Viracta Therapeutics Announces Orphan Drug Designation Granted by the U.S. FDA to Nana-val for the Treatment of Nasopharyngeal Carcinoma

First orphan drug designation for Nana-val granted in EBV⁺ solid tumors

Seventh orphan drug designation for Nana-val globally; fifth granted by the FDA

SAN DIEGO, Dec. 12, 2023 (GLOBE NEWSWIRE) -- Viracta Therapeutics, Inc. (Nasdaq: VIRX), a clinical-stage precision oncology company focused on the treatment and prevention of virus-associated cancers that impact patients worldwide, today announced that the U.S. Food and Drug Administration (FDA) has granted an orphan drug designation (ODD) to Nana-val (nanatinostat in combination with valganciclovir), the company's all-oral investigational therapy targeting Epstein-Barr virus (EBV)-associated cancers, for the treatment of nasopharyngeal carcinoma (NPC). This represents the first ODD granted for Nana-val in Epstein-Barr virus-positive (EBV⁺) solid tumors and outside of EBV-associated lymphomas. The FDA previously granted Nana-val ODD for the treatment of T-cell lymphoma, post-transplant lymphoproliferative disorder, plasmablastic lymphoma, and EBV⁺ diffuse large B-cell lymphoma, not otherwise specified.

"This orphan drug designation highlights the urgent need for new targeted treatment options for patients with rare diseases such as nasopharyngeal carcinoma, which is highly associated with EBV," said Mark Rothera, President and Chief Executive Officer of Viracta. "We are encouraged by the interim data from the Phase 1b/2 study of Nana-val in patients with recurrent or metastatic EBV-positive nasopharyngeal carcinoma, supporting the continued advancement of the study with a new split daily dosing regimen at higher doses. With sites open and enrolling the sixth dose cohort of the study, we are on track to expand into the Phase 2 portion in 2024. The growing clinical data in both the lymphoma and solid tumor settings, further validates the therapeutic potential of Nana-val to treat EBV-positive cancers, an underserved area of high unmet medical need.”

The FDA’s Office of Orphan Products Development grants orphan status to drugs and biologics being developed to treat, diagnose, or prevent a rare disease or condition affecting fewer than 200,000 people in the U.S. ODD is designed to provide drug developers with various benefits to support the development of novel drugs, including the potential for seven years of market exclusivity upon FDA approval for the disease or condition for which the drug has ODD, eligibility for tax credits toward qualified clinical trial costs, exemptions from certain FDA application fees, reduced annual product user fees, clinical trial protocol design and drug development assistance, and potential qualification for expedited drug development programs.

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

This Phase 1b/2 trial (NCT05166577) is an open-label, multinational clinical trial evaluating Nana-val alone and in combination with pembrolizumab. The Phase 1b dose escalation part is designed to evaluate safety and to select the recommended Phase 2 dose (RP2D) of Nana-val in patients with recurrent or metastatic (R/M) Epstein-Barr virus-positive (EBV⁺) nasopharyngeal carcinoma (NPC). Along with the U.S. Food and Drug Administration’s Project Optimus initiative, at the start of Phase 2, up to 40 patients with R/M EBV⁺ NPC will be randomized to receive either the RP2D or a dose level below the RP2D in a dose-optimization cohort. Once the RP2D has been confirmed, up to 60 patients with R/M EBV⁺ NPC will be randomized to receive Nana-val at the RP2D with or without pembrolizumab to further evaluate antitumor activity, safety and tolerability, pharmacokinetics, and potential pharmacodynamic biomarkers. 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 or refractory (R/R) EBV⁺ lymphoma (NAVAL-1) as well as a multinational Phase 1b/2 clinical trial in patients with recurrent or metastatic (R/M) EBV⁺ NPC and other EBV⁺ solid tumors.

About EBV-Associated Cancers

Approximately 90% of the world’s adult population is infected with 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-positive (EBV⁺) lymphomas. EBV is estimated to be associated with approximately 2% of the global cancer burden including lymphoma, nasopharyngeal carcinoma (NPC), and gastric cancer.

About Viracta Therapeutics, Inc.

Viracta is a clinical-stage 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 (R/R) Epstein-Barr virus-positive (EBV⁺) lymphoma (NAVAL-1), as well as a multinational, open-label Phase 1b/2 clinical trial for the treatment of patients with recurrent or metastatic (R/M) EBV⁺ nasopharyngeal carcinoma (NPC) 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 clinical trials and updates regarding the same, the Company’s expectations of the significance and implications of the preliminary interim data from its clinical trials and preclinical studies disclosed herein, the Company’s expectations related to the FDA submission process and timelines and expectations regarding our target patient populations. 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 and Viracta's ability to manufacture or supply nanatinostat, valganciclovir, and pembrolizumab for clinical testing.

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.