Beam Therapeutics announced new data for its Engineered Stem Cell Antibody Evasion (ESCAPE) conditioning platform, showcasing a potential paradigm shift in transplant medicine. The data, presented at the 66th American Society of Hematology (ASH) Annual Meeting and Exposition, demonstrated that conditioning with an anti-CD117 antibody enabled engraftment of base-edited hematopoietic stem cells (HSCs) and induced robust, durable production of fetal hemoglobin (HbF) in a non-human primate (NHP) model.
ESCAPE: A Novel Approach to Transplant Conditioning
The ESCAPE platform comprises two investigational drug products: BEAM-103, an anti-CD117 monoclonal antibody (mAb) designed to suppress or eliminate CD117-expressing hematopoietic stem and progenitor cells, and BEAM-104, a cell therapy that edits the HBG1/2 gene promoter region to elevate HbF, along with a CD117 edit to prevent BEAM-103 binding.
This innovative approach aims to provide a non-genotoxic alternative to traditional myeloablative conditioning, potentially expanding access to curative therapies for patients with sickle cell disease (SCD) and beta-thalassemia. "The data presented today at ASH represent a potential paradigm shift—the first in nearly 70 years—in transplant medicine," said Giuseppe Ciaramella, Ph.D., president of Beam Therapeutics.
Preclinical Study Highlights
The preclinical study, conducted at the National Institutes of Health, involved multiplex base-editing of CD34+ cells from three rhesus NHPs with BEAM-104 to edit CD117 and HBG1/2. The NHPs were conditioned with BEAM-103 CD117 mAb at doses of 10 mg/kg or 25 mg/kg, seven days before transplantation. Post-transplant, additional BEAM-103 treatments maintained selective pressure on unedited cells.
Key findings from the study include:
- Long-term engraftment of HSCs in the marrow, demonstrated by the presence of edited cells in the periphery beyond 6 months.
- Rapid and near-complete replacement of wild-type erythroid cells by edited cells, leading to early induction of therapeutically relevant HbF levels. HbF-containing cells reached >80% post-transplant, with all NHPs achieving >40% γ-globin, a key HbF constituent.
- BEAM-103 dosing was well-tolerated, with no need for transfusions, antibiotics, or supportive care. Unlike busulfan conditioning, NHPs showed only minor declines in neutrophil counts and platelet levels.
- The CD117 base-edit exhibited normal receptor function in vitro and in vivo, with no changes to CD117 signaling, structure, or expression observed following editing. Normal hematopoietic reconstitution was observed post-transplantation in NHP studies.
Clinical Development Plans
Beam Therapeutics is on track to initiate Phase 1-enabling studies by the end of 2024, with plans to advance BEAM-103 and BEAM-104 for development in sickle cell disease and beta-thalassemia. These data provide a strong foundation for advancing ESCAPE into the clinic, with the potential to transform transplant medicine for patients with these diseases and beyond.
