Viracta Therapeutics, Inc. reported positive topline results from Stage 1 of the pivotal Phase 2 NAVAL-1 trial from both arms of the relapsed or refractory (R/R) Epstein-Barr virus-positive (EBV+) peripheral T-cell lymphoma (PTCL) cohort. Patients were randomized to either nanatinostat monotherapy (n=10) or to nanatinostat in combination with valganciclovir (Nana-val, n=10). These data were featured in an oral presentation during the 2024 Joint Annual Congress of Taiwan Society of Blood and Marrow Transplantation and The Hematology Society of Taiwan.

Key takeaways from the pivotal Phase 2 NAVAL-1 trial in patients with R/R EBV+ PTCL: Nana-val (nanatinostat in combination with valganciclovir) demonstrated greater efficacy than nanatinostat monotherapy and was generally well-tolerated. The median duration of response continues to mature. Overview: A total of 20 patients with primarily Stage III-IV disease (who had received =1 [median of 2] prior systemic PTCL therapies) were randomized (1:1) to receive nanatinostat (20 mg orally once daily, 4 days/week) alone or as Nana-val in combination with valganciclovir (900 mg orally once daily, 7 days/week).

Patients who did not respond to nanatinostat monotherapy after 6 weeks of treatment were offered the opportunity to cross over to receive Nana-val. Efficacy was evaluated as of the February 7, 2024 data cutoff date. In the Nana-val arm, the overall response rate (ORR) was 50% and the complete response rate (CRR) was 20% in the intent-to-treat (ITT) population (N=10); the ORR was 71% and the CRR was 29% in the efficacy-evaluable population (N=7).

In the nanatinostat monotherapy arm, the ORR and CRR were 10% and 0%, respectively, in the ITT population (N=10), and the ORR was 13% in the efficacy-evaluable population (N=8). Five nanatinostat monotherapy patients crossed over to receive Nana-val, two of whom remain on Nana-val treatment with stable disease as of the data cutoff. Safety was also evaluated as of the February 7, 2024 data cutoff date.

The most common treatment-related adverse events in both treatment arms were thrombocytopenia, anemia, fatigue, decreased appetite, nausea, diarrhea, and weight loss. These adverse events were primarily mild to moderate in severity and generally manageable or reversible.