Chemotherapy response score: Validation of a three-tier system to quantify histopathologic response to neoadjuvant chemotherapy in ovarian carcinoma.

e17539 Background: Neoadjuvant chemotherapy (NACT) with interval debulking surgery is considered for patients with advanced-stage ovarian carcinoma (OC) who are not ideal candidates for primary debulking surgery due to advanced age, frailty, poor performance status, comorbidities, or who have disease unlikely to be optimally resected. Moreover, response to NACT may be a suitable surrogate end point for long-term clinical outcome in ovarian cancer. The aim of the present study is to evaluate the utility of a three-tier Chemotherapy Response Score (CRS) and validate whether residual disease or evidence of regression following NACT may provide prognostic information in ovarian cancer. Methods: We conducted a retrospective single-institution study of patients who received NACT with carboplatin and paclitaxel for FIGO stage III/IV ovarian cancer. Response to NACT was graded as no or minimal tumor response (CRS1); appreciable tumor response amid readily identifiable viable tumor (CRS2); or complete/near-complete response with no residual tumor or minimal scattered tumor foci (CRS3) as described previously (Böhm S, et al. J Clin Oncol 33:2457-2463). Multivariate progression free survival (PFS) and overall survival (OS) analyses were performed accounting for age, FIGO stage and BRCA status. Results: Of the 86 patients accrued to date, median age was 65 years, 62% had stage IV disease and 16% had a somatic/germline BRCA mutation. CRS scores 1, 2 and 3 were found in 26 (30%), 43 (50%) and 17 (20%) of cases, respectively, and were associated with PFS (log rank p = 0.002). A high CRS score predicted improved PFS and OS (CRS 2/3 vs 1; median PFS 17.3 vs. 11.8 mo, adjusted hazard ratio (HR), 0.33; 95%CI 0.17-0.62; p < 0.001; median OS 47.9 vs. 38.3 mo, adjusted HR 0.36, 95%CI 0.15-0.88, p = 0.026). Similarly, when comparing CRS 3 with 1/2, the high score predicted improved outcome for PFS but not OS (median PFS 17.3 vs. 14.7 mo, adjusted HR, 0.42; 95%CI 0.19-0.95; p = 0.037; median OS 48.6 vs. 46.5 mo, adjusted HR 0.43, 95%CI 0.14-1.35, p = 0.149). Conclusions: In this study, we validate a simple three-tier chemotherapy response scoring system for assessing histopathologic response of OC to NACT. Residual disease and evidence of complete/near complete regression following NACT provides prognostic information in OC. CRS may serve as a potential surrogate marker for long-term outcome and be a useful alternative intermediate end point in future clinical trials.

SMAD4 Loss is Associated with Response to Neoadjuvant Chemotherapy with Hydroxychloroquine in Patients with Pancreatic Adenocarcinoma

Background SMAD4, a tumor suppressor gene, is inactivated or deleted in 60–90% of pancreatic adenocarcinomas (PDA). Loss of SMAD4 allows tumor progression by limiting cell cycle arrest and apoptosis and increasing metastases. SMAD4 deficient PDA cells are resistant to radiotherapy by upregulating autophagy, a cell survival mechanism that counteracts apoptotic mechanisms and allows intracellular recycling of macromolecules and organelles. Hydroxychloroquine (HCQ) is an orally available autophagy inhibitor with an established toxicity profile. We studied whether HCQ treatment in SMAD4 deficient PDA may prevent therapeutic resistance induced by autophagy upregulation. Methods We retrospectively analyzed the SMAD4 status of PDA patients enrolled in two prospective clinical trials evaluating administration of preoperative HCQ. The first dose escalation trial demonstrated the safety of preoperative gemcitabine with HCQ (NCT01128296). More recently, a randomized trial of gemcitabine/nab-paclitaxel +/- HCQ evaluated Evans Grade histopathologic response (NCT01978184). Immunohistochemistry of resected specimens for SMAD4 was previously performed. Patients not treated at the max HCQ dose (n = 5), not resected (n = 2) or with SMAD4 staining unavailable were excluded (n = 10). The effect of SMAD4 loss on response to HCQ and chemotherapy was studied for association with clinical outcome. Fisher’s exact test and log-rank test were used to assess response and survival. Results 52 patients receiving HCQ with neoadjuvant chemotherapy were studied. 25 of these patients had SMAD4 loss (48%). 76% of HCQ treated patients with SMAD4 loss obtained a histopathologic response ≥ 2A, compared to only 37% with SMAD4 intact (p = 0.006). In contrast with prevailing views, loss of SMAD4 was not associated with a detriment in median overall survival in HCQ treated patients (34.43 months in SMAD4 loss vs. 27.27 months in SMAD4 intact, p = 0.18). Conclusions The addition of HCQ to neoadjuvant chemotherapy in patients with PDA may improve treatment response in those with SMAD4 loss. Further study of the relationship between SMAD4, autophagy and treatment outcomes in PDA is warranted.

