No abstract

379 Background: A single priming dose of T (anti-CTLA-4) added to D (anti-PD-L1) in the STRIDE (Single T Regular Interval D) regimen, formerly T300+D, showed encouraging clinical activity and limited toxicity in a phase 2 uHCC study (Study 22, NCT02519348), suggesting single exposure to T is sufficient to improve upon D activity. HIMALAYA (NCT03298451) evaluated the efficacy and safety of STRIDE or D vs sorafenib (S) in uHCC. Methods: HIMALAYA is an open-label, multicenter, phase 3 study, in which pts with uHCC and no prior systemic therapy were initially randomized to STRIDE (T 300 mg plus D 1500 mg [one dose] plus D 1500 mg every 4 weeks [Q4W]), D (1500 mg Q4W), S (400 mg twice daily), or T 75 mg Q4W (4 doses) plus D 1500 mg Q4W (T75+D). Recruitment to T75+D ceased after a planned analysis of Study 22 showed T75+D did not meaningfully differ from D. The primary objective was overall survival (OS) for STRIDE vs S. The secondary objective was OS noninferiority (NI) of D to S (NI margin: 1.08). Secondary endpoints included progression-free survival (PFS), objective response rate (ORR; RECIST v.1.1), duration of response (DoR), and safety. Results: In total, 1171 pts were randomized to STRIDE (N=393), D (N=389), or S (N=389). At data cutoff (DCO), the primary objective was met: OS was significantly improved for STRIDE vs S (hazard ratio [HR], 0.78; 96% confidence interval [CI], 0.65–0.92; p=0.0035; Table). D met the objective of OS NI to S (HR, 0.86; 96% CI, 0.73–1.03). ORRs were higher for STRIDE (20.1%) and D (17.0%) than for S (5.1%). No new safety signals were identified. Grade 3/4 treatment-related adverse events (TRAEs) occurred in 25.8% (STRIDE), 12.9% (D), and 36.9% (S) of pts. Grade 3/4 hepatic TRAEs occurred in 5.9% (STRIDE), 5.2% (D), and 4.5% (S) of pts. No TRAE of esophageal varices hemorrhage occurred. Rates of TRAEs leading to discontinuation were 8.2% (STRIDE), 4.1% (D), and 11.0% (S). Conclusions: HIMALAYA was the first large phase 3 trial with a diverse, representative uHCC population and extensive long-term follow-up to assess both mono- and combination immunotherapy. D was noninferior to S with favorable safety. The combination of a single priming dose of T plus D in STRIDE displayed superior efficacy and a favorable benefit-risk profile vs S. STRIDE is a proposed, novel, first-line standard of care systemic therapy for uHCC. Clinical trial information: NCT03298451. [Table: see text]

Background: Tumor budding (Bd) has been demonstrated to be a promising prognostic factor in many carcinomas and in gastric cancer. It may represent an optimal additional parameter that is helpful for risk stratification in gastric adenocarcinoma. Hence, the present research was designed to predict the survival outcomes of gastric cancer in Vietnam, applying the tumor budding criteria of the International Tumor Budding Consensus Conference (ITBCC) 2016. Methods: The present study was conducted on 109 gastric cancer patients who underwent surgery but did not receive neo-adjuvant chemotherapy from 2012 to 2015. The patients’ clinicopathological features were recorded. Bd was evaluated according to the 2016 ITBCC criteria and classified as Bd1 (0–4 buds), Bd2 (5–9 buds), and Bd3 (≥10 buds) grades, in addition to being categorized into 2 main Bd groups: low (<10 buds) and high (≥10 buds) Bd. Kaplan–Meier and log-rank models were applied to analyze survival proportions. Results: Of all the patients, 22.9% were classified as Bd1, 31.2% as Bd2, and 45.9% as Bd3 grades. Furthermore, 54.1% patients were categorized into the low and 45.9% into the high Bd groups. Patients with Bd1 and Bd2 grades (the low Bd group) exhibited the best prognosis, with 5-year overall survival (OS) rates of 85.7%, 90.8%, and90.3%, respectively. Patients with Bd3 grade (the high Bd group exhibited the worst prognosis, and none of them lived for 5 years (p < 0.001). Similar to OS rates, disease-free survival (DFS) rates markedly reduced from the Bd1 to Bd3 grade: Bd1, 95.0%; Bd2, 84.7%; and Bd3, 0% (p < 0.001). Conclusion: Patients with different gastric cancer Bd grades exhibited significantly different OS and DFS rates. The present study findings suggest that the ITBCC criteria can be used to stratify Bd for the treatment and prognosis of gastric cancer patients in Vietnam.

