Low viscosity silicone with less shrinkage for brain slices

Plastination consists of replacing lipid and water with a curable polymer. This technique has numerous advantages, of which the production of non-toxic, inert, highly durable, dry, and easy maintenance and storage specimens stand out. Like all anatomical techniques, plastination also has disadvantages, and one of them is tissue shrinkage. The feasibility of using low viscosity domestic silicone (0,1Pa.s at 20°C) to plastinate brain slices was examined. Twenty humans, 10 millimeters (mm) brain slices were impregnated, ten slices each with two polymers [10 with domestic low viscosity polymer - P1 and 10 slices with Biodur® (0,45-0,6Pa.s at 20°C) S10]. Shrinkage was accessed by volume and area measurements. Volume shrinkage was significantly less in the slices impregnated with low viscosity domestic polymer, demonstrating the feasibility to plastinate brain slices with domestic low viscosity silicone polymer.

The World Health Organization classification of pancreaticobiliary cytopathology stratifies risk of malignancy and outcome for endoscopic ultrasound-guided fine-needle aspiration of the pancreas

BACKGROUND

The World Health Organization (WHO) has recently published a classification for reporting pancreaticobiliary cytopathology with differences compared to the Papanicolaou Society of Cytopathology (PSC) classification.

METHODS

Retrospective data were collected from pancreatic endoscopic ultrasound-guided fine-needle aspirations from 2014 to 2017 at a pancreatic cancer center. Absolute risk of malignancy (AROM), relative risk (to benign), performance characteristics, and overall survival were calculated for the entire cohort with comparison of cysts and solid lesions.

RESULTS

In total, 2562 cases were included: 16% cyst (n = 411) and 84% solid (n = 2151). The histologic confirmation rate was 43% (n = 1101) and the median follow-up (for benign) was 56 months. For WHO I-VII, overall AROM (%) was 23, 22, 62, 13, 65, 97, and 100; cyst AROM was 7, 0, 19, 13, 38, 78, and 100; and solid AROM was 50, 29, 70, 15, 100, 99, and 100. For PSC I-VI, overall AROM (%) was 23, 29, 64, 0 (IVa), 60 (IVb), 97, and 100; cyst AROM was 7, 0, 19, 0, 21, 78, and 100; and solid AROM was 50, 35, 73, 0, 92, 99, and 100. The difference in relative risk for a cyst (vs. solid) overall was 0.38 for WHO and 0.26 for PSC. WHO and PSC categories showed stratification for the probability of overall survival.

CONCLUSIONS

Cystic versus solid lesion type can dramatically affect AROM, particularly for nondiagnostic (I), benign (II), atypical (III), and WHO V categories. WHO IV conveys a similarly low AROM for cystic and solid types. Both classifications stratify the probability of overall survival, including the newly introduced categories WHO IV and WHO V.

Progressive plasticity during colorectal cancer metastasis

Metastasis is the principal cause of cancer death, yet we lack an understanding of metastatic cell states, their relationship to primary tumor states, and the mechanisms by which they transition. In a cohort of biospecimen trios from same-patient normal colon, primary and metastatic colorectal cancer, we show that while primary tumors largely adopt LGR5 + intestinal stem-like states, metastases display progressive plasticity. Loss of intestinal cell states is accompanied by reprogramming into a highly conserved fetal progenitor state, followed by non-canonical differentiation into divergent squamous and neuroendocrine-like states, which is exacerbated by chemotherapy and associated with poor patient survival. Using matched patient-derived organoids, we demonstrate that metastatic cancer cells exhibit greater cell-autonomous multilineage differentiation potential in response to microenvironment cues than their intestinal lineage-restricted primary tumor counterparts. We identify PROX1 as a stabilizer of intestinal lineage in the fetal progenitor state, whose downregulation licenses non-canonical reprogramming.

Endoscopic papillectomy for ampullary lesions in patients with familial adenomatous polyposis compared with sporadic lesions: a propensity score-matched cohort

BACKGROUND

Familial adenomatous polyposis (FAP) is a rare inherited syndrome that predisposes the patient to cancer. Treatment of FAP-related ampullary lesions is challenging and the role of endoscopic papillectomy has not been elucidated. We retrospectively analyzed the outcomes of endoscopic papillectomy in matched cohorts of FAP-related and sporadic ampullary lesions (SALs).

METHODS

This retrospective multicenter study included 1422 endoscopic papillectomy procedures. Propensity score matching including age, sex, comorbidity, histologic subtype, and size was performed. Main outcomes were complete resection (R0), technical success, complications, and recurrence.

RESULTS

Propensity score matching identified 202 patients (101 FAP, 101 SAL) with comparable baseline characteristics. FAP patients were mainly asymptomatic (79.2 % [95 %CI 71.2-87.3] vs. 46.5 % [95 %CI 36.6-56.4]); P < 0.001). The initial R0 rate was significantly lower in FAP patients (63.4 % [95 %CI 53.8-72.9] vs. 83.2 % [95 %CI 75.8-90.6]; P = 0.001). After repeated interventions (mean 1.30 per patient), R0 was comparable (FAP 93.1 % [95 %CI 88.0-98.1] vs. SAL 97.0 % [95 %CI 93.7-100]; P = 0.19). Adverse events occurred in 28.7 %. Pancreatitis and bleeding were the most common adverse events in both groups. Severe adverse events were rare (3.5 %). Overall, 21 FAP patients (20.8 % [95 %CI 12.7-28.8]) and 16 SAL patients (15.8 % [95 %CI 8.6-23.1]; P = 0.36) had recurrence. Recurrences occurred later in FAP patients (25 [95 %CI 18.3-31.7] vs. 2 [95 %CI CI 0.06-3.9] months).

CONCLUSIONS

Endoscopic papillectomy was safe and effective in FAP-related ampullary lesions. Criteria for endoscopic resection of ampullary lesions can be extended to FAP patients. FAP patients have a lifetime risk of relapse even after complete resection, and require long-time surveillance.

Endoscopic and Surgical Management of Non-Metastatic Ampullary Neuroendocrine Neoplasia: A Multi-Institutional Pancreas2000/EPC Study

INTRODUCTION

Ampullary neuroendocrine neoplasia (NEN) is rare and evidence regarding their management is scarce. This study aimed to describe clinicopathological features, management, and prognosis of ampullary NEN according to their endoscopic or surgical management.

METHODS

From a multi-institutional international database, patients treated with either endoscopic papillectomy (EP), transduodenal surgical ampullectomy (TSA), or pancreaticoduodenectomy (PD) for ampullary NEN were included. Clinical features, post-procedure complications, and recurrences were assessed.

RESULTS

65 patients were included, 20 (30.8%) treated with EP, 19 (29.2%) with TSA, and 26 (40%) with PD. Patients were mostly asymptomatic (n = 46; 70.8%). Median tumor size was 17 mm (12-22), tumors were mostly grade 1 (70.8%) and pT2 (55.4%). Two (10%) EP resulted in severe American Society for Gastrointestinal Enterology (ASGE) adverse post-procedure complications and 10 (50%) were R0. Clavien 3-5 complications did not occur after TSA and in 4, including 1 postoperative death (15.4%) of patients after PD, with 17 (89.5%) and 26 R0 resection (100%), respectively. The pN1/2 rate was 51.9% (n = 14) after PD. Tumor size larger than 1 cm (i.e., pT stage >1) was a predictor for R1 resection (p < 0.001). Three-year overall survival and disease-free survival after EP, TSA, and PD were 92%, 68%, 92% and 92%, 85%, 73%, respectively.