260 T cell infiltrating repertoire diversity is associated with enhanced survival following neoadjuvant therapy in patients with resectable pancreatic cancer

BackgroundPancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy, characterized by a desmoplastic stromal reaction and an immunosuppressive tumor microenvironment (TME)1. The metabolic stress within the PDAC TME promotes autophagy, a form of programmed cell survival associated with chemotherapeutic resistance and immune evasion.2, 3MethodsWe conducted a randomized phase II study of preoperative gemcitabine and nab-paclitaxel with or without autophagy inhibition with oral hydroxychloroquine (HCQ) in patients with resectable PDAC. Autophagy inhibition increased Evans Grade histopathologic response and immune infiltrate.4Utilizing multiplex immunohistochemistry and dimer avoidance multiplex PCR-NGS5 in a subset of RNA extracted FFPE tumor specimens, we evaluated the adaptive immune response and immune correlates of response.ResultsPatients receiving HCQ had a greater CD4/CD8 immune infiltration (p = 0.033). Independent of treatment, a higher tumor immune infiltration score,6 was associated with improved overall survival (p = 0.035). Bulk tumor immunosequencing revealed a clonally expanded T cell receptor (TCR) Vβ (115±84 unique CDR3s (uCDR3s) of 3.3 × 104±2.4 total CDR3s) and B cell receptor (BCR) IgH (9.8 × 104±5.2 uCDR3s of 1.4 × 105±0.76 total CDR3s) repertoire compared to a paucity of TCR Vδ clones (2±1 uCDR3s of 43±60 total CDR3s). Patients with a higher than median TCR Vβ Diversity 50 Index (D50, proportion of uCDR3s that make up 50% of the total CDR3s) had significantly higher tumor CD4 (p = 0.003) and CD8 (p = 0.031) counts. Patients with a higher than median TRC Vβ D50 also had a reduced lymph node ratio (p = 0.039) and greater overall survival (p = 0.037, figure 1). Conversely, patients with a higher than median BCR IgH D50 had worse overall survival (p = 0.0241). Given the dichotomy of the TCR and BCR repertoire diversity and association with clinical outcome, we further analyzed the individual ratio of TRC Vβ:BCR IgH CDR3s and found that patients with a higher than median TRC Vβ:BCR IgH ratio had a greater Evan’s Grade histopathologic response (p = 0.069).Abstract 260 Figure 1Following neoadjuvant therapy, patients with resectable pancreatic cancer with a higher than median intratumoral TCR Vβ Diversity 50 (n=9, 4.624 HR; 95 CI [0.971, 21.83]) have greater overall survival compared to patients with lower than median intratumoral TCR Vβ Diversity 50 (n=10, 0.2163 HR; 95 CI [0.458, 1.021]). Representative tree maps of high and low TRC Vβ D50, where each rounded rectangle represents a unique CDR3, with the size of the rectangle corresponding to the relative frequency of the CDR3 clones across the entire repertoireConclusionsPDAC TIL repertoire with high TCR Vβ diversity is associated with decreased positive lymph node ratio and greater overall survival following neoadjuvant therapy. The divergent outcomes associated with increased intratumoral TCR and BCR diversity suggest a host response that may favor opposing T and B cell lymphocytic expansion. Regulation of this relationship may be explained by tumor MHC class I expression[3] or the presence of CD141+ cross presenting dendritic cells7, 8 and tertiary lymphoid structures,9 currently under investigation. Examination of repertoire modulating therapies is warranted.Trial RegistrationThis trial (NCT01978184) was approved by the protocol review committee and IRB 13–074 at the University of Pittsburgh and performed in full accordance with the guidelines for good clinical practice and the Declaration of Helsinki. Written informed consent was obtained from all patients prior to any protocol treatment.ReferencesHo WJ, Jaffee EM, Zheng L. The tumour microenvironment in pancreatic cancer - clinical challenges and opportunities. Nat Rev Clin Oncol 2020;17(9):527–540.Boone BA, Zeh HJ, 3rd, Bahary N. Autophagy inhibition in pancreatic adenocarcinoma. Clin Colorectal Cancer 2018;17(1):25–31.Yamamoto K, Venida A, Yano J, et al. Autophagy promotes immune evasion of pancreatic cancer by degrading MHC-I. Nature 2020;581(7806):100–105.Zeh HJ, Bahary N, Boone BA, et al. A Randomized phase ii preoperative study of autophagy inhibition with high-dose hydroxychloroquine and gemcitabine/nab-paclitaxel in pancreatic cancer patients. Clin Cancer Res 2020;26(13):3126–3134.Han J, Lotze MT. The adaptome as biomarker for assessing cancer immunity and immunotherapy. Methods Mol Biol2020; 2055:369–397.Hwang WT, Adams SF, Tahirovic E, Hagemann IS, Coukos G. Prognostic significance of tumor-infiltrating T cells in ovarian cancer: a meta-analysis. Gynecol Oncol. 2012;124(2):192–198.Spranger S, Dai D, Horton B, Gajewski TF. Tumor-Residing Batf3 Dendritic Cells Are Required for Effector T Cell Trafficking and Adoptive T Cell Therapy. Cancer Cell 2017;31(5):711–723 e714.Jang JE, Hajdu CH, Liot C, Miller G, Dustin ML, Bar-Sagi D. Crosstalk between regulatory T cells and tumor-associated dendritic cells negates anti-tumor immunity in pancreatic cancer. Cell Rep 2017;20(3):558–571.Bruno TC. New predictors for immunotherapy responses sharpen our view of the tumour microenvironment. Nature 2020;577(7791):474–476.

