Phase II trial of durvalumab (MEDI4736) with/without tremelimumab for advanced hepatocellular carcinoma after palliative hypofractionated radiotherapy.

TPS630 Background: Hepatocellular Carcinoma (HCC) is among the most common types and leading causes of cancer death globally, and the incidence is on the rise. For patients with advanced hepatocellular carcinoma (HCC), immune checkpoint inhibitors (ICI) in combination with anti-angiogenic agents or other ICI improve survival compared with tyrosine kinase inhibition. Though ICI-based regimens can achieve prolonged responses in some patients and prolong overall survival, only a subset of patients achieve durable responses. There is an urgent need for strategies to overcome primary and acquired resistance. Many of these patients have symptomatic sites of disease which could benefit from local palliative radiotherapy. Radiotherapy also has the potential to elicit an abscopal immune response when combined with ICI. We hypothesize that combining Radiation Treatment (RT) with Durvalumab or the combination of Durvalumab + Tremelimumab (combination D+T in STRIDE regimen showed OS improvement in HIMALAYA trial in 1st line HCC) will achieve a meaningful response rate in advanced HCC patients after progression on other ICI-based therapies. Methods: This is an open label, single center, two-arm, non-comparative phase II trial. Key eligibility criteria are; histologically-diagnosed HCC with progression during or after prior PD-(L)1 checkpoint inhibitor immunotherapy and at least 1 RECIST 1.1-measurable tumor present which has not received RT or other local therapy prior to enrollment, ECOG 0-1, and Child Pugh score of A, B7, or B8. Patients are assigned sequentially to either single-agent durvalumab initiated starting 3 to 10 days after completing RT (25 Gy in 5 fractions to 1-5 sites of disease), at fixed dose of 1500 mg IV every 28 days, or a single fixed dose of tremelimumab of 300 mg IV administered on Day 1, initiated within 3-10 days of completing RT, in combination with durvalumab at fixed dose of 1500 mg IV every 28 days; for up to 24 months or until confirmed radiographic progression. The primary end point is overall response rate (ORR) and secondary endpoints include proportion of participants with adverse events, overall survival, progression free survival and duration of response. Exploratory endpoints include profiling of peripheral blood mononuclear cell immune cells and plasma biomarkers. We plan to accrue 30 patients to this study, 15 to each Arm, to evaluate ORR which would allow us to detect at least a 20% ORR, which would be a clinically meaningful improvement in efficacy in this population with otherwise poor treatment options assuming a statistical power of 87% and a directional 5% statistical significance level based upon an exact binomial test. The trial is open and enrolling. Clinical trial information: NCT04430452 .