BridgeBio’s BBO-8520 is a selective, covalent KRAS(G12C) inhibitor which differentiates itself from the pack by engaging the (ON) state of the protein, potentially conferring increased clinical benefit in KRAS(G12C)-driven cancers, including overcoming resistance to current treatments. Disclosed at the 2024 AACR Annual Meeting in San Diego, is currently in a Ph. I trial in patients with advanced non-small-cell lung cancer. This article covers the structure, mechanism of action and preclinical efficacy that marks this compound out as one to watch.

Arvinas’ ARV-393 is an orally bioavailable PROTAC that degrades BCL6 via CRBN-mediated ubiquitination and proteasomal degradation intended for the treatment of NHL. At the AACR San Diego 2024 meeting, Arvinas disclosed the structure and discovery story of this molecule, which exhibits first-in-class potential. This article covers the key SAR observations that led to the invention of this orally bioavailable PROTAC®, its performance in a triple-hit, high-grade BCL and R-CHOP-resistant cell line, and why sustaining BCL6 knockdown beyond 24 hours was critical for the success of this program.

RMC-9805 is a first-in-class, covalent KRAS(G12D)(ON) molecular glue inhibitor from Revolution Medicines that uses a cyclophilin A (CypA)-recruiting tricomplex mechanism combined with a finely tuned aziridine covalent handle to inhibit the previously “undruggable” KRAS(G12D) mutant. Read our coverage of the discovery story, disclosed at the AACR 2024 meeting in San Diego, to discover how structural and modeling insights were key to engaging a poorly nucleophilic mutant Asp, how RMC-9805 synergizes with PD-1 inhibitors, and the progress this remarkable compound is making in the clinic.

PLX-4545 is an oral CRBN-based molecular glue degrader of IKZF2 in Ph. I trials. It potentially addresses anti-tumor immunity suppression within the TME, critical in checkpoint blocker resistance. Tumors use IKZF2 to regulate the function of regulatory T cells and inhibit effector T cells. IKZF2 depletion in regulatory T cells enhances the anti-tumor response. The discovery and structural data of PLX-4545 were presented by Kevin Freeman-Cook at the ACS Fall 2024 First-Time Disclosures session in Denver, CO. We are reporting the discovery story and its potential impact on immuno-oncology.

EOS-984 is an oral, potential first-in-class, highly selective ENT1 inhibitor from iTeos currently in clinical trials for advanced solid tumors. The drug, which was identified through SBDD and optimization of the vasodilator dilazep, targets the immunosuppressive effects of adenosine, which helps tumors evade immune detection. This is an excellent case study on the importance of understanding a molecule's bioactive conformation to reduce the entropy of binding and enhance potency.