REGULUS: MRI-guided Adaptive SABR for Liver Cancers

Phase II Trial of REal Time MRI GUided Adaptive Stereotactic Ablative Radiotherapy for Liver Cancers Using a Single Session, Simulation Free Workflow

Single arm unblinded study of simulation-free MRI-guided SABR with adaptive replanning in one session for treatment of patients with liver cancers

Study Overview

• Status: Recruiting
• Conditions: HCC; Intrahepatic Cholangiocarcinoma; Liver Metastases; Liver Cancer
• Intervention / Treatment: Radiation: MRI-guided adaptive stereotactic ablative body radiotherapy (SABR)

• Study Type: Interventional
• Enrollment (Estimated): 62
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Eleanor Brown; Phone Number: 650-497-8966; Email: eleanor9@stanford.edu

Study Locations

• United States
  • California
    • Palo Alto, California, United States, 94304
      • Recruiting
      • Stanford University
      • Contact: Eleanor Brown; Phone Number: 650-497-8966; Email: eleanor9@stanford.edu
      • Principal Investigator: Erqi L Pollom, MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Histologically confirmed HCC, intrahepatic cholangiocarcinoma, or metastatic cancer. In the case of suspected HCC in patients with known cirrhosis, noninvasive criteria recommended by the European Association for the Study of Liver Diseases (lesion > 1 cm with arterial phase hyperenhancement and venous phase washout) or LI-RADS score of 5 may be used
• ≥ 18 years old at time of study enrollment
• Child-Pugh A status
• Eastern Cooperative Oncology Group (ECOG) Performance Status of 0, 1, or 2
• Life Expectancy > 6 months
• For women of childbearing potential or who are not postmenopausal (see Appendix F for Definition of Menopausal Status), a negative urine or serum pregnancy test must be done.
• Ability to understand and the willingness to provide written informed consent.
• Patients treated with prior liver-directed therapies with the exception of radioembolization are eligible for this study if they otherwise meet eligibility criteria

Exclusion Criteria:

• Prior treatment with radioembolization
• Cytotoxic chemotherapy or investigational agent within 1 week of SABR
• Prior radiotherapy overlapping with study treatment site
• Female patients who are pregnant
• Contraindication to having an MRI scan or inability to tolerate MRI
• Presence of a pacemaker or other implanted cardiac device
• Direct tumor extension into the stomach, duodenum, small bowel or large bowel
• Patient unable to breath hold > 15 seconds

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: MRI-guided Adaptive Stereotactic Ablative Body Radiotherapy (SABR); Participants will receive a single fraction of MRI-guided adaptive stereotactic ablative body radiotherapy (SABR) using the MRIdian system. Treatment includes daily adaptive planning based on MRI to optimize dose delivery to the tumor and minimize dose to surrounding normal tissue. Eovist contrast is administered before treatment to enhance visualization. Patients perform an inspiratory breath hold during radiation delivery to minimize motion.

Radiation: MRI-guided adaptive stereotactic ablative body radiotherapy (SABR); A single fraction of MRI-guided adaptive stereotactic ablative body radiotherapy (SABR) will be delivered using the MRIdian system. Treatment includes adaptive planning based on daily MRI imaging to update tumor and organ-at-risk contours and optimize the radiation dose. On the day of treatment, Eovist contrast is administered 20 minutes before therapy to enhance tumor visualization. Patients perform an inspiratory breath hold during radiation delivery to minimize motion. The total dose is 30-40 Gy delivered in one fraction using external beam techniques.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
1-year Overall Survival (OS)	Overall survival will be defined as the time from treatment to death from any cause. Patients alive at the time of analysis will be censored at last follow-up.	1 year after SABR

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Rate of Grade ≥ 2 Gastrointestinal (GI) Adverse Events	Proportion of participants experiencing CTCAE v5.0 grade ≥ 2 gastrointestinal adverse events (including fatigue, nausea, diarrhea, or GI pain) attributable to SABR.	Within 90 days of completing SABR
Rate of Grade ≥ 2 Radiation Pneumonitis	Proportion of participants experiencing CTCAE v5.0 grade ≥ 2 radiation pneumonitis attributable to SABR.	Within 90 days of completing SABR
Rate of Grade ≥ 2 Chest Wall Toxicity	Proportion of participants experiencing CTCAE v5.0 grade ≥ 2 chest wall toxicity attributable to SABR.	Within 90 days of completing SABR
Change from Baseline in EORTC QLQ-C30 Global Health Status/Quality of Life Score up to 1 Year Post-SABR	Patient-reported global health status and quality of life will be assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 (EORTC QLQ-C30). Scores range from 0 to 100, with higher scores indicating better global health status and overall quality of life.	Up to 1 year post-SABR
Change from Baseline in FACT-Hep Total Score up to 1 Year Post-SABR	Patient-reported quality of life will be evaluated using the Functional Assessment of Cancer Therapy-Hepatobiliary (FACT-Hep) questionnaire. The FACT-Hep consists of the FACT-General (FACT-G) plus additional hepatobiliary-specific items. Total scores range from 0 to 180, with higher scores indicating better health-related quality of life.	Up to 1 year post-SABR
Change from Baseline in COST-FACIT Total Score up to 1 Year Post-SABR	Financial toxicity will be assessed using the Comprehensive Score for Financial Toxicity (COST-FACIT) questionnaire. Scores range from 0 to 44, with higher scores indicating lower financial toxicity (better financial well-being).	Up to 1 year post-SABR
Rate of Patients With Total Delivery Time > 120 Minutes	Percentage of patients with total SABR delivery time exceeding 120 minutes.	Baseline

Collaborators and Investigators

• Sponsor: Stanford University
• Collaborators: Viewray Inc.

Study record dates

Study Major Dates

• Study Start (Actual): January 23, 2026
• Primary Completion (Estimated): January 1, 2030
• Study Completion (Estimated): January 1, 2030

Study Registration Dates

• First Submitted: October 23, 2025
• First Submitted That Met QC Criteria: October 28, 2025
• First Posted (Actual): October 31, 2025

Study Record Updates

• Last Update Posted (Actual): February 9, 2026
• Last Update Submitted That Met QC Criteria: February 5, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Neoplasms by Histologic Type; Digestive System Neoplasms; Digestive System Diseases; Liver Diseases; Neoplasms, Glandular and Epithelial; Adenocarcinoma; Carcinoma; Liver Neoplasms; Cholangiocarcinoma
• Other Study ID Numbers: IRB-82587

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes