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.

Inaxaplin (VX-147), developed by Vertex, is an inhibitor of APOL1 channel activity currently in a Ph. II/III pivotal study for the treatment of chronic kidney disease caused by specific variants of the APOL1 gene. It was recently granted Breakthrough Therapy designation by the FDA and PRIME designation by the EMA. The discovery story, which is an excellent case study for the use of MetID. Inaxaplin has been called “the most important genomic-driven drug discovery for chronic kidney disease this century”, acting on a target with a fascinating human genetic validation story.

“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.

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.

The arachidonic acid (AA) metabolite, 20-hydroxy-5,8,11,14-eicosatetranoic acid (20-HETE), has been extensively studied as a modulator of kidney function and a mediator of kidney diseases over decades. The receptor for 20-HETE, the G-coupled protein receptor GPR75, was only recently identified (2017), and GPR75/20-HETE pathway modulators are of industry interest in many disease areas including obesity (e.g. 2020 Regeneron patent filing) and kidney diseases (e.g. 2018 Taisho patent filing).