ritlecitinib

Ritlecitinib (PF-06651600) is a potent JAK3-selective inhibitor (IC50: 33.1 nM).

(2R,5S)-Ritlecitinib ((2R,5S)-PF-06651600) is a potent and selective inhibitor of JAK3 with IC 50 of 144.8 nM[1].

Ritlecitinib, also known as PF-06651600, is a potent and selective JAK3 inhibitor. PF-06651600 is a potent and low clearance compound with demonstrated in vivo efficacy. The favorable efficacy and safety profile of this JAK3-specific inhibitor PF-06651600 led to its evaluation in several human clinical studies. JAK3 was among the first of the JAKs targeted for therapeutic intervention due to the strong validation provided by human SCID patients displaying JAK3 deficiencies.

AMP423 is a naphthyl derivative of 2-cyanoaziridine-1-carboxamide with structural similarity to the pro-oxidant anti-tumor agent imexon. AMP423 was active in SCID mice bearing 8226/S myeloma and SU-DHL-6 B-cell lymphoma tumors, with a median tumor growth delay (T-C) of 21 days (P = 0.0002) and 5 days (P = 0.004), respectively, and a median tumor growth inhibition (T/C) of 33.3% (P = 0.03) and 82% (P = 0.01), respectively. In non-tumor-bearing mice, AMP423 was not myelosuppressive.