CONCLUSION

Management of ampullary NEN is challenging. EP should not be performed in lesions larger than 1 cm or with a endoscopic ultrasonography T stage beyond T1. Local resection by TSA seems safe and feasible for lesions without nodal involvement. PD should be preferred for larger ampullary NEN at risk of nodal metastasis.

A platform trial of neoadjuvant and adjuvant antitumor vaccination alone or in combination with PD-1 antagonist and CD137 agonist antibodies in patients with resectable pancreatic adenocarcinoma

A neoadjuvant immunotherapy platform clinical trial allows for rapid evaluation of treatment-related changes in tumors and identifying targets to optimize treatment responses. We enrolled patients with resectable pancreatic adenocarcinoma into such a platform trial (NCT02451982) to receive pancreatic cancer GVAX vaccine with low-dose cyclophosphamide alone (Arm A; n = 16), with anti-PD-1 antibody nivolumab (Arm B; n = 14), and with both nivolumab and anti-CD137 agonist antibody urelumab (Arm C; n = 10), respectively. The primary endpoint for Arms A/B - treatment-related change in IL17A expression in vaccine-induced lymphoid aggregates - was previously published. Here, we report the primary endpoint for Arms B/C: treatment-related change in intratumoral CD8+ CD137+ cells and the secondary outcomes including safety, disease-free and overall survivals for all Arms. Treatment with GVAX+nivolumab+urelumab meets the primary endpoint by significantly increasing intratumoral CD8+ CD137+ cells (p = 0.003) compared to GVAX+Nivolumab. All treatments are well-tolerated. Median disease-free and overall survivals, respectively, are 13.90/14.98/33.51 and 23.59/27.01/35.55 months for Arms A/B/C. GVAX+nivolumab+urelumab demonstrates numerically-improved disease-free survival (HR = 0.55, p = 0.242; HR = 0.51, p = 0.173) and overall survival (HR = 0.59, p = 0.377; HR = 0.53, p = 0.279) compared to GVAX and GVAX+nivolumab, respectively, although not statistically significant due to small sample size. Therefore, neoadjuvant and adjuvant GVAX with PD-1 blockade and CD137 agonist antibody therapy is safe, increases intratumoral activated, cytotoxic T cells, and demonstrates a potentially promising efficacy signal in resectable pancreatic adenocarcinoma that warrants further study.

Diagnostic features of low- and high-grade mucinous neoplasms in pancreatic cyst FNA cytology

BACKGROUND

Pancreatic cyst cytology evaluates for neoplastic mucin and epithelial grade. This study describes cytological features of low- and high-grade mucinous neoplasms (MNs) using gastrointestinal contaminants for comparison.

METHODS

Histologically confirmed pancreatic cystic neoplasms were reviewed by a panel of cytopathologists to identify which, among 26 selected cytologic features, correlate significantly with low- and high-grade MN. A test for greater than or equal to four of eight high-grade features (three-dimensional architecture, high nuclear:cytoplasmic ratio, moderate nuclear membrane abnormalities, loss of nuclear polarity, hyperchromasia, >4:1 nuclear size variation in one cluster, karyorrhexis, and necrosis) was assessed for identifying a high-grade neoplasms. Additional characteristics of the cohort such as cyst fluid carcinoembryonic antigen results, molecular testing, Papanicolaou Society of Cytopathology classification, and select high-risk clinical features are described.

RESULTS

Endoscopic ultrasound fine-needle aspirations from 134 MN and 17 serous cystadenomas containing gastrointestinal contaminants were included. The MN consisted of 112 (84%) intraductal papillary MNs (low-grade = 69, 62%; high-grade = 24, 21%; and invasive = 19, 17%) and mucinous cystic neoplasms (low-grade = 20, 90%; high-grade = 2, 10%). Half had greater than five clusters of epithelium for analysis. Compared with gastrointestinal contaminants, mucin from MN was thick and colloid-like (40% vs. 6%, p < .01), covered >20% of the smear area (32% vs. none, p < .01), and contained histiocytes (46% vs. 18%, p = .04). Greater than or equal to four of eight select high-grade features was present in 36% of high-grade MN with sensitivity 37% and 98% specificity.

CONCLUSION

Colloid-like features, >20% of smear, and histiocytes correlated with MN. Testing for greater than or equal to four high-grade features had low sensitivity and high specificity for high-grade MN.

Performance of the 7 th and 8 th Editions of the American Joint Committee on Cancer Staging System in Patients with Intraductal Papillary Mucinous Neoplasm-Associated PDAC : A Multi-institutional Analysis

OBJECTIVE

To validate the 7 th and 8 th editions of the AJCC staging system for patients with invasive carcinomas arising in association with IPMN (IPMN-associated PDAC).

BACKGROUND DATA

Although several studies have validated AJCC systems in patients with conventional PDAC, their applicability to IPMN-associated PDAC has not been assessed.

METHODS

Two hundred seventy-five patients who underwent resection for IPMN-associated PDAC between 1996 and 2015 at 3 tertiary centers and had data on the size of the invasive component and lymph node status were identified. Concordance probability estimates (CPE) were calculated and recursive partitioning analysis was employed to identify optimal prognostic cutoffs for T and N.

RESULTS

The CPE for the 7 th and 8 th editions of the AJCC schema were relatively good (0.64 for both) and similar for colloid and tubular subtypes (0.64 for both). The 8 th edition introduced T1a sub-staging and a new distinction between N1 and N2. The utility of the former was confirmed, although the latter did not improve prognostic discrimination. The successful validation of the 8th edition of the AJCC criteria in patients with tubular and colloid subtypes allowed us to compare these patients in early vs late T and N stages which showed that with advanced disease, the prognostic superiority of colloid tumors over their tubular counterparts diminishes.

CONCLUSIONS

Our findings support the use of the AJCC 8 th edition in the IPMN-associated PDAC population, but suggest that certain cutoffs may need to be revisited. In advanced AJCC stages, patients with colloid vs tubular subtypes have comparable prognosis.

