Progress in the treatment of anal cancer: an overview of the latest investigational drugs

INTRODUCTION

Anal cancer, a rare malignancy accounting for 2.5-3.0% of gastrointestinal cancers, primarily manifests as squamous cell carcinoma associated with HPV. Recent years have witnessed significant advancements in managing squamous cell carcinoma of the anus (SCCA), particularly with the introduction of immune checkpoint inhibitors (ICIs) and randomized data on front-line chemotherapy.

AREAS COVERED

This review discusses the current standard treatments for both early and advanced SCCA, based on published data. The authors then describe the new approaches, focusing on ICI combinations, targeted agents, T-cell adoptive therapy, and HPV-therapeutic vaccines.

EXPERT OPINION

The current standard treatment for SCCA includes front-line carboplatin and paclitaxel, with pembrolizumab and nivolumab as later-line options. While modified DCF has shown promise in single-arm studies, its role as a front-line therapy requires confirmation through randomized data. We eagerly anticipate the results of phase 3 trials investigating the front-line chemo-immunotherapy for metastatic SCCA and ICI consolidation following chemoradiation for early-stage SCCA. Novel approaches like T-cell adoptive therapy, HPV-therapeutic vaccines, and bifunctional antibodies combined with HPV vaccines are in early-stage trials for HPV-mediated tumors, including HPV-positive SCCA. These approaches targeting HPV epitopes may eventually gain tumor-agnostic approval, although their role in SCCA may take time to establish.

Biomarker Analysis from a Phase I/Ib Study of Regorafenib and Nivolumab in Mismatch Repair-Proficient Advanced Refractory Colorectal Cancer

Previously, we reported the modest but durable anticancer activity of regorafenib/nivolumab in mismatch repair-proficient (pMMR) refractory colorectal cancer in our I/Ib study. Our finding suggests the necessity of biomarkers for better selection of patients. Baseline clinical and pathological characteristics, blood and tumor samples from the patients in the trial were collected and evaluated to discover potential biomarkers. The obtained samples were assessed for immunohistochemistry, ELISA and RNA sequencing. Their correlations with clinical outcome were analyzed. A high albumin level was significantly associated with improved progression-free survival (PFS), overall survival (OS) and disease control. Non-liver metastatic disease showed prolonged PFS and OS. Low regulatory T-cell (Treg) infiltration correlated with prolonged PFS. Low MIP-1β was associated with durable response and improved OS significantly. Upregulation of 23 genes, including CAPN9, NAPSA and ROS1, was observed in the durable disease control group, and upregulation of 10 genes, including MRPS18A, MAIP1 and CMTR2, was associated with a statistically significant improvement of PFS. This study suggests that pretreatment albumin, MIP-1β, non-liver metastatic disease and Treg infiltration may be potential predictive biomarkers of regorafenib/nivolumab in pMMR colorectal cancer. Further studies are needed to confirm these findings.

Radioembolization with Yttrium-90 Glass Microspheres as a First-Line Treatment for Unresectable Intrahepatic Cholangiocarcinoma-A Prospective Feasibility Study

PURPOSE

To evaluate the safety and effectiveness of yttrium-90 (90Y) radioembolization as first-line treatment for unresectable intrahepatic cholangiocarcinoma (ICC).

MATERIALS AND METHODS

This prospective study enrolled patients who had never received chemotherapy, liver embolization, and radiation therapy. The tumors were solitary in 16 patients, multiple in 8 patients, unilobar in 14 patients, and bilobar in 10 patients. Patients underwent transarterial radioembolization with 90Y-labeled glass microspheres. The primary end point was hepatic progression-free survival (HPFS). Secondary end points were overall survival (OS), tumor response, and toxicity.

RESULTS

Twenty-four patients (age, 72.3 years ± 9.3; 12 women) were included in the study. The median delivered radiation dose was 135.5 Gy (interquartile range, 77.6 Gy). The median HPFS was 5.5 months (95% CI, 3.9-7.0 months). Analysis failed to identify any prognostic factor associated with HPFS. Imaging response at 3 months showed 56% disease control, and the best radiographic response was 71% disease control. The median OS from the radioembolization treatment was 19.4 months (95% CI, 5.0-33.7). Patients with solitary ICC had significantly longer median OS than patients with multifocal ICC: 25.9 months (95% CI, 20.8-31.0 months) versus 10.7 months (95% CI, 8.0-13.4 months) (P = .02). Patients with progression on the 3-month imaging follow-up had significantly shorter median OS than patients who had stable disease at 3 months: 10.7 months (95% CI, 0.7-20.7 months) versus 37.3 months (95% CI, 16.5-58.1 months) (P = .003). Two (8%) Grade 3 toxicities were reported.

CONCLUSIONS

First-line treatment of ICC with radioembolization showed promising OS and minimal toxicity, especially in patients with solitary tumor. Radioembolization may be considered as a first-line treatment option for unresectable ICC.

Association of Age With Treatment-Related Adverse Events and Survival in Patients With Metastatic Colorectal Cancer

Importance

While the incidence of early-onset metastatic colorectal cancer (mCRC) has been increasing, studies on the age-related disparity in this group of patients are limited.

Objective

To evaluate the association of age with treatment-related adverse events and survival in patients with mCRC and explore the potential underlying factors.

Design, Setting, and Participants

This cohort study included 1959 individuals. Individual data on 1223 patients with mCRC who received first-line fluorouracil and oxaliplatin therapy in 3 clinical trials, and clinical and genomic data of 736 patients with mCRC from Moffitt Cancer Center were used to assess genomic alterations and serve as an external validation cohort. All statistical analyses were conducted from October 1, 2021, through November 12, 2022.

Exposures

Metastatic colorectal cancer.

Main Outcomes and Measures

Survival outcomes and treatment-related adverse events were compared among patients in 3 age groups: younger than 50 (early onset), 50 to 65, and older than 65 years.

Results

In the total population of 1959 individuals, 1145 (58.4%) were men. Among 1223 patients from previous clinical trials, 179 (14.6%) in the younger than 50 years group, 582 (47.6%) in the 50 to 65 years group, and 462 (37.8%) in the older than 65 years group had similar baseline characteristics except for sex and race. The younger than 50 years group had significantly shorter progression-free survival (PFS) (hazard ratio [HR], 1.46; 95% CI, 1.22-1.76; P < .001) and overall survival (OS) (HR, 1.48; 95% CI, 1.19-1.84; P < .001) compared with the 50 to 65 years group after adjustment for sex, race, and performance status. Significantly shorter OS in the younger than 50 years group was confirmed in the Moffitt cohort. The younger than 50 years group had a significantly higher incidence of nausea and vomiting (69.3% vs 57.6% [50-65 years] vs 60.4% [>65 years]; P = .02), severe abdominal pain (8.4% vs 3.4% vs 3.5%; P = .02), severe anemia (6.1% vs 1.0% vs 1.5%; P < .001), and severe rash (2.8% vs 1.2% vs 0.4% P = .047). The younger than 50 years group also had earlier onset of nausea and vomiting (1.0 vs 2.1 vs 2.6 weeks; P = .01), mucositis (3.6 vs 5.1 vs 5.7 weeks; P = .05), and neutropenia (8.0 vs 9.4 vs 8.4 weeks; P = .04), and shorter duration of mucositis (0.6 vs 0.9 vs 1.0 weeks; P = .006). In the younger than 50 years group, severe abdominal pain and severe liver toxic effects were associated with shorter survival. The Moffitt genomic data showed that the younger than 50 years group had a higher prevalence of CTNNB1 mutation (6.6% vs 3.1% vs 2.3%; P = .047), ERBB2 amplification (5.1% vs 0.6% vs 2.3%; P = .005), and CREBBP mutation (3.1% vs 0.9% vs 0.5%; P = .05), but lower prevalence of BRAF mutation (7.7% vs 8.5% vs 16.7%; P = .002).

Conclusions and Relevance

In this cohort study of 1959 patients, those with early-onset mCRC showed worse survival outcomes and unique adverse event patterns, which could be partially attributed to distinct genomic profiles. These findings may inform individualized management approaches in patients with early-onset mCRC.

A phase II study of atezolizumab (ATEZO) and bevacizumab (BEV) in combination with Y90 TARE in patients (pts) with hepatocellular carcinoma (HCC): Y90+/- BEAT

TPS629

Background: The anti–PD-L1 antibody ATEZO prevents PD-L1 from interacting with PD-1 and B7.1, thus reinvigorating antitumor T cell activity. Anti-VEGF BEV can increase dendritic cell maturation, enhance T cell infiltration, and reduce myeloid-derived suppressor cells and regulatory T-cells in tumors. This combination has been FDA approved for first-line treatment of advanced HCC based on the IMbrave150 study. On the other hand, locoregional radiotherapy (e.g., Y90 TARE) enhances the diversity of the intratumoral T cell receptor repertoire. It is the standard of care for pts with intermediate-stage HCC (iHCC). Based on preclinical and clinical data, we hypothesize that the combination of Y90 TARE, BEV, and ATEZO induces synergistic tumor-killing. Methods: This is an open-label, multicenter, randomized phase II study of Y90 TARE and BEV plus ATEZO compared with Y90 TARE alone in pts with unresectable IHCC (NCT04541173). The primary study objective is to assess and compare the progression-free survival (PFS) (per mRECIST 1.1) of pts in each arm. The main secondary objective is to determine the safety and tolerability (CTCAE v5) of TARE combined with ATEZO and BEV in pts with HCC. Exploratory objectives are to assess the role of the immunoscore and PD-L1 expression levels in the prediction of improved clinical outcome in pts receiving Y-90 TARE and BEV plus ATEZO; the composition of tumor-infiltrating immune cell subtypes in predicting response to a chosen therapy; how Y90 therapy affects the proportion of antigen-presenting cells in the tumor; and symptoms experienced by pts receiving TARE and BEV plus ATEZO treatment, using patient-reported outcomes. Eligible pts have either HCC that is not amenable to surgical resection, confirmed by pathology review, or at least BCLC stage B HCC outside of downstaging criteria. Other standard eligibility criteria apply. Pts must have a pretreatment liver biopsy taken and then be randomized 1:1 to TARE (Arm A) or TARE followed by ATEZO and BEV (Arm B). Pts will have TARE mapping during week (wk) 1 and TARE treatment during wk 2. In Arm B, pts will start BEV plus ATEZO 4 wks (±1 wk) after TARE treatment. Pts will have abdominal MRI or CT scans every 12 weeks, CT scans of the chest every 24 wks. Disease progression will be captured by both RECIST 1.1 and mRECIST. We plan to assess the safety of TARE with BEV and ATEZO in the first 10 pts randomized to Arm B for two cycles. If there are no Grade ≥ 3 unexpected toxicities possibly, probably or definitely related to combined TARE plus BEV plus ATEZO, the study will continue to accrue 128 pts in total. Pts will continue study treatment (Arm B) for a total of 24 months from initiation of TARE or until intolerable toxicity or disease progression occur, whichever is earlier. Clinical trial information: NCT04541173 .

Biomarker analysis to predict response in patients with metastatic mismatch repair proficient colorectal cancer treated with regorafenib and nivolumab

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Background: We previously conducted a phase I/Ib study with regorafenib and nivolumab in patients with refractory metastatic mismatch repair proficient (pMMR) colorectal cancer (CRC). This study aimed to investigate the biomarkers that predict the treatment response. Methods: Out of the 51 patients who received regorafenib and nivolumab, 22 archival pretreatment tumor samples were subjected to the Xerna TME Panel, a machine learning-based RNA-sequencing biomarker assay and were classified into one of four TME biomarker subtypes: Angiogenesis (A), Immune Active (IA), Immune Desert (ID), or Immune Suppressed (IS). Potential predictive biomarkers including the TME subtypes, KRAS (wild type vs mutant), PD-L1 (negative vs. positive, samples with > 1% tumor cells for PD-L1 were considered positive), CD8 expression (low vs. high), and Treg cells (low vs. high) in tumor microenvironment were evaluated for correlation with overall survival (OS), progression free survival (PFS) and disease control rate (DCR, defined as complete response + partial response + stable disease). Results: Among the 22 patients, 16 (72.7%) had liver metastasis and 15 (68.2%) had lung metastasis. KRAS mutation was found in 16 (68.2%) patients. 11/21 (52.4%) were positive for PD-L1. 12 (54.5%) had high CD8 expression, whereas 9/21 (42.9%) had high Treg cells in tumor microenvironment. Ten (45.5%) patients were classified as biomarker-positive (IA + IS subtypes) and 12 (54.5%) were biomarker-negative (A + ID) based on Xerna TME panel. Two (9.1%) patients achieved partial response, 12 (54.5%) had stable disease, and five (22.7%) developed progressive disease. The median PFS was 5.6 months and median OS was 13.1 months. No significant correlation was observed between RAS mutation (p = 0.664, p = 0.609), PD-L1 expression (p = 0.287, p = 0.173), CD8 (p = 0.152, p = 0.456) and PFS or OS. Low Treg was found to be associated with prolonged PFS (median: 9.8 vs. 1.9 months, p = 0.011) but not OS (p = 0.280). Similarly, only low Treg level was related with DCR (83.3% vs. 33.3%, p = 0.032). While not reaching statistical significance, Xerna TME biomarker-positive patients showed trends for higher median PFS (7.9 months vs. 4.1 months, p = 0.254), median OS (15.75 months vs. 11.9 months, p = 0.378), and higher DCR (70% vs. 58%, p = 0.675) compared to biomarker-negative patients. Additionally, the two patients with partial responses were Xerna TME biomarker-positive. Conclusions: Our study demonstrated that low Treg in tumor microenvironment is correlated with better prognosis in patients with refractory metastatic pMMR CRC who were treated with regorafenib plus nivolumab. Xerna TME panel analysis of these patients also showed trends for predictive clinical benefit. Prospective and larger cohort studies are needed to better define predictive biomarkers for this combination in the future.

