Viracta Presents New Clinical Results on Lead Epigenetic Drug Candidate for EBV-Associated Lymphomas at the 2019 ASCO Annual Meeting
Overall Objective Response Rate (ORR) of 58% in relapsed/refractory patients

PR Newswire, San Diego, June 3, 2019 – Viracta Therapeutics, Inc. presented updated results today at the 2019 ASCO Annual Meeting from the Ph1b portion of the ongoing Phase 1b/2 clinical trial of nanatinostat in combination with the antiviral valganciclovir for the treatment of relapsed/refractory EBV-associated lymphomas.

Updated Phase 1b/2 Results Presented at ASCO

The Phase 1b/2 clinical study [NCT03397706] evaluates three doses of the combination of nanatinostat with an antiviral valganciclovir for the treatment of EBV-associated cancers. Both drugs are taken orally and can be given on an out-patient basis.

  • Responses were observed across all doses, and in B- and T-cell subtypes, including Hodgkin's Lymphoma.
  • The overall objective response rate (ORR) of 58%, complete response rate (CRR) of 33%, and disease stabilization rate (DSR) of 75% is encouraging, and warrants advancement to the Phase 2 stage of the study.
  • The combination was well-tolerated and the most common adverse events were hematologic, easily managed, and resolved without sequalae or bleeding events.
  • A cohort evaluating intermittent dosing of nanatinostat (4 days on and 3 days off) in combination with daily valganciclovir is being evaluated as the recommended Phase 2 dose.

“Today’s presentation at ASCO highlights the potential of our proprietary Kick and Kill therapeutic approach to treat a wide range of EBV positive cancer patients, with responses seen across all doses in both T cell and B cell lymphomas in our ongoing Phase 1b/2 study,” said Ivor Royston, MD, Viracta’s CEO. “These data enable us to move forward with a well-tolerated dose combination into the Phase 2 portion of our study, which we expect to initiate in the third quarter of 2019.”

“Targeting the EBV virus to treat cancer is an elegant epigenetic approach that may modify the interaction between the virus and the tumor microenvironment, while stimulating the immune response. This approach, while in the early stages of research, has now proven successful, with promising results demonstrated with nanatinostat and valganciclovir in patients,” said Pierluigi Porcu, MD, Director, Division of Hematologic Malignancies and Hematopoietic Stem Cell Transplantation, and Professor of Medical Oncology, Dermatology, and Cutaneous Biology, at the Sidney Kimmel Cancer Center – Jefferson Health (SKCC).

Currently, there are no approved treatments for EBV-associated lymphomas that specifically target the virus.

The Company’s ASCO 2019 poster can be accessed on the Viracta website.

About Nanatinostat

Nanatinostat (VRx-3996) is a histone deacetylase (HDAC) inhibitor that is being investigated in a range of clinical indications. Nanatinostat is selective for Class 1 HDACs, including isoforms targeted in Viracta’s Kick & Kill therapeutic approach. Viracta is investigating nanatinostat in a Phase 1b/2 clinical study [NCT03397706] in combination with an antiviral valganciclovir for the treatment of EBV-associated cancers. Both drugs are taken orally and can be given on an out-patient basis. Recently, the nanatinostat plus valganciclovir combination therapy received Orphan Drug Designation (ODD) from the U. S. Food & Drug Administration (FDA) for three sub-types of EBV-associated cancers: post-transplant lymphoproliferative disorder (PTLD), plasmablastic lymphoma, and angioimmunoblastic T cell lymphoma.

About EBV-Associated Cancers

Approximately 95% of the world’s adult population is infected with Epstein-Barr Virus (EBV). Infections are commonly asymptomatic or associated with mononucleosis. Following infection, the virus remains latent in a small subset of lymphatic cells for the duration of the patients’ life. Cells containing latent virus are increasingly susceptible to malignant transformation. Patients who are immunocompromised are at an increased risk of developing EBV lymphomas. In addition, EBV is also associated with a variety of solid tumors, including nasopharyngeal carcinoma and gastric cancer.

About The Kick & Kill Platform

Viracta’s Kick & Kill therapeutic platform is designed to create a pipeline of novel therapies to treat viral-associated cancers and other serious diseases. The “Kick” activates genes that have been epigenetically suppressed by a virus or cancer. The “Kill” activates a therapeutic that will selectively and directly kill virus-harboring cells or activate suppressed immune response genes. The approach holds the potential for development in combination with other immunotherapies.

About Viracta Therapeutics, Inc.

Viracta is a clinical-stage drug development company focused on advancing novel epigenetic therapeutics derived from its proprietary Kick & Kill therapeutic approach to benefit patients with viral-associated cancers and other serious diseases. Viracta has entered into partnerships with Shenzhen Salubris Pharmaceutical Co., Ltd. to bring treatments for EBV-associated cancers to China, and with NantKwest, Inc. to utilize nanatinostat in combination with their clinical-stage Natural Killer (NK) cell immunotherapy. Viracta plans to enter into additional geographic and combination therapy partnerships.

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