Adjuvant chemotherapy for resected intrahepatic cholangiocarcinoma confers no survival advantage

560

Background: Randomized data suggest improved survival with adjuvant chemotherapy for biliary tract cancers, but subset analyses of intrahepatic cholangiocarcinoma (ICC) show limited survival benefit. This study uses a large bi-institutional cohort of resected ICC patients to evaluate the impact of adjuvant therapy on recurrence patterns and overall survival (OS) and compares these findings to data from a national cancer registry. Methods: Patients with resected ICC were identified within a bi-institutional cohort (Duke and Memorial Sloan Kettering, 1997-2020) and the National Cancer Database (NCDB, 2010-2018). Patients were stratified by treatment with adjuvant chemotherapy (adj). Site of first recurrence was categorized as local (liver only), regional (liver and perihepatic nodes), nodal (perihepatic nodes only), distant, or mixed (both liver and distant). OS was compared with Kaplan-Meier methods. Results: 367 patients underwent resection for ICC, and 163 (44%) patients received adjuvant therapy. Median follow-up was 33 vs. 44 months (adj vs observation (obs), p=0.15). 263 (72%) patients had recurrent disease, most commonly in the liver (72%). There was no difference in recurrence patterns stratified by treatment with adjuvant chemotherapy (% recurrence, adj vs obs; local: 42 vs 42; regional: 2 vs 2; nodal: 0 vs 3; distant only: 27 vs 26; mixed: 29 vs 27, p=0.5). OS was the same between groups (adj vs obs; 42 vs 49 months, p=0.3) and when stratified by recurrence site (p=0.5). Similarly, in an NCDB cohort of 1,159 ICC patients over the same time period, there was no association between adjuvant therapy and OS (adj vs obs; 49 vs 57 months, p=0.1). Conclusions: In this retrospective dual registry analysis, corroborated by national data, adjuvant chemotherapy was not associated with an improvement in OS in ICC patients subjected to curative intent resection. Further, adjuvant therapy had no impact on the high rate of hepatic recurrence, suggesting that alternative strategies, such as liver directed therapies, are needed to improve recurrence rates and OS.

Phase II trial of maximal ablative irradiation because of encasement (MAIBE) for patients with potentially resectable locally advanced pancreatic cancer

710

Background: For patients with localized but not immediately resectable pancreatic adenocarcinoma (PDAC), the role for local therapy remains undefined. Phase II MAIBE trial studied ablative radiation (A-RT) followed by consideration of surgery for patients with locally advanced pancreatic cancer (LAPC) who remain unresectable after induction chemotherapy. Methods: Participants with histologically confirmed PDAC judged unresectable by multidisciplinary review using NCCN definition after completing 3-6 months of mFOLFIRINOX (FFX) or Gemcitabine/Nab-paclitaxel (GN) were eligible. They received hypofractionated A-RT (either 67.5Gy in 15 fractions or 75Gy in 25 fractions based on anatomy) with concurrent capecitabine followed by consideration of resection within 1-3 months. Primary endpoints included resectability (80% power to detect resectability improvement from 15% in historical controls to 30% with α = 0.05) and overall survival (OS) from A-RT. Secondary endpoints included safety of surgical resection after ablative RT using 90-day Clavien-Dindo Classification of adverse events (AE). Results: Between 6/2018 and 4/2022, 47 eligible participants underwent A-RT. Median age was 67 (range, 50-80) years, 24 (51%) were male with a median tumor size of 3.95 (1.6 – 8.3) cm and CA19-9 of 92 ( < 1-1601) U/mL. Forty-four patients (94%) received at least 1 cycle of FFX with a median duration of chemotherapy (FFX or GN) of 3.5 months (1.0 – 9.4). Sixteen (34%) underwent a laparoscopy and 12 (26%) underwent a resection (Pancreaticoduodenectomy, N = 11; distal pancreatectomy, N = 1) at a median time of 3.2 months (1.9-16.9 months) from start of A-RT. The rate of resection satisfied our prespecified boundary of 11. R0 rate was 58.3%. Two-year OS from A-RT for the entire cohort was 38.9% (95% CI, 21.9 – 55.6%), including 37.1% (18.5 - 55.8%) in non-surgical and 39.4% (7.0- 72.1%) in surgical groups. There were no deaths within 90 days of surgery and 9 surgical AEs were recorded in 6 participants, including grade 1 (n = 1), grade 2 (n = 5), grade 3 (n = 2) and grade unknown (n = 1). Conclusions: In patients with LAPC and no metastatic disease after 3-6 months of chemotherapy, A-RT results in a favorable rate of resection without excess surgical toxicity. Promising 2-year OS rates were noted in both resected and non-resected patients. Clinical trial information: NCT03523312 .

Genetic heterogeneity of intrahepatic cholangiocarcinoma: Implications for outcome

595

Background: Intrahepatic cholangiocarcinoma (IHC) is characterized by marked clinical heterogeneity, likely the result of multiple cells of origin and variable driver gene alterations. The hidden-genome classifier is a statistical algorithm that classifies tumors by integrating multi-level genomic features. In this study, we trained the hidden-genome classifier with extrahepatic cholangiocarcinoma (EHC), gallbladder cancer (GBC) and hepatocellular carcinoma (HCC) as extremes of a spectrum to quantify the genetic heterogeneity of IHC with a view toward improved tumor classification. Methods: An IRB approved retrospective review of patients with biopsy confirmed IHC, EHC, GBC and HCC was conducted. All tumors were subjected to MSK-IMPACT to determine the mutational profile. A two-class model was built and internally validated with the genomic data of EHC/GBC as one class and HCC as the other class. IHC tumors were analyzed in the model and classified into three groups based on their proportional genetic resemblance to EHC/GBC (Biliary Class) or HCC (HCC Class), with the remainder as Intermediate Class. The classification thresholds were 90% resemblance to EHC/GBC or HCC and were determined by the inflection point of predicted survival. The survivals of the three groups were analyzed and compared. Results: A total of 1497 patients were included: IHC (733), EHC (208), GBC (258) and HCC (298). 527 IHC tumors with complete metagenetic information were analyzed in the model, showing a continuous spectrum of alterations, ranging from Biliary Class (122 tumors), Intermediate Class (375 tumors) to HCC Class (30 tumor). The biliary-class IHC was characterized by frequent alterations of IDH1 R132C, KRAS, SMAD4, ERBB2 gain, MDM2 gain, and CKDN2A loss, while the HCC-class IHC was primarily characterized by TERT alterations. In patients with unresected IHCs, the median survival ranged from 1 year (CI 0.77, 1.5) in Biliary Class, 1.8 years (CI 1.5, 2.0) in Intermediate Class, to 2 years (CI 0.93, NR) in HCC Class. In patients subjected to resection, the median survival of Biliary Class (2.4 years, CI 2.1, NR) was lower than both the Intermediate Class (5.1 years, CI 4.8, 6.9) and the HCC Class (3.4 years, CI 2.7, NR). Conclusions: By integrating multi-level genomic features, we leveraged the mutational heterogeneity to classify IHC based on its resemblance to EHC/GBC or HCC tumors. We found that the survival in IHC patients appeared to decline with increasing genomic similarity to Biliary Class. The results support a genomic basis for IHC’s variable clinical behavior and point to a role of mutational testing to guide clinical intervention. [Table: see text]

Adjuvant modified FOLFIRINOX (mFFX) for resected pancreatic cancer (PDAC): Real world outcomes (RWO)