Histopathologic Response Is a Positive Predictor of Overall Survival in Patients Undergoing Neoadjuvant/Perioperative Chemotherapy for Locally Advanced Gastric or Gastroesophageal Junction Cancers—Analysis from a Large Single Center Cohort in Germany

There is conflicting evidence regarding the efficacy of neoadjuvant/perioperative chemotherapy (NCT) for gastro-esophageal cancer (GEC) on overall survival. This study aimed to analyze the outcomes of multimodal treatments in a large single center cohort. We performed a retrospective analysis of patients treated with NCT, followed by intended curative oncological surgery for locally advanced gastric cancer. Uni- and multivariate regression analysis were performed to identify the predictors of overall survival. From over 3000 patients, 702 eligible patients were analyzed. In the univariate analysis clinical stage, application of preoperative PLF, requirement of surgical extension, UICC-stage, grading, R-status, Lauren histotype, and HPR were the prognostic survival factors. In multivariate analysis PLF regimen, UICC-stages, R-status, Lauren histotype, and histopathologic regression (HPR) were significant predictors of overall survival. Overall HPR-rate was 26.9%. HPR was highest in the cT2cN0 stage (55.9%), and lowest in the cT3/4 cN+ stage (21.6%). FLOT demonstrated the highest HPR (37.5%). Independent predictors for HPR were the clinical stage and grading. Kaplan Meier analyses demonstrated significant survival benefits for the responding patients (p < 0.0001). HPR after NCT was an important prognostic factor to predict overall survival for locally advanced GEC. FLOT should be the preferred regimen in patients undergoing NCT ahead of surgery.

