiomas. As genomic DNA methylation profiling can prognostically stratify these lesions, we sought to determine whether any existing chemotherapies might be effective against meningiomas with high-risk methylation profiles. A previously published dataset of meningioma methylation profiles was used to screen for clinically significant CpG methylation events and associated cellular pathways. Based on these results, patient-derived meningioma cell lines were used to test candidate drugs in vitro and in vivo, including efficacy in conjunction with radiotherapy. We identified 981 genes for which methylation of mapped CpG sites was related to progression-free survival in meningiomas. Associated molecular pathways were cross-referenced with FDA-approved cancer drugs, which nominated Docetaxel as a promising candidate for further preclinical analyses. Docetaxel arrested growth in 17 meningioma cell sources, representing all tumor grades, with a clinically favorable IC50 values ranging from 0.3 nM to 10.7 mM. The inhibitory effects of this medication scaled with tumor doubling time, with maximal benefit in fast-growing lesions. The combination of Docetaxel and radiation therapy increased markers of apoptosis and double-stranded DNA breaks, and extended the survival of mice engrafted with meningioma cells relative to either modality alone. Global patterns of DNA methylation may be informative for the selection of chemotherapies against meningiomas, and existing drugs may enhance radiation sensitivity in high-risk cases.

An MRI-based radiomics model to predict clear cell renal cell carcinoma growth rate classes in patients with von Hippel-Lindau syndrome.

Upfront knowledge of tumor growth rates of clear cell renal cell carcinoma in von Hippel-Lindau syndrome (VHL) patients can allow for a more personalized approach to either surveillance imaging frequency or surgical planning. In this study, we implement a machine learning algorithm utilizing radiomic features of renal tumors identified on baseline magnetic resonance imaging (MRI) in VHL patients to predict the volumetric growth rate category of these tumors. A total of 73 VHL patients with 173 pathologically confirmed Clear Cell Renal Cell Carcinoma (ccRCCs) underwent MRI at least at two different time points between 2015 and 2021. Each tumor was manually segmented in excretory phase contrast T1 weighed MRI and co-registered on pre-contrast, corticomedullary and nephrographic phases. Radiomic features and volumetric data from each tumor were extracted using the PyRadiomics library in Python (4544 total features). Tumor doubling time (DT) was calculated and patients were divided into two groups: DT < = 1year and DT > 1year. Random forest classifier (RFC) was used to predict the DT category. To measure prediction performance, the cohort was randomly divided into 100 training and test sets (80% and 20%). Model performance was evaluated using area under curve of receiver operating characteristic curve (AUC-ROC), as well as accuracy, F1, precision and recall, reported as percentages with 95% confidence intervals (CIs). The average age of patients was 47.2 ± 10.3years. Mean interval between MRIs for each patient was 1.3years. Tumors included in this study were categorized into 155 Grade 2; 16 Grade 3; and 2 Grade 4. Mean accuracy of RFC model was 79.0% [67.4-90.6] and mean AUC-ROC of 0.795 [0.608-0.988]. The accuracy for predicting DT classes was not different among the MRI sequences (P-value = 0.56). Here we demonstrate the utility of machine learning in accurately predicting the renal tumor growth rate category of VHL patients based on radiomic features extracted from different T1-weighted pre- and post-contrast MRI sequences.

Volume Doubling Time of Pulmonary Carcinoid Tumors Measured by Computed Tomography

IntroductionPulmonary carcinoid tumor (PCT) is a rare neuroendocrine lung neoplasm comprising approximately 2% of lung cancer diagnoses. It is classified as either localized low-grade (typical) or intermediate-grade (atypical) subtypes. PCT is known clinically to be a slow-growing cancer, however few studies have established its true growth rate when followed over time by computed tomography (CT). Therefore, we sought to determine the volume doubling time for PCTs as visualized on CT imaging. Materials and MethodsWe conducted a retrospective analysis of all PCTs treated at our institution between 2006 and 2020. Nodule dimensions were measured using a Picture Archiving and Communication System or retrieved from radiology reports. Volume doubling time was calculated using the Schwartz formula for PCTs followed by successive CT scans during radiographic surveillance. Consistent with Fleischner Society guidelines, tumors were considered to have demonstrated definitive growth by CT only when the interval change in tumor diameter was greater than or equal to 2 mm. ResultsThe median volume doubling time of 13 typical PCTs was 977 days, or 2.7 years. Five atypical PCTs were followed longitudinally, with a median doubling time of 327 days, or 0.9 years. ConclusionsTypical pulmonary carcinoid features a remarkably slow growth rate as compared to more common lung cancers. Our analysis of atypical pulmonary carcinoid included too few cases to offer definitive conclusions. It is conceivable that clinicians following current nodule surveillance guidelines may mistake incidentally detected typical carcinoids for benign non-growing lesions when followed for less than 2 years in low-risk patients.

