Efficacy in female patients was consistent with the overall study population, with no clinically meaningful sex-related differences in achievement of IGA 0/1 or EASI-75 responses versus placebo.

The recommended adult dose is 100 mg orally once daily, taken at approximately the same time each day with or without food; tablets should be swallowed whole and may be used with or without concomitant medicated topical therapies. Treatment should not be initiated if baseline platelet count, neutrophils, lymphocytes or haemoglobin are markedly reduced, and therapy should be discontinued if there is insufficient clinical improvement after 12 weeks. Missed doses should be taken as soon as possible unless it is less than 12 hours before the next scheduled dose, and treatment should be temporarily interrupted for serious infection or significant laboratory abnormalities in line with monitoring guidance.

No sex-based dose adjustments are required, as gender does not have a clinically meaningful effect on abrocitinib exposure. The dose should be reduced to 50 mg once daily in adults with moderate renal impairment (eGFR 30 to <60 mL/min) or when co-administered with dual strong CYP2C19 plus moderate CYP2C9 inhibitors, or strong CYP2C19 inhibitors alone. No adjustment is needed in mild renal or mild-to-moderate hepatic impairment, whereas use is not recommended in severe renal impairment or end-stage renal disease and is contraindicated in severe hepatic impairment.

No sex-specific differences in adverse reactions were identified in the available sources.

The most commonly reported adverse reactions (≥2% with the 200 mg dose) in placebo‑controlled studies were nausea (15.1%; very common), headache (7.9%), acne (4.8%), herpes simplex (4.2%), increased blood creatine phosphokinase (3.8%), dizziness (3.4%) and upper abdominal pain (2.2%). Infections overall were more frequent with abrocitinib than placebo, with common events including herpes simplex, herpes zoster and pneumonia. Laboratory abnormalities included thrombocytopenia and lymphopenia, hyperlipidaemia, and creatine phosphokinase elevations; venous thrombotic events including deep vein thrombosis and pulmonary embolism were observed in the clinical trial programme only with the 200 mg dose, which is not approved in Switzerland. The most frequent serious adverse reactions were infections (0.3%), mainly herpes simplex, herpes zoster and pneumonia. Nausea led to discontinuation in about 0.4% of patients, and overall higher incidence rates of serious adverse events and treatment‑emergent adverse events leading to permanent discontinuation were reported in abrocitinib‑treated patients than in placebo recipients.

Use is contraindicated during pregnancy and breastfeeding. There are no or limited human data, but animal studies have shown reproductive toxicity including embryo-foetal lethality, skeletal variations, dystocia and reduced postnatal survival at exposures above the clinical range; abrocitinib is excreted into rat milk, a risk to the breastfed infant cannot be excluded, and women of childbearing potential should use effective contraception during treatment and for 1 month after the final dose.

Nonclinical data indicate sex-specific reproductive effects: oral administration of abrocitinib caused temporary reductions in female fertility that reversed about one month after treatment cessation, while no adverse effects on male fertility or spermatogenesis were observed at high exposure multiples.