Biomarker analysis from a phase I/I1b study of regorafenib and nivolumab (rego/nivo) in microsatellite stable (MSS) colorectal cancer (CRC)

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Background: Our previous phase I/Ib study revealed modest clinical efficacy of rego/nivo in refractory MSS-CRC, implying benefits in selected populations. This has prompted us to investigate predictive biomarkers. Methods: Pre-treatment tumor samples from the previous phase Ib rego/nivo study were obtained and assessed for mRNA sequencing (RNAseq). Response-associated transcripts were identified using DESeq2 method and annotated using gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis. Results: A total of 19 pretreatment tumor samples were analyzed including 14 patients (pts) with disease control (DC) (2 partial response and 12 stable disease) and 5 pts with progression disease (PD). We observed significant upregulation of 89 genes including SFTPB ( P<0.001), SFTPA1 ( P<0.001), ERICH6B ( P<0.001) , XIST ( P<0.001), IGHV2-26 ( P<0.001), RETNLB ( P=0.005), VWA5B1 ( P=0.033), IGHV3-53 ( P<0.001), POTEH ( P=0.015), IGHV1-3 ( P=0.001) and downregulation of 70 genes including AFAP1-AS1 ( P=0.022), PRSS21( P<0.001), NTSR1 ( P<0.001), CALB1 ( P=0.033), FAM83A ( P=0.013), TBL1Y ( P=0.045), WNT7A ( P=0.022), PADI1 ( P<0.001), KRT6A ( P=0.030), KRT17 ( P=0.002) on RNA sequencing in the DC compared to PD. GO pathway enrichment analyses revealed 44 significantly upregulated pathways including positive regulation of B cell activation ( P<0.001), B cell receptor signaling pathway ( P<0.001), Phagocytosis engulfment ( P<0.001), Fc-gamma receptor signaling pathway involved in phagocytosis ( P<0.001), endocytosis ( P<0.001), immunoglobulin receptor binding ( P<0.001), serine-type endopeptidase activity ( P<0.001) in the DC compared with PD group. Nine downregulated pathways including cell-substrate junction assembly ( P<0.001), extracellular matrix (ECM) organization ( P=0.030), and ephrin receptor activity ( P=0.046) were observed in the DC compared with PD. KEGG pathway enrichment analysis revealed 8 significantly downregulated pathways including PI3K-Akt signaling ( P=0.009), ECM-receptor interaction ( P=0.006), Focal adhesion ( P=0.028), and Glycine, serine and threonine metabolism ( P=0.007) pathways in the DC compared with PD. Conclusions: RNAseq and following gene set enrichment analysis between pts with DC and PD revealed several dysregulated pathways involving immune regulation including macrophage and B cell activation, and also PI3-Akt signaling, ECM organization/receptor interaction, and adhesion, which are consistent with previous translational studies in other solid tumors. These dysregulated genes and pathways related to differentially expressed genes may need to be further evaluated as potential predictive biomarkers for rego/nivo or other tyrosine kinase inhibitor plus PD-1 blockade in MSS-CRC.

The role of socioeconomic deprivation in gastrointestinal cancer clinical trial enrollment at an NCI-designated comprehensive cancer center

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Background: Socioeconomic deprivation has been described as a barrier to cancer clinical trial participation. However, few studies have examined socioeconomic deprivation using patient-level or granular geocoded designations. To overcome this challenge, the Area Deprivation Index (ADI) was used to assess neighborhood socioeconomic deprivation in a cohort of gastrointestinal cancer clinical trial patients at an NCI-Designated Comprehensive Cancer Center. Methods: Patients enrolled in a gastrointestinal cancer clinical trial from 2008 to 2019 with an identifiable ADI national rank were identified. Socioeconomic deprivation was assessed using the ADI, a publicly available, validated dataset that ranks census block groups into percentiles using variables such as income, education, employment, and housing characteristics. For this study, ADI was categorized as quintiles listed in the table. Statistical analyses included Chi-square and Kruskal-Wallis tests. Results: The median age of the cohort (N=1,334) was 62.0 years. Most patients were male (54.3%). Race included White (88.2%), African American (6.8%), and Asian (1.5%) patients. Hispanic/Latinx patients made up 6.7% of the cohort. The median ADI was 46. The proportion of enrollees from lowest to highest ADI quintile was 11.2%, 29.3%, 27.3%, 19.1%, and 13.1%. Trial enrollment differed by ADI and age (p=0.019), gender (p=0.042), race (p<0.001), and insurance (p=0.001). Conclusions: In this study, patients enrolled in gastrointestinal cancer clinical trials had lower neighborhood socioeconomic deprivation than the national or state average. African American, Hispanic/Latinx, female, and uninsured patients comprised a lower proportion of enrollees compared to catchment area estimates (10.6%, 17.7%, 51.3%, and 12.4%, respectively). These findings suggest inequity in clinical trial enrollment and warrant further studies to identify drivers of these disparities. [Table: see text]

Effect of immunotherapy on the survival outcomes in tumor mutational burden-high (TMB-H) microsatellite stable (MSS) metastatic colorectal cancer (mCRC): A single-institution experience

239

Background: The benefit of immunotherapy for patients with mCRC with high tumor mutational burden (TMB-H) has been widely debated. In 2020, the FDA approved the use of pembrolizumab for the treatment of patients with TMB-H unresectable or metastatic solid tumors, with TMB-H defined as ≥10 mutations/Mb on a commercial tissue-based assay, based on KEYNOTE 158 results. However, the clinical value of applying this universal cut off to mCRC needs further investigation. Methods: We queried Moffitt Cancer Center (MCC) databases for patients with MSS mCRC, harboring TMB-H (tested with tissue and/or liquid biopsies) who received immunotherapy between January 2018 and December 2021. Patients with incomplete records were excluded. Clinical data were extracted by trained staff from electronic medical records. Objective response rate was measured by using clinical assessment from chart review. Results: We identified 40 patients with TMB-H MSS mCRC 13 of whom received immune checkpoint inhibitor therapy. Female patients represented 31% (n=4) of the 13 treated patients. Median age for the patients was 60 years (range 34-71. Thirty-eight percent (n=5) of the primary tumors originated in the right side. Thirty-one percent (n=4) presented with stage 4 CRC at diagnosis. Histopathology was adenocarcinoma in 92% (n=12) and one had neuroendocrine differentiation. Tumors were well-differentiated 8% (n=1), moderately differentiated 46% (n=6), or poorly differentiated 23% (n=3). Four patients (31%) had POLE/ POLD-1 mutations. The objective response rate (ORR) was 31% (4/13) with responses limited to tumors only with POLE/ POLD-1 mutations (100%, 4/4). The median progression free survival (mPFS) was 3.8 months for the overall cohort and 28.5 months for patients with POLE/POLD-1 mutated tumors. Agent specific analysis showed mPFS for patients treated with pembrolizumab was 3.5 months (mean 5.2; range 0.6-15.7), and 3.4 months (mean 12.1; range 0.5-12.1) for patients treated with nivolumab. Five patients received immunotherapy in combination with regorafenib. The mPFS for these patients was 3.4 months (mean 3.8; range 0.5-8.0). Of five patients with TMB>30 (38%), 4 (80%) had POLE/POLD-1 mutated tumors. One case without POLE/POLD-1 mutations, but with a TMB>30 did not experience any response. Conclusions: Although TMB-H demonstrated therapeutic significance in the KEYNOTE 158 study, the utility of 10 mutations/MB as a universal cutoff warrants additional evaluation. Here we report that a TMB-H cutoff value of ≥ 10 for patients with MSS CRC was not associated with clinically meaningful response to immunotherapy, but patients with MSS CRC with POLE/ POLD-1 mutations may be more likely to benefit from immunotherapy.

Tumor Response-speed Heterogeneity as a Novel Prognostic Factor in Patients With Metastatic Colorectal Cancer

PURPOSE

Differential tumor response to therapy is partially attributed to tumor heterogeneity. Additional efforts are needed to identify tumor heterogeneity parameters in response to therapy that is easily applicable in clinical practice. We aimed to describe tumor response-speed heterogeneity and evaluate its prognostic value in patients with metastatic colorectal cancer.

PATIENTS AND METHODS

Individual patient data from Amgen (NCT00364013) and Sanofi (NCT00305188; NCT00272051) trials were retrieved from Project Data Sphere. Patients in the Amgen 5-fluorouracil, leucovorin, oxaliplatin (FOLFOX) arm were used to establish response-speed heterogeneity. Its prognostic value was subsequently validated in the Sanofi FOLFOX arms and the Amgen panitumumab+FOLFOX arm. Kaplan-Meier method and Cox proportional hazards models were used for survival analyses.

RESULTS

Patients with high response-speed heterogeneity in the Amgen FOLFOX cohort had significantly shorter ( P <0.001) median progression-free survival (PFS) of 7.27 months (95% CI, 6.12-7.96 mo) and overall survival (OS) of 16.0 months (95% CI, 13.8-18.2 mo) than patients with low response-speed heterogeneity with median PFS of 9.41 months (95% CI, 8.75-10.89 mo) and OS of 22.4 months (95% CI, 20.1-26.7 mo), respectively. Tumor response-speed heterogeneity was a poor prognostic factor of shorter PFS (hazard ratio, 4.17; 95% CI, 2.49-6.99; P <0.001) and shorter OS (hazard ratio, 2.57; 95% CI, 1.64-4.01; P <0.001), after adjustment for other common prognostic factors. Comparable findings were found in the external validation cohorts.

CONCLUSION

Tumor response-speed heterogeneity to first-line chemotherapy was a novel prognostic factor associated with early disease progression and shorter survival in patients with metastatic colorectal cancer.

Biomarker analysis from a phase II multi-institutional study of nivolumab in patients with advanced refractory biliary tract cancer

BACKGROUND

Our previous phase II study demonstrated that nivolumab provides modest but durable clinical efficacy in patients with refractory biliary tract cancer, suggesting the significant clinical benefit of nivolumab in selected patients and the necessity of predictive biomarkers. We evaluated clinicopathological characteristics and tumour microenvironment of the patients who were enrolled the trial to identify potential biomarkers.

METHODS

Baseline clinicopathological characteristics and pretreatment tumour samples were collected. The obtained tumour samples were assessed for whole exome sequencing, RNA sequencing and immunohistochemistry. Their correlations with clinical outcome were analysed.

RESULTS

Pretreatment tumour evaluation revealed PD-L1 expression on tumour, CD8 T cell infiltration and high ratio of CD8 T cell/regulatory T cell in tumour microenvironment were significantly associated with prolonged progression-free survival (PFS), while PD-1 expression on lymphocytes and CD68 macrophages infiltration in tumour microenvironment had no predictive role. Asian patients (N = 3) had improved PFS and disease control rate compared with non-Asian (N = 54). A six-gene predictive model was constructed by evaluation of total 23,550 candidate genes from RNA sequencing of baseline tumour samples using LASSO-Cox regression analysis, and high score of the six-gene prediction model was associated with prolonged PFS.

CONCLUSION

This study suggests that PD-L1 expression on tumour, CD8 T cell infiltration and high ratio of CD8/regulatory T cells and six-gene expression profile in tumour microenvironment may be potential predictive biomarkers of nivolumab in biliary tract cancers. Further studies are needed to confirm these findings.

Clinical and molecular characterization of fusion genes in colorectal cancer

e15568

Background: Next-generation sequencing (NGS) based molecular profiling technologies have revealed several oncogenic fusion genes that are actionable with small molecule inhibitors leading to practice change, particularly in lung cancer. The molecular and clinical characteristics of these gene fusions are not well defined in colorectal cancer patients (CRC). In this study, we aimed to define clinical and molecular characteristics of fusion genes in patients with CRC who underwent molecular profiling. Methods: Molecular characteristics of tissue confirmed 917 CRC patients were retrieved from the Moffit Cancer Center Clinical Genomics Action Committee database. Patients’ demographic and clinicopathological features and treatment history were collected from the database. All fusion genes were shown by hybridization-based NGS computational algorithms that determined cancer‐related genes, including single‐nucleotide variations, indels, microsatellite instability (MSI) status. Results: Among a total of 917 patients, 24 patients with CRC (2.6%) were found to have at least one fusion gene with a total number of 26 pathogenic fusions. The gene fusions are shown in Table. The most common, potentially targetable, fusion genes in our cohort were (1) RET fusions 0.5% (5/917), (2) ALK fusions 0.4% (4/917), (3) ROS1 fusions 0.2% (2/917), (4) NTRK1 fusion 0.1% (1/917), (5) NRG1 fusion 0.1% (1/917). Fusion genes were more common in MSI-H CRC (N = 27), and 3 (11.1%) patients with MSI-H CRC were found to have fusion genes [(RET (2) and NTRK(1)]. Fusion genes were present in both RAS wild-type (54%; 13/24) and RAS mutant (46%; 11/24) tumors. Most patients were older than 50 years (75%, 18/24) and had left-sided tumor (61.1%) tumor. Conclusions: Fusion genes are rare events in CRC. While fusion genes seem to be more prevalent in MSI-H CRC, RAS status does not correlate with the frequency of fusion genes. Actionable RET and ALK/ROS gene fusion are more common than NTRK fusion genes in this cohort of CRC patients.[Table: see text]

Anatomic patterns of recurrence in biliary tract cancers: does primary tumor site matter?