685

Background: Adjuvant mFFX (5-fluorouracil, leucovorin, irinotecan, oxaliplatin) is a standard-of-care for fit patients (pts) with resected PDAC, owing to the immediate practice-changing PRODIGE 24/CCTG PA6 trial (2018). Five-year follow-up: median overall survival (mOS) 53.3 months (m) and median disease-free survival (mDFS) 21.4 m for mFFX vs 35.5 m and 12.8 m for gemcitabine (Conroy, JAMA Onc, 2022). RWO for pts outside a clinical trial are lacking. Herein, we report RWO for pts with resected PDAC and intent for adjuvant mFFX at Memorial Sloan Kettering (MSK). Methods: Institutional databases were queried to identify pts with resected PDAC who received any dose of adjuvant mFFX. Demographic, clinicopathologic, genomic, dosing details, and survival data were abstracted from medical and pharmacy records. Primary endpoint was to determine recurrence-free survival (RFS) calculated from start date mFFX to disease recurrence or death and OS calculated from start date mFFX to death. Secondary endpoints included dose reductions, significant treatment delay, toxicity profile, patterns of failure, genomic associations with outcome. RFS and OS are estimated using the Kaplan-Meier method. Study approved by MSK IRB. Results: N = 114 pts with resected PDAC treated with mFFX (> 1 dose) identified between 01/2015- 01/2022. Median age: 67 years (range 35 to 82); N = 43 (38%) > 70 years, N = 18 (16%) > 75 years, N = 2 (2%) > 80 years. Baseline Performance Status recorded in N = 104: N = 31 (30%) ECOG 0, N = 64 (62%) ECOG 1, N = 9 (9%) ECOG 2. Disease stage: N = 36 (32%) stage III, N = 61 (54%) stage II, and N = 17 (15%) pts stage I. Resection status: N = 91 (80%) R0, N = 23 (20%) R1. Presence of lymphovascular invasion: N = 92 (81%), perineural invasion N = 106 (93%). Median baseline CA 19-9: 20 U/mL (IQR; 9, 38). Median follow up: 22.4 m (range 6.2, 50.4). Median time from surgery to start mFFX: 7.4 weeks (IQR; 6.1, 9.3). Median # of mFFX doses received: 12 (IQR; 12, 12), N = 90 (79%) pts completed 12 doses. Dosing details available N = 112. N = 55 (49%) prescribed less than full dose of > one drug at baseline. Dose reductions: N = 57 (51%). N = 69 (62%) received < 12 doses oxaliplatin. N = 97 (87%) received growth factor support. mRFS: 31 m (95% CI; 23, Not Reached). N = 18 (16%) were hospitalized for treatment related adverse events, no therapy related mortality. N = 24 (21%) received adjuvant radiation therapy. One-year OS rate: 93% (95% CI; 89%, 98%) and 2-year OS rate: 78% (95%CI: 70%, 88%). Among patients with recurrence (N = 44), most common sites of first recurrence were: liver (N = 18, 41%), local (N = 14, 32%), and lung (N = 9, 20%). Conclusions: These data endorse mFFX as standard therapy for resected PDAC. The survival signals are encouraging in a prognostically unfavorable albeit select patient population (relative to PRODIGE 24). Dose adjustments to facilitate optimizing tolerability is key. Additional genomic and subtype analyses are underway.

Concordance in oncogenic alterations between primary and recurrent/metastatic cholangiocarcinoma pairs using targeted next-generation sequencing

604

Background: The genetic background of cholangiocarcinoma (CCA) commonly involves alterations in kinase signaling, tumor suppression, oxidative stress modulation, and proto-oncogenic coupling pathways. Novel agents targeting such pathways have shown promise in systemic treatment; however, studies examining differences in the mutational landscapes between primary and recurrent, metastatic, or progressive disease after systemic therapy are lacking. The present study aimed to determine if recurrent, metastatic, or progressive disease genetically parallels the primary or not. Methods: Patients with biopsy proven CCA (primary tumor and paired recurrent/metastatic or progressive disease) from two institutions (MSKCC and Duke) were identified. Targeted next-generation sequencing (Integrated Mutation Profiling of Actionable Cancer Targets (IMPACT)) capturing single nucleotide variants, copy number alterations, and structural variants was used to compare driver alteration concordance across the paired samples. Subgroup analyses were performed based on exposure to systemic therapy in patients with disease progression and tumor type (intrahepatic versus extrahepatic). Results: Sample pairs from 65 patients with intrahepatic (ICCA, n=54) and extrahepatic CCA (ECCA, n=11) were analyzed. Median time between samples was 19.6 months (range 2.7 - 122.9). Some de novo alterations were identified in recurrent/metastatic samples, but overall concordance (70%) was demonstrated between patient pairs for common oncogenic driver genes (Table). Subgroup analyses of summative ICCA and ECCA mutations revealed concordance of 65% and 88%, respectively. Concordance was also demonstrated between pairs exposed to systemic therapy between sample collections (n=50, 71%). Conclusions: In this dataset of CCA patients, a concordance rate of 70% was identified in the genomic alterations between primary and recurrent/metastatic pairs, and this did not appear to be altered by prior treatment with systemic chemotherapy. While limited by sample size, concordance in ICCA pairs was lower than that seen in ECCA. [Table: see text]

Phase I trial of adjuvant autogene cevumeran, an individualized mRNA neoantigen vaccine, for pancreatic ductal adenocarcinoma

2516

Background: Pancreas ductal adenocarcinoma (PDAC) is a lethal cancer that claims ̃90% of patients in <24 months of diagnosis. PDAC is also refractory to immunotherapy as most tumors exhibit an immune excluded/desert phenotype. However, although characterized by low mutation rates, most PDACs harbor mutations that can generate immunogenic neoantigens. Here, we report the results of a phase-I trial of autogene cevumeran, a systemic RNA-lipoplex individualized neoantigen-specific immunotherapy (iNeST) vaccine, to stimulate immunity against neoantigens in resected PDAC patients. Methods: We conducted an investigator-initiated, single-center, phase-I trial of adjuvant autogene cevumeran containing up to 20 neoantigens in each individualized vaccine, identified from resected PDACs using real-time next generation sequencing and bioinformatic neoantigen discovery. Following surgery, patients received atezolizumab (1 dose; week 6), autogene cevumeran (8 weekly doses starting week 9; doses 9,10 – weeks 17, 46), and modified (m) FOLFIRINOX (12 cycles; starting week 21). Primary endpoint: safety. Other endpoints: feasibility (actual vs. target treatment time), vaccine response (responder = positivity by two independent blood assays: IFNg ELISpot and T cell clonal expansion), and recurrence-free survival (RFS). Target accrual: n=20. Results: n=19 patients underwent surgery and received atezolizumab at 6.3 weeks (median; 95% CI 6.0–6.57) after surgery with no ≥ grade 3 (Gr3) adverse events. n=16/19 patients (84%) received autogene cevumeran at 9.4 weeks (median; 95% CI 9–10) after surgery. n=1/19 (5%) had insufficient neoantigens for vaccine manufacture. n=1/16 (6%) developed a vaccine-related Gr3 fever and hypertension. n=15/16 vaccinated patients (94%) received mFOLFIRINOX (median 12 cycles; 95% CI 7–12). Autogene cevumeran expanded polyclonal (median 7.5 clones, 95% CI 2–28), IFNg-producing neoantigen-specific CD8+ T cells in 50% (n=8/16) of patients from undetectable levels to large fractions (median 2.9%, Table) of all blood T cells. At an early median follow-up of 15 months, vaccine responders (n=8) had a longer RFS vs. non-responders (n=8) (median not reached vs. 13.7 months, HR 0.08, 95% CI 0.01-0.5, P = 0.007). Conclusions: Autogene cevumeran is safe, feasibly manufactured in a clinically relevant timeframe, and immunogenic in PDAC. Vaccine induced neoantigen-specific immunity preliminarily correlates with improved PDAC outcome. Further clinical trials in PDAC are warranted. (This imCORE Network project was funded by Genentech Inc and BioNTech; additional funding from Stand Up To Cancer, Lustgarten Foundation). Clinical trial information: NCT04161755. [Table: see text]

