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

Not Applicable

Not yet recruiting

• Conditions: Advanced Unresectable Hepatocellular Carcinoma
• Interventions: Drug: RBS2418; Drug: STRIDE (durvalumab + tremelimumab)

• Registration Number: NCT07175441
• Lead Sponsor: Riboscience, LLC.

Brief 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.

Study Timeline

• Status Verified: 2025-09
• Study First Submitted: 2025-09-09
• Study First Submitted QC: 2025-09-09
• Study First Posted: 2025-09-16
• Last Update Submitted: 2025-09-16
• Last Update Posted: 2025-09-22
• Study Start: 2025-10-01
• Primary Completion: 2027-04
• Study Completion: 2027-08-01

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 220

Inclusion Criteria

1. At least 18 years of age on the day of signing informed consent.
2. Male and female participants with advanced, unresectable HCC who are eligible to receive STRIDE regimen as first line therapy.
3. Willing to submit a pre-treatment tissue sample (archival or fresh tissue if archival is not available).

Exclusion Criteria

1. BCLC stage D disease at the time of screening or prior to first dose of RBS2418.
2. Child-Pugh class equal or higher than B8 at the time of screening or within 7 days prior to the first dose of study treatment.
3. Eligible for curative treatments (e.g., surgical resection, liver transplantation, or local ablation).
4. Evidence of rapid progression on prior therapy resulting in rapid clinical deterioration.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Arm A: RBS2418, 200mg BID, plus STRIDE	RBS2418	RBS2418 200 mg PO, BID in combination with STRIDE regimen
Arm A: RBS2418, 200mg BID, plus STRIDE	STRIDE (durvalumab + tremelimumab)	RBS2418 200 mg PO, BID in combination with STRIDE regimen
Arm B: RBS2418, 800mg BID, plus STRIDE	RBS2418	RBS2418 800 mg PO, BID in combination with STRIDE regimen
Arm B: RBS2418, 800mg BID, plus STRIDE	STRIDE (durvalumab + tremelimumab)	RBS2418 800 mg PO, BID in combination with STRIDE regimen
Arm C: STRIDE alone (control)	STRIDE (durvalumab + tremelimumab)	STRIDE regimen

Primary Outcome Measures

Name	Time	Method
Progression Free Survival (PFS)	From randomization until the first radiographic documentation of objective progression or death from any cause, assessed up to 2 years.	Time in months from randomization until the first radiographic documentation of objective progression, as assessed using RECIST 1.1, or death from any cause.

Secondary Outcome Measures

Name	Time	Method
Overall Survival (OS)	From randomization until death from any cause, assessed up to 2 years.	Time in months from the date of randomization to the date of death from any cause.
Overall Response Rate (ORR) by RECIST 1.1	From randomization to initial response, assessed up to 2 years	ORR is defined as the percentage of participants who achieve a complete response (CR) or partial response (PR) during the study using RECIST 1.1, among those with measurable disease.
Duration of Response (DOR) by RECIST 1.1	From initial response to disease progression or death, assessed up to 2 years	DOR is defined as time from initial response to disease progression or death.
Disease Control Rate (DCR)	From randomization to end of treatment or disease progression, assessed up to 2 years.	DCR is defined as the percentage of participants who achieve a complete response (CR), partial response (PR) or stable disease (SD).

Trial Locations

Locations (1)

Johns Hopkins; 🇺🇸 Baltimore, Maryland, United States