Background

Recommendations for postoperative surveillance and adjuvant therapy following curative-intent resection for biliary tract cancers-including intrahepatic and extrahepatic cholangiocarcinoma (IHCCA and EHCCA) and primary gallbladder cancer (GBC)-are uniform across primary tumor site. However, these tumors may have distinct patterns of recurrence.

Methods

A retrospective observational cohort study was performed at a specialty cancer center. Patients undergoing resection of IHCCA, EHCCA, and GBC were identified (2005-2020). Recurrence-free survival (RFS) was estimated using Kaplan-Meier and Cox proportional hazard methods. Anatomic patterns of initial site of recurrence were described and compared.

Results

There were 142 patients included; 50 IHCCA, 32 EHCCA, and 60 GBC. Median RFS was 30.8 months, which was not significantly different between IHCCA, EHCCA, or GBC in univariate analysis or after adjustment. Nodal positivity was significantly associated with poor RFS (HR 3.92, P≤0.001). The most common initial site of recurrence overall was intrahepatic (n=49/64, 77%), in isolation (n=32) or synchronous with other site of recurrence (n=17). Significant differences in anatomic pattern of recurrence were observed (P=0.049) with IHCCAs more commonly recurring with simultaneous hepatic-pulmonary disease (n=5/22, 23%; EHCCA n=2/19, 10%; GBC n=1/23, 4%), GBC more commonly recurring within the porta (n=7/23, 30%; IHCCA n=0; EHCCA n=1/19, 5%), and EHCCA more commonly recurring within the peritoneum (n=5/19, 26%; IHCCA n=2/22, 9%, GBC n=2/23, 9%).

Conclusions

Patterns of initial recurrence appear to differ between primary tumor site, likely reflecting underlying differences in anatomy and biology. These data could help inform future studies for adjuvant therapy as well as timing and anatomic focus for surveillance imaging.

Efficacy and safety of NT-I7, long-acting interleukin-7, plus pembrolizumab in patients with advanced solid tumors: Results from the phase 2a study

2514

Background: Checkpoint inhibitors (CPIs) are usually ineffective in patients (pts) with immune-cold microsatellite stable colorectal cancer (MSS-CRC) or pancreatic cancer (PDAC) and in those who progressed on previously treated with antibodies against PD1 or PD-L1. Here, we report the combination of NT-I7 plus pembrolizumab (pembro) on CPI-naïve MSS-CRC and PDAC cohorts, and patients (pts) with CPI-treated triple-negative breast cancer (TNBC), non-small cell lung cancer (NSCLC), and small cell lung cancer (SCLC) cohorts of this ongoing phase 2a trial. Methods: Pts with CPI-naïve relapsed/refractory (R/R) MSS-CRC and PDAC, and CPI-treated R/R TNBC, NSCLC, and SCLC, were enrolled. NT-I7 (efineptakin alfa) 1200 µg/kg intramuscularly every 6 weeks and 200 mg pembro intravenously every 3 weeks were administered until disease progression/unacceptable toxicity. The primary endpoint of the Phase 2a is the objective response rate (ORR), assessed by RECIST v1.1 and iRECIST. The secondary endpoints are duration of response (DoR), disease control rate, progression-free survival, and overall survival. Results: As of 14 Jan 2022, 92 pts with metastatic or locally advanced cancer who had received a median of 3 prior treatments were enrolled in the study; 32 in PDAC, 28 in MSS-CRC, 22 in NSCLC, 6 in TNBC, and 4 in SCLC. The median age was 62 years [29-81], ECOG PS 0 in 23 (25%), 1 in 68 (74%) and 2 in 1 (1%). Among 71 evaluable pts, the median follow up (months) was 7.7, 5.3, 5.0, 3.7, and 2.4 in TNBC, MSS-CRC, NSCLC, PDAC and SCLC, respectively. The ORR was 50% (1/2) in SCLC, 12% (3/25) in MSS CRC, 8% (2/26) in PDAC 6% (1/16) in NSCLC and 0% (0/2) in TNBC per iRECIST; and 50% (1/2) in SCLC, 4% (1/25) in MSS CRC, and 4% (1/26) in PDAC per RECIST 1.1. All 7 responders are ongoing. The two PDAC pts had DoR over 1.35 months (mos) and 6.64 mos with the best tumor reduction 100% and 72% respectively. The one SCLC pt had DoR over 1.5 mos with the tumor reduction 67%. The one NSCLC pt had DoR over 2.73 mos with the tumor reduction 60%, and the three MSS-CRC pts had DoR 6.34, 2.96, and 0.03 mos with the tumor reduction 60%, 56%, and 43% respectively. A sustained and significant (approximate 3X from baseline) increase of peripheral lymphocytes in all arms was observed as shown in our previous report. Among 92 treated pts, NT-I7-related adverse events (AEs) occurred in 67 (72.8%) pts, including 52 (56.5%) Grade (G)1-2, 13 (14.1%) G3, and 2 (2.2%) G4. There were no NT-I7 related G5 AEs. Additional updated efficacy, safety and biomarker data will be presented. Conclusions: The combination of NT-I7 and pembro demonstrated antitumor activity and manageable toxicity profile in heavily pretreated pts with CPI-naïve MSS-CRC and PDAC and CPI-treated TNBC, NSCLC, and SCLC, suggesting that the addition of NT-I7 to CPI can overcome the primary resistance to CPI in the former group and acquired resistance in the latter. Clinical trial information: NCT04332653.

Disparity of treatment-related adverse events and outcome in patients with early-onset metastatic colorectal cancer (mCRC)

6560

Background: While the incidence of newly diagnosed early-onset mCRC has been increasing, disparity of treatment-related adverse events (AE) and outcomes of this patient population has been inadequately studied with inconclusive findings. We aimed to evaluate such age-related disparity and explore potential underlying causes. Methods: We used individual patient data from 3 clinical trials in Project Data Sphere where 756 and 467 patients with mCRC received first-line FOLFOX in study 1 (NCT 00305188, NCT00272051) and study 2 (NCT00364013), respectively. Clinical NGS data of 763 patients with mCRC from prospectively maintained Moffitt Clinical Genomics Database were used to assess genomic alterations. Patients were categorized into 3 age groups: <50, 50-65, and >65 years. Continuous and categorical variables were compared with t test and χ2 test, respectively. Kaplan-Meier method and log-rank test were used for survival analysis. Benjamini-Hochberg procedure was used to adjust for multiple comparisons. Results: Among 1986 patients included, 341 (17.2%) in the <50 group, 912 (45.9%) in the 50-65 group, 733 (36.9%) in the >65 group had similar baseline characteristics. Outcomes: Patients in the <50 group had shorter median OS compared to the 50-65 (15.5 vs 20.5 month, p=0.003) and >65 groups (15.5 vs 20.8 months, p=0.004) and shorter median PFS compared to the 50-65 (8.1 vs 9.4 month, p=0.039) and >65 groups (8.1 vs 8.6 months, p=0.07) in study 1. Findings were confirmed in study 2. Toxicity: Compared to other age groups, the <50 group had a higher incidence of severe (grade≥3) abdominal pain (8.4% vs 3.4%, p=0.01), severe anemia (6.1% vs 1.2%, p=0.001), nausea/vomiting (69.3% vs 58.8%, p=0.02), but lower incidence of severe diarrhea (6.1% vs 10.8%, p=0.02), severe neutropenia (25.7% vs 44.2%, p<0.001), and severe fatigue (4.5% vs 7.3%, p=0.02). The <50 group had earlier onset of nausea/vomiting (1.0 vs 2.3 weeks, p=0.01), mucositis (3.6 vs 5.4 weeks, p=0.05), and neutropenia (8.0 vs 9.0 weeks, p=0.04), and shorter duration of mucositis (0.6 vs 0.9 weeks, p=0.006). Outcomes + toxicity: In the <50 group, abdominal pain was associated with worse OS (HR 1.6, p=0.01). In contrast, fatigue (HR 0.66, p=0.03) and mucositis (HR 0.67, p=0.046) were associated with better OS. Neuropathy was associated with better PFS (HR 0.61, p=0.009). Genomics: Our NGS data showed that the <50 group had more ERBB2 amplification (10.5% vs 4.0%, p=0.04) and a trend of more TP53 mutations (80.2% vs 72.0%, p=0.07). These findings were confirmed in an independent mCRC cohort (n=471, MSK, Gastroenterology 2020). Conclusions: Patients with early-onset mCRC had worse outcome and unique treatment-related AE patterns. Distinct genomic profiles could explain some of the disparities. Our findings might improve a personalized management approach in patient selection for chemotherapy, counseling and AE monitoring.

An open-label, multicenter, randomized phase II study of atezolizumab and bevacizumab with Y90 TARE in patients with unresectable hepatocellular carcinoma (HCC)

TPS4177

Background: The anti–PD-L1 antibody atezolizumab (ATEZO) prevents PD-L1 from interacting with PD-1 and B7.1, thus reinvigorating antitumor T cell activity. Anti-VEGF bevacizumab (BEV) increases dendritic cell maturation, enhances T cell infiltration, and reduces myeloid-derived suppressor cells and regulatory T cells in tumors. ATEZO + BEV is FDA approved for first-line treatment of advanced HCC based on the IMbrave 150 study. Locoregional radiotherapy (e.g., Y90 TARE) enhances the diversity of the intratumoral T cell receptor repertoire and increases tumor antigen release. We hypothesize that the Y90 TARE + BEV + ATEZO combination induces synergistic tumor killing and prolongs progression-free survival in patients (pts) receiving Y90 TARE (HR = 0.6 when compared to Y-90 TARE alone). Methods: Eligible pts have HCC that cannot be surgically resected (confirmed by pathology review), is at least BCLC stage B, and is outside Milan criteria. Other requirements include ECOG PS of 0-1 at screening, measurable disease by RECIST 1.1, no prior systemic therapy, and FLR estimated at ≥ 40% post local therapy. Pts must have a pretreatment liver biopsy taken and then be randomized 1:1 to TARE (Arm A) or TARE + ATEZO + BEV (Arm B). Pts will have TARE mapping followed by TARE treatment. In Arm B, pts will begin TARE treatment followed by BEV + ATEZO (4 wks [± 1 wk] later). Pts will have abdominal MRI or CT scans every 12 weeks and CT scans of the chest every 24 wks. The primary study objective is to assess and compare pts' progression-free survival (per mRECIST 1.1) in each study arm. The main secondary objective is to determine the safety and tolerability (CTCAE v5) of pts in Arm B. Exploratory objectives are to define the use of cellular and circulating biomarkers in the prediction of improved clinical outcomes of pts in Arm B. Symptoms experienced by pts in both arms using patient-reported outcomes will be assessed. Disease progression will be captured by both RECIST 1.1 and mRECIST. We plan to assess the safety of Y90 TARE + BEV + ATEZO in the first 10 pts randomized to Arm B for two cycles, and if there are no grade ≥ 3 unexpected toxicities possibly, probably, or definitely related to combined TARE + BEV + ATEZO, continue to accrue 128 pts in total (current enrollment n- = 5). Pts will continue study treatment (Arm B) for a total of 24 months from initiation of TARE or until intolerable toxicity or disease progression occur, whichever is earlier. Enrollment began in September 2020. Clinical trial information: NCT04541173.

Characterization of NTRK alterations in metastatic colorectal cancer

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Background: Increased molecular profiling ability has resulted in the recognition of important actionable genes that can be used to direct targeted therapies in colorectal cancers (CRC). Neurotrophin receptor tyrosine kinase (NTRK) gene fusions are one of these molecular alterations that are potentially actionable with novel targeted therapeutics. However, other biologically pathogenic NTRK alterations, including point mutations, are not yet actionable in CRC. This study aimed to characterize NTRK alterations, including fusions in metastatic CRC patients. Methods: Molecular characteristics of 917 patients with CRC were collected from the Moffitt Cancer Center Clinical Genomics Action Committee database. Demographic, clinicopathological, and molecular data and treatment history were abstracted from electronic medical records. Mutations with potential oncogenic activity are considered “potentially pathogenic”, while alterations with proven oncogenic activity such as fusions are considered “pathogenic”. Results: There were 917 patients with CRC from November 2013 to December 2021, and 77 of them had NTRK alterations excluding synonymous mutations (8.3%, 77/917). Six patients had potentially pathogenic NTRK alterations, including one NTRK rearrangement (0.6%, 7/917); however, only 1 patient had an actionable pathogenic NTRK1 fusion (0.1%, 1/917), while the others (70) were a variant of unknown significance (VUS). The majority of NTRK alterations were missense mutations (92%; 71/77). The NTRK1 fusion partner was LMNA and occurred in the setting of an MSI-H tumor (3.7%; 1/27). Among patients with pathogenic and potentially pathogenic alterations (N = 7), there was only 1(14%) patient who had low tumor mutation burden (TMB) (< 10 mut/MB). Most patients were older than 50 years (70.1%, 54/77) and male (58.4%, 45/77). Thirty-six patients (46..7%) had right-sided tumor, while 41 patients (53.2%) left-sided. Across all NTRK alterations cohort, MSI-H was found in 10.3% (7/77), and POLE/POLD1 pathogenic mutations were seen in 6.4% (5/77) patients. Conclusions: NTRK gene fusion is a relatively rare event (< 1%) in CRC, including the MSI-H subtype. The majority of NTRK alterations in CRC are VUS, and they are not actionable, and they tend to be seen in the tumors with high TMB (TMB > 10). Hypermutator tumors cause frequent VUS alterations in the NTRK gene with unknown clinical relevance.

