Armed with promising alopecia PhII, Concert edges forward with modified JAK inhibitor — but safety will still be key
Concert Pharma has scored a fresh round of positive Phase II data for its JAK inhibitor amid an ongoing rivalry with Pfizer, paving the way for a late-stage showdown in alopecia areata. It’s also cautiously staking a claim about safety at a time the whole class is under a cloud of uncertainty.
The glowing results — in which both the 8 mg and 12 mg twice-daily doses of CTP-543 hit the primary endpoint of relieving hair loss — recouped some enthusiasm for the drug lost in its interim readout. Investigators reported that 58% of patients in the 12 mg cohort achieved at least 50% relative reduction in the overall Severity of Alopecia Tool (SALT) while 47% in the 8 mg group saw that improvement, compared to 9% for placebo (p <0.001 in both cases).
Shares $CNCE climbed 2.48% to $10.32.
Concert is dropping the 4 mg dose from the upcoming Phase III study after concluding its difference with placebo is not statistically significant.
The biotech is going up against two Pfizer drugs for alopecia areata, an autoimmune disorder that can cause hair loss not just on the scalp but the beard, eyebrows, and other areas of the body for both men and women. CTP-543 inhibits JAK1 and JAK2, while PF-06651600 targets JAK3 and PF-06700841 blocks TYK2 and JAK1.
While JAK, or Janus kinase, are believed to play an important role in inflammatory processes via signaling for over 50 cytokines and growth factors, drugs in the class have recently been implicated for serious side effects. These concerns were in part exemplified by Pfizer’s own blockbuster Xeljanz after FDA and EMA regulators restricted its use due to a higher risk of blood clots and death. And AbbVie’s FDA approval for upadacitinib (Rinvoq) days ago came with a black box warning about infections and thrombosis.
In its press release Concert highlighted that “no thromboembolic events were reported during the trial,” and the only serious adverse event possibly related to treatment was a bacterial infection on the face (facial cellulitis).
Other side effects include headache, nasopharyngitis, upper respiratory tract infection and acne. The breakdown:

Similarly, Pfizer has observed infections, gastrointestinal and skin/subcutaneous tissue issues in their Phase II alopecia areata study.
“We are highly focused on the need for an effective and safe treatment for alopecia areata, and we plan to advance CTP-543 into Phase 3 testing next year,” Concert chief development officer James Cassella said in a statement.
But Concert will have more than one battle to fight. Since CTP-543 is a deuterated version of Jakafi, Incyte has filed — and won — a patent challenge that it is now appealing.
Social image: Alopecia, Shutterstock