Immunogenomic characterization of biliary tract cancers: Biomarker enrichment for benefit to immune checkpoint blockade

4083

Background: Several immunomodulatory molecules (PD-L1, B7H4, and CD276) have been associated with biliary tract cancer (BTC) subgroups, suggesting potential value to immune checkpoint blockade (ICB) in this lethal disease. Phase II monotherapy (pembrolizumab or nivolumab), and combination (atezolizumab and cobimetinib) ICB trials reported low response rates in unselected advanced BTC with a wide range of responses. A recent randomized phase III trial (TOPAZ-1) reported an overall survival (OS) benefit among patients (pts) with advanced BTC treated with chemotherapy and anti-PD-L1 ICB. However, no correlation between PD-L1 expression and OS was noted and biomarker enrichment strategy in BTC for immunotherapy remains a key to optimize OS. Methods: From our comprehensive clinico-genomic database for BTC at Memorial Sloan Kettering (MSK), a retrospective genomic landscape and neoantigen analysis was performed using MSK-IMPACT. Potential immunogenic subgroups were evaluated: homologous recombination deficiency (HRD) defined by pathogenic alterations in BRCA1/2, PALB2, and BAP1, microsatellite stability high (MSI-H) defined by MSIsensor score ≥10, and tumor mutation burden (TMB)>10. Clinical outcomes with anti-PD-1 ICB were evaluated. Results: Among N=1,190 pts with BTC, N=1,346 samples were sequenced between 03/2014 and 01/2022. Key actionable alterations included (%): IDH1, 2 (13, 3), FGFR2 fusions (9), ERBB2 amplification (5), BRAF V600E (2), RNF43 (2), POLE (2), NTRK1 fusion (<1). There were N=230 (17%) patients with putatively more immunogenic BTC (iBTC) identified by HRD [ BRCA1/2 (1, 2.4), PALB2 (1), BAP1 (9)], TMB>10, and MSI-H. Frequency, location (intrahepatic, ICC; extrahepatic, ECC; gallbladder, GBC), TMB, and genomic instability score (GIS) are summarized (Table). Among iBTC subgroup, N=32 pts received ICB. Their median follow up was 29.1 months. Median lines of prior therapy was 3. Median PFS was 5.6 M (95%CI: 1.2-10.1) and OS was 33.4 M (23.1-43.6). Conclusion: A subgroup of BTC pts (iBTC) benefit from ICB. Apart from MSI-H and TMB>10, other genomically-defined subgroups such as HRD may benefit from ICB. Prospective studies are needed to evaluate a better biomarker enrichment strategy beyond PD-L1 and TMB, that can represent other immunogenic aspects of tumor neoantigen and microenvironment. [Table: see text]

Neoadjuvant and adjuvant antitumor vaccination alone or combination with PD1 blockade and CD137 agonism in patients with resectable pancreatic adenocarcinoma

558

Background: Utilizing a vaccine that induces and activates host effector T cells and co-administering it with immune modulating agents that enhance anti-tumor T cell activity is a potential strategy for overcoming pancreatic adenocarcinoma’s (PDA) resistance to immunotherapy. Our prior clinical trial demonstrated a GM-CSF-secreting, allogeneic tumor cell vaccine (GVAX) increases infiltrating CD8+ T cells in PDA. Follow up preclinical work demonstrated therapeutic synergy between GVAX and PD-1inhibition (PD1) with efficacy further enhanced by CD137 agonism (CD137). Methods: This was a 3-arm trial of neoadjuvant & adjuvant GVAX-based therapy in resectable (r) PDA patients (pts). Adults with clinically resectable, untreated PDA were enrolled in 1 of 3 study treatments: Arm A (GVAX alone), Arm B (GVAX + PD1 [Nivolumab]), or arm C (GVAX + PD1 + CD137 [Urelumab]). Treatment was given as follows: Day 1 - Cyclophosphamide 200mg/m2 IV (All Arms), Nivolumab 480mg IV (Arms B, C), Urelumab 8mg IV (Arm C); Day 2 – GVAX ID (All Arms). Pts were treated at 3 timepoints: 1) once 2 weeks prior to surgery; 2) once post-surgical recovery prior to standard of care adjuvant chemotherapy (SOC); 3) every month (up to 4 mo) following completion of SOC (if disease-free). SOC regimes included (m)FOLFIRINOX, Gem +/- Cap/NAB-Paclitaxel. The study was powered for a primary biologic endpoint: treatment-related change in intratumoral CD8+CD137+ T cells. Clinical endpoints included disease-free survival (DFS: time from surgery to recurrence), overall survival (OS: time from surgery to death), and safety. Results: 38 pts (N = 15 [Arm A], N = 13 [Arm B], N = 10 [Arm C]) were eligible for efficacy analysis (had R0/R1 resection) and 45 pts (N = 17 [A], N = 17 [B], N = 11 [C]) were eligible for safety analysis (had ≥1 dose of study treatment). Demographics, surgical pathology features, and SOC durations were similar in all Arms. At median follow up of 23 mo [A], 26 mo [B], and 22 mo [C], median DFS (95% CI) was 14.82 mo (6.0, NA), 16.23 mo (7.49, NA) and not reached (16.33, NA) for Arms A, B, C, respectively. There was no DFS benefit to adding PD1 compared to GVAX alone (HR 0.98 [95% CI 0.42, 2.27], p = 0.96). Combination CD137 + PD1 + GVAX was associated with marginally significant improved DFS compared to GVAX alone (HR 0.38 [95%CI 0.12, 1.19], p = 0.097) and GVAX + PD1 (HR 0.38 [95%CI 0.12, 1.21], p = 0.103). Median OS (95% CI) was 25.0 mo (18.8, NA), 26.4 mo (20.3, NA), and not yet reached for Arms A, B, C, respectively. There were no serious adverse events. In Arm C, 1 pt had grade 3 rash that delayed treatment and there was 1 instance of grade 2 AST/ALT elevation. The biologic endpoint will be reported at the meeting. Conclusions: Despite a small sample size, combining GVAX with dual immune-targeting of PD-1 blockade and CD137 agonism was safe and may enhance DFS in rPDA pts treated in the perioperative and post-adjuvant settings. Clinical trial information: NCT02451982.