Pembrolizumab (pembro) plus mFOLFOX7 or FOLFIRI for metastatic colorectal cancer (CRC) in KEYNOTE-651: Long-term follow-up of cohorts B and D

3521

Background: Response to antiPD-1 monotherapy is poor in patients (pts) with advanced microsatellite stable (MSS)/mismatch-repair proficient (pMMR) CRC. Combination of chemotherapy with antiPD-1 pembro may potentiate the antitumor immune response and provide greater antitumor activity than either agent alone. Combination of pembro and mFOLFOX7 or FOLFIRI in the ongoing phase 1b multicohort KEYNOTE-651 (NCT03374254) study in metastatic MSS/pMMR CRC showed antitumor activity. We present results with approximately 20 mo of additional follow-up. Methods: Pts had metastatic MSS/pMMR CRC and were previously untreated (cohort B) or received 1 prior line including a fluoropyrimidine + oxaliplatin (cohort D). Pts received pembro 200 mg Q3W + mFOLFOX7 Q2W (cohort B) or pembro 200 mg Q3W + FOLFIRI Q2W (cohort D). Primary end points were safety (DLT) and RP2D. Secondary end point was ORR per RECIST v1.1 by investigator review. DOR, DCR, and PFS per RECIST v1.1, and OS were exploratory end points. Results: Median study follow-up (range) at data cutoff (Oct 15, 2021) was 30.2 mo (25.0-43.6) for cohort B (n = 31) and 33.5 mo (25.2-43.2) for cohort D (n = 32). Treatment was discontinued in 29 pts (94%) in cohort B and 28 pts (88%) in cohort D, mostly because of PD (61% and 66%, respectively). At prior analysis (Feb 10, 2020), RP2D was confirmed as the starting dose in both cohorts; no new DLT had occurred. In cohort B, gr 3/4 TRAEs occurred in 18 pts (58%), most commonly neutropenia and decreased neutrophil count (both n = 5; 16%); 19 pts (61%) discontinued drug because of a TRAE. In cohort D, gr 3/4 TRAEs occurred in 17 pts (53%), most commonly, neutropenia (n = 7; 22%), diarrhea and fatigue (both n = 4; 13%); 3 pts (9%) discontinued drug because of a TRAE. There were no gr 5 TRAEs in either cohort. Efficacy by cohort and KRAS mutation status are below (Table). PD-L1 data and DNA/RNA-based biomarker data including GEP, consensus signatures, TMB, and LoF mutations will be included in the presentation. Conclusions: After 2.5 y of follow-up, the combination of pembro with either mFOLFOX7 or FOLFIRI continued to demonstrate a manageable safety profile with no new safety signals. Efficacy data from these single-arm cohorts appear comparable to historical data for current SOC. Clinical trial information: NCT03374254. [Table: see text]

Pembrolizumab (pembro) plus binimetinib (bini) with or without chemotherapy (chemo) for metastatic colorectal cancer (mCRC): Results from KEYNOTE-651 cohorts A, C, and E

3573

Background: Response to antiPD-1 monotherapy is poor in microsatellite stable (MSS)/mismatch-repair proficient (pMMR) mCRC; the combination of antiPD-1 pembro + anti-MEK bini, with or without chemo, may improve upon this limited response. KEYNOTE-651 (NCT03374254) is an open-label phase 1b multicenter trial of pembro + bini (cohort A) or pembro + bini + chemo (mFOLFOX7 in cohort C, FOLFIRI in cohort E) in MSS/pMMR mCRC. Preliminary results from the dose-finding phase at 2 dose levels (DL) of bini are presented. Methods: Patients (pts) had MSS/pMMR mCRC and must have been previously treated with fluoropyrimidine, irinotecan, and oxaliplatin in cohort A, or with fluoropyrimidine + oxaliplatin-based regimen in cohort E; pts were previously untreated in cohort C. Pts received pembro 200 mg Q3W + bini 30 mg BID (cohort A, DL1), pembro 200 mg Q3W+ bini 30 mg BID + mFOLFOX7 Q2W (cohort C, DL1) or pembro 200 mg Q3W + bini 30 mg BID + FOLFIRI Q2W (cohort E, DL1). Bini dose escalation to 45 mg BID (DL2) was planned in cohorts A, C, and E, with a target dose-limiting toxicity (DLT) of 30%. Primary end point was safety (DLT). Secondary end point was ORR. DCR, PFS, and OS were exploratory. ORR, DCR, and PFS were assessed by investigator per RECIST v1.1. Results: Median study follow-up at data cutoff (Oct 15, 2021) was 36 mo (range, 32-43) for cohort A, 17 mo (2-24) for cohort C, and 11 mo (2-25) for cohort E. In cohort A, 1/6 pts (17%) had DLT at DL1; no DLT occurred in 14 pts (0%) at DL2. In cohort A, gr 3/4 TRAEs occurred in 3/6 pts (50%) at DL1 and 8/14 pts (57%) at DL2. In cohort C, 3/9 evaluable pts (33%) had DLT at DL1; thus, bini dose was not escalated to DL2. In cohort C, gr 3/4 TRAEs occurred in 9/11 total pts (82%). In cohort E, 1/5 evaluable pts (20%) had DLT at DL1 and 5/10 evaluable pts (50%) had DLT at DL2. Enrollment was stopped in cohort E, DL2 and bini dose was de-escalated to DL1; 2/4 additional pts (50%) had DLT at DL1 (total 3/9 pts [33%] had DLT in cohort E, DL1). In cohort E, gr 3/4 TRAEs occurred in 5/9 pts (56%) at DL1 and 10/11 total pts (91%) at DL2. No gr 5 TRAEs occurred in any cohort. ORR was 0% in cohort A; limited efficacy was seen in cohorts C and E (Table). Conclusions: Bini could be safely combined with pembro in cohort A. However, with bini + pembro + chemo, the 45-mg dose of bini was not well tolerated and required dose reduction to 30 mg. Addition of bini to pembro + chemo did not improve efficacy; therefore, enrollment was prematurely closed in cohorts C and E. Efficacy by KRAS mutation status will be shown. Clinical trial information: NCT03374254. [Table: see text]

A phase II study of TAS-102 (FTD/TPI) in combination with ramucirumab (RAM) in advanced, refractory gastric (GC) or gastroesophageal junction (GEJ) adenocarcinomas (GEAs)

302

Background: The RAINBOW trial established the standard of care for treatment of metastatic GEAs with ramucirumab and paclitaxel after failure of fluoropyrimidine and platinum-based chemotherapy. While the combination achieved an objective response rate (ORR) of 28%, the incidence of any grade neuropathy was 46%. Therefore, there is an unmet need for novel treatment combinations that minimize the long-term toxicity of neuropathy. In a recently published Asian study, the combination of RAM+TAS-102 showed good disease control and acceptable toxicity profile. Methods: This was a single arm, single institution phase II trial using the combination of TAS-102 plus RAM in refractory GEAs. Patients (pts) received RAM 8mg/kg intravenously on day 1 and 15, and TAS-102 35mg/m2 orally twice daily on days 1-5 and days 8-12 every 28-day cycle. The primary endpoint was 6-months overall survival (OS) rate and secondary endpoints were progression free survival (PFS), ORR and safety profile. The trial was registered at www.clinicaltrials.gov (NCT03686488). Results: At data cut-off of August 15, 2021, 23 pts were enrolled. Baseline demographics are as follows: median age of 62 years (range: 23-74), median lines of prior therapy of 1 (1: 14 pts vs ≥2: 9 pts) and location of primary tumor (GEJ:19 vs GC: 4). 6-month OS rate was 56.2%. Median OS was 6.2 month (95% CI: 5.4-7.0) and median PFS was 4.9 months with median observation of 2.3 months. Of 17 evaluable pts defined as more than one baseline imaging, 1 (6%) had partial response (PR) and 15 (88%) had stable disease (RECIST v1.1). Eleven pts came off the study due to progression of disease, 8 for toxicities and 4 for consent withdrawal. Most common treatment-emergent adverse events (TEAEs) were diarrhea (39%), fatigue (39%) and hypertension (39%). Total 11 pts (48%) experienced grade 3 and 4 TEAEs, and most common Gr3 and 4 TEAEs were neutropenia (17%) and anemia (13%). Conclusions: The combination of RAM and TAS-102 showed very similar disease control rate as the study in Asia. The combination has now shown modest activity in advanced GEAs and should be investigated further now in the context of patients receiving immunotherapy-based treatment as first-line treatment. A randomized phase II study is currently enrolling patients with ramucirumab and TAS-102 or paclitaxel. Clinical trial information: NCT03686488.

KEYNOTE-B79 phase 1b trial to evaluate the allogeneic CAR T-cells CYAD-101 and pembrolizumab in refractory metastatic colorectal cancer patients

TPS227

Background: The allogeneic chimeric antigen receptor (CAR) T-cell treatment CYAD-101 utilizes the NKG2D receptor that targets eight ligands expressed on tumor cells and also on stromal and immunosuppressive immune cells of the tumor microenvironment. CYAD-101 co-expresses a T-cell receptor (TCR) inhibitory peptide with the aim to eliminate the potential of graft versus host disease (GvHD), the main safety risk associated with engineered cells of allogeneic origin. In the previous alloSHRINK trial (NCT03692429), CYAD-101 was administered post FOLFOX preconditioning chemotherapy to 15 patients with progressive metastatic colorectal cancer (mCRC) who were previously treated with FOLFOX. Overall, the treatment was well tolerated with no evidence of GvHD. The disease control rate was 73.3% with two patients presenting a confirmed partial response per RECIST’s criteria (4 months and 8 months of duration from first CYAD-101 infusion) and nine had stable disease with a median duration of 4.6 months. Evidence of increase in the TCR repertoire and modulation of the cytokine profile post-treatment with CYAD-101 were observed implying that CYAD-101 may also be modulating the immune suppressive environment in patients mirroring what was demonstrated in pre-clinical models. We considered that a sequential therapy with the anti-PD1 monoclonal antibody pembrolizumab to further release the anti-tumor potential of this expanded T-cell population may drive deeper, more durable and new clinical responses beyond that currently demonstrated with the CAR T-cells alone. Methods: The phase 1b KEYNOTE-B79 trial (NCT04991948) will evaluate, according to a Simon’s two stage study design, the safety and clinical activity of three consecutive infusions of CYAD-101 (1x109 cells per infusion) post FOLFOX preconditioning chemotherapy with two-week interval between cycles, followed by pembrolizumab treatment (200 mg administered every three weeks for up to two years) in microsatellite stable/mismatch-repair proficient mCRC patients with recurrent/progressing disease after at least one metastatic line of therapy, which must include FOLFOX chemotherapy. The pembrolizumab treatment will be initiated 3 weeks after the last CYAD-101 infusion to fall outside the classical time window of potential CAR T-cell toxicities (e.g., cytokine release syndrome). The co-primary endpoints of the trial are the occurrence of dose-limiting toxicities (DLTs) at any time from the first FOLFOX preconditioning treatment up to 3 weeks after the first pembrolizumab treatment and the objective response rate (ORR) at the tumor assessment planned 6 weeks after the first pembrolizumab treatment administration. The KEYNOTE-B79 study will be initiated in Q4-2021 in five sites in USA and Europe. Clinical trial information: NCT04991948.

Core homologous recombination mutations and improved survival in nonpancreatic GI cancers

663

Background: GI malignancies continue to be a major cause of cancer related deaths, despite advances in therapy options. In pancreatic cancer, the presence of homologous recombination mutations (HRM) has been shown to confer increased sensitivity to platinum chemotherapy. However, the role of HRM mutations in other GI cancers remains to be determined. The focus of this study is to evaluate the prognostic nature of core and noncore HRM in nonpancreatic GI cancers. Additionally, we aim to understand the predictive nature of these mutations related to platinum exposure. Methods: This was a retrospective review of patients at Moffitt Cancer Center with a primary stage IV nonpancreatic GI cancer treated with platinum therapy. All patients had next generation sequencing and were in the Clinical Genomics Action Committee database between 1/1/2013 and 11/1/2020. All patients had either a core HRM (BRCA1, BRCA2, PALB2) or noncore HRM (such as ATM, ATR, BARD1, BRIP1, FANCA, NBN, and RAD51). Patients were grouped into core HRM vs. noncore HRM. Response was stratified between responders (complete response and partial response) vs. non responders (stable disease and progressive disease), based on RECIST criteria. Progression free survival and overall survival were estimated using Kaplan-Meier method, and the log-rank test was used to assess the difference in progression free survival (PFS) and overall survival (OS) by HRM status and type of platinum therapy used. Results: There were 72 patients included in the study: the majority of patients were male (65.3%) and Caucasian (87.5%). Twenty-one (29.2%) patients had a core HRM and 51 (70.8%) had a noncore HRM. There was no significant difference in response rate between patients with core HRM and patients with noncore HRM for evaluable patients (n = 66): 20.0% of patients with core HRM vs. 21.7% of patients with noncore HRM demonstrated a response to platinum therapy (p = 0.41). An improved OS was noted for patients with core HRM vs. those with noncore HRM at 68.9 vs. 24.3 months (p = 0.019). An improved PFS was also seen in patients with core HRM at 10.4 months vs. 6.3 months with noncore HRM (p = 0.027). There was no difference in PFS based on type of platinum therapy used (oxaliplatin vs. carboplatin vs. cisplatin), while an improved OS was noted for patients treated with oxaliplatin vs. carboplatin vs. cisplatin at 43.1 vs. 28.2 vs. 16.0 months (p = 0.011). Conclusions: Our study demonstrated that in stage IV nonpancreatic GI malignancies treated with platinum therapy, patients with core HRM had a greater OS and PFS compared to those with noncore HRM, suggesting a potential prognostic and predictive role of these mutations. Further studies are needed to confirm our findings.