Abstract 2721: Accurate prediction of tumor growth and doubling times for triple negative breast cancer (TNBC) allows for patient-specific assessment of tumor aggressiveness

Abstract TNBC is the most aggressive of breast cancer subtypes and lacks targeted therapies. Thus, tumor aggressiveness is an important factor to determine escalation of care for TNBC patients. Currently, aggressiveness is evaluated based on tumor spread and markers of cell growth. Although these features are significantly associated with tumor volume doubling time (TVDT), TVDT distributions are not simply separated by any of these criteria. Therefore, for single patients, no clear predictor of TVDT (tumor aggressiveness) exists. We sought to test the SimBioSys TumorScope (TS), a biophysical modeling software, to determine whether it could be used for predicting tumor growth and TVDT in TNBC patients. We used the TS software to simulate tumor growth in 30 TNBC patients. We compared the calculated TVDTs from our simulations to values obtained from literature. Using our metabolic modeling platform, we simulated tumor average specific growth rates (SGRs) from RNA-seq data taken from the TCGA BRCA data set. We found that coordinated gene expression profiles act to regulate SGR differentially across breast cancer receptor subtypes (p = 2x10-16), with ER+/PR+ tumors growing slowest (SGR = 0.49 %/day +/- 0.33, median +/- stdev) and TNBC tumors growing fastest (SGR = 1.03 %/day +/- 0.35), which match well with previously reported values of SGR in breast cancers (reported SGR = 0.175 +/- 0.979 %/day for Luminal A and SGR = 1.003 +/- 1.121 %/day for TNBC, mean +/- stdev). We next tested how these growth rates are integrated with tumor biology to produce TVDTs on the order of 100-200 days in TNBC patients. We selected 30 patients with TNBC whose MRI data and electronic medical record (EMR) information are available in our TumorBank to use for this study. We then selected representative TNBC tumor metabolic models and mapped patients to these metabolic models based on patient phenotype. We used clinical measurements to predict unspecified model parameters for TS simulations, resulting in a model with a single free parameter (growing fraction of tumor cells). We tuned this parameter within reported values to simulate TVDT in our patient cohort. Simulating the growth of these tumors resulted in a median TVDT = 163 days with a standard deviation of 111 days, closely matching clinically measured TVDTs in TNBC patients (reported mean TVDT = 127 +/- 48 days). In summary, TS biophysical modeling software accurately predicts TVDTs in TNBC patients. Importantly, this was accomplished without parameter fitting outside of physiologically-measured values and serves as a powerful validation of the our modeling approach. In the future, this high accuracy modeling framework can be further personalized by accounting for additional patient features, including, but not limited to, patient-specific mitotic index, blood chemistry data, and tumor-specific RNA-sequencing. Citation Format: John Whitman, Daniel Cook, Snehal Patel, Lance Munn, John A. Cole, The SimBioSys Team. Accurate prediction of tumor growth and doubling times for triple negative breast cancer (TNBC) allows for patient-specific assessment of tumor aggressiveness [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 2721.

Abstract 4026: JDQ443, a covalent inhibitor of KRASG12C with a novel binding mode, shows broad antitumor activity in KRASG12C preclinical models as a single agent and in combination with inhibitors of SHP2, MEK or CDK4/6

