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.

Nuvalent’s lead compound, NVL-520, is an oral, brain-penetrant, TRK-sparing, and potential best-in-class ROS1 kinase inhibitor that recently entered Ph. II of the ARROS-1 trial (NCT05118789) in patients with advanced ROS1-positive NSCLC. This article highlights what makes the Nuvalent’s NVL-520 program scientifically notable, including what gives it a potential best-in-class profile as a ROS1 inhibitor, the emerging toxicology of hard-to-avoid off-targets, an interesting synthetic route to the small macrocycle, and more.

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.

Jecure’s JT001 is a selective inhibitor of NLRP3 inflammasome and among the earlier compounds in this now highly competitive space. In 2018, Genentech bought Jecure Therapeutics for an undisclosed amount, gaining access to Jecure’s NLRP3 inhibitor JT001. While there are many other NLRP3 inhibitors now in the space, JT001 is an interesting example of an initial attempt to overcome liver toxicity with well-known NLRP3 inhibitor MCC950. However, the molecule ran into its own kidney toxicity issues, making this an intriguing toxicology case study.

Genentech announced that fenebrutinib (GDC-0853), a non-covalent BTK inhibitor entering Ph. III, showed significant human CNS exposure and reduced new brain lesions in Ph. II for relapsing multiple sclerosis. Fenebrutinib is the only reversible BTK inhibitor in Ph. III for MS, and has the opportunity to differentiate on safety relative to covalent inhibitors. This case study highlights notable challenges overcome in the discovery of fenebrutinib including surprising metabolism, animal-specific on-target toxicity, and more.