Viracta Therapeutics Provides an Update on the Phase 1b/2 Trial of Nana-val in Patients with Advanced Epstein-Barr Virus-Positive (EBV+) Solid Tumors and Announces Upcoming Poster Presentation at the ASCO Annual Meeting

Trial has advanced to the second dose escalation cohort with no dose-limiting toxicities observed to-date

SAN DIEGO, June 2, 2022 /PRNewswire/ -- Viracta Therapeutics, Inc. (Nasdaq: VIRX), a precision oncology company targeting virus-associated malignancies, today announced that the Safety Monitoring Committee for the ongoing Phase 1b/2 study of Nana-val in patients with EBV⁺ solid tumors (VT3996-301) has reviewed safety data from the first dose cohort of patients with recurrent or metastatic nasopharyngeal cancer (RM-NPC) and has approved advancing to the next dose level. Newly enrolled patients will enter the trial's second cohort and receive nanatinostat 30 mg orally, 4 days per week, in combination with valganciclovir 900 mg orally daily. Preliminary safety and efficacy data from the trial are expected in the second half of this year.

"Treatment options are limited for patients with RM-NPC, and we are very pleased with the progress thus far in this trial," said Lisa Rojkjaer, M.D., Chief Medical Officer of Viracta. "We look forward to enrolling the next cohort which moves us closer to determining the recommended dose of Nana-val for evaluation in additional patients with RM-NPC and other EBV-positive solid tumors."

In addition, the company also announced an upcoming poster presentation at the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting, which will summarize the design of the Phase 1b/2 trial in patients with EBV⁺ RM-NPC and other EBV⁺ solid tumors.

Poster Title: A Phase 1b/2 Study of Nanatinostat and Valganciclovir in Patients with Advanced Epstein-Barr Virus Positive (EBV⁺) Solid Tumors and in Combination with Pembrolizumab in Patients with Recurrent/Metastatic Nasopharyngeal Carcinoma (RM-NPC)
Session Title: Head and Neck Cancer
Session Date and Time: Monday June 6, 2022, 1:15 – 4:15 pm CDT
Poster Number: 93b
Presenter: A. Dimitrios Colevas, M.D., Stanford Cancer Institute

A copy of the ASCO poster will be available by visiting the Events and Webcasts page of the Viracta website following the conference's conclusion. The poster's corresponding abstract is currently available on the ASCO Annual Meeting Website.

The 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 portion is designed to evaluate safety and to determine the recommended Phase 2 dose (RP2D) of Nana-val in patients with EBV⁺ RM-NPC. In Phase 2, up to sixty patients with EBV⁺ RM-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.

Nanatinostat is an orally available histone deacetylase (HDAC) inhibitor being developed by Viracta. Nanatinostat is selective for specific isoforms of Class I HDACs, which is key to inducing viral genes that are epigenetically silenced in 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.

Viracta is a precision oncology company targeting virus-associated malignancies. 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/refractory Epstein-Barr virus-positive (EBV⁺) lymphoma (NAVAL-1), as well as a multinational Phase 1b/2 trial for the treatment of EBV⁺ recurrent or metastatic nasopharyngeal carcinoma and other EBV⁺ solid tumors. Viracta is also pursuing the application of its inducible synthetic lethality approach in other virus-related cancers.

For additional information please visit www.viracta.com.

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 trials and updates regarding the same; the expected 2022 milestones and key upcoming events and their significance; and other statements that are not historical facts. 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.
[email protected]

SOURCE Viracta Therapeutics, Inc.