NCT07175441

Evaluation of RBS2418 in Combination With Tremelimumab Plus Durvalumab in Participants With Advanced Unresectable Hepatocellular Carcinoma

A Phase 2a, Multicenter, Randomized, Open-Label Study to Assess the Efficacy, Safety, and Tolerability of RBS2418 in Combination With Tremelimumab Plus Durvalumab for Participants With Advanced Unresectable Hepatocellular Carcinoma

• Status: Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 220 (estimated)
• Sponsor: Riboscience, LLC. · Industry
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

RBS2418 is a targeted immune modulator that inhibits ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1). It is designed to promote anti-tumor immunity by preserving endogenous 2'-3' cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) from hydrolysis, thereby activating antigen-presenting cells and promoting robust T cell activation. Ideally, RBS2418 acts synergistically with CTLA-4 inhibitors, such as those in the STRIDE regimen (Tremelimumab plus Durvalumab). The hypothesis is that RBS2418 combined with STRIDE will be safe, well-tolerated, highly immunogenic, and enhance anti-tumor responses in adult participants with advanced, unresectable hepatocellular carcinoma (HCC) compared to STRIDE alone.

Detailed description

In this Phase 2a study, participants must have advanced, unresectable HCC confirmed by radiology, histology or cytology. Participants must be eligible to receive the STRIDE regimen as first line therapy. Participants must have measurable disease per RECIST 1.1, an Eastern Cooperative Oncology Group (ECOG) performance score of 0, 1 or 2, and predicted life expectancy of at least 12 weeks. Up to approximately 220 participants will be enrolled and will receive therapy as part of their respective treatment group. Participants will receive study treatment of RBS2418 at two different dose levels (200mg and 800mg) twice daily in combination with STRIDE or STRIDE alone with a treatment period consisting of 28-day cycles up to two years or until there is progressive disease, death, withdrawal, or study completion, whichever comes first. Adverse Events (AEs) will be monitored throughout the study and graded in severity according to the guidelines outlined in the NCI CTCAE v5.0. AEs will be collected until up to 30 days after the last dose of RBS2418 or until resolution, whichever comes first. SAEs will be collected for 90 days after the last dose of RBS2418, or if the participant initiates new anti-cancer therapy, then 30 days after the RBS2418 last dose, whichever is earlier.

Conditions

• Advanced Unresectable Hepatocellular Carcinoma

Interventions

Type	Name	Description
DRUG	RBS2418	RBS2418 is a specific immune modulator that works through the inhibition of ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) and is designed to lead to anti-tumor immunity by protecting endogenous 2'-3'-cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) from hydrolysis and leading to the activation of antigen-presenting cells followed by T cell activation.
DRUG	STRIDE (durvalumab + tremelimumab)	STRIDE: Tremelimumab 300 mg IV (Cycle 1 Day 1 only) Plus Durvalumab 1500 mg IV every 4 weeks

Timeline

• Start date: 2026-04-01
• Primary completion: 2027-04-01
• Completion: 2027-08-01
• First posted: 2025-09-16
• Last updated: 2026-03-19

Locations

3 sites across 1 country: United States

Regulatory

• FDA-regulated drug study