On May 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 financial results for the first quarter of 2023 and recent clinical program updates (Press release, Viracta Therapeutics, MAY 8, 2023, View Source [SID1234631183]).

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"With progress from both of our clinical programs accelerating, we have the opportunity to achieve several important milestones this year. NAVAL-1 is enrolling at a rapid pace, and we look forward to readouts across multiple subtypes that could trigger our first advancement into Stage 2 in the months ahead," said Mark Rothera, President and Chief Executive Officer of Viracta. "On the solid tumor front, we are currently seeking to optimize the dose of Nana-val and are pleased to see that its safety profile continues to support further dose escalation into our trial’s fifth dose level. Following the completion of the Phase 1b portion of the trial, we look forward to selecting our recommended Phase 2 dose and advancing our efforts around Nana-val as a potential tumor agnostic therapy for EBV-associated cancers."

Program Highlights and Anticipated Milestones

Pivotal NAVAL-1 trial of Nana-val in relapsed/refractory (R/R) EBV+ lymphoma

NAVAL-1 continues to enroll across each of the trial’s lymphoma subtype cohorts with more than 70 sites open globally.
An update on NAVAL-1’s first lymphoma subtype that may advance from Stage 1 to Stage 2 is anticipated in the second quarter of 2023.
Potential for additional update(s) on other NAVAL-1 lymphoma subtype(s) in the second half of 2023.
Phase 1b/2 trial of Nana-val in patients with recurrent/metastatic (R/M) EBV+ nasopharyngeal carcinoma (NPC) and other advanced EBV+ solid tumors

The trial has advanced into the fifth dose level of the Phase 1b dose escalation portion; no dose-limiting toxicities have been reported to date.
Clinical data previously reported across the first three dose levels (n=10) include one confirmed partial response (PR) at the third dose level and three patients achieving stable disease.
The Company remains on track to report complete Phase 1b dose escalation data and select a recommended Phase 2 dose (RP2D) in the second half of 2023.
Initiation of the trial’s Phase 2 randomized expansion cohort designed to evaluate Nana-val at the RP2D with or without pembrolizumab in patients with R/M EBV+ NPC is expected in the second half of 2023.
Initiation of the trial’s exploratory Phase 1b expansion cohort designed to evaluate Nana-val at the RP2D in patients with other advanced EBV+ solid tumors, including gastric carcinoma, leiomyosarcoma and lymphoepithelioma, is expected in the second half of 2023.
First Quarter 2023 Financial Results

Cash position – Cash, cash equivalents and short-term investments totaled approximately $80.3 million as of March 31, 2023, which Viracta expects will be sufficient to fund its operations into late 2024 excluding any additional borrowing under a $50.0 million credit facility, of which $25.0 million remains available, at the Company’s request, subject to the discretion of the lenders.
Research and development expenses – Research and development expenses were approximately $7.6 million for the three months ended March 31, 2023, compared to approximately $6.1 million for the three months ended March 31, 2022. The increase in research and development expenses was primarily driven by increases in costs incurred to support the advancement and expansion of our clinical development programs, including incremental costs to support NAVAL-1, our pivotal trial in R/R EBV+ lymphoma, and the initiation of our Phase 1b/2 trial for the treatment of EBV+ solid tumors, as well as an increase in personnel-related costs.
General and administrative expenses – General and administrative expenses were approximately $4.6 million for the three months ended March 31, 2023, compared to $4.3 million for the same period in 2022. The increase in general and administrative expenses can be attributed to an increase in personnel-related costs.
Net loss – Net loss was approximately $12.2 million, or $0.32 per share, (basic and diluted) for the quarter ended March 31, 2023, compared to a net loss of $10.5 million, or $0.28 per share (basic and diluted) for the same period in 2022.
About NAVAL-1

NAVAL-1 (NCT05011058) is a global, multicenter trial of Nana-val in R/R EBV+ lymphoma. The trial employs a Simon two-stage design where participants are enrolled into six indication cohorts based on EBV+ lymphoma subtype in Stage 1. If a pre-specified activity threshold is reached within a lymphoma subtype in Stage 1 (n=10), additional patients will be enrolled in Stage 2 for a total of 21 patients. EBV+ lymphoma subtypes demonstrating promising activity in Stage 2 may be further expanded following discussion with regulators to potentially support registration.

About the Phase 1b/2 Trial of Nana-val in R/M EBV+ NPC and Other EBV+ Solid Tumors

This Phase 1b/2 trial (NCT05166577) is an open-label, multinational trial evaluating Nana-val alone and in combination with pembrolizumab. The Phase 1b dose escalation part is designed to evaluate safety and to determine the RP2D of Nana-val in patients with R/M EBV+ NPC. In Phase 2, up to 60 patients with R/M EBV+ NPC will be randomized to receive Nana-val at the RP2D with or without pembrolizumab to evaluate safety, overall response rate, and potential pharmacodynamic markers. Additionally, patients with other advanced EBV+ solid tumors will be enrolled to receive Nana-val at the RP2D in a Phase 1b dose expansion cohort.

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.