Velsecorat (AZD7594) is an inhaled, non-steroidal glucocorticoid receptor modulator and antedrug (soft drug) for treatment of asthma and other respiratory conditions that has completed several Ph. II studies . While the paper states that the results support progression into Ph. III studies, a Ph. III study does not appear to have started and [...]

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 [...]

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.

Sovleplenib (HMPL-523) is an orally bioavailable Syk inhibitor being developed by HUTCHMED and is currently in Ph. II and Ph. III clinical trials for several autoimmune diseases. Derived from an HTS hit and SAR optimization, the discovery story of sovleplenib serves as an excellent case study on how to design a next-generation Syk inhibitor devoid of off-target kinase activity, mitigated hERG activity, and more.

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.