Association of BRAF V600E mutation with survival in patients with metastatic mismatch repair-deficient colorectal cancer

174

Background: Colorectal cancer (CRC), while one of the most common cancer diagnoses, can behave heterogeneously based on molecular characteristics. A subset of patients (pts) with CRC are characterized with mismatch repair deficiency (MMR-d), these pts exhibit encouraging responses to immunotherapy. The predictive nature of various factors, such as BRAF status, age, and MMR-D protein loss type, have been investigated in pts with MMR-d CRC. However, the prognostic role of these factors has not been well established. The purpose of this study was to identify characteristics that influence survival in MMR-d mCRC. Methods: This study evaluated pts with MMR-d mCRC in the Flatiron database. Overall survival (OS) was determined from date of diagnosis of stage IV disease to date of death and stratified based on age greater than or less than 50 years, BRAF mutation status, RAS mutation status, and type of MMR gene loss. For statistical analysis, the Chi-Square test was implemented to determine the prognostic significance of clinical and molecular features. Univariate and multivariate analyses were determined through the Cox regression model. Results: There were 1,101 pts in the study. The majority of pts were older than 50 (79.7%), Caucasian (75%), and had ECOG 0-1 (83.4%). Among the 803 pts with known BRAF status, 44.3% (n=356) had BRAF V600E mutation and 55.7% (n=447) were BRAF wildtype. Pts with BRAF V600E mutation had OS of 18.9 months vs. 33.2 months for pts with wild type BRAF (HR 1.52, 95% CI: 1.25-1.86, p<0.001). Pts older than 50 had a lower median OS vs. those who were ≤50 at 21.4 months vs. 38.7 months (HR 1.66, 95% CI: 1.33-2.07, p<0.001). When comparing MSH2/MSH6 mutations to MLH1/PMS2, a trend towards improved OS was seen with median survival of 35.2 months vs. 22.7 months, respectively (HR 0.79, 95% CI: 0.61-1.02, p=0.067). On multivariate analysis, BRAF mutation and older age continued to be associated with differences in survival, while KRAS mutation and specific MMR gene loss did not. Conclusions: BRAF V600E mutation and age greater than 50 are associated with decreased survival for pts with MMR-D mCRC. KRAS mutations and specific MMR alterations are not associated with differences in survival.

Metagenomics and chemotherapy-induced nausea: A roadmap for future research

Uncontrolled chemotherapy-induced nausea and vomiting can reduce patients' quality of life and may result in premature discontinuation of chemotherapy. Although nausea and vomiting are commonly grouped together, research has shown that antiemetics are clinically effective against chemotherapy-induced vomiting (CIV) but less so against chemotherapy-induced nausea (CIN). Nausea remains a problem for up to 68% of patients who are prescribed guideline-consistent antiemetics. Despite the high prevalence of CIN, relatively little is known regarding its etiology independent of CIV. This review summarizes a metagenomics approach to the study and treatment of CIN with the goal of encouraging future research. Metagenomics focuses on genetic risk factors and encompasses both human (ie, host) and gut microbial genetic variation. Little work to date has focused on metagenomics as a putative biological mechanism of CIN. Metagenomics has the potential to be a powerful tool in advancing scientific understanding of CIN by identifying new biological pathways and intervention targets. The investigation of metagenomics in the context of well-established demographic, clinical, and patient-reported risk factors may help to identify patients at risk and facilitate the prevention and management of CIN.

FGFR4 inhibitors for the treatment of hepatocellular carcinoma: a synopsis of therapeutic potential

INTRODUCTION

The mainstay pharmacological approaches to patients with hepatocellular carcinoma (HCC) are tyrosine kinase inhibitors, antiangiogenic agents, and immune checkpoint inhibitors in combination therapy. Aberrant signaling of fibroblast growth factor 19 (FGF19) and its corresponding receptor, fibroblast growth factor receptor 4 (FGFR4), are a driver of HCC cell growth and survival. However, the clinical potential of agents targeting aberrant FGF19/FGFR4 signaling has not been adequately explored.

AREAS COVERED

We evaluate the existing literature on aberrant signaling of FGF19/FGFR4 in HCC and address the recent preclinical and clinical advances of selective FGFR4 inhibitors in the treatment of advanced HCC. Our literature search was performed in September 2021 on clinical trials and ongoing studies published in journals or presented in conferences for cancer research.

EXPERT OPINION

Preclinical studies show selective FGFR4 inhibitors to be highly potent. These inhibitors also show promise in clinical trials and demonstrate manageable on-target side effects. An emphasis should be placed on the development of predictive biomarkers and on enhancing the understanding of primary and acquired resistance mechanisms. This will inspire rationale combination therapy strategies for testing in future clinical trials.

Efficacy of olaparib therapy in metastatic pancreatic ductal adenocarcinoma (PDAC) with homologous recombination deficiency (HRD)

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Background: Pancreatic cancer is one of the deadliest malignancies, with a 5 year OS of around 3%. Up to 3% of unselected patients (pts) with (PDAC) have the BRCA 1/2 mutation, while up to 15% possess HRD (ARID1A, ATM, BAP1, BARD1, BRIP1, CHEK1/2, FANCA, PALB2, RAD50, RAD51). PARP inhibitors, like olaparib, demonstrate clinical benefit in metastatic PDAC with BRCA mutations (mBRCA) and may have a role in those with HRD. The objective of this study is to determine the role of PARP inhibition in PDAC with HRD. Methods: This was a retrospective chart review of metastatic PDAC pts with germline (g) or somatic (s) mBRCA or HRD who received olaparib. An analysis of PFS and OS was performed for PDAC pts with mBRCA vs. HRD. Results: Forty-six pts with metastatic pancreatic cancer were identified to have mBRCA (n = 13) or HRD (n = 23) and received olaparib in our database. Median age was 73 years for mBRCA and 66 years for HRD. Five pts received olaparib as maintenance therapy after disease control with platinum: 2 mBRCA and 3 HRD pts. Six pts with mBRCA and 7 pts with HRD were platinum naïve prior to olaparib. Zero pts with mBRCA and 3 pts with HRD received olaparib after disease progression on platinum. The median (med)PFS for mBRCA vs. HRD was 6.1 months vs. 2.8 months (HR 0.5, 95% CI: 0.2-1.1, p = 0.07). The medOS for mBRCA vs. HRD was 7.7 vs. 5.3 months (HR 0.7, 95% CI: 0.2-1.9, p = 0.4). Of those with mBRCA who received olaparib, prior cisplatin exposure (n = 8) vs. cisplatin naïve (n = 5) led to medPFS of 6.1 vs. 7.8 months (HR 1.8, 95% CI 0.5-6.7, p = 0.3) and medOS of 6.8 months vs. 9.5 months (HR 1.5, 95% 0.3-6.4, p = 0.6). Six pts with HRD including gCHEK2 c.407T > C, gCHEK2 c.1461+1 G > A, gPALB2 gain (exon 11), sFANCI p.N1252S, sATM p.V2716A, sARID1A Q944fs*14 were noted to have disease control of at least 3 months on olaparib. Only one of these pts received olaparib as maintenance therapy after platinum. The medPFS was 6.1 months and medOS was not reached. One pt with HRD (sFANCI N1252S) had progressive disease on platinum prior to olaparib, but had stable disease > 5 months with olaparib. Conclusions: Our study suggests olaparib may have anticancer activity in PDAC with certain HRD. In addition, olaparib may have a role outside maintenance therapy in PDAC with mBRCA. Prospective studies are needed to confirm these findings.

A phase 1 study of TAK-164, an anti-guanylyl cyclase C (GCC) antibody-drug conjugate (ADC), in patients (pts) with advanced gastrointestinal (GI) cancers expressing GCC

3050

Background: TAK-164 is a second-generation ADC comprising a human IgG1 monoclonal antibody targeting GCC conjugated to a DNA-damaging alkylating agent by a peptide linker. TAK-164 demonstrated cytotoxic and antitumor activity in GCC-expressing cells and xenograft mouse models. This first-in-human study investigated the safety, pharmacokinetics (PK), and preliminary efficacy of TAK-164. Methods: Adult pts with GCC-positive, advanced/metastatic GI cancers received TAK-164 intravenously on day 1 of a 21-day cycle (Q3W). Dose escalation proceeded based on cycle 1 safety data via a Bayesian model of modified toxicity probability interval starting at 0.004 mg/kg. Results: Thirty-one pts were enrolled. Median age was 58 years (range 32–72), 58.1% of pts were female and 64.5% had colon carcinoma. The median number of prior lines of therapy was 4 (range 2–9). TAK-164 was given at 0.004 (n = 1), 0.008 (n = 1), 0.016 (n = 1), 0.032 (n = 5), 0.064 (n = 7), 0.12 (n = 7), 0.16 (n = 2), 0.19 (n = 3), 0.25 (n = 3) and 0.32 mg/kg (n = 1). No pts had dose-limiting toxicities (DLT) in cycle 1 up to 0.32 mg/kg. Three pts had adverse events (AEs) after cycle 1 considered to be DLTs: 1 pt receiving 0.19 mg/kg (grade 3 pyrexia and grade 5 hepatic failure) and 2 pts receiving 0.25 mg/kg (1 pt had grade 3 nausea, and grade 4 platelet count decrease and neutrophil count decrease; 1 pt had grade 4 hepatic failure and grade 4 platelet count decrease). Dosing was capped at 0.19 mg/kg due to hepatic toxicity and the recommended phase 2 dose (RP2D) was determined as 0.064 mg/kg based on safety and tolerability beyond cycle 1. Overall, pts received a median of 2 (range 1–8) treatment cycles. TAK-164-related treatment-emergent AEs (TEAEs) reported in 77.4% of pts included platelet count decrease (58.1%), fatigue (38.7%), and anemia (32.3%). TAK-164-related grade ≥3 TEAEs reported in 32.3% of pts included platelet count decrease (12.9%), alanine aminotransferase increase, aspartate aminotransferase increase, fatigue, and anemia (all 9.7%). Three pts discontinued due to TAK-164-related TEAEs. There was a dose-dependent increase in TAK-164 maximum plasma concentration and exposure over the range 0.016–0.32 mg/kg, with no meaningful accumulation in PK with repeat Q3W dosing. One pt receiving TAK-164 0.19 mg/kg showed γH2AX induction via immunohistochemistry in a post-treatment biopsy, demonstrating target engagement. One pt with low baseline GCC expression who received 5 cycles of TAK-164 0.008 mg/kg had an unconfirmed partial response at cycle 4; 11 of 25 (44.0%) evaluable pts had a best overall response of stable disease. Conclusions: TAK-164 appeared to have a manageable safety profile up to 0.064 mg/kg in pts with advanced GI cancers; hepatic toxicity was identified as a potential risk. The RP2D was determined as 0.064 mg/kg but was considered insufficient to derive significant clinical benefit. Clinical trial information: NCT03449030.

Updated results of a phase 1b study of regorafenib (REG) 80 mg/day or 120 mg/day plus pembrolizumab (PEMBRO) for first-line treatment of advanced hepatocellular carcinoma (HCC)

4078

Background: REG, a multikinase inhibitor, and PEMBRO, an anti-PD-1 mAb, are approved as monotherapies in advanced HCC after progression on sorafenib. This phase 1b dose-finding study investigated first-line REG plus PEMBRO in advanced HCC. Methods: Patients (pts) in the first cohort received a starting REG dose of 120 mg/day orally for 3 weeks (wks) on/1 wk off, which could be escalated (160 mg) or reduced (80 mg) in later cohorts, plus a fixed dose of PEMBRO 200 mg IV every 3 wks. Due to a high dose modification rate in the REG 120 mg cohort, an exploratory REG 80 mg cohort was introduced. Primary objective was safety and tolerability; secondary aims were to assess the maximum tolerated dose (MTD), recommended phase 2 dose, and anti-tumor activity. Results: 35 pts started on REG 120 mg/day and 22 on REG 80 mg/day. Median age was 66 yrs (range 29–81), 84% of pts were male, 70%/30% had ECOG PS 0/1, 26%/74% were BCLC stage B/C, 100% were C–P A, 46% had extrahepatic spread, and 32% had macrovascular invasion. MTD of REG was 120 mg/day. Grade (Gr) 3/4 treatment-emergent adverse events (TEAE) occurred in 86% of pts on REG 120 mg and 50% on REG 80 mg (Table). Most common Gr 3/4 TEAE for REG 120 mg/80 mg were AST increased (23%/9%), lipase increased (20%/5%), ALT increased (17%/9%), and hypertension (17%/9%). TEAE led to REG/PEMBRO dose reductions or interruptions in 71%/57% of pts on REG 120 mg and 59%/45% on REG 80 mg. Median treatment duration (range) was 3.0 months (mo; 0.2–20.5) for REG 120 mg and 3.5 mo (0.03–24.4) for PEMBRO, and 3.5 mo (0.7–10.8) for REG 80 mg and 3.5 mo (0.8–11.3) for PEMBRO. Of 32 evaluable pts on REG 120 mg, 10 (31%) had a partial response (PR) and 18 (56%) had stable disease (SD); disease control rate (DCR) was 88% (RECIST v1.1). Of 22 pts on REG 80 mg, 4 (18%) had a PR and 16 (73%) had SD; DCR was 91%. As of 17 Dec 2020, 16 pts remain on treatment (REG 120 mg n = 5; REG 80 mg n = 11); median follow up was 11.7 mo and 6.9 mo, respectively. REG pharmacokinetic exposure was as expected for 80 mg and 120 mg doses. Flow cytometry analysis of sequential peripheral blood showed changes in subsets of T-cells and monocytes, which may contribute to clinical benefit. Conclusions: First-line REG plus PEMBRO in advanced HCC showed no new safety signals and encouraging anti-tumor activity (DCR ̃90%). The REG 80 mg cohort appeared to have lower rates of dose reductions and interruptions due to TEAE vs REG 120 mg. Efficacy data for the REG 80 mg cohort are preliminary due to short follow-up. Clinical trial information: NCT03347292. [Table: see text]

Pretreatment CT and PET radiomics predicting rectal cancer patients in response to neoadjuvant chemoradiotherapy

Background

The purpose of this study was to characterize pre-treatment non-contrast computed tomography (CT) and ¹⁸F-fluorodeoxyglucose positron emission tomography (PET) based radiomics signatures predictive of pathological response and clinical outcomes in rectal cancer patients treated with neoadjuvant chemoradiotherapy (NACR T).

