The Food and Drug Administration (FDA) has granted Orphan Drug designation to imsidolimab for the treatment of generalized pustular psoriasis.

Imsidolimab is an anti-interleukin-36 (IL-36R) receptor antibody that is administered as a subcutaneous (SC) injection. In September 2019, the Company announced positive topline data from a phase 2 trial (GALLOP) evaluating imsidolimab SC every 4 weeks in patients with moderate to severe generalized pustular psoriasis (n=10). 

An interim analysis of the trial showed that the first 2 patients who completed 16 weeks of treatment both achieved the primary end point of improvement on the Clinical Global Impression scale (used to assess clinical response to treatment) at day 29 and day 113 without requiring rescue therapy. Moreover, skin pustules were observed to be completely cleared in both patients by day 8 and through day 113. Additional clinical data from the GALLOP study are expected to be announced in the second half of 2020. 

Currently, there are no FDA-approved therapies specifically for generalized pustular psoriasis. Management of the disease may include use of biologic therapy (ie, infliximab, adalimumab, etanercept), oral retinoids, cyclosporine, apremilast or methotrexate. 

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The Company is also evaluating the use of imsidolimab in a phase 2 trial involving patients with palmoplantar pustulosis; topline data are expected in the second half of 2020.

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