Abstract Background: Oncogenic mutations occurring in the KRAS component of the RAS/MAPK pathway slow nucleotide cycling between its active (GTP-bound) and inactive (GDP-bound) states, shifting it towards the active state and increasing oncogenic signaling. Among these mutations, the glycine-to-cysteine mutation of amino acid 12 (KRASG12C), found in ~13% of non-small cell lung cancer (NSCLC) and ~4% of colorectal cancer (CRC), can be specifically targeted and irreversibly locked in the inactive state by covalent modification of Cys12. We have previously reported the discovery and preclinical profile of JDQ443, a selective, oral, covalent inhibitor of KRASG12C that binds under the Switch II loop. Here, we report its antiproliferative and antitumor activity against panels of cancer cell lines as well as cell- (CDX) and patient-derived (PDX) tumor xenografts. Methods: JDQ443 antiproliferative activity was assessed by a high-throughput cell viability assay in a large panel of KRASG12C (n=17) and non-G12C (n=233) cell lines. Single-agent antitumor activity was assessed against a panel of KRASG12C CDX models from NSCLC (LU99, H2122, H2030, and HCC44), pancreatic (Mia PaCa-2), and esophageal (KYSE410) cancer cell lines, plus one non-G12C lung line (H441; KRASG12V). JDQ443 in vivo activity against a panel of KRASG12C NSCLC (n=10) and CRC (n=9) PDX models was assessed either as a single agent or in combination with TNO155 (SHP2 inhibitor [i]), trametinib (MEKi), or ribociclib (CDK4/6i). In vivo combination studies with TNO155 were also performed in CDX models (LU99, H2030, HCC44, and KYSE410). Results: In vitro, JDQ443 demonstrated potent antiproliferative activity selectively towards KRASG12C cell lines. Dose-dependent tumor growth inhibition/regression was observed for all KRASG12C CDX models, but not for the H441 KRASG12V model, and was independent of once-daily (QD) or twice-daily (BID) dosing. Single-agent antitumor activity (best average response, duration of reduction in tumor doubling time) was observed across both PDX panels and was improved by all three combination treatments. The JDQ443/TNO155 combination improved single-agent activity across CDX models, with comparable antitumor benefit maintained at QD or BID TNO155 schedules in two of three models (LU99 and KYSE410). Combination with TNO155 allowed a reduced dose of JDQ443 to achieve similar target occupancy and antitumor activity versus JDQ443 alone. Conclusions: JDQ443 demonstrates significant activity against a broad range of KRASG12C solid tumor models, both in vitro and in vivo, that is increased when combined with agents targeting both upstream and downstream components of the RAS signaling pathway. The combination benefit of JDQ443 + TNO155 over JDQ443 alone is maintained at reduced doses for both agents. Citation Format: Andreas Weiss, Hans Voshol, Diana Graus Porta, Carmine Fedele, Dario Sterker, Ruben De Kanter, Rowan Stringer, Toni Widmer, Alice Loo, Daniel A. Guthy, Kim S. Beyer, Nils Ostermann, Catherine LeBlanc, Marc Gerspacher, Andrea Vaupel, Richard Sedrani, Frederic Zecri, Saveur-Michel Maria, Francesco Hofmann, Peter Hammerman, Jeff Engelman, Edwige Lorthiois, Simona Cotesta, Saskia M. Brachmann. JDQ443, a covalent inhibitor of KRASG12C with a novel binding mode, shows broad antitumor activity in KRASG12C preclinical models as a single agent and in combination with inhibitors of SHP2, MEK or CDK4/6 [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 4026.

Abstract 719: Preclinical testing of CD73 inhibitors for pancreatic cancer immunoprevention

Abstract Introduction: Pancreatic ductal adenocarcinoma (PDAC) is characterized by a profoundly immunosuppressive microenvironment. Innovative therapeutic strategies are urgently needed to stop the progression of precancerous lesions into aggressive PDAC, which remains a lethal malignancy. The goal of this research project is to test the immunopreventive strategies by targeting the ectonucleotidase CD73, one of the gatekeeper enzymes responsible for adenosine production and the formation of immunosuppressive tumor microenvironment in this malignancy. We hypothesize that inhibition of CD73 will prevent pancreatic intraepithelial neoplasia (PanIN) formation and progression to PDAC by reversing immunosuppression. Materials and methods: A syngeneic PDAC mouse model was employed by injecting 100k murine pancreatic cancer (KPC) cells in flanks of C57BL/6 female mice. Oral gavage of AB680 (small molecule CD73 inhibitor) was given three days/week at 10mg/kg starting the day after KPC injections and tumor sizes were measured weekly. Toxicity was analyzed by serum ALT analysis. At the time of death 6 weeks post-KPC inoculation, tumor volume and mass were recorded. In another experiment, AB680 was administered 3 days/week at 10mg/kg for 5 weeks. CyTOF immunoprofiling of digested tumors from control and AB680 treated mice and HPLC analysis on serum from the time of death were performed. Results: In experiment 1, by week three of the study, there was a significant difference in tumor volume between the control and AB680 treated groups (P=0.02). However, in weeks 4-5 AB680 reduced tumor growth compared to vehicle controls, but the grouped statistical analysis was not significant. When observing individual tumors, there was a reduction in tumor size in 30% of the AB680 treated mice between weeks 3-5, but the difference was not statistically different. ALT analysis determined AB680 does not induce liver toxicity. For experiment 2 (3x/week treatment with AB680), there was a significant reduction in tumor growth. Activated CD8-positive T cells, dendritic cells, and macrophages were significantly increased in the syngeneic tumors from AB680 treated mice. The intratumoral adenosine levels were significantly decreased in AB680 treated mice compared to vehicle treated mice. Conclusion: We conclude oral gavage delivery of CD73 inhibitor AB680 at 10mg/kg (6x/week) reduces tumor growth in KPC syngeneic tumor bearing mice. Treatment with AB680 at 10mg/kg 3x/week significantly increases tumor doubling time, significantly alters intratumoral immune cell populations, and results in a significant decrease in intratumoral adenosine levels. In addition, we observed a significant increase in infiltration of activated CD8-positive T cells indicating oral gavage delivery using AB680 reverses immunosuppression in vivo. [Supported by NCI 75N91019D00021/75N91020F00002] Citation Format: Kanchan Singh, Vidhi Chandra, Lincoln Ballew, Tingting Mills, Erika Y. Faraoni, Trent Clark, Lana A. Vornik, Michelle I. Savage, Holger K. Eltzschig, Altaf Mohammed, Shizuko Sei, Powel H. Brown, Florencia McAllister, Jennifer Bailey-Lundberg. Preclinical testing of CD73 inhibitors for pancreatic cancer immunoprevention [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 719.

