RBL LLC announced the launch of Sentinel BioTherapeutics at the 2025 ASCO Annual Meeting, marking the Houston-based venture studio's first company spin-out since its formation in October 2024. The clinical-stage company is developing innovative immune-priming therapies designed to enhance the effectiveness of checkpoint inhibitors against solid tumors that traditionally show poor response to immunotherapy.
Novel IL-2 Delivery Platform
Developed in the laboratory of bioengineering expert Omid Veiseh Ph.D. at Rice University, Sentinel's platform enables sustained and local delivery of the cytokine interleukin-2 (IL-2) to activate the immune system. The allogeneic encapsulated cell-based system enables constitutive expression of human IL-2, offering a new paradigm for treating cancers such as ovarian cancer and mesothelioma that typically respond poorly to checkpoint inhibitors.
"We believe this is a powerful, new approach that can increase the sensitivity of solid tumors to immunotherapy," said Rima Chakrabarti, M.D., the company's Chief Executive Officer and managing partner at RBL. "Data from a Phase 1 study show the significant potential of our IL-2-producing cell-based platform to specifically stimulate immune checkpoint expression, supporting the rationale for using our agent in combination with immunotherapy."
Clinical Data and ASCO Presentation
Sentinel's Phase 1 data were presented in a poster at the 2025 ASCO Annual Meeting in Chicago. The presentation highlighted clinical biomarker data showing the ability of the company's IL-2 immune priming therapy to induce dose-dependent increases in CTLA-4 expression on both CD8+ and CD4+ T cells, supporting its use as a priming agent for effective checkpoint inhibition.
The poster, titled "Phase I Study of Sustained and Local Delivery of Intraperitoneal IL-2 using Encapsulated Cells in Patients with Platinum-Resistant High-Grade Serous Carcinoma," was presented during the Gynecologic Cancer session on June 1, 2025.
Lead Program and Regulatory Status
Sentinel's lead program SENT001, formerly known as AVB-001, stimulates effector T cell activity and immune checkpoint expression to enhance the efficacy of checkpoint inhibitors in patients with primary or secondary peritoneal and pleural cancer. The company holds a fast-track designation for PROC and orphan disease designation for mesothelioma.
With the backing of RBL, Sentinel is moving forward with GMP manufacturing and clinical trial preparation plans in high unmet need solid tumor indications. The company has plans to initiate "immune priming" clinical trials for peritoneal solid tumors.
Strategic Vision
"The launch of Sentinel represents a major milestone in RBL's mission to support companies that are transforming bold scientific ideas into therapeutic products with the potential for rapid patient impact," said Paul Wotton, Chief Executive Officer and Managing Partner of RBL and Chairman of Sentinel. "Sentinel's cytokine factory platform is the breakthrough technology that we believe has the potential to define the next era of cancer treatment."
The company positions itself as part of the growing Houston biotech ecosystem supported by the Rice Biotech Launch Pad and RBL, with access to infrastructure, financial support, and strategic guidance through the Texas Medical Center Helix Park.