Materials and methods

An exploratory analysis was performed using pre-treatment non-contrast CT and PET imaging dataset. The association of tumor regression grade (TRG) and neoadjuvant rectal (NAR) score with pre-treatment CT and PET features was assessed using machine learning algorithms. Three separate predictive models were built for composite features from CT + PET.

Results

The patterns of pathological response were TRG 0 (n = 13; 19.7%), 1 (n = 34; 51.5%), 2 (n = 16; 24.2%), and 3 (n = 3; 4.5%). There were 20 (30.3%) patients with low, 22 (33.3%) with intermediate and 24 (36.4%) with high NAR scores. Three separate predictive models were built for composite features from CT + PET and analyzed separately for clinical endpoints. Composite features with α = 0.2 resulted in the best predictive power using logistic regression. For pathological response prediction, the signature resulted in 88.1% accuracy in predicting TRG 0 vs. TRG 1-3; 91% accuracy in predicting TRG 0-1 vs. TRG 2-3. For the surrogate of DFS and OS, it resulted in 67.7% accuracy in predicting low vs. intermediate vs. high NAR scores.

Conclusion

The pre-treatment composite radiomics signatures were highly predictive of pathological response in rectal cancer treated with NACR T. A larger cohort is warranted for further validation.

A Phase 2 Multi-institutional Study of Nivolumab for Patients With Advanced Refractory Biliary Tract Cancer

Importance

Currently, there is no established second-line systemic treatment for biliary tract cancer (BTC). Preclinical data have demonstrated that the presence of tumor-infiltrating CD8 T cells and programmed cell death 1 ligand 1-expressing tumor cells in the tumor microenvironment of BTC supports the rationale of using programmed cell death 1 protein blockade immunotherapy in BTC.

Objective

To evaluate anticancer activity of nivolumab in patients with advanced refractory BTC.

Design, Setting, and Participants

In this single-group, multicenter phase 2 study of nivolumab, 54 patients with histologically confirmed BTC whose disease progressed while undergoing treatment with at least 1 line but no more than 3 lines of systemic therapy were enrolled between October 5, 2016, and December 26, 2018. Analysis was performed on an intention-to-treat basis.

Interventions

Nivolumab, 240 mg, was delivered intravenously every 2 weeks for 16 weeks, and then 480 mg was delivered intravenously every 4 weeks until disease progression or unacceptable toxic effects occurred.

Main Outcomes and Measures

The primary end point was investigator-assessed objective response rate, and the secondary end points were progression-free survival, overall survival, and incidence of adverse events.

Results

A total of 54 patients (27 men and 27 women; median age, 65 years [range, 28-86 years]) enrolled, and 46 (22 men and 24 women; median age, 65 years [range, 28-86 years]) were examined for objective response with radiologic imaging. The investigator-assessed objective response rate was 22% (10 of 46), including 1 unconfirmed partial response, with a disease control rate of 59% (27 of 46). Central independent review found an objective response rate of 11% (5 of 46), including 1 unconfirmed partial response, with a disease control rate of 50% (23 of 46). All patients who responded to treated (hereafter referred to as responders) had mismatch repair protein-proficient tumors. The median duration of investigator-assessed response was not reached, with a median follow-up of 12.4 months. Among the intention-to-treat population, median progression-free survival was 3.68 months (95% CI, 2.30-5.69 months) and median overall survival was 14.24 months (95% CI, 5.98 months to not reached). Programmed cell death 1 ligand 1 expression in tumors was associated with prolonged progression-free survival (hazard ratio, 0.23; 95% CI, 0.10-0.51; P < .001). The most common treatment-related grade 3 or 4 toxic effects were hyponatremia (3 of 54 [6%]) and increased alkaline phosphatase (2 of 54 [4%]).

Conclusions and Relevance

This study found that nivolumab was well tolerated and showed modest efficacy with durable response in patients with refractory BTC. Further studies are warranted to verify the findings and evaluate biomarkers for improved treatment selection for patients.

Trial Registration

ClinicalTrials.gov Identifier: NCT02829918.

Results of a phase Ib study of regorafenib (REG) 80 mg/day plus pembrolizumab (PEMBRO) for first-line treatment of advanced hepatocellular carcinoma (HCC)

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Background: In a phase Ib study, REG 120 mg/day plus PEMBRO for first-line treatment of advanced HCC showed no unexpected safety signals and encouraging anti-tumor activity. At the maximum tolerated dose (MTD) of REG (120 mg/day), approximately three-quarters of patients (pts) had a REG dose reduction or interruption due to a treatment-emergent adverse event (TEAE). Here, we present preliminary data for the REG 80 mg/day cohort. Methods: This is an ongoing, dose-finding study in pts who had no prior systemic therapy. In the first cohort, pts received REG 120 mg/day orally for 3 weeks on/1 week off plus PEMBRO 200 mg intravenously q 3 weeks. In later cohorts, the REG dose could be escalated (160 mg/day) or reduced (80 mg/day); the PEMBRO dose is fixed. The primary objective is safety and tolerability. Secondary objectives are to define the MTD and recommended phase II dose and assess anti-tumor activity. Results: By July 24, 2020, 16 pts were treated with REG 80 mg/day. Median age was 67 years (range 56–79), 25%/75% were Barcelona Clinic Liver Cancer stage B/C, 100% Child–Pugh A, and 69%/31% had Eastern Cooperative Oncology Group performance status 0/1. Grade (Gr) 3 TEAEs occurred in 8/16 pts (50%) and there were no Gr 4 TEAEs (Table); one pt experienced Gr 5 pneumonitis (not drug related). There were no reports of Gr 3 hand–foot skin reaction or Gr 3 maculopapular rash, and one report (6%) of Gr 3 rash. TEAEs led to a REG dose reduction or interruption in 50% of pts and to a PEMBRO dose interruption in 25% of pts. Median treatment duration (range) including pts ongoing was 4.1 months (0.4–7.1) for REG and 3.8 months (0.03–7.2) for PEMBRO. Of 13 evaluable pts, 2 (15%) had a partial response and 9 (69%) had stable disease (Response Evaluation Criteria in Solid Tumors v1.1); disease control rate was 85%. Conclusions: These preliminary results for the combination of REG 80 mg/day plus PEMBRO for first-line treatment of advanced HCC were consistent with the REG 120 mg/day cohort. The combination showed no unexpected safety signals and encouraging anti-tumor activity. Assessment of REG 80 mg/day plus PEMBRO is ongoing. Clinical trial information: NCT03347292. [Table: see text]

A phase II study of atezolizumab (ATEZO) and bevacizumab (Bev) in combination with Y90 TARE in patients (Pts) with hepatocellular carcinoma (HCC)

TPS358

Background: The anti–PD-L1 antibody ATEZO prevents PD-L1 from interacting with PD-1 and B7.1, thus reinvigorating antitumor T cell activity. Anti-VEGF BEV can increase dendritic cell maturation, enhance T cell infiltration, and reduce myeloid-derived suppressor cells and regulatory T-cells in tumors. This combination has been FDA approved for first-line treatment of advanced HCC based on the IMbrave 150 study. On the other hand, locoregional radiotherapy (e.g., Y90 TARE) enhances the diversity of the intratumoral T cell receptor repertoire. It is the standard of care for pts with intermediate-stage HCC (iHCC). Based on preclinical and clinical data, we hypothesize that the combination of Y90 TARE, BEV, and ATEZO induces synergistic tumor-killing. Methods: This is an open-label, multicenter, randomized phase II study of Y90 TARE and BEV plus ATEZO compared with Y90 TARE alone in pts with unresectable IHCC. The primary study objective is to assess and compare the progression-free survival (PFS) (per mRECIST 1.1) of pts in each arm. The main secondary objective is to determine the safety and tolerability (CTCAE v5) of TARE combined with ATEZO and BEV in pts with HCC. Exploratory objectives are to assess the role of the immunoscore and PD-L1 expression levels in the prediction of improved clinical outcome in pts receiving Y-90 TARE and BEV plus ATEZO; the composition of tumor-infiltrating immune cell subtypes in predicting response to a chosen therapy; how Y90 therapy affects the proportion of antigen-presenting cells in the tumor; and symptoms experienced by pts receiving TARE and BEV plus ATEZO treatment, using patient-reported outcomes. Eligible pts have either HCC that is not amenable to surgical resection, confirmed by pathology review, or at least BCLC stage B HCC outside of downstaging criteria. Other standard eligibility criteria apply. Pts must have a pretreatment liver biopsy taken and then be randomized 1:1 to TARE (Arm A) or TARE followed by ATEZO and BEV (Arm B). Pts will have TARE mapping during week (wk) 1 and TARE treatment during wk 2. In Arm B, pts will start BEV plus ATEZO 4 wks (±1 wk) after TARE treatment. Pts will have abdominal MRI or CT scans every 12 weeks, CT scans of the chest every 24 wks, and a second tumor biopsy at 4 wks. Disease progression will be captured by both RECIST 1.1 and mRECIST. We plan to assess the safety of TARE with BEV and ATEZO in the first 10 pts randomized to Arm B for two cycles. If there are no grade ≥ 3 unexpected toxicities possibly, probably or definitely related to combined TARE plus BEV plus ATEZO, the study will continue to accrue 128 pts in total. Pts will continue study treatment (Arm B) for a total of 24 months from initiation of TARE or until intolerable toxicity or disease progression occur, whichever is earlier. Enrollment began in September 2020. Clinical trial information: NCT04541173.

Results of biomarker analysis from phase II trial of nivolumab in refractory biliary tract cancer

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Background: Our previous phase II study demonstrated that nivolumab provides modest but durable clinical efficacy in patients (pts) with refractory biliary tract cancer (BTC), suggesting the significant clinical benefit of nivolumab in selected pts and identification of potential predictive biomarkers. Here, we report outcomes from the biomarker analysis. Methods: Pre-treatment tumor samples were obtained and assessed for immunohistochemistry (IHC) with PD-1 and PDL-1 antibodies, mRNA sequencing (RNAseq), and whole exome sequencing (WES). Clinical efficacy was correlated with the molecular analysis. Prior cisplatin exposure was reviewed to evaluate the impact of cisplatin on the tumor mutational burden (TMB) and clinical outcome. Results: Among 46 pts who had tumor response evaluation, 31 pts received cisplatin prior to nivolumab, and 15 were cisplatin-naive. Pre-treatment tumor samples were assessed for IHC (n = 42), RNAseq (n = 11), and WES (n = 11) based on tissue availability. There was no statistically significant correlation between prior cisplatin exposure and clinical outcome. Among 42 available tumor samples, 18 (43%) expressed PD-L1 positivity ( > 1%), which was associated with a statistically significant prolonged progression free survival (PFS). Median PFS was 10.4 months for PD-L1 positive vs 2.4 months for PD-L1 negative (HR 0.23, 95% CI 0.10-0.51; P < 0.001), while there was no statistically significant correlation between PD-1 expressing tumor infiltrating lymphocytes and clinical outcome. There was also no statistically significant difference in TMB of cisplatin-exposed (n = 8) vs. cisplatin-naïve tumor samples (n = 3) (9162, SD = 150 vs. 8898, SD = 806, p = 0.62). In comparing the group with prolonged disease control of at least 16 weeks (n = 4) to those with rapid disease progression (n = 7) who had mRNA sequencing performed, levels of AC005609.1, FAT3, TMEM151A, ADARB2, FAM153A were all significantly upregulated (p < 0.01), while levels of CLCA1, MUC2, IGHV3-43, SWORA6, and CRISP3 were all significantly downregulated (p < 0.01). Conclusions: Prior cisplatin exposure did not lead to statistically significant differences in clinical outcome or TMB in advanced BTC pts treated with nivolumab. However, PD-L1 expression > 1% correlated with improved PFS, and variations in level of certain mRNA sequences were noted when comparing pts who had rapid disease progression vs. prolonged disease control with nivolumab. This suggests that BTC pts with positive PD-L1 expression and a particular mRNA profile may have a favorable response to nivolumab. Further studies are needed to confirm these findings. Clinical trial information: NCT02829918.