824 High quality neoantigens are immunoedited in long-term pancreatic cancer survivors

Background

Cancer immunoediting predicts that T cells selectively kill tumor cells expressing immunogenic mutations (neoantigens) resulting in less immunogenic clones to outgrow in tumors.1 Although established through longitudinal studies of how tumors evolve in immune-proficient and -deficient mice,1 2 whether the human immune system naturally targets neoantigens to edit tumors, and the principles that identify the edited neoantigens, remains unclear.

Methods

To investigate if immune selective pressures on neoantigens alter how human tumors evolve, we longitudinally studied how 70 human pancreatic ductal adenocarcinomas (PDACs) - a poorly immunogenic cancer largely presumed to not be subject to immunoediting - evolved over 10 years. We use exome sequencing, neoantigen identification, and clonal reconstruction to compare how primary PDACs evolve to recurrence in rare long-term PDAC survivors previously shown to have more immunogenic tumors3 (n = 9 patients, n = 9 primary, 22 recurrent tumors), to short-term survivors with less immunogenic primary tumors (n = 6 patients, n = 6 primary, 33 recurrent tumors). To identify immunogenic “high quality” neoantigens, we use neopeptide-T cell functional assays and computational modeling to extend and apply a previously developed neoantigen quality model3 4 by predicting high quality neoantigens as arising from amino acid substitutions with sufficient antigenic distance from cognate wild-type peptides to differentially bind the MHC or activate a T cell.

Results

Compared to short-term survivors, we observe that long-term survivors evolve fewer recurrent tumors with longer latency, and distinct tissue tropism. To evaluate if differential immune pressures explained these differences, we discover that despite longer times to evolve, long-term survivors evolve genetically less heterogeneous tumors with fewer clones, fewer nonsynonymous mutations, and fewer neoantigens. To identify if high quality neoantigens are selectively edited in recurrent tumors of long-term survivors, we observe that neoantigens with greater antigenic distance (“less self”) are more depleted in primary and recurrent tumors of long- compared to short-term survivors. Furthermore, we find that long-term survivors evolve markedly fewer new neoantigens of strikingly lower quality, to indicate clones with high quality neoantigens are immunoedited.

Conclusions

We submit longitudinal evidence that the human immune system naturally edits neoantigens in PDAC. Furthermore, we present a model that describes how cancer neoantigens evolve under immune pressure over time, with implications for cancer biology and therapy. More broadly, our results argue that immunoediting is a fundamental cancer suppressive mechanism that can be quantified to predict tumor evolution.

Acknowledgements

This work was supported by NIH U01 CA224175 (V.P.B), a Stand Up to Cancer Convergence Award (B.D.G, V.P.B.), a Damon Runyon Clinical Investigator Award (V.P.B), and the Avner Pancreatic Cancer Foundation (A.J, A.G). Services by the Integrated Genomics Core were funded by the NCI Cancer Center Support Grant (P30 CA08748), Cycle for Survival, and the Marie-Josée and Henry R. Kravis Center for Molecular Oncology.

References

Shankaran V, et al. IFNgamma and lymphocytes prevent primary tumour development and shape tumour immunogenicity. Nature 2001;410:1107–1111.

Matsushita H, et al. Cancer exome analysis reveals a T-cell-dependent mechanism of cancer immunoediting. Nature 2012;482:400–404.

Balachandran VP, et al. Identification of unique neoantigen qualities in long-term survivors of pancreatic cancer. Nature 2017;551:512–516.

Łuksza M, et al. A neoantigen fitness model predicts tumour response to checkpoint blockade immunotherapy. Nature 2017;551:517–520.

Ethics Approval

This study was performed in strict compliance with all institutional ethical regulations and approved by the institutional review boards of Memorial Sloan Kettering Cancer Center (MSK), the Garvan Institute of Medical Research, and the The Johns Hopkins Hospital (JHH). We obtained informed consent from all patients.

Abstract LB005: High quality neoantigens are immunoedited in long term survivors of pancreatic cancer

Cancer immunoediting, a hallmark of cancer, predicts that lymphocytes recognize tumor-specific mutations (neoantigens) to kill immunogenic tumor cells and select less immunogenic clones to survive in immunocompetent hosts. Yet, though proven in mice, whether immunoediting governs how human tumors evolve naturally, and the principles of how the immune system edits tumors remain unclear. Here, we report that T cell rich tumors of rare long-term survivors of human pancreatic ductal adenocarcinoma longitudinally lose immunogenic features predicted by a fitness model based on immune recognition of high quality neoantigens. We find that compared to T cell poor tumors in short-term survivors, long-term survivors evolve less immunogenic recurrent tumors over 10 years with fewer clones, fewer neoantigens, and new neoantigens of markedly lower quality, to indicate that the immune system edits lower fitness clones with high-quality neoantigens. To explore if the immune system more broadly selects against non-self-like changes in host genomes, we define a minimal amino acid substitution distance sufficient for T cell receptors to discriminate self from non-self mutations. We find that both primary and recurrent tumors in long but not short-term survivors are enriched in self-like mutations, to suggest that the immune system depletes non-self-like mutations. Thus, we submit longitudinal evidence that the immune system edits neoantigens to sculpt recurrent human pancreatic ductal adenocarcinomas, a lethal tumor largely considered resistant to endogenous immune attack. Furthermore, we demonstrate that the neoantigen quality fitness model predicts how immune pressure changes tumor cell populations over time, with significant implications for cancer biology and immunotherapy. More broadly, our results argue that cancer immunoediting is a fundamental principle of how human cancers evolve in immunocompetent hosts.

Citation Format: Marta Luksza, Zachary Sethna, Luis Rojas, Kevin Soares, Yuval Elhanati, Jayon Lihm, David Hoyos, Rajya Kappagantula, Alvin M. Moore, Erin Patterson, Christine Iacobuzio-Donahue, Benjamin Greenbaum, Vinod P. Balachandran. High quality neoantigens are immunoedited in long term survivors of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB005.

Anti-pancreatic tumor efficacy of a Listeria-based, Annexin A2-targeting immunotherapy in combination with anti-PD-1 antibodies

BACKGROUND

Immune checkpoint inhibitors are not effective for pancreatic ductal adenocarcinoma (PDAC) as single agents. Vaccine therapy may sensitize PDACs to checkpoint inhibitor treatments. Annexin A2 (ANXA2) is a pro-metastasis protein, previously identified as a relevant PDAC antigen that is expressed by a GM-CSF-secreting allogenic whole pancreatic tumor cell vaccine (GVAX) to induce an anti-ANXA2 antibody response in patients with PDAC. We hypothesized that an ANXA2-targeting vaccine approach not only provokes an immune response but also mounts anti-tumor effects.

METHODS

We developed a Listeria-based, ANXA2-targeting cancer immunotherapy (Lm-ANXA2) and investigated its effectiveness within two murine models of PDAC.

RESULTS

We show that Lm-ANXA2 prolonged the survival in a transplant model of mouse PDACs. More importantly, priming with the Lm-ANXA2 treatment prior to administration of anti-PD-1 antibodies increased cure rates in the implanted PDAC model and resulted in objective tumor responses and prolonged survival in the genetically engineered spontaneous PDAC model. In tumors treated with Lm-ANXA2 followed by anti-PD-1 antibody, the T cells specific to ANXA2 had significantly increased INFγ expression.

