This multicenter, randomized, controlled study was conducted to explore the safety and efficacy of low-dose baricitinib plus danazol for ITP patients who had failed corticosteroids and at least one recommended subsequent treatment. Participants were randomly assigned to receive baricitinib plus danazol (n = 108) or danazol alone (n = 108) by a central, interactive web-based system. Patients and caregivers were not blinded to group assignment. Efficacy assessments were performed in the intention-to-treat population by investigators blinded to group assignment. The primary endpoint was 6-month durable response. Forty-nine (45.4%) patients in the combination arm and 22 (20.4%) patients in the monotherapy arm achieved 6-month durable response (P < 0.001). The safety analysis set included patients who received at least one dose of study medication (n = 108 in the combination arm and n = 105 in the monotherapy arm). Fifty-two (48.1%) patients receiving baricitinib plus danazol and 47 (44.7%) patients receiving danazol alone reported at least one adverse event. Each arm reported two patients who developed an adverse event causing study discontinuation and one patient who developed a grade 3 or more severe adverse event. Low-dose baricitinib plus danazol might be a novel option for difficult-to-treat ITP.