Chugai’s PCO371 is an oral, biased agonist and "molecular wedge" of the class B GPCR, PTHR1, that first entered development for hypoparathyroidism in 2015 (NCT02475616). While Class A GPCRs, which typically have compact ligandable pockets are the most common targets for approved drugs, Class B GPCRs like PTHR1, GLP-1R, and CGRP are notoriously difficult to drug since they normally bind large peptides with long transmembrane tunnels that are not easily bound by small molecules. This article explains what makes PCO371 a big deal for GPCR drug discovery.

Merck’s macrocyclic PCSK9 protein-protein interaction (PPI) inhibitor, MK-0616, is a once-daily PCSK9-lowering and LDL-cholesterol-lowering small molecule that has recently demonstrated antibody-like efficacy as an oral agent in the clinic. The program highlights numerous technical achievements at the forefront of modern drug discovery, and will set a standard for modern “classics in drug discovery” for some time.

GS-9688 (selgantolimod) is a potent and selective TLR8 agonist sparing related receptor TLR7, and is intended to induce better immune responses in chronic hepatitis B. Since systemic activation of TLR8 was undesirable, selgantolimod was designed to have high first-pass hepatic clearance to induce effective antiviral immunity in the liver but [...]

On Mar. 14th, 2024, resmetirom (REZDIFFRA™) became the first and only medicine approved by the FDA for the treatment of NASH (non-alcoholic steatohepatitis, aka MASH). Resmetirom, an oral, liver-targeting, once-daily THR-β-selective agonist originally discovered at Roche Nutley, was first highlighted as a Molecule of the Month in Dec. 2022. Now, with the FDA’s accelerated approval, this 2023 Molecule of the Year nominee reflects a historic milestone for liver drug discovery. This article reviews how the molecule works, how it was discovered, and why it’s a big deal.

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.