Pediatric high-grade gliomas represent 8–12% of all primary tumors of the nervous system in children. Five-year survival for these pediatric aggressive tumors is poor (15–35%) indicating the need to develop better treatments for pediatric high-grade gliomas. In this work we used SF188 and SJ-GBM2 cell lines to study the function of the ubiquitin carboxyl-terminal esterase L1 (UCHL1), a deubiquitinase de-regulated in several cancers, in pediatric high-grade gliomas. UCHL1 depletion in SF188 and SJ-GBM2 glioma cells was associated with decreased cell proliferation and invasion, along with a reduced ability to grow in soft agar and to form spheres (i.e. self-renewal measure). A 70% reduction in Wnt signaling was also observed in the SF188 and SJ-GBM2 UCHL1 knockdowns (KDs) using a TCF-dependent TOPflash reporter assay. Transcriptome comparisons of UCHL1 KDs versus vector control identified a list of 306 differentially expressed genes (at least 2-fold change; p <0.05) which included genes known to be involved in cancer like ACTA2, POSTN, LIF, FBXL7, FBXW11, GDF15, HEY2, but also potential novel genes such us IGLL5, ABCA4, AQP3, AQP4, CALB1, and ALK. Bioinformatics gene ontology (GO) analysis of these 306 genes revealed significant enrichment in “signal peptides”, “extracellular matrix”and “secreted proteins” GO Terms. “Angiogenesis and blood vessel development”, “neuron differentiation/development”, cell adhesion”, and “cell migration” also showed significant enrichment in our GO analysis. Top canonical pathways identified by Ingenuity Pathway Analysis (IPA) included “Clathrin-mediated Endocytosis Signaling” (p = 5.14x10-4), “Virus Entry via Endocytic Pathways” (p = 6.15x 10−4), and “High Mobility Group-Box 1 (HMGB1) Signaling” (p = 6.15x10-4). While FGF2, IL1B, TNF and PDGFB were predicted as top upstream regulators (p < 2x10-16) of the UCHL1 KD-associated transcriptome. Aberrant expression of UCHL1 in pediatric high-grade gliomas may promote cell invasion, transformation, and self-renewal properties, at least in part, by modulating Wnt/Beta catenin activity. UCHL1 might act as an oncogene in glioma within the gene network that imparts stem-like characteristics to these cancer cells.

437 Background: The prognosis for patients (pts) with advanced UC remains poor, particularly for those unable to tolerate platinum-based chemotherapy. Defects in DNA damage repair (e.g., mutations in homologous recombination repair [HRR] genes) are common in UC and render tumor cells sensitive to poly(ADP-ribose) polymerase (PARP) inhibition. HRR gene mutations (HRRm) and PARP inhibition may enhance the antitumor response of immune checkpoint inhibitors. We conducted a randomized phase II study to evaluate D (anti–PD-L1) in combination with O (a PARP inhibitor) or placebo (P) as a first-line treatment for platinum-ineligible pts with unresectable, stage IV UC (BAYOU; NCT03459846). Methods: Eligible pts were an age of ³18 years with an ECOG performance status (PS) of 0, 1, or 2, histologically or cytologically confirmed transitional cell carcinoma, and who had not received prior systemic therapy for unresectable, stage IV disease. Pts were randomized 1:1 to receive D (1500 mg IV q4w) plus O (orally at 300 mg BID) vs D (1500 mg IV q4w) plus O-matching placebo (P). Pts were stratified according to centrally-determined HRR status (mutant vs wild-type) and Bajorin risk index (a composite of visceral metastases and ECOG PS [0, 1 vs 2]). The primary endpoint was progression-free survival (PFS) by RECIST v1.1 (investigator assessed) in the intention-to-treat (ITT) population. Secondary endpoints included overall survival (OS) in the ITT population and PFS in the subset of pts with HRRm. The data cutoff occurred on October 15, 2020. Results: A total of 154 pts were randomized to receive D+O (n = 78) or D+P (n = 76). Among all randomized pts at baseline, 17%, 42%, and 40% had an ECOG PS of 0, 1, or 2, respectively, and 20% had an HRRm. Median PFS was not significantly different between D+O and D+P in the ITT population (Table). In the subset of pts with HRRm, median PFS was 5.6 months in the D+O group and 1.8 months in the D+P group (Table). In the ITT population, median OS (95% CI) was 10.2 months (7.0–13.9) in the D+O group and 10.7 months (7.2–17.3) in the D+P group (HR 1.07, 95% CI 0.72–1.61). Among all treated pts, grade 3 or 4 treatment-related adverse events occurred in 18% and 9% in the D+O and D+P groups, respectively, with one death due to anemia in the D+P group. Conclusions: The BAYOU study did not meet its primary endpoint. However, the results of pre-planned secondary analyses suggest a potential role for PARP inhibition in UC pts harboring HRRm. No new safety signals were observed. Clinical trial information: NCT03459846. [Table: see text]