We are developing first-in-class degraders of cyclin-dependent kinase 4 (CDK4) and cyclin-dependent kinase 6 (CDK6), important targets for a range of cancers and clinically validated in the context of certain breast cancers. In preclinical breast cancer models, our lead candidates demonstrated superiority to CDK4/6 inhibitors through potent and highly selective degradation of CDK4 and CDK6, robust inhibition of phosphorylated Rb, cell cycle arrest and ultimately superior in vivo efficacy in breast cancer xenografts. Beyond this increased efficacy potential, we believe our degraders of CDK4 and CDK6 are differentiated to CDK4/6 inhibitor approaches through the ability to overcome key resistance mechanisms that limit the impact of inhibitors (~20% of patients have intrinsic resistance and up to 70% have acquired resistance to CDK4/6 inhibitors) and through significantly enhanced penetration of the blood-brain-barrier. We have nominated a CDK4/6 degrader development candidate, which is currently in IND-enabling studies, and we anticipate commencing clinical trials in 2024.

We are developing degraders of Son of Sevenless 1 (SOS1), an important upstream target in the Kirsten rat sarcoma virus (KRAS) pathway. We are also in early stages of discovery in developing degraders directly targeting KRAS. KRAS is the most frequently mutated cancer-causing oncogene and is mutated in over 20% of all human cancers, including an estimated 90% of pancreatic tumors, 45% of colorectal tumors, and 30% of lung tumors. In preclinical models, we have demonstrated that our lead candidates rapidly and potently degraded SOS1 by up to 90% with inhibition of pan-KRAS mutant cancer cell lines.

We are exploring collaboration opportunities for our first-in-class degraders of Phosphodiesterase 4 (PDE4), a highly validated target for auto-immune and inflammatory diseases. Our PDE4 degraders are highly selective picomolar degraders of the PDE4D isoform that have shown up to 4,000-fold superior potency compared to PDE4 and JAK1/JAK2 inhibitors in inhibition of key inflammatory cytokines such as TNF-α, IFN-γ and IL-1β in preclinical models. We also believe the design of our PDE4 degraders has the potential to avoid several of the key gastrointestinal tolerability issues experienced by patients taking PDE4 inhibitors, enabling an overall favorable tolerability profile relative to other oral agents used for inflammatory diseases.

BTX-1188 is the first ever rationally designed dual-targeting molecular glue degrader of GSPT1 and IKZF1/3 that we are developing for the treatment of acute myeloid leukemia and solid tumors. We believe that the combination of degrading GSPT1, a promising oncology target, and IKZF1/3, clinically validated immunomodulatory targets, enables potential for a broader therapeutic window relative to GSPT1-only degradation. We see particular potential for BTX-1188 in biomarker driven solid tumor populations, particularly for those patients whose solid tumors are MYC over-expressed. The IND application for BTX-1188 has already been cleared by the U.S. Food and Drug Administration. We are currently conducting formulation research with BTX-1188 with the goal of enhancing the oral bioavailability of this molecular glue and resuming enrollment in a previously initiated Phase 1 clinical study.

Biotheryx has entered into a research collaboration and license agreement with Incyte to discover and develop molecular glue degraders for multiple historically undruggable novel oncology targets.