Viracta Therapeutics’ Pivotal NAVAL-1 Trial Achieves Efficacy Threshold for Expansion in Relapsed or Refractory EBV-positive Peripheral T-Cell Lymphoma (R/R EBV+ PTCL)

Early data observed from NAVAL-1 in R/R EBV+ PTCL consistent with Phase 1b/2 clinical trial

SAN DIEGO, June 28, 2023 (GLOBE NEWSWIRE) — Viracta Therapeutics, Inc. (Nasdaq: VIRX), a precision oncology company focused on the treatment and prevention of virus-associated cancers that impact patients worldwide, today announced that the relapsed or refractory EBV⁺ peripheral T-cell lymphoma (R/R EBV⁺ PTCL) cohort of its pivotal NAVAL-1 clinical trial has met the pre-specified efficacy threshold for expansion into Stage 2 of the study. The efficacy threshold for expansion of NAVAL-1 cohorts from Stage 1 to Stage 2 is based upon a pre-specified minimum number of objective responses achieved within the first 10 patients enrolled.

“Initial data from the PTCL cohort in NAVAL-1 show a strong signal of efficacy that is in-line with our promising Phase 1b/2 data and sufficient to advance to Stage 2. We now look forward to completing enrollment in Stage 1 and are taking steps to further accelerate enrollment through Stage 2,” said Mark Rothera, President and Chief Executive Officer of Viracta. “Given the lack of effective therapies available for patients with PTCL, today’s announcement represents an important step towards addressing a pressing unmet medical need. The advancement of the first cohort into Stage 2 establishes PTCL as the leading indication for the NAVAL-1 clinical trial and provides added momentum to our global clinical program.”

NAVAL-1 enrollment continues worldwide with updates on potential additional cohort advancements expected in the second half of 2023.

About NAVAL-1
NAVAL-1 (NCT05011058) is a global, multicenter trial of Nana-val in relapsed or refractory (R/R) EBV⁺ lymphoma. The trial employs a Simon two-stage design where, in Stage 1, participants are enrolled into six indication cohorts based on EBV⁺ lymphoma subtype. 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 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 or 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.

About EBV-Associated Cancers
Approximately 90% 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 cells for the duration of the patient’s life. Cells containing latent virus are increasingly susceptible to malignant transformation. Patients who are immunocompromised are at an increased risk of developing EBV⁺ lymphomas. EBV is estimated to be associated with approximately 2% of the global cancer burden including lymphoma, nasopharyngeal carcinoma and gastric cancer.

About Viracta Therapeutics, Inc.
Viracta is a precision oncology company focused on the treatment and prevention of virus-associated cancers that impact patients worldwide. Viracta’s lead product candidate is an all-oral combination therapy of its proprietary investigational drug, nanatinostat, and the antiviral agent valganciclovir (collectively referred to as Nana-val). Nana-val is currently being evaluated in multiple ongoing clinical trials, including a pivotal, global, multicenter, open-label Phase 2 basket trial for the treatment of multiple subtypes of relapsed or refractory Epstein-Barr virus-positive (EBV⁺) lymphoma (NAVAL-1), as well as a multinational, open-label Phase 1b/2 trial for the treatment of EBV⁺ recurrent or metastatic nasopharyngeal carcinoma and other advanced EBV⁺ solid tumors. Viracta is also pursuing the application of its “Kick and Kill” approach in other virus-related cancers.

For additional information please visit www.viracta.com.

Forward Looking Statements
This communication contains “forward-looking” statements within the meaning of the Private Securities Litigation Reform Act of 1995, including, without limitation, statements regarding: the details, timeline and expected progress for Viracta’s ongoing and anticipated trials and updates regarding the same, including the progress and potential cohort advancements of NAVAL-1. Risks and uncertainties related to Viracta that may cause actual results to differ materially from those expressed or implied in any forward-looking statement include, but are not limited to: Viracta’s ability to successfully enroll patients in and complete its ongoing and planned clinical trials; Viracta’s plans to develop and commercialize its product candidates, including all oral combinations of nanatinostat and valganciclovir; the timing of initiation of Viracta’s planned clinical trials; the timing of the availability of data from Viracta’s clinical trials; previous preclinical and clinical results may not be predictive of future clinical results; the timing of any planned investigational new drug application or new drug application; Viracta’s plans to research, develop and commercialize its current and future product candidates; the clinical utility, potential benefits and market acceptance of Viracta’s product candidates; Viracta’s ability to manufacture or supplying nanatinostat, valganciclovir and pembrolizumab for clinical testing; Viracta’s ability to identify additional products or product candidates with significant commercial potential; developments and projections relating to Viracta’s competitors and its industry; the impact of government laws and regulations; Viracta’s ability to protect its intellectual property position; and Viracta’s estimates regarding future expenses, capital requirements and need for additional financing in the future.

These risks and uncertainties may be amplified by the COVID-19 pandemic, which has caused significant economic uncertainty. If any of these risks materialize or underlying assumptions prove incorrect, actual results could differ materially from the results implied by these forward-looking statements. Additional risks and uncertainties that could cause actual outcomes and results to differ materially from those contemplated by the forward-looking statements are included under the caption “Risk Factors” and elsewhere in Viracta’s reports and other documents that Viracta has filed, or will file, with the SEC from time to time and available at www.sec.gov.

The forward-looking statements included in this communication are made only as of the date hereof. Viracta assumes no obligation and does not intend to update these forward-looking statements, except as required by law or applicable regulation.

Investor Relations Contact:
Ashleigh Barreto
Head of Investor Relations & Corporate Communications
Viracta Therapeutics, Inc.
abarreto@viracta.com

SOURCE Viracta Therapeutics, Inc.