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.

Atrasentan, an ETA receptor antagonist discovered by Abbott (AbbVie) in the 1990s, was initially developed for prostate cancer. Due to insufficient clinical data for approval, AbbVie shifted its focus to chronic kidney diseases, conducting a large trial (SONAR) with over 5,000 patients. AbbVie later exited kidney disease drug development and out-licensed atrasentan to Chinook. Novartis then surprised everyone with a $3.2B buyout of Chinook. This case exemplifies the complexities of drug discovery for kidney diseases and the long journey from initial research to clinical success.

“Compound 9” is the first potent M3-selective positive allosteric modulator, with potential utility as a biological tool compound. It does have secondary activity against M5 at high doses though. It’s quite a large zwitterion, which is somewhat unusual for GPCRs.

Zilucoplan is a macrocyclic peptide-containing drug with 15 amino acids in total, targeting the challenging-to-drug C5 complement protein and formulated for self-administered once-daily SC injection. In Sept. 2023, zilucoplan received its first global approval in Japan, followed in Oct. 2023 by FDA approval for gMG patients who are AChR antibody-positive, making zilucoplan the first drug derived from mRNA display for cyclic peptides to be approved. This case study discusses how zilucoplan was discovered and why it’s an important scientific milestone for the industry.

Vadadustat (Vafseo) from Akebia Therapeutics is an oral hypoxia-inducible factor prolyl-4-hydroxylase domain (HIF-PHD) inhibitor developed for anemia in patients with chronic kidney disease (CKD). It received FDA approval on March 27th, 2024 for patients on dialysis for at least three months, after regulatory challenges including an earlier complete response letter due to safety concerns. This makes vadadustat the second FDA-approved HIF-PHD inhibitor for the treatment of anemia in CKD for dialysis-dependent patients after GSK’s daprodustat’s approval in Feb. 2023.