PRN1008 (rilzabrutinib, Sanofi) is an oral, reversible covalent Bruton’s tyrosine kinase (BTK) inhibitor in a Ph. III trial for immune thrombocytopenia. A simultaneously published inhibitor, PRN473, is in development as a topical treatment for atopic dermatitis. Following target discovery in 1993, and subsequent approval of the first [...]

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.

GDC-2394 (Genentech) is an oral NLRP3 inflammasome inhibitor. The NLRP3 inflammasome is the best studied and most characterized inflammasome , with the protein playing a key role in the detection of inflammatory danger signals which are a hallmark of many inflammatory diseases. Hyperactivation of the NLRP3 has been implicated in the [...]

Kymera's KT-474 is the first oral degrader to demonstrate activity in clinical trials outside cancer and Sanofi recently started a Ph. II trial with the molecule in AD, restoring life to IRAK4 as an immunology target. This article highlights why Kymera’s KT-474 program is scientifically notable, including how it differentiates from small molecule inhibitors, potential competitiveness with biologics, the first reported cryo-EM ternary complex of a heterobifunctional degrader, and why this 2023 Molecule of the Year Nominee will likely be considered a “landmark in drug discovery” for some time.

Jecure’s JT001 is a selective inhibitor of NLRP3 inflammasome and among the earlier compounds in this now highly competitive space. In 2018, Genentech bought Jecure Therapeutics for an undisclosed amount, gaining access to Jecure’s NLRP3 inhibitor JT001. While there are many other NLRP3 inhibitors now in the space, JT001 is an interesting example of an initial attempt to overcome liver toxicity with well-known NLRP3 inhibitor MCC950. However, the molecule ran into its own kidney toxicity issues, making this an intriguing toxicology case study.