Viracta Therapeutics to host R&D Day highlighting Nana-val

Viracta Therapeutics plans to highlight new preliminary clinical and preclinical data from studies of nanatinostat and valganciclovir, its all-oral investigational therapy targeting Epstein-Barr virus associated cancers, during an R&D Day, Wednesday, October 4, 2023, at 8:00 a.m. EDT. The R&D Day will feature presentations by members of Viracta’s senior management team focusing on its highest priority EBV+ lymphoma indications in the pivotal NAVAL-1 trial, namely, peripheral T-cell lymphoma and diffuse large B-cell lymphoma as well as its advanced EBV+ solid tumor program in patients with recurrent or metastatic EBV+ nasopharyngeal carcinoma. In addition, the R&D Day will feature presentations by expert key opinion leaders who will discuss the high unmet medical needs of EBV-associated lymphomas. Initial preliminary data from the pivotal NAVAL-1 clinical trial of Nana-val in patients with relapsed or refractory EBV+ lymphoma: As of the data cutoff date of June 30, 2023, initial results from the first five patients with R/R EBV+ PTCL treated with Nana-val showed an overall response rate and complete response rate of 40%. The EBV+ PTCL cohort met the efficacy threshold for expansion into Stage 2 of the study, which was based upon having achieved two objective responses within the first five of 10 patients to be enrolled in Stage 1 of the study. Median duration of response has not yet been reached. Anticipated 2024 milestones: Completion of enrollment into Stage 2 of the R/R EBV+ PTCL cohort, Engagement with FDA on additional requirements for accelerated approval, Presentation of Stage 2 data. Additional response and durability assessments from the Phase 1b/2 trial of Nana-val in patients with R/R EBV+ lymphoma as of the May 4, 2023 data cutoff date: Median DoR for patients with R/R EBV+ PTCL was 17.3 months with an ORR/CRR of 50%/38%. In patients with R/R EBV+ DLBCL, additional response assessments from a formulation pharmacokinetics bridging substudy included two additional responders, one complete response and one partial response, resulting in an ORR/CRR of 67%/33%. Median DoR in the R/R EBV+ DLBCL cohort has not yet been reached, with three patients remaining in response and on continued study treatment with DoRs of 11.1 months, 36.8 months and 41.9 months/ Additional follow-up further demonstrated that Nana-val was generally well tolerated with manageable, if not reversible, low-grade toxicities; the most commonly observed treatment-emergent adverse events were hematologic or gastrointestinal in nature as well as low-grade creatinine elevations. New interim clinical data in Phase 1b/2 study of Nana-val in advanced EBV+ solid tumors highlight the opportunity to dose escalate further with an innovative dosing regimen supported by new preclinical data to potentially drive additional responses in this patient population: Enrollment completed through the fifth dose level of the Phase 1b dose escalation portion of the trial without any dose-limiting toxicities reported. Best responses to date included two PRs at the higher dose levels plus five stable diseases in 17 patients with R/M EBV+ NPC. In a preclinical murine EBV+ gastric cancer xenograft model, split daily Nana-val dosing had superior anti-tumor activity than intermittent once-daily dosing, which supports the evaluation of this split daily dosing regimen in patients with advanced EBV+ solid tumors. Anticipated 2024 milestones: Up to three additional dose levels are planned with Nana-val on an SDD schedule to select a recommended Phase 2 dose, Initiation of the clinical trial’s randomized Phase 2 expansion cohort designed to evaluate Nana-val at the recommended Phase 2 Dose with or without pembrolizumab in patients with R/M EBV+ NPC, Initiation of the clinical 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.