PF-04965842 is a selective Janus kinase 1 (JAK1) inhibitor, demonstrating potent activity against JAK1 with an IC50 of 29 nM. Its selectivity is evident from its significantly higher IC50 values for other JAK family members: 803 nM for JAK2, > 10,000 nM for JAK3, and 1,250 nM for TYK2. This selectivity profile suggests that PF-04965842 preferentially targets JAK1 over other JAK isoforms, which could be advantageous in reducing off-target effects and improving therapeutic outcomes in conditions where JAK1 signaling is implicated.

Providing storage is as stated on the product vial and the vial is kept tightly sealed, the product can be stored for up to 24 months.
Wherever possible, you should prepare and use solutions on the same day. However, if you need to make up stock solutions in advance, we recommend that you store the solution as aliquots in tightly sealed vials at -20°C. Generally, these will be useable for up to one month. Before use, and prior to opening the vial we recommend that you allow your product to equilibrate to room temperature for at least 1 hour.