NEW YORK – Viracta Therapeutics on Monday said the first patient with Epstein-Barr virus (EBV)-positive advanced cancer has received treatment in a Phase Ib/II trial evaluating Nana-val, which combines nanatinostat and valganciclovir, alone and in combination with the PD-1 inhibitor pembrolizumab (Merck's Keytruda).
San Diego-based Viracta is aiming to enroll 88 patients with EBV-positive recurrent or metastatic nasopharyngeal carcinoma and other advanced EBV-positive solid tumors in the trial.
In the Phase Ib portion, EBV-positive NPC patients will receive escalating doses of Nana-val so Viracta can assess the treatment's safety and establish a Phase II dose. In the Phase II portion, the company will randomize up to 60 EBV-positive NPC patients to Nana-val with or without pembrolizumab, with the goal of evaluating safety, overall response rate, and pharmacodynamic markers.
In a Phase Ib expansion cohort, Viracta will enroll patients with other EBV-positive solid tumors, who will receive Nana-val at the recommended Phase II dose. The firm will also track patients' duration of response, disease control, and progression-free and overall survival in the study.
Nana-val comprises the histone deacetylase (HDAC) inhibitor nanatinostat and the antiviral agent valganciclovir. Nanatinostat inhibits isoforms of Class I HDACs, which in turn induces viral genes epigenetically silenced in EBV-associated cancers. In addition to this Phase Ib/II trial in EBV-positive advanced NPC and other solid tumors, Viracta is evaluating the activity of Nana-val in a Phase II, registrational basket trial involving patients with different subtypes of relapsed or refractory EBV-positive lymphoma.
"The initiation of dosing in this clinical trial represents an important milestone for Viracta and is a critical step in potentially expanding the clinical applicability of the targeted all-oral Nana-val combination beyond lymphoma," Lisa Rojkjaer, chief medical officer of Viracta, said in a statement. "Advanced NPC patients have poor outcomes and are in urgent need of effective treatment options."
Each year, EBV infection is known to cause around 2 percent of new lymphoid and epithelial cancer cases globally, and approximately 180,000 patients die from EBV-positive cancers.