CDI (Clostridioides difficile) infection is a leading cause of healthcare-associated diarrhea with significant morbidity and mortality, and with the rise of hypervirulent and resistant strains, novel and selective antibiotics to treat these infections are needed. Cadazolid, a hybrid antibiotic that combines pharmacophores of two classes of antibacterials, demonstrated potent activity in vitro against relevant C. difficile strains, while avoiding native gut flora. Additionally, the compound was designed to be gut-restricted, with minimal systemic circulation following PO dosing.

AZ-PRMT5i-1 is an orally bioavailable MTA-cooperative PRMT5 inhibitor that specifically targets MTAP-deleted cancers and is structurally related to AZ’s clinical candidate, AZ3470. This case study is an excellent example of utilizing bioisosteric replacements for polar guanidine headgroups, rigidifying scaffolds through spirocyclization to reduce rotatable bonds, and leveraging fluorine atoms beyond simply blocking metabolic soft spots.

BMS-986408 is an oral, dual DGK ⍺ and ζ inhibitor currently in a Ph. I/II trial in patients with solid tumors. The compound was identified stemming from a phenotypic screening approach, and subsequent target deconvolution revealed DGK to be the target. If approved, it would be a first-in-class intracellular checkpoint inhibitor of DGK. This is an excellent case study on how to overcome a DILI risk associated with BSEP inhibition, as well as how to improve solubility and PK properties of your compounds through the introduction of polarity, reduction of aromatic rings, and increase in f(sp3).

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.

Despite the remarkable emergence of HAART in the 1990s, the fight against HIV infection is by no means finished. At the ACS Fall 2024 meeting in Denver, CO, Gilead Sciences presented the structure and discovery story of elunonavir (GS-1156), a novel HIV protease inhibitor with remarkable metabolic stability and a human half-life exceeding two weeks. Based on BMS’ atazanavir, the compound incorporates structural elements inspired by Gilead’s HCV NS5A inhibitor program which led to ledipasvir, as “stabilizer” motifs to avoid the extensive CYP metabolism seen in current inhibitors.