Botensilimab plus balstilimab in relapsed/refractory microsatellite stable metastatic colorectal cancer: a phase 1 trial.

Microsatellite stable metastatic colorectal cancer (MSS mCRC; mismatch repair proficient) has previously responded poorly to immune checkpoint blockade. Botensilimab (BOT) is an Fc-enhanced multifunctional anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) antibody designed to expand therapy to cold/poorly immunogenic solid tumors, such as MSS mCRC. BOT with or without balstilimab (BAL; anti-PD-1 antibody) is being evaluated in an ongoing expanded phase 1 study. The primary endpoint is safety and tolerability, which was evaluated separately in the dose-escalation portion of the study and in patients with MSS mCRC (using combined dose-escalation/dose-expansion data). Secondary endpoints include investigator-assessed RECIST version 1.1-confirmed objective response rate (ORR), disease control rate (DCR), duration of response (DOR) and progression-free survival (PFS). Here we present outcomes in 148 heavily pre-treated patients with MSS mCRC (six from the dose-escalation cohort; 142 from the dose-expansion cohort) treated with BOT and BAL, 101 of whom were considered response evaluable with at least 6 months of follow-up. Treatment-related adverse events (TRAEs) occurred in 89% of patients with MSS mCRC (131/148), most commonly fatigue (35%, 52/148), diarrhea (32%, 47/148) and pyrexia (24%, 36/148), with no grade 5 TRAEs reported and a 12% discontinuation rate due to a TRAE (18/148; data fully mature). In the response-evaluable population (n = 101), ORR was 17% (17/101; 95% confidence interval (CI), 10-26%), and DCR was 61% (62/101; 95% CI, 51-71%). Median DOR was not reached (NR; 95% CI, 5.7 months-NR), and median PFS was 3.5 months (95% CI, 2.7-4.1 months), at a median follow-up of 10.3 months (range, 0.5-42.6 months; data continuing to mature). The combination of BOT plus BAL demonstrated a manageable safety profile with no new immune-mediated safety signals and encouraging clinical activity with durable responses. ClinicalTrials.gov identifier: NCT03860272 .

Overcoming resistance to programmed cell death protein 1 (PD-1) blockade with allogeneic invariant natural killer T-cells (iNKT).

Gastric cancer is the 5th most common malignancy worldwide with only 36% of patients with metastatic disease surviving beyond 5 years. Despite therapeutic improvements with the advent of immune checkpoint inhibitors, most patients with gastric cancer develop disease progression related to tumor resistance. Novel immunotherapeutic approaches, including invariant natural killer (iNKT) cells, are in clinical development and represent potential therapeutic options to overcome resistance. AgenT-797 is an allogeneic human unmodified iNKT derived from healthy donors. Activation of iNKT cells by tumor lipid antigens can trigger direct cytotoxicity and promote indirect anti-tumor immune responses such as recruitment and activation of T cells, NK cells, and dendritic cells through secretion of cytokines and IFNγ. We describe immune modulation leading to durable tumor response in a patient with microsatellite instability-high (MSI-H) advanced gastric adenocarcinoma treated with agent-797 after progression on standard chemotherapy and anti-PD-1 therapy.

A Large-Scale Proteomics Resource of Circulating Extracellular Vesicles for Biomarker Discovery in Pancreatic Cancer.

Pancreatic cancer has the worst prognosis of all common tumors. Earlier cancer diagnosis could increase survival rates and better assessment of metastatic disease could improve patient care. As such, there is an urgent need to develop biomarkers to diagnose this deadly malignancy earlier. Analyzing circulating extracellular vesicles (cEVs) using 'liquid biopsies' offers an attractive approach to diagnose and monitor disease status. However, it is important to differentiate EV-associated proteins enriched in patients with pancreatic ductal adenocarcinoma (PDAC) from those with benign pancreatic diseases such as chronic pancreatitis and intraductal papillary mucinous neoplasm (IPMN). To meet this need, we combined the novel EVtrap method for highly efficient isolation of EVs from plasma and conducted proteomics analysis of samples from 124 individuals, including patients with PDAC, benign pancreatic diseases and controls. On average, 912 EV proteins were identified per 100µL of plasma. EVs containing high levels of PDCD6IP, SERPINA12 and RUVBL2 were associated with PDAC compared to the benign diseases in both discovery and validation cohorts. EVs with PSMB4, RUVBL2 and ANKAR were associated with metastasis, and those with CRP, RALB and CD55 correlated with poor clinical prognosis. Finally, we validated a 7-EV protein PDAC signature against a background of benign pancreatic diseases that yielded an 89% prediction accuracy for the diagnosis of PDAC. To our knowledge, our study represents the largest proteomics profiling of circulating EVs ever conducted in pancreatic cancer and provides a valuable open-source atlas to the scientific community with a comprehensive catalogue of novel cEVs that may assist in the development of biomarkers and improve the outcomes of patients with PDAC.