CONCLUSIONS

For the first time, a listeria vaccine-based immunotherapy was shown to be able to induce a tumor antigen-specific T cell response within the tumor microenvironment of a "cold" tumor such as PDAC and sensitize the tumor to checkpoint inhibitor therapy. Moreover, this combination immunotherapy led to objective tumor responses and survival benefit in the mice with spontaneously developed PDAC tumors. Therefore, our study supports developing Lm-ANXA2 as a therapeutic agent in combination with anti-PD-1 antibody for PDAC treatment.

Long-term survival benefit of upfront chemotherapy in patients with newly diagnosed borderline resectable pancreatic cancer

The use of neoadjuvant chemotherapy or radiation for borderline resectable pancreatic adenocarcinoma (BL-PDAC) is increasing. However, the impact of neoadjuvant chemotherapy and radiation therapy on the outcome of BL-PDAC remains to be elucidated. We performed a retrospective analysis of 93 consecutive patients who were diagnosed with BL-PDAC and primarily followed at Johns Hopkins Hospital between February 2007 and December 2012. Among 93 patients, 62% received upfront neoadjuvant chemotherapy followed by chemoradiation, whereas 20% received neoadjuvant chemoradiation alone and 15% neoadjuvant chemotherapy alone. Resectability following all neoadjuvant therapy was 44%. Patients who underwent resection with a curative intent had a median overall survival (mOS) of 25.8 months, whereas those who did not undergo surgery had a mOS of 11.9 months. However, resectability and overall survival were not significantly different between the three types of neoadjuvant therapy. Nevertheless, 22% (95% CI, 0.13-0.36) of the 58 patients who received upfront chemotherapy followed by chemoradiation remained alive for a minimum of 48 months compared to none of the 19 patients who received upfront chemoradiation. Among patients who underwent curative surgical resection, 32% (95% CI, 0.19-0.55) of those who received upfront chemotherapy remained disease free at least 48 months following surgical resection, whereas none of the eight patients who received upfront chemoradiation remained disease free beyond 24 months following surgical resection. Neoadjuvant therapy with upfront chemotherapy may result in long-term survival in a subpopulation of patients with BL-PDAC.

Modified Staging Classification for Pancreatic Neuroendocrine Tumors on the Basis of the American Joint Committee on Cancer and European Neuroendocrine Tumor Society Systems

Purpose The European Neuroendocrine Tumor Society (ENETS) and the American Joint Committee on Cancer (AJCC) staging classifications are two widely used systems in managing pancreatic neuroendocrine tumors. However, there is no universally accepted system. Methods An analysis was performed to evaluate the application of the ENETS and AJCC staging classifications using the SEER registry (N = 2,529 patients) and a multicentric series (N = 1,143 patients). A modified system was proposed based on analysis of the two existing classifications. The modified system was then validated. Results The proportion of patients with AJCC stage III disease was extremely low for both the SEER series (2.2%) and the multicentric series (2.1%). For the ENETS staging system, patients with stage I disease had a similar prognosis to patients with stage IIA disease, and patients with stage IIIB disease had a lower hazard ratio for death than did patients with stage IIIA disease. We modified the ENETS staging classification by maintaining the ENETS T, N, and M definitions and adopting the AJCC staging definitions. The proportion of patients with stage III disease using the modified ENETS (mENETS) system was higher than that of the AJCC system in both the SEER series (8.9% v 2.2%) and the multicentric series (11.6% v 2.1%). In addition, the hazard ratio of death for patients with stage III disease was higher than that for patients with stage IIB disease. Moreover, statistical significance and proportional distribution were observed in the mENETS staging classification. Conclusion An mENETS staging classification is more suitable for pancreatic neuroendocrine tumors than either the AJCC or ENETS systems and can be adopted in clinical practice.

Minimally invasive resection of choledochal cyst: a feasible and safe surgical option

BACKGROUND

The use of minimally invasive surgery (MIS) for choledochal cyst (CC) has not been well documented. We sought to define the overall utilization and outcomes associated with the use of the open versus MIS approach for CC. We examined the factors associated with receipt of MIS for CC, as well as characterized perioperative and long-term outcomes following open versus MIS for CC.

METHODS

Between 1972 and 2014, a total of 368 patients who underwent resection for CC were identified from an international, multicenter database. A 2:1 propensity score matching was used to create comparable cohorts of patients to assess the effect of MIS on short-term outcomes.

RESULTS

Three hundred thirty-two patients had an open procedure, whereas 36 patients underwent an MIS approach. Children were more likely to be treated with a MIS approach (children, 24.0 % vs. adults, 2.1 %; P<0.001). Conversely, patients who had any medical comorbidity were less likely to undergo MIS surgery (open, 26.2 % vs. MIS, 2.8 %; P=0.002). In the propensity-matched cohort, MIS resection was associated with decreased length of stay (open, 7 days vs. MIS, 5 days), lower estimated blood loss (open, 50 mL vs. MIS, 17.5 mL), and longer operative time (open, 237 min vs. MIS, 301 min) compared with open surgery (all P<0.05). The overall and degree of complication did not differ between the open (grades I-II, n=13; grades III-IV, n=15) versus MIS (grades I-II, n=5; grades III-IV, n=5) cohorts (P=0.85). Five-year overall survival was 98.6 % (open, 98.0 % vs. MIS, 100.0 %; P=0.45); no patient who underwent MIS developed a subsequent cholangiocarcinoma.

CONCLUSIONS

MIS resection of CC was demonstrated to be a feasible and safe approach with acceptable short-term outcomes in the pediatric population. MIS for benign CC disease was associated with similar perioperative morbidity but a shorter length of stay and a lower blood loss when compared with open resection.

The impact of postoperative complications on the administration of adjuvant therapy following pancreaticoduodenectomy for adenocarcinoma

BACKGROUND

The impact of postoperative complications on the administration of adjuvant therapy following pancreaticoduodenectomy (PD) for adenocarcinoma is still unclear.

METHODS

A retrospective review of all patients undergoing PD at our institution between 1995 and 2011 was performed. Clinicopathological data, including Clavien-Dindo complication grade, time to adjuvant therapy (TTA), and survival, were analyzed.

RESULTS

A total of 1,144 patients underwent PD for adenocarcinoma between 1995 and 2011. The overall complication rate was 49.1 % and clinically severe complications (≥IIIb) occurred in 4.2 %. Overall, 621 patients (54.3 %) were known to have received adjuvant therapy. The median TTA was 60 days. Although the presence of a complication was associated with a delay in TTA (p = 0.002), the grade of complication was not (p = 0.112). On multivariate analysis, only age > 68 years (p < 0.001) and length of stay >9 days (p = 0.002) correlated with no adjuvant therapy. Patients with postoperative complications were more likely to receive single adjuvant chemotherapy or radiation therapy (31.4 %) than were patients without complications (17.1 %; p < 0.001). Patients without a complication had a longer median survival compared with patients who experienced complications (19.5 vs. 16.1 months; p = 0.001). Patients without complications who received adjuvant therapy had longer median survival than patients with complications who received no adjuvant therapy (22.5 vs. 10.7 months; p < 0.001). Multivariate analysis demonstrated that complications [hazard ratio (HR) 1.16; p = 0.023] and adjuvant therapy (HR 0.67; p < 0.001) were related to survival.