Abstract 3289: PD-1 peptide/IL-12 combination gene therapy for the treatment of melanoma

Abstract Immune checkpoint inhibitors (ICIs) such as PD-1 targeting antibodies nivolumab and pembrolizumab are FDA approved as therapies for many cancers. These ICIs inhibit PD-1 ligand binding, removing interference with T cell function, allowing T cell proliferation, and restoring the anti-tumor activity. Potential factors predicting checkpoint blockade success include PD-L1 expression, the presence of tumor infiltrating lymphocytes, microsatellite instability, and tumor mutational burden. ICIs are most effective clinically in combination therapies. Here, we devised a simple ICI gene therapy as a possible alternative to traditional and expensive monoclonal antibodies. We designed plasmids encoding the mouse sequences homologous to the nivolumab and pembrolizumab binding regions, which overlap the PD-1 ligand binding site. We hypothesized that, when produced intratumorally, each PD-1 peptide should bind PD-L1 and block T cell binding. Since B16F10 mouse melanoma cells and tumors express PD-L1, we tested this theory in this model. We directly demonstrated peptide-PD-L1 binding histologically on B16F10 mouse melanoma tumors. Systemic expression of the encoded peptides did not induce changes in general demeanor, discomfort or weight changes in mice, implying that intratumor expression would also be non-toxic. We then tested these peptide plasmids therapeutically. Intratumor electroporation delivery of the peptide plasmids to palpable B16F10 mouse melanoma tumors significantly increased tumor doubling time and induced approximately 10% long-term tumor regression. Delivery of a plasmid encoding IL-12 induced long-term tumor regression in approximately 40% of mice as well as a reduction myeloid-derived suppressor cells and T regulatory cells and an increase infiltration of CD8+ T cells, creating an inflamed tumor microenvironment. This modulation of the tumor microenvironment suggested the potentiation of a combination therapy. This combination synergistically increased long-term regression to 80-100%, depending on the peptide plasmid delivered, over either PD-1 peptide or IL-12 gene therapy alone. These results demonstrated that the delivery of immune regulators with differing activities may be a promising and potentially inexpensive alternative to monoclonal antibody therapies. Citation Format: Loree Heller, Guilan Shi, Jody Synowiec, Richard Heller. PD-1 peptide/IL-12 combination gene therapy for the treatment of melanoma [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 3289.

