Viracta Therapeutics Announces First Clinical Response in Epstein-Barr Virus-Positive (EBV+) Solid Tumor Setting and Outlines Key 2023 Clinical Objectives

On January 8, 2023 Viracta Therapeutics, Inc. (Nasdaq: VIRX), a precision oncology company focused on the treatment and prevention of virus-associated cancers that impact patients worldwide, reported its new clinical data from the Phase 1b/2 trial of Nana-val in patients with EBV+ R/M NPC and other EBV+ solid tumors and outlined its key 2023 clinical objectives (Press release, Viracta Therapeutics, JAN 8, 2023, View Source [SID1234626117]).

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"We begin 2023 with important new data from our advanced EBV-positive solid tumor trial. A partial response at this point in the dose escalation phase is highly encouraging, particularly given the safety data to-date and the lack of dose-limiting toxicities in the first three dose levels. We are now enrolling patients into the trial’s fourth dose level, with a further update expected after the completion of the dose escalation portion of the study," said Mark Rothera, President and Chief Executive Officer of Viracta. "Combined with our Phase 1b/2 results in lymphoma, these early data in recurrent or metastatic nasopharyngeal carcinoma support our ambition to develop Nana-val as a tumor-agnostic therapy for EBV-associated cancers, particularly in indications of high unmet medical need. Seeing our first clinical response outside of lymphoma gives us confidence as we work toward our 2023 objectives in solid tumors, which include establishing a recommended Phase 2 dose and exploring Nana-val in additional EBV-positive solid tumor indications. We believe our team, clinical strategy and strong balance sheet leave us well positioned to advance Nana-val’s development through multiple milestones in both the lymphoma and solid tumor settings in 2023 and beyond."

New Phase 1b data on Nana-val in patients with EBV+ R/M NPC

One PR and one disease progression were reported in evaluable patients in the third dose level
Preliminary safety data from the first three dose levels was previously presented at the European Society for Medical Oncology Immuno-Oncology Congress (ESMO-IO) in December 2022, showing Nana-val was well-tolerated with no dose limiting toxicities
Enrollment in the fourth dose level is ongoing
Key 2023 Clinical Objectives

Nana-val in patients with EBV+ R/R lymphoma

Pivotal NAVAL-1 study open for enrollment at more than 60 sites globally; the study footprint is expected to expand further in 2023
Anticipate providing an update on NAVAL-1’s first lymphoma subtype that may advance from Stage 1 to Stage 2 in the first half of 2023
Expect to provide additional updates from other lymphoma subtype(s) throughout 2023
Nana-val in patients with advanced EBV+ solid tumors

Anticipate completion of the Phase 1b dose escalation portion of the trial and selection of the recommended Phase 2 dose (RP2D) in 2023
Anticipate initiating the Phase 2 randomized expansion portion of the trial, designed to evaluate Nana-val at the RP2D with or without pembrolizumab in patients with EBV+ R/M NPC, in the second half of 2023
Anticipate initiating the exploratory Phase 1b cohort designed to evaluate Nana-val at the RP2D in other EBV+ solid tumors in the second half of 2023

Cash Position and Anticipated Runway

Viracta strengthened its balance sheet by exercising its option to draw the $20 million tranche from its non-dilutive $50 million credit facility with Silicon Valley Bank (SVB) and Oxford Finance LLC (Oxford). Viracta intends to use this additional capital to support Nana-val’s development in EBV+ R/M NPC and to explore its potential in other advanced EBV+ solid tumor indications. As a result, Viracta ended 2022 with over $90 million in cash, cash equivalents, and investments, and has an anticipated cash runway into late 2024.

About Nana-val (Nanatinostat and Valganciclovir)

Nanatinostat is an orally available histone deacetylase (HDAC) inhibitor being developed by Viracta. Nanatinostat is selective for specific isoforms of Class I HDACs, which are key to inducing viral genes that are epigenetically silenced in Epstein-Barr virus (EBV)-associated malignancies. Nanatinostat is currently being investigated in combination with the antiviral agent valganciclovir as an all-oral combination therapy, Nana-val, in various subtypes of EBV-associated malignancies. Ongoing trials include a pivotal, global, multicenter, open-label Phase 2 basket trial in multiple subtypes of relapsed/refractory EBV+ lymphoma (NAVAL-1) as well as a multinational Phase 1b/2 trial in patients with EBV+ recurrent or metastatic nasopharyngeal carcinoma and other EBV+ solid tumors.