Association of SMAD4 loss with response to neoadjuvant chemotherapy with the autophagy inhibitor hydroxychloroquine in patients with pancreatic adenocarcinoma.

761 Background: SMAD4, a tumor suppressor gene, is inactivated or deleted in 60-90% of pancreatic adenocarcinomas (PDA). Loss of SMAD4 allows tumor progression by limiting cell cycle arrest and apoptosis and increasing metastases. SMAD4 deficient PDA cells are resistant to radiotherapy by upregulation of autophagy, a cell survival mechanism that allows intracellular recycling of macromolecules and organelles. Hydroxychloroquine (HCQ) is a known autophagy inhibitor, suggesting that HCQ treatment in SMAD4 deficient PDA may prevent therapeutic resistance induced by autophagy upregulation. Methods: We retrospectively analyzed the SMAD4 status of PDA patients enrolled in two prospective clinical trials evaluating preoperative HCQ. The first dose escalation trial demonstrated the safety of preoperative gemcitabine with HCQ ( NCT01128296 ). More recently, a randomized trial of gemcitabine/nab-paclitaxel +/- HCQ evaluated Evans Grade histopathologic response ( NCT01978184 ). Immunohistochemistry of resected specimens for SMAD4 was previously performed. Patients not treated at the max HCQ dose (n = 5), not resected (n = 2) or with SMAD4 staining unavailable were excluded (n = 10). The effect of SMAD4 loss on response to HCQ and chemotherapy was studied for association with clinical outcome. Fisher’s exact test and log-rank test were used to assess response and survival. Results: 52 patients receiving HCQ with neoadjuvant chemotherapy and 24 patients receiving neoadjuvant chemotherapy alone were studied. Of the HCQ group, 25 patients had SMAD4 loss (48%), compared with 15 control patients (63%, p = 0.32). 76% of HCQ treated patients with SMAD4 loss obtained a histopathologic response ≥2A, compared to only 37% with SMAD4 intact (p = 0.006). In the control group, loss of SMAD4 was associated with a nonsignificant detriment in 3 year OS (25% vs. 78%, p = 0.3) that was less apparent in patients treated with HCQ (46% vs. 47%, p = 0.18). Conclusions: The addition of HCQ to neoadjuvant chemotherapy in PDA may improve treatment response in patients with SMAD4 loss. Further study of the relationship between SMAD4, autophagy and treatment outcomes in PDA is warranted.

Impact of dose reduction and treatment delay of neoadjuvant chemotherapy in gastric and esophageal adenocarcinoma

Background Neoadjuvant chemotherapy in resectable gastric and esophageal adenocarcinoma is often hampered by toxicities and fragile patients resulting in dose reductions and/or treatment delays. The aim of this study was to assess how these treatment modifications affect outcome. Methods A series of 63 consecutive patients treated 2008-2014 with neoadjuvant EOX (epirubicin, oxaliplatin and capecitabine) and surgical resection, with or without adjuvant treatment, were reviewed. Chemotherapy dose index (DI), i.e. the ratio of actual to planned cumulative dose, and time index (TI), i.e. the ratio of planned to actual total duration, were calculated. Associations of neoadjuvant EOX DI and TI with histopathologic response were analysed with binary logistic regression. Time to recurrence (TTR) and overall survival (OS) were estimated using Kaplan-Meier analyses. Results Statistically significant associations were found between neoadjuvant EOX TI >= 0.95 and a major histopathologic response (0-10% residual cancer cells) and between neoadjuvant EOX DI >= 0.95 and a response with 0-50% residual cancer cells. Significantly improved TTR and OS were seen in patients with a major histopathologic response. Conclusions Our results suggest that treatment delays of neoadjuvant chemotherapy in gastric or esophageal adenocarcinoma should be avoided in order to achieve a major response.