Investigate the efficacy of immunotherapy for treatment of pancreatic adenocarcinoma (PDAC) with mismatch repair deficiency (dMMR)

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Background: Immune checkpoint inhibitors (ICI) have been approved in solid tumors with dMMR. However, only limited data are available for PDAC with dMMR given the rarity of dMMR in PDAC. We evaluated efficacy of ICIs in PDAC with dMMR. Methods: Retrospective clinical and pathologic data were collected for patients (pts) with pancreatic adenocarcinoma from May 2017 to June 2020 at Moffitt cancer center. Results: We identified 10 pts with dMMR PDAC. The median age was 64.5 years (range: 42-86) and 4 pts were male. 4 pts had resectable disease, 3 had locally advanced and 3 had metastatic disease at initial diagnosis. MSH6 deficiency (def) was found in 2 cases, PMS2 def in 2, MLH/PMS2 def in 5, and MSH2/MSH6 in 1. 7 pts were treated with ICIs. 3 pts had locally advanced and 4 had metastatic disease when they started ICIs. 5 received Pembrolizumab (pem), 1 received ipilimumab/ nivolumab (ipi/nivo), and 1 received pem then ipi/nivo after progressive disease (PD) on pem. The median number of prior lines of chemotherapy was 1 (range 0-2). 6 pts were evaluable, and 1 had rapid disease progression after 1 dose of pem. Among 6 evaluable pts, 3 had an objective response (1: complete response and 2: partial response), and 2 had stable disease (SD). Median progression-free survival was 8.2 mo, and median overall survival was not reached with median follow-up (FU) of 6.8 mo. The median duration of response was not reached with a median FU of 22.6 mo. The pt with CR remained disease-free for up to 22 months. The pt whose treatment was switched to ipi/nivo after PD on pem achieved SD > 4mo on ipi/nivo. While on immunotherapy, one patient with ipi/nivo developed immunotherapy associated rash requiring systemic steroids, and another on pem developed hypothyroidism requiring levothyroxine. Conclusions: This series suggest ICIs can provide durable clinical efficacy in pts with dMMR PDAC.

Association between post-treatment (tx) alpha-fetoprotein (AFP) reduction and outcomes in real-world (rw) U.S. patients (pts) with advanced HCC (aHCC)

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Background: A decrease in post-tx AFP may be associated with improved outcomes in clinical trials. However, the impact of AFP reduction after initiation of a first-line (1L) tyrosine kinase inhibitor (TKI) therapy on outcomes is unclear among pts with aHCC treated in routine clinical practice. Methods: This analysis utilized data from the nationwide Flatiron Health electronic health record (EHR)-derived de-identified database and included pts with aHCC with ≥2 visits between 1/1/2011-7/31/2019 who received 1L TKI. Pts with a baseline serum AFP value (closest to 1L initiation within -30 to +7 days) and a post-tx AFP value (closest to 8 weeks after 1L initiation within ±2 weeks) were included. Post-tx AFP reduction was defined as a ≥20% decrease from baseline AFP, and no reduction as a <20% decrease or any increase. Rw overall survival (rwOS) was defined as time from post-tx AFP measurement to death (censored at last EHR activity). Rw progression-free survival (rwPFS) was based on clinician documentation and defined as the first progression event or death after post-tx AFP measurement (censored at last clinic note date). Adjusted hazard ratios (aHR) for reduction vs no reduction (reference) were estimated using multivariable Cox proportional hazards models adjusted for potential confounders and baseline AFP. Effect modification was assessed by conducting tests for interactions with analyses stratified by HCC risk factors. Results: 441 pts were included in the study. 8% had documented history (hx) of hepatitis B (HBV), 52% hepatitis C (HCV), 47% obesity/diabetes (DM), 42% heavy alcohol use, and 11% no documented risk factor. Median baseline AFP was 210 ng/mL (IQR 237 - 2981) and 150 ng/mL (IQR 17 - 1311) among pts with reduction (N = 150) and no reduction (N = 291). There was a 35% decrease in hazard of death for pts with reduction vs no reduction (median rwOS 10.3 vs 6.7 months; Table). Similarly, a 35% decrease in hazard of rw progression or death was observed for pts with reduction vs no reduction (aHR=0.65; 95% CI: 0.52-0.81; median rwPFS 4.4 vs 2.4 months). Reduction (vs no) was associated with better rwOS among pts with hx of HCV, obesity/DM or alcohol use vs without the respective risk factor, however, no statistically significant interactions were observed (Table). Conclusions: Results show post-tx AFP reduction may be prognostic for rwPFS and rwOS in pts with aHCC treated with 1L TKI. Further research may clarify if prognostic value differs by HCC risk factor profile. [Table: see text]

Phase 2 study of copanlisib in combination with gemcitabine and cisplatin in advanced biliary tract cancers

BACKGROUND

Biliary tract cancer (BTC) has a poor prognosis despite treatment with first-line gemcitabine and cisplatin. In BTC, PI3K/AKT pathway activation has been shown to increase resistance to chemotherapy, which may be overcome with PI3K inhibition. This phase 2 study evaluated the safety and efficacy of copanlisib, a PI3K inhibitor, with gemcitabine and cisplatin in advanced BTCs. The role of PTEN expression in outcomes was also explored.

METHODS

Patients with advanced/unresectable BTC received gemcitabine, cisplatin, and copanlisib as their first-line treatment. The primary endpoint was progression-free survival (PFS) at 6 months. Secondary endpoints were the response rate (RR), median overall survival (OS)/PFS, and safety profile. An assessment of PTEN expression by immunohistochemistry was also performed along with molecular profiling.

RESULTS

Twenty-four patients received at least 1 dose of the study drug. The PFS rate at 6 months was 51%; the median OS was 13.7 months (95% CI, 6.8-18.0 months), and the median PFS was 6.2 months (95% CI, 2.9-10.1 months). Nineteen patients were evaluable for RR: 6 patients achieved a partial response (31.6%), and 11 (57.9%) had stable disease. The most common grade 3/4 adverse events were a decreased neutrophil count (45.83%), anemia (25%), increased lipase (25%), and hypertension (20.8%). Twenty patients had tissue evaluable for the PTEN status. The PFS for low (n = 9) and high PTEN expression (n = 11) was 8.5 and 4.6 months, respectively (P = .19). The median OS for low and high PTEN expression groups was 17.9 and 7.0 months, respectively (P = .19).

CONCLUSIONS

The addition of copanlisib to gemcitabine and cisplatin does not improve PFS at 6 months. However, future studies using PTEN as a potential biomarker should be considered.

LAY SUMMARY

The addition of copanlisib, a PI3K inhibitor, to standard chemotherapy for advanced biliary tract cancers was assessed for efficacy and safety. Twenty-four patients with advanced biliary tract cancer received treatment in this study. There was no difference in survival with the addition of copanlisib in comparison with standard chemotherapy. Copanlisib may be more effective and increase survival in patients with low PTEN expression levels. Further studies are needed to confirm this. No unexpected adverse events occurred.

Abstract 4293: Final result of lenvatinib and capecitabine in combination with external beam radiation in treatment of locally advanced rectal cancer: Phase I clinical trial

Purpose: Targeting dual/multiple angiogenesis receptor has been shown to augment tumor response. Lenvatinib, a multikinase inhibitor aimed towards FGFR/ PDGFR/ KIT/RET has shown potent antitumor activity in preclinical models. This study aims to understand the effectiveness and safety of lenvatinib and capecitabine combined with radiation in patients with locally advanced rectal cancer (LARC).

Methods: Patients with MRI or endoscopic ultrasound confirmed stage II or stage III rectal cancer were enrolled in 3 cohorts. All cohorts received standard dose 850 mg/m2 PO BID of capecitabine and external beam radiation (180 cGY) on day 1-5 weekly for 5 ½ to 6 weeks. Oral lenvatinib was administered in dose escalation manner in 3 cohorts of 3 patients per dose level (DL), with an expansion cohort at the MTD [cohort 1:14 mg daily; cohort 2: 20 mg daily; cohort 3:24 mg daily]. At the MTD dose, 10 additional patients were added to further evaluate safety and efficacy.

Results: Twenty patients were enrolled and received at least 1 dose of study drug. One patient was deemed not eligible due to having stage IV disease at the time of diagnosis and is only reviewed for toxicity. 3/19 patients had stage II and 16/19 had stage III cancer at time of enrollment. 73.6% (14/19) patients enrolled were male and 26.4% (5/19) were female. The median age was 55 years (42,73). There was no noted dose limited toxicity at maximum tolerated dose (24 mg) of lenvatinib. There were no grade 4 adverse events. The most common grade 3 toxicities were hypertension observed in 15% (3/20) and lymphopenia in 15% (3/20) patients. Other grade 3 toxicities included rectal pain, hyponatremia, lymphopenia, leukocytosis and transaminitis, each noted in 5% (1/20) patients respectively. 19 patients underwent surgery in 6-10 weeks following completion of dual-targeted therapy and radiation. Median time to surgery was 62 days. There were no peri-operative adverse events. 14/19 patients underwent low anterior resection and 5 have had abdominoperineal resection. 7/19 (36.8%) showed complete pathological response (cPR), and downstaging were seen in 73.7% of the patients (14/19). The mean neoadjuvant rectal cancer score (NAR) was 10.4 and median NAR was 8.43.

Conclusion: The combination of lenvatinib and capecitabine plus radiation shows encouraging safety and efficacy results. Larger randomized study is warranted to verify our findings.

Citation Format: Ankita Tandon, Jessica M. Frakes, Rutika Mehta, Sarah Hoffe, Iman Imanirad, Maria E. Martinez Jimenez, Julian Sanchez, Mokenge Malafa, Seth Felder, Sophie Dessureault, Richard D. Kim. Final result of lenvatinib and capecitabine in combination with external beam radiation in treatment of locally advanced rectal cancer: Phase I clinical trial [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4293.

The Application of Circulating Tumor DNA in the Screening, Surveillance, and Treatment Monitoring of Colorectal Cancer

Precision medicine with genetic profiling of tumor tissue has become an essential part of routine clinical practice in colorectal cancer. However, tissue genetic profiling suffers from clonal evolution, tumor heterogeneity, and time needed to deliver critical information for prompt clinical decision making. In contrast, liquid biopsy with plasma circulating tumor DNA provides genetic and epigenetic information from both the primary and metastatic colorectal cancer, which can potentially capture tumor heterogeneity and evolution with time and treatment. In addition, liquid biopsy with circulating tumor DNA is minimally invasive, quicker, and easily repeatable with high patient compliance to provide both qualitative and quantitative molecular information in real-time. We provide an overview on the potential clinical applications of circulating tumor DNA in the screening, surveillance, and treatment monitoring of colorectal cancer.

Modeling precision genomic-based radiation dose response in rectal cancer

Aim: Genomic-based risk stratification to personalize radiation dose in rectal cancer. Patients & methods: We modeled genomic-based radiation dose response using the previously validated radiosensitivity index (RSI) and the clinically actionable genomic-adjusted radiation dose. Results: RSI of rectal cancer ranged from 0.19 to 0.81 in a bimodal distribution. A pathologic complete response rate of 21% was achieved in tumors with an RSI <0.31 at a minimal genomic-adjusted radiation dose of 29.76 when modeling RxRSI to the commonly prescribed physical dose of 50 Gy. RxRSI-based dose escalation to 55 Gy in tumors with an RSI of 0.31-0.34 could increase pathologic complete response by 10%. Conclusion: This study provides a theoretical platform for development of an RxRSI-based prospective trial in rectal cancer.

A multi-institutional phase 2 trial of regorafenib in refractory advanced biliary tract cancer

BACKGROUND

Regorafenib is an oral multikinase inhibitor targeting angiogenesis, oncogenesis, and cancer proliferation/metastasis. This study evaluated the efficacy of regorafenib in refractory biliary tract cancer (BTC) in a multi-institutional phase 2 study.

METHODS

Patients with BTC who progressed on at least 1 line of systemic therapy received regorafenib at 160 mg daily for 21 days on and 7 days off. The primary endpoint was 6-month overall survival (OS), and the secondary endpoints were median OS, progression-free survival (PFS), and objective response rates. Pretreatment plasma was collected for cytokine evaluation.

RESULTS

A total of 39 patients were enrolled, and 33 were evaluable for efficacy. The median PFS and OS were 3.7 and 5.4 months, respectively, with survival rates of 46.2% at 6 months, 35.9% at 12 months, and 25.6% at 18 months for the intention-to-treat population. For the 33 evaluable patients who received regorafenib for at least 3 weeks, the median PFS and OS were 3.9 and 6.7 months, respectively, with survival rates of 51.5% at 6 months, 39.4% at 12 months, and 27.3% at 18 months. The objective response rate was 9.1%, and the disease control rate was 63.6%. Twenty-eight patients (71.8%) experienced grade 3/4 adverse events. Among the 23 cytokines analyzed, elevated baseline vascular endothelial growth factor D (VEGF-D) was associated with shorter PFS, whereas elevated baseline interleukin 6 (IL-6) and glycoprotein 130 (GP130) were associated with shorter OS.

CONCLUSIONS

Regorafenib demonstrated modest clinical efficacy in heavily pretreated patients with BTC. Further exploration of biomarkers is warranted to identify a group of patients with BTC who may benefit from regorafenib.