CONCLUSION

Complications and no adjuvant therapy are common following PD for adenocarcinoma. Postoperative complications delay TTA and reduce the likelihood of multimodality adjuvant therapy. Identifying patients at increased risk for complications and those unlikely to receive adjuvant therapy warrants further investigation as they may benefit from a neoadjuvant approach.

Immunotherapy converts nonimmunogenic pancreatic tumors into immunogenic foci of immune regulation

Pancreatic ductal adenocarcinoma (PDAC) is considered a "nonimmunogenic" neoplasm. Single-agent immunotherapies have failed to demonstrate significant clinical activity in PDAC and other "nonimmunogenic" tumors, in part due to a complex tumor microenvironment (TME) that provides a formidable barrier to immune infiltration and function. We designed a neoadjuvant and adjuvant clinical trial comparing an irradiated, granulocyte-macrophage colony-stimulating factor (GM-CSF)-secreting, allogeneic PDAC vaccine (GVAX) given as a single agent or in combination with low-dose cyclophosphamide to deplete regulatory T cells (Treg) as a means to study how the TME is altered by immunotherapy. Examination of resected PDACs revealed the formation of vaccine-induced intratumoral tertiary lymphoid aggregates in 33 of 39 patients 2 weeks after vaccine treatment. Immunohistochemical analysis showed these aggregates to be regulatory structures of adaptive immunity. Microarray analysis of microdissected aggregates identified gene-expression signatures in five signaling pathways involved in regulating immune-cell activation and trafficking that were associated with improved postvaccination responses. A suppressed Treg pathway and an enhanced Th17 pathway within these aggregates were associated with improved survival, enhanced postvaccination mesothelin-specific T-cell responses, and increased intratumoral Teff:Treg ratios. This study provides the first example of immune-based therapy converting a "nonimmunogenic" neoplasm into an "immunogenic" neoplasm by inducing infiltration of T cells and development of tertiary lymphoid structures in the TME. Post-GVAX T-cell infiltration and aggregate formation resulted in the upregulation of immunosuppressive regulatory mechanisms, including the PD-1-PD-L1 pathway, suggesting that patients with vaccine-primed PDAC may be better candidates than vaccine-naïve patients for immune checkpoint and other immunomodulatory therapies.

Gamma-aminobutyric acid agonists for neuroleptic-induced tardive dyskinesia

BACKGROUND

Chronic antipsychotic drug treatment may cause tardive dyskinesia (TD), a long-term movement disorder. Gamma-aminobutyric acid (GABA) agonist drugs, which have intense sedative properties and may exacerbate psychotic symptoms, have been used to treat TD.

OBJECTIVES

To determine the effects of GABA agonist drugs (baclofen, gamma-vinyl-GABA, gamma-acetylenic-GABA, progabide, muscimol, sodium valproate and tetrahydroisoxazolopyridine (THIP)) for people with antipsychotic-induced tardive dyskinesia (TD) and schizophrenia or other chronic mental illnesses.

SEARCH STRATEGY

We updated the previous Cochrane review by searching the Cochrane Schizophrenia Group Register (September 2003). We searched references for further trial citations and, where possible, contacted authors.

SELECTION CRITERIA

Randomised controlled trials comparing use of non-benzodiazepine GABA agonist drugs with placebo or no intervention, involving people with schizophrenia or other chronic mental illnesses with signs of antipsychotic-induced TD.

DATA COLLECTION AND ANALYSIS

Working independently, we selected and critically appraised studies, extracted data and analysed on an intention-to-treat basis. Where possible and appropriate we calculated risk ratios (RR) and their 95% confidence intervals (CI) with the number needed to treat (NNT). For continuous data Weighted Mean Differences (WMD) were calculated.

MAIN RESULTS

We identified eight small poorly reported studies for inclusion. For the outcome of 'no clinically important improvement in tardive dyskinesia' GABA agonist drugs were not clearly better than placebo (n = 108, RR 0.83 CI 0.6 to 1.1). Deterioration in mental state was more likely to occur in people receiving GABA medication (n = 95, RR 2.47 CI 1.1 to 5.4), but this effect was influenced by the decision to assign a negative outcome to those who dropped out before the end of the study. A greater proportion of people allocated GABA medication may fail to complete the trial compared with those allocated placebo (20% versus 9%), but this difference was not statistically significant (n = 136, RR 1.99 CI 0.8 to 4.7). There is a suggestion of an increase in ataxia (loss of power of muscular coordination) for both baclofen and sodium valproate (n = 95, RR 3.26 CI 0.4 to 30.2), and in sedation (n = 113, RR 2.12 CI 0.8 to 5.4) compared with placebo, but this was not significant. Withdrawal of tetrahydroisoxazolopyridine (THIP) may cause seizures.

REVIEWERS' CONCLUSIONS

Evidence of the effects of baclofen, progabide, sodium valproate, or THIP for people with antipsychotic-induced TD is inconclusive and unconvincing. Any possible benefits are likely to be outweighed by the adverse effects associated with their use.

cis-acting elements involved in transcriptional regulation of the herpes simplex virus type 1 latency-associated promoter 1 (LAP1) in vitro and in vivo

Latency-associated promoter 1 (LAP1) of herpes simplex virus type 1 is required to generate a series of latency-associated transcripts (LATs) in sensory neurons of latently infected animals. Sequence analysis and DNA binding studies have suggested the existence of several cis-acting elements within LAP1 that are potentially important for promoter function, although their role in LAT gene expression during latency is largely unexplored. In this report, we present evidence that the LAP1 TATA box is essential for transcription initiation in vitro. A reduction in LAT synthesis measured by in situ hybridization and reverse transcription-PCR (RT-PCR) of rat brain tissue latently infected with a LAP1 TATA substitution virus demonstrated that this sequence was required for full LAP1 activity in vivo. Analysis of additional site-directed and 5'-deletion mutants of LAP1 by in vitro transcription-primer extension assays showed that upstream elements including the USF and cyclic AMP response element (CRE) site specifically contributed to LAP1 function and that sequences beginning at position -620 relative to the transcription start site were essential for full promoter activity. The combination of deleting USF, CRE, and TATA completely abolished LAT expression in the brain, identifying these as essential elements for the neuron-specific functioning of LAP1 during latency. Mutation of the transcription start site did not abolish transcription, suggesting the absence of an initiator element. However, one of the most exciting findings from this study is that the region downstream of the TATA box appears to contain a true enhancer that is not only essential for transcription, but also functional when positioned 1.6 kb downstream of the start site of transcription. It was concluded that (i) the TATA box was essential for full transcriptional activity from LAP1 both in vitro and in vivo, (ii) the USF element and CRE contribute to LAP1 function during latency in combination with the TATA element, (iii) multiple trans-acting factors besides the USF- and CRE-binding proteins were required for full promoter activity in vitro, and (iv) sequences downstream of the TATA box enhanced promoter activity in vitro.