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.

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.

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.

Chiesi Farmaceutici’s CHF-6523 is an inhaled, lung-restricted, selective PI3Kδ inhibitor designed to provide relief to patients with COPD. Its development involved optimization of permeability and solubility as well as identification of a solid form amenable for dry powder inhalation. Disclosed at the EFMC-ISMC 2024 joint conference in Rome, Italy, this article covers the structure, development, and early clinical data of CHF-6523, which ultimately indicates that PI3Kδ inhibition may not provide clinical effect in reduction of lung inflammation.

Recently, a surge of (pre)clinical compounds inhibiting the NLRP3 inflammasome, often featuring a hexahydroindacene ring system, has emerged, including Nodthera’s ND-0796. In a push for new chemotypes, AZ and Mitsubishi Tanabe have disclosed their clinical compound, AZD4144, which is currently in Ph. I trials in healthy volunteers. The discovery story detailed their efforts to overcome PLD (phospholipidosis), genotoxicity, and hERG inhibition in a non-classical pharmacophore series. The discovery was presented by Anders Johansson at the EFMC-ISMC 2024 Meeting in Rome.