Host genetics influence response to targeted immunotherapy and effector cell capacity to perform key immune functions

Abstract Targeted immunotherapies have revolutionized cancer treatment, markedly improving patient cancer outcomes. Despite this rise to prominence as first line treatments for various malignancies, only a subset of patients respond to targeted immunotherapy. Trastuzumab targets tumor associated antigen (TAA) epidermal growth factor 2 (HER2). Differential response to trastuzumab suggests host genetics may influence response to treatment. To model this interaction, we utilize a genetically heterogeneous Diversity Outbred (DO) mouse model in an F1 cross (DOxBALB/c)F1. These genetically diverse mice (n=126) were orthotopically implanted with TUBO (BALB/c-syngeneic tumor) and treated with αNeu (7.16.4) mAb therapy. Like the human population, we observe a divergent response to therapy. Via genetic linkage analysis, we identify loci that correlate to a robust response. We confirm these loci in vivo using recombinant inbred collaborative cross (CC) strains containing/lacking driver loci (CCxBALB/c)F1. These loci alone are not sufficient to fully account for durable response to therapy; however, here we identify strains that uniformly eliminate tumor and conversely, are consistently refractory to treatment. Utilizing tissues from these strains, we evaluate canonical mechanisms of mAb therapy and show that tumor doubling time correlates with bone marrow derived macrophage capacity to phagocytose opsonized tumor in vitro via confocal microscopy. To better understand which cell populations of tumor infiltrate are expressing transcripts from these loci, we perform transcriptomic analysis on putative responder/non-responder strains, allowing us to see key differences in tumor infiltrating immune cell populations. Supported by NIH R37 CA220482, DMC Foundation, P30 CA022453

EXPRESSION OF P53 PROTEIN ASSOCIATES WITH ANTI-PD-L1 TREATMENT RESPONSE ON HUMAN-DERIVED XENOGRAFT MODEL OF GATA3/CR5/6-NEGATIVE RECURRENT NONMUSCULAR INVASIVE BLADDER UROTHELIAL CARCINOMA

Annotation: The study investigated the prognostic role of p53 expression in patients with GATA3 / CR5 / 6-negative recurrent nonmuscular invasive bladder cancer on the background of anti-PD-L1 treatment using a xenograft model in immunodeficient BALB / c nu / nu mice obtained from a patient. Twenty lines of patient-derived xenografts of relapsed high-PD-L1(+) double-negative NMIBC were developed, of which 10 lines represented high-grade tumors and the other ones—low-grade bladder cancer. Acceptors of each grade-related branch received specific anti-PD-L1 antibodies. Animals’ survival, tumor-doubling time, and remote metastasis were followed during the post-interventional period. PD-L1, GATA3, CR5/6, and p53 protein expressions in engrafted tumors were assessed by immunohistochemistry. The expression of p53 protein is an independent factor affecting the animals’ survival time of anti-PD-L1-treated mice with low-grade high-PD-L1(+) double-negative nonmuscular invasive bladder cancer. P53 expression may be considered as a prognostic factor for the anti-PD-L1 treatment efficacy of low-grade high-PD-L1-positive GATA3(-)/CR5/6(-)-relapsed noninvasive bladder cancer.

Management of incidentally detected small anterior mediastinal nodules: Which way to go?

ObjectivesWith increasing use of CT screening for lung cancers, there is a tendency toward increased detection of asymptomatic small anterior mediastinal nodules (SAMNs). In face of high rate of non-therapeutic surgery in these patients, workup and follow-up strategy for such lesions remains to be established. Materials and MethodsThis is a real-world study in patients with SAMNs (baseline diameter ≤ 3 cm) during 2013–2018. Interval growth of the nodules was reviewed. Accuracy of preoperative diagnosis was evaluated, and tumor doubling time (TDT) was calculated in resected tumors. ResultsA total of 419 patients were entered into the study, among them 91 received surgery. Eighty-four patients (92.3%) turned out to have thymic tumors, with a non-therapeutic surgery rate of only 6.6%. For 73 patients receiving both CT and MRI examinations, the sensitivity for diagnosing thymic tumors by CT alone was merely 72.1%, which was significantly improved to 97.1% (p < 0.001) when MRI was incorporated. Among 38 thymic tumor patients who had previous CT scan before surgery, significant difference in median TDT was seen between low-grade tumors and intermediate-/high-grade tumors (23.8 vs. 10.1 months, p = 0.021). Of the 328 patients not receiving surgery, 269 (82.0%) were diagnosed of having benign cysts by CT + MRI, followed by 24 (7.3%) lymph nodes, 22 (6.7%) thymic hyperplasia, and 13 (4%) thymic tumors. During follow-up (median 33 months), 319 (97.3%) lesions remained unchanged. ConclusionThe majority of incidentally detected SAMNs remain stable during long-term follow-up. Incorporating MRI with CT scan is helpful in differentiating benign cysts from small thymic tumors, thus avoiding non-therapeutic intervention. Follow-up is safe and warranted upon first detection when high-grade malignancies could be ruled out by careful imaging studies.