Pfizer's JAK3 Inhibitor Ritlecitinib Granted First Clinical Approval in China for Ulcerative Colitis

Source: PharmaCube Info

Author: Sunshine

Recently, the CDE official website showed that Pfizer's Ritlecitinib capsule (PF-06651600) clinical trial application was approved for the treatment of adult patients with moderate to severe active ulcerative colitis. This is the second indication for which Ritlecitinib has been approved for clinical trials in China, following alopecia areata.

Ritlecitinib is an oral targeted Janus kinase 3 (JAK3) inhibitor that achieves JAK isoform selective inhibition through covalent interaction with the unique residue CYS-909 of JAK3. Compared with first-generation pan-JAK inhibitors, this drug has more advantages in reducing toxicity.

Notably, Ritlecitinib tablets for the treatment of patients aged ≥12 with moderate to severe alopecia areata (including alopecia totalis [AT] and alopecia universalis [AU]) received breakthrough therapy designations from both the FDA and CDE. On August 4, 2021, Pfizer announced positive topline results from the Phase IIb/III clinical trial of ritlecitinib, administered orally once daily, for the treatment of alopecia areata. Both the 30mg and 50mg dose groups met the primary efficacy endpoint of improved hair regrowth.

Pfizer currently has three JAK inhibitors in its product pipeline. In addition to ritlecitinib, Xeljanz (tofacitinib) was the first JAK inhibitor approved for the treatment of rheumatoid arthritis, with global sales reaching $2.437 billion in 2020 (+45%); Cibinqo (abrocitinib) is a JAK1 inhibitor that has been launched in the EU, the US, and other regions for the treatment of atopic dermatitis.

In addition to alopecia areata and ulcerative colitis, Pfizer is also conducting clinical trials abroad for ritlecitinib in the treatment of vitiligo, rheumatoid arthritis, and Crohn's disease.