Outcomes of Lynch syndrome (LS) patients treated with immune checkpoint inhibitors (ICI)

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Background: LS is caused by a germline mutation in one of several DNA mismatch repair (MMR) genes: MLH1, MSH2, MSH6 or PMS2 (d-MMR). A minority of LS patients have MMR proficient tumors (p-MMR). ICI therapy has dramatically changed outcome of d-MMR (majority of LS patients. However, data about response to ICI in LS patients, irrespective of their tumor MMR status is scarce. The aim of this study was to evaluate outcomes of ICI therapy in all LS associated Cancer. Methods: This was a retrospective analysis of LS associated cancers treated with one of the 6 ICIs at our center. We also looked at age, sex, microsatellite status, response and survival. Results: Out of 262 LS patients analyzed, 194 had cancer and 22 received ICIs. Among the patients analyzed, the mean age at diagnosis of 1st cancer was 51 yrs. There were 10 females (47%). 10 patients had colorectal (45%), 3 urothelial (14%), 2 renal cell, 2 cholangiocarcinoma and one each of esophageal, ovarian, uterine, glioblastoma multiforme and pancreatic cancer. One patient died from progressive disease after receiving a single dose and was not included in the analysis. 17 patients (80%) received Pembrolizumab, 11 patients were microsatellite unstable (MSI), 3 were microsatellite stable (MSS) while 7 were unknown. 2 patients achieved complete response (CR) (10%), 1 patient had partial response (PR) (5%), 13 had stable disease (62%) while 5 had progressive disease (23%) leading to a disease control rate (DCR) of 76%. Of the 3 known MSS Lynch syndrome patients, 2 did not respond while the 3rd continues to respond at 9 months of therapy. Of the 5 patients who had PD, 2 were MSS, 2 unknown and 1 MSI. Among the 16 patients who responded, 15 of 16 (94%) had sustained response and have not experienced disease progression or relapse. 3 of these patients have been off therapy (1 due to immune related adverse evet) and have had no relapse. One responder progressed after 18 cycles of therapy. The DCR was 71% at 12 months as well as 48 months of follow up. Median progression survival has not been reached. Similarly, median overall survival has not been reached. Conclusions: Our study is the one of the largest reported analysis of LS associated cancer patients treated with ICIs and included LS patients with both MSI and MSS tumors. Though small, our data suggests robust DCR and prolonged responses in Lynch associated MSS tumors treated with ICI. This encouraging response in MSS tumors along with higher response rates in LS associated cancers as compared to non-LS MSI tumors, suggests that there may be additional drivers of response to ICI in LS patients leading to superior responses.

CT-based radiomic features to predict pathological response in rectal cancer: A retrospective cohort study

INTRODUCTION

Innovative biomarkers to predict treatment response in rectal cancer would be helpful in optimizing personalized treatment approaches. In this study, we aimed to develop and validate a CT-based radiomic imaging biomarker to predict pathological response.

METHODS

We used two independent cohorts of rectal cancer patients to develop and validate a CT-based radiomic imaging biomarker predictive of treatment response. A total of 91 rectal cancer cases treated from 2009 to 2018 were assessed for the tumour regression grade (TRG) (0 = pathological complete response, pCR; 1 = moderate response; 2 = partial response; 3 = poor response). Exploratory analysis was performed by combining pre-treatment non-contrast CT images and patterns of TRG. The models built from the training cohort were further assessed using the independent validation cohort.

RESULTS

The patterns of pathological response in training and validation groups were TRG 0 (n = 14, 23.3%; n = 6, 19.4%), 1 (n = 31, 51.7%; n = 15, 48.4%), 2 (n = 12, 20.0%; n = 7, 22.6%) and 3 (n = 3, 5.0%; n = 3, 9.7%), respectively. Separate predictive models were built and analysed from CT features for pathological response. For pathological response prediction, the model including 8 radiomic features by random forest method resulted in 83.9% accuracy in predicting TRG 0 vs TRG 1-3 in validation.

CONCLUSION

The pre-treatment CT-based radiomic signatures were developed and validated in two independent cohorts. This imaging biomarker provided a promising way to predict pCR and select patients for non-operative management.

Randomised phase II trial (SWOG S1310) of single agent MEK inhibitor trametinib Versus 5-fluorouracil or capecitabine in refractory advanced biliary cancer

BACKGROUND

The rationale for the evaluation of trametinib in advanced biliary cancer (BC) is based on the presence of mitogen-activated protein kinase alterations and on earlier promising results with MEK inhibitors in BC.

METHODS

Patients with histologically proven BC who progressed on gemcitabine/platinum were randomised to trametinib daily (arm 1) versus fluoropyrimidine therapy (infusional 5-fluorouracil or oral capecitabine, arm 2). The primary end-point was overall survival (OS). Secondary end-points included progression free survival (PFS) and response rate. A planned interim futility analysis of objective response was performed on the first 14 patients registered to the trametinib arm.

RESULTS

The study was stopped early based on the lack of measurable response in the trametinib arm. A total of 44 eligible patients were randomised (24 patients in arm 1 and 20 patients in arm 2). Median age was 62 years and the primary sites of tumour were cholangiocarcinoma (68%) and gallbladder (32%). The overall response rate was 8% (95% CI 0%-19%) in arm 1 versus 10% (95% CI 0%-23%) in arm 2 (p > .99) Median OS was 4.3 months for arm 1 and 6.6 months for arm 2. The median PFS was 1.4 months for arm 1 and 3.3 months for arm 2.

CONCLUSIONS

This is the first prospective randomised study of a targeted agent versus chemotherapy for the second-line treatment of BC. In this unselected population, the interim analysis result of unlikely benefit with trametinib resulted in early closure.

Phase II Study of Ensituximab, a Novel Chimeric Monoclonal Antibody, in Adults with Unresectable, Metastatic Colorectal Cancer

PURPOSE

Patients with metastatic colorectal cancer refractory to chemotherapy have limited treatment options. Ensituximab (NEO-102) is a novel chimeric mAb targeting a variant of MUC5AC with specificity to colorectal cancer.

PATIENTS AND METHODS

Single-arm, phase II trial assessed the efficacy and safety of ensituximab in patients with advanced, refractory cancer who expressed MUC5AC antigen in tumor tissue. Ensituximab was administered intravenously every 2 weeks with 3 mg/kg as recommended phase II dose (RP2D). A minimum sample size of 43 patients was required on the basis of the assumption that ensituximab would improve median overall survival (OS) by 7 months using a one-sided significance level of 10% and 80% power. Written informed consent was obtained from all patients.

RESULTS

Sixty-three patients with advanced, refractory colorectal cancer were enrolled and 53 subjects were treated in phase II arm. Median age was 58 years and 46% of the patients were female. Among 57 evaluable patients, median OS was 6.8 months. No responses were observed, and stable disease was achieved in 21% of the patients. The most common treatment-related adverse events (AE) at RP2D included fatigue (38%), anemia (30%), nausea (15%), vomiting (11%), increased bilirubin (9%), constipation (8%), decreased appetite (6%), and diarrhea (6%). Serious AEs at least possibly related to ensituximab occurred in 4 patients and included anemia, nausea, increased bilirubin, and hypoxia. No patients discontinued treatment due to drug-related AEs.

CONCLUSIONS

Ensituximab was well tolerated and demonstrated modest antitumor activity in patients with heavily pretreated refractory colorectal cancer.

Phase I study of preoperative capecitabine and lenvatinib with external radiation therapy in locally advanced rectal adenocarcinoma

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Background: Neoadjuvant chemo-radiation is a standard of care for locally advanced rectal cancer. Patients with pathologic complete response (pCR) have improved outcomes with less local and systemic failure. Dual targeting with platelet derived growth factor (PDGF) and vascular endothelial growth factor receptor (VEGFR) in combination with radiation can escalate tumor response with radiation. Lenvatinib is an oral multi-kinase inhibitor and had shown potent anti-tumor activity in xenograft models cultured with human colorectal cancer (CRC) lines. Methods: Patients with stage II or III rectal cancer, confirmed by endoscopic ultrasound or MRI, were recruited in 3 cohorts of 3 patients per dose level, with an expansion cohort at the MTD. Lenvatinib oral daily dose started at 14 mg (cohort 1) and was escalated to 20 mg (cohort 2) followed by 24 mg (cohort 3). In this 3+3 design, patients received dose escalation of lenvatinib with standard doses of capecitabine (850 mg/m2 PO BID) concurrent with external beam radiation on days 1-5 weekly for 28 treatments. Following completion patients underwent surgery in 6-10 weeks. Results: Twenty patients with median age of 55 were enrolled in 3 cohorts (1 patient was ineligible). There were no dose limiting toxicity at the maximum tested dose of lenvatinib (24 mg). Two patients are still awaiting surgery. 12 patients have undergone low anterior resection and 5 patients have had abdominoperineal resection. Therefore, out of 17 patients, 29.4% (5/17) showed pCR, and downstaging was observed in 71% of the patients (12/17). The mean neoadjuvant rectal cancer score (NAR) was 11.4 and median NAR was 8.43. Six patients had grade 3 adverse events (AEs) (1 rectal pain,1 transaminitis, 2 lymphopenia, 1 HTN, 1 with both leukocytosis and hyponatremia). No grade 4 AEs were noted. Most common AEs were hypertension, rectal pain, nausea, diarrhea, fatigue and dermatitis. No peri operative complications were observed. Conclusions: The study shows that the combination of lenvatinib and capecitabine with radiation is well tolerated in locally advanced rectal cancer with promising mean NAR score. The encouraging results will need to be validated in a randomized study. Clinical trial information: NCT02935309.

First-line durvalumab + monalizumab, mFOLFOX6, and bevacizumab or cetuximab for metastatic microsatellite-stable colorectal cancer (MSS-CRC)

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Background: Targeting multiple immune checkpoint pathways and combining checkpoint inhibition with chemotherapy may enhance response in MSS-CRC. In a Phase 1/2, multicenter, open-label study, the anti-PD-L1 antibody durvalumab (D) was added to monalizumab (M; an anti-NKG2A antibody). In dose-exploration cohorts, D+M was added to chemotherapy and a biologic agent (bevacizumab [DMCB] or cetuximab [DMCC]) for first-line treatment of advanced/metastatic MSS-CRC. Initial data showed DMCB was well tolerated and clinically active. Here we report updated efficacy and safety of DMCB and initial safety of DMCC. Methods: Eligible patients (pts) had MSS-CRC ( RAS/BRAF wt with a left-sided colon primary tumor in the DMCC cohort) and ECOG PS 0–1. They received D 1500 mg Q4W, M 750 mg Q2W, mFOLFOX6 Q2W and bevacizumab 5 mg/kg Q2W or cetuximab 250/400 mg/m2 QW (up to 500 mg/m2 Q2W) for up to 3 yr. The primary endpoint was safety and tolerability; secondary endpoints included antitumor activity. Results: As of Aug 26, 2019, 18 pts received DMCB and 17 pts received DMCC. Treatment-emergent adverse events (AEs) occurred in 100.0% of the DMCB cohort (most commonly fatigue, nausea and peripheral neuropathy) and 94.1% of the DMCC cohort (most commonly peripheral neuropathy, rash and dermatitis acneiform). The AEs were grade 3/4 in 77.8% of pts receiving DMCB and 70.6% of pts receiving DMCC, and were serious in 38.9% and 47.1%, respectively. Response was evaluable in 17 pts receiving DMCB; objective response rate was 41.2% (all PRs; Table). Responses occurred early and the median duration of response has not yet been reached. Conclusions: In advanced/metastatic MSS-CRC, first-line DMCB and DMCC had a manageable safety profile and DMCB showed promising preliminary activity. Clinical trial information: NCT02671435.

[Table: see text]

Phase II study of copanlisib in combination with gemcitabine and cisplatin in advanced cholangiocarcinoma

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Background: First line therapy for advanced cholangiocarcinoma (CCA) is currently gemcitabine and cisplatin. However, survival rarely exceeds one year with this regimen. PI3K/AKT activation has been shown to increase resistance to chemotherapy in CCA; therefore, inhibiting this pathway may improve chemotherapy’s efficacy. This phase II study evaluated the safety and efficacy of copanlisib, a potent and reversible pan-class I PI3K inhibitor, with gemcitabine and cisplatin in advanced CCA. Methods: Between July 2016 and April 2019, pts with histologically confirmed advanced/unresectable CCA received cisplatin (25 mg/m2), gemcitabine (1000mg/m2), and copanlisib 60mg on day 1 and 8, every 21 days as first line treatment. The primary endpoint was PFS at 6 months. Secondary endpoints were RR, median OS and PFS, and safety profile. A single-arm Simon’s two-stage minimax design with one-sided 10% type I error and 80% power was used. Based on ABC-01 and ABC-02 studies, PFS6 for gemcitabine and cisplatin were 57.1% and 59.3%, respectively. Therefore, PFS6 of 57% was considered not to warrant further study and ≥72% to warrant further investigation. Results: Twenty-four pts received at least one dose of the study drug (62.5% female, median age 64 years), with 70.8% intrahepatic, 16.7% extrahepatic, and 12.5% gallbladder cancer. For all pts, median OS was 13.9 months (95% CI: 6.8-17.9) and median PFS was 6.2 months (95% CI: 1.3-11.1). PFS at 6 and 12 months was 57.0% and 42.2%, and 6 and 12-month OS was 73.9% and 53.2%, respectively. Only 19 pts were considered evaluable for RR. Five pts were either lost to follow up, withdrew consent, or died before a second scan was done. Six pts achieved PR (31.5%) and 11 (57.9%) had SD. Grade 3 or higher adverse events (AE) occurred in 75% of pts. The most common grade 3/4 AEs were decreased neutrophil count (40%) and increased lipase (20%). Treated related AEs led to drug discontinuation for 3 pts (12.5%) and dose modification for 7 pts (29.2%). Conclusions: Gemcitabine, cisplatin, and copanlisib in combination did not meet the primary endpoint of 6-month PFS. However, additional correlative work is ongoing to identify a possible biomarker for copanlisib. Clinical trial information: NCT02631590.