Facts and Hopes in Immunotherapy of Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most challenging cancers to treat. For patients with advanced and metastatic disease, chemotherapy has yielded only modest incremental benefits, which are not durable. Immunotherapy has revolutionized the treatment of other solid tumors by leading to cures where none existed only a decade ago, yet it has made few inroads with PDAC. A host of trials with promising preclinical data have failed, except for in a small minority of patients with selected biomarkers. There is, however, a glimmer of hope, which we seek to cultivate. In this review, we discuss recent advances in the understanding of the uniquely immunosuppressive tumor microenvironment (TME) in PDAC, learnings from completed trials of checkpoint inhibitors, TME modifiers, cellular and vaccine therapies, oncolytic viruses, and other novel approaches. We go on to discuss our expectations for improved preclinical models of immunotherapy in PDAC, new approaches to modifying the TME including the myeloid compartment, and emerging biomarkers to better select patients who may benefit from immunotherapy. We also discuss improvements in clinical trial design specific to immunotherapy that will help us better measure success when we find it. Finally, we discuss the urgent imperative to better design and execute bold, but rational, combination trials of novel agents designed to cure patients with PDAC.

A Preclinical and Phase Ib Study of Palbociclib plus Nab-Paclitaxel in Patients with Metastatic Adenocarcinoma of the Pancreas.

Purpose: To assess the preclinical efficacy, clinical safety and efficacy, and MTD of palbociclib plus nab-paclitaxel in patients with advanced pancreatic ductal adenocarcinoma (PDAC). Experimental Design: Preclinical activity was tested in patient-derived xenograft (PDX) models of PDAC. In the open-label, phase I clinical study, the dose-escalation cohort received oral palbociclib initially at 75 mg/day (range, 50‒125 mg/day; modified 3+3 design; 3/1 schedule); intravenous nab-paclitaxel was administered weekly for 3 weeks/28-day cycle at 100‒125 mg/m2. The modified dose-regimen cohorts received palbociclib 75 mg/day (3/1 schedule or continuously) plus nab-paclitaxel (biweekly 125 or 100 mg/m2, respectively). The prespecified efficacy threshold was 12-month survival probability of ≥65% at the MTD. Results: Palbociclib plus nab-paclitaxel was more effective than gemcitabine plus nab-paclitaxel in three of four PDX models tested; the combination was not inferior to paclitaxel plus gemcitabine. In the clinical trial, 76 patients (80% received prior treatment for advanced disease) were enrolled. Four dose-limiting toxicities were observed [mucositis (n = 1), neutropenia (n = 2), febrile neutropenia (n = 1)]. The MTD was palbociclib 100 mg for 21 of every 28 days and nab-paclitaxel 125 mg/m2 weekly for 3 weeks in a 28-day cycle. Among all patients, the most common all-causality any-grade adverse events were neutropenia (76.3%), asthenia/fatigue (52.6%), nausea (42.1%), and anemia (40.8%). At the MTD (n = 27), the 12-month survival probability was 50% (95% confidence interval, 29.9-67.2). Conclusions: This study showed the tolerability and antitumor activity of palbociclib plus nab-paclitaxel treatment in patients with PDAC; however, the prespecified efficacy threshold was not met. Trial Registration: Pfizer Inc (NCT02501902). Significance: In this article, the combination of palbociclib, a CDK4/6 inhibitor, and nab-paclitaxel in advanced pancreatic cancer evaluates an important drug combination using translational science. In addition, the work presented combines preclinical and clinical data along with pharmacokinetic and pharmacodynamic assessments to find alternative treatments for this patient population.

Organoid Sensitivity Correlates with Therapeutic Response in Patients with Pancreatic Cancer.

PURPOSE: Pancreatic ductal adenocarcinoma (PDAC) remains a significant health issue. For most patients, there are no options for targeted therapy, and existing treatments are limited by toxicity. The HOPE trial (Harnessing Organoids for PErsonalized Therapy) was a pilot feasibility trial aiming to prospectively generate patient-derived organoids (PDO) from patients with PDAC and test their drug sensitivity and correlation with clinical outcomes. EXPERIMENTAL DESIGN: PDOs were established from a heterogeneous population of patients with PDAC including both basal and classical PDAC subtypes. RESULTS: A method for classifying PDOs as sensitive or resistant to chemotherapy regimens was developed to predict the clinical outcome of patients. Drug sensitivity testing on PDOs correlated with clinical responses to treatment in individual patients. CONCLUSIONS: These data support the investigation of PDOs to guide treatment in prospective interventional trials in PDAC.

The Interplay of the Extracellular Matrix and Stromal Cells as a Drug Target in Stroma-Rich Cancers.

The tumor microenvironment (TME) is a complex neighborhood that consists of immune cells, fibroblasts, pericytes, adipocytes, endothelial and neuronal cells, and the extracellular matrix proteins. TME also consists of physical factors, such as oxygen availability, changing pH, interstitial fluid pressure, and tissue stiffness. As cancer progresses, the physical properties and the cells in the TME change significantly, impacting the efficacy of the therapies and modulating drug resistance. This has led to the development of several new treatments targeting the TME. This review focuses on recent advances on the role of TME in drug resistance, with a particular focus on the ongoing clinical trials aiming at disrupting the TME- and the extracellular matrix-mediated protection against therapies.