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

On December 12, 2023 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, reported 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) (Press release, Viracta Therapeutics, DEC 12, 2023, View Source [SID1234638503]). 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.

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"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.