Vorasidenib (AG-881) is a brain-penetrant allosteric inhibitor of mutant isocitrate dehydrogenases 1 and 2 (mIDH1/2) from Agios and Celgene that made headlines summer 2023 due to its stunning efficacy for treatment of glioma in patients with mIDH1/2. This Featured Case Study reviews how it was discovered, how it works, and why it matters.

Pfizer’s ritlecitinib, a first-in-class, selective, oral covalent inhibitor of JAK3 and the TEC family of kinases, was FDA-approved in June 2023 for the treatment of severe alopecia areata. Ritlecitinib derives its JAK-family kinase selectivity from the covalent modification of a unique cysteine on JAK3. This annotation reviews the discovery of ritlecitinib, highlighting the interpretation of selectivity assays, the PK optimization, the evolution of the JAK3 therapeutic hypothesis, and how this 2023 Molecule of the Year nominee has become a classic case study for covalent drug discovery.

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.

AbbVie’s ABBV-467 is a highly potent, selective MCL-1 (myeloid cell leukemia-1) inhibitor which entered the clinic in 2022 in a Ph. I trial in patients with advanced hematologic cancers. MCL-1 has had a rough time in the clinic with multiple trials being halted or terminated due to cardiac toxicity, which is suspected to be an on-target effect. AbbVie’s approach with ABBV-467 was to target a highly potent/short half-life compound which could induce rapid apoptosis and tumor regressions in a short exposure period before the onset of any adverse events. Is this the end for MCL-1?

AstraZeneca recently disclosed the structure and discovery journey of their oral small molecule PCSK9 inhibitor, AZD0780, during the ACS Fall 2024 First Time Disclosures session in Denver. Discover how the team identified a fragment hit targeting a previously unexplored pocket, verified its novel mechanism of action, and successfully advanced it into a clinical compound now in Ph. II trials for patients with dyslipidemia.