First-in-human clinical outcomes with NG-350A, an anti-CD40 expressing tumor-selective vector designed to remodel immunosuppressive tumor microenvironments

Background: Tumor-selective oncolytic viral vectors are promising anticancer therapeutics; however, challenges with dosing and potency in advanced/metastatic cancers have limited efficacy and usage. NG-350A is a next-generation blood-stable adenoviral vector engineered to express an agonist anti-cluster of differentiation (CD)40 antibody without affecting tumor-selectivity and oncolytic potency.

Methods: Intravenous and intratumoral (IT) administration of NG-350A was assessed in a phase Ia/Ib study in patients with metastatic/advanced epithelial tumors (NCT03852511). Dose-escalation was performed separately for intravenous (four dose levels available, each with infusions on Days 1, 3 and 5 of a 57-day treatment period) and IT (single injection on D1 only or injections on Days 1, 8, 15 and 22) administration. The primary objective was safety and tolerability; secondary objectives included determining a recommended dose, pharmacokinetics, and immunogenicity.

Results: In total, 25 heavily pretreated patients received NG-350A (16 with intravenous and 9 with IT administration). Intravenous and IT dosing were both well tolerated, with no evidence of transgene-related or off-target viral toxicity. Intravenous and IT dosing resulted in dose-dependent increases in systemic NG-350A C_max. Despite both routes of administration inducing anti-virus antibodies, sustained persistence of NG-350A in blood samples was observed up to 7 weeks after the last dose, particularly with higher intravenous dose levels. Delivery of NG-350A to tumors was demonstrated in biopsy samples following both routes of administration; a dose-dependent pattern was seen with intravenous infusion, with four patients remaining positive for vector DNA in biopsies at Day 57. Transgene messenger RNA from replicating NG-350A was detected in 5/12 patients with intravenous treatment and 1/9 patients with IT injection, and sustained increases in inflammatory cytokines were observed following dosing, particularly with higher intravenous dose levels.

Conclusions: This phase 1a study provided initial proof-of-mechanism for NG-350A, with strong evidence of tumor delivery, viral replication and transgene expression-particularly after intravenous dosing. The lack of transgene-related or off-target viral toxicity was consistent with the highly selective delivery and replication of NG-350A, even after systemic delivery. The efficacy of intravenous-dosed NG-350A will now be evaluated in combination with pembrolizumab (NCT05165433), as well as with chemoradiotherapy (NCT06459869).

Trial registration number: NCT05165433, NCT06459869.