This study is a multicenter, randomized, double-blind Phase 3 trial designed to evaluate how well two different doses of the drug ianalumab work, and how safe they are, compared to a placebo. This research involves adults with primary ITP who are receiving standard first-line corticosteroid treatment and who showed a positive response to these corticosteroids at any point before being randomly assigned to a study group. At least 225 participants will be randomly divided into three equal groups: one group will receive the lower dose of ianalumab, another will receive the higher dose, and the third group will receive the placebo. The study will be broken down into three main parts: an initial screening period to determine eligibility, a randomized treatment period where participants receive their assigned medication, and a follow-up period to monitor how effective the treatment was and check for any side effects.

Who can Participate

Inclusion Criteria: • Male or female participants aged 18 years and older on the day of signing informed consent • Primary ITP diagnosed within 3 months before initiating first-line ITP therapy (corticosteroids, IVIG). • Platelet count below 30 G/L before starting any first-line ITP therapy (corticosteroids, IVIG). • Response (platelet count ≥50 G/L) to corticosteroids (+/- IVIG) at any time prior to randomization. Note: Platelet counts measured within 7 days of platelet transfusion will not be considered as response. Exclusion Criteria: • Evans syndrome or any other cytopenia • Current life-threatening bleeding • Previous ITP treatment, including splenectomy, except for corticosteroids and/or IVIG initiated as first-line therapy for up to 28 days before randomization and rescue corticosteroids and/or IVIG given prior to confirmed diagnosis of primary ITP • Prior use of B-cell depleting therapