Minimal Systemic Exposure with Maximal Delgocitinib Cream Use in Patients with Severe Chronic Hand Eczema in the DELTA 2 Randomized, Vehicle-Controlled, Double-Blind, Phase 3 Trial

Delgocitinib cream is a topical pan-Janus kinase inhibitor approved for adults with moderate to severe Chronic Hand Eczema (CHE) in the USA, Canada, European Union, and multiple other countries. Here, we assessed the systemic exposure of twice-daily topical application of delgocitinib cream 20 mg/g in adults with moderate to severe CHE treated under normal or maximal use conditions in the DELTA 2 trial and compared with the systemic exposure in adults with moderate to severe atopic dermatitis (AD) from a delgocitinib cream phase 1 AD trial. Blood sampling was performed 2–6 h after delgocitinib cream application at weeks 1, 4, and 16 in DELTA 2. In the delgocitinib cream phase 1 trial, blood sampling was performed prior to application and at six timepoints (0–12 h) post-application on day 1 and day 8. Geometric mean delgocitinib plasma concentrations were calculated in DELTA 2 and peak delgocitinib plasma concentrations (geometric mean Cmax) were calculated in the phase 1 trial. In DELTA 2, patients treated with delgocitinib cream under normal (n = 294; body surface area [BSA], 1.48%; application, 7.3 g/week) or maximal use conditions (n = 19; BSA, 2.17%; application, 13.7 g/week) showed geometric mean delgocitinib plasma concentrations at week 1 of 0.19 ng/mL (n = 268) and 0.58ng/mL, respectively. In the phase 1 trial, patients (n = 14; BSA, 33.6%; application, 72.3 g/week) showed a geometric mean Cmax of 1.20 ng/mL (n = 13) on day 8. Delgocitinib cream 20 mg/g resulted in minimal systemic exposure among adults with moderate to severe CHE, including those treated under maximal use conditions. Low systemic exposure was also observed in adults with moderate to severe AD, despite substantially greater BSA involvement and higher delgocitinib cream usage, highlighting the properties of delgocitinib cream’s novel formulation. NCT03826901 (phase 1, delgocitinib cream); study start date: 20 February 2019; primary completion date: 29 October 2021; study completion date: 29 October 2021. NCT04872101 (DELTA 2); study start date: 25 May 2021; primary completion date: 27 December 2022; study completion date: 6 January 2023.