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.

BAY 2413555 is a M2R PAM that has the potential to counter parasympathetic withdrawal and restore autonomic balance in heart failure patients. The preclinical and clinical data of BAY 2413555 showed it has positive effects on heart rate and heart rate variability and a relatively long human t1/2 of 37 h. The Ph. I trial, however, was terminated in March 2024 due to findings from a chronic toxicology study. This article covers the discovery of BAY 2413555, presented by Alexandros Vakalopoulos of Bayer at the EFMC-ISMC 2024 conference in Rome and published in the Journal of Medicinal Chemistry.

In August 2024, seladelpar (LivdelziTM) became the first FDA-approved selective agonist of PPARδ (peroxisome proliferator-activated receptor δ), following an almost 20-year journey from the original discovery and patent publications. Originally developed by CymaBay in collaboration with Johnson & Johnson, approval was granted to Gilead Sciences following their February 2024 purchase of CymaBay Therapeutics for $4.3B. Seladelpar was approved as a second-line treatment for patients with primary biliary cholangitis.

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.