EBNA1 Inhibitor for Treatment of EBV-positive DLBCL - PROJECT SUMMARY The Epstein-Barr Virus (EBV) is responsible for approximately 200,000 new cancer cases each year worldwide. Among these, EBV+ Diffuse Large B-Cell Lymphoma (DLBCL) is an emergent global cancer threat in patients without overt immunosuppression, irrespective of age, and represents a growing unmet medical need. New therapeutic approaches are needed to treat EBV+ DLBCL. Only one viral-encoded protein, EBNA1, is consistently expressed in all known EBV-associated malignancies and is a validated target for inhibition of EBV- dependent transformation and carcinogenesis. Investigators at the Wistar Institute have developed VK-2019, a first-in-class EBNA1 inhibitor as a therapeutic agent, selecting it from over 2500 candidate inhibitor compounds during the hit-to-lead and lead optimization phases. VK-2019 meets or exceeds industry-accepted criteria for potency, selectivity, metabolic stability, drug suitability, drug safety, toxicology and bioavailability. We anticipated that VK-2019 would have a favorable safety profile because there are no human orthologs of EBNA1. Based on preclinical evidence and a first-in-human Phase I clinical study in patients with advanced nasopharyngeal carcinoma (NPC), VK-2019 met all safety, tolerability and pharmacokinetic endpoints with few documented adverse events (AEs) or Severe Adverse Events (SAEs). In this early study, we observed stable disease in more than a third and a significant decrease in EBV plasma levels, a known biomarker of NPC progression, in more than half of the patients, that correlated with pharmacokinetic exposure. We believe that data from this Phase I study are encouraging in terms of both on target effect and clinical benefit, and supports a follow-on proof-of-concept study in patients with EBV-positive DLBCL. The purpose of this grant is to fund a phase Ib clinical trial of daily oral administration of VK-2019 to (1) further confirm the safety profile and determine any dose-limiting toxicities (DLT) in advanced EBV+ DLBCL patient populations; (2) understand the effects of treatment on EBV-specific biomarkers, including EBV and cellular gene expression and (3) study the effects of treatment on the tumor microenvironment and immune response. The clinical trial infrastructure necessary for the conduct of this study is already in place at the Sidney Kimmel Cancer Center at Thomas Jefferson University. This clinical trial will provide critical information on the safety, tolerability, and preliminary efficacy of VK-2019 in a EBV+ DLBCL patient population. This application brings together basic and translational investigators to understand whether EBNA1 inhibitors can be a therapeutic option for latent EBV infection and cancer and examines the mechanism of action.
