First-in-Class Antifolate Linker-Drug Platform 

Treatment resistance to TOPO1i and TUBi payload ADCs is an apparent problem for cancer patients

Unlike the TOPO1i and TUBi payloads that comprise approximately 85% of ADCs entering the clinic, our antifolate platform provides a differentiated approach designed to expand treatment options for patients facing difficult-to-treat cancers. Preclinical results demonstrate both in vitro and in vivo efficacy across solid tumor indications, with optimal ADC properties that overcome resistance to TOPO1 payloads. The platform is advancing to the clinic and available for partnering, offering a novel solution to an emerging challenge in oncology.  

ByonBoosT™: First-in-Class Phosphonate Linker-Drug Platform

Checkpoint inhibitors (CPIs) provide durable responses and are a key treatment for many types of cancer. However, 60-80% of patients do not respond to immunotherapy, resulting in a need for well-tolerated treatments that complement currently approved CPIs and overcome resistance and toxicity. One of the main resistance mechanisms is MHC downregulation, which occurs in 40-90% of tumors and limits recognition by classical αβ T cells, the primary target of current immunotherapies.  

Need for well-tolerated immunotherapy that complements currently approved checkpoint inhibitor therapies 

Byondis’s first-in-class ByonBoosT™ phosphonate platform addresses this critical unmet need through a fundamentally different approach: powering tumor-selective activation of γδ T cells, which provide MHC-independent recognition of cancer cells. Unlike conventional immunotherapies that depend on MHC expression, our immunostimulatory phosphonate payload indirectly activates γδ T cells to selectively eliminate cancer cells, overcoming checkpoint inhibitor resistance and toxicity. Our ByonBoost ADCs have shown a clean profile in initial NHP safety and PK/PD studies.