Benzinga | Sep 9, 2021 10:04AM EDT

Sanofi's BTK Inhibitor Disappoints In Phase 3 Autoimmune Disease Trial

* Sanofi SA's (NASDAQ:SNY) BTK inhibitor, rilzabrutinib, has flunked its first major clinical test.

* Rilzabrutinib was Principia Biopharma Inc's one of the key candidates that Sanofi acquired last year for $3.68 billion.

* Investigators randomized 131 newly diagnosed or relapsing moderate-to-severe pemphigus patients to take rilzabrutinib or placebo orally.

* The primary endpoint looked at the number of patients in each arm who were in complete remission and taking 5 mg or less of corticosteroids a day from week 29 to week 37 of the study. By that yardstick, rilzabrutinib was no better than placebo.

* Pemphigus is characterized by blisters and ulceration affecting the skin and mucous membranes.

* Sanofi is yet to give up on the drug, in any case.

* A Phase 3 trial in the rare blood disorder immune thrombocytopenia and a Phase 2 study in the autoimmune condition IgG4-related disease are continuing.

* And Sanofi plans to start mid-phase trials in immunological diseases including asthma, atopic dermatitis, chronic spontaneous urticaria, and warm autoimmune hemolytic anemia by the end of the year.

* Read Next: Sanofi's $1.9 Billion Bet On Kadmon: What You Need to Know.

* Price Action: SNY stock is down 1.56% at $49.34 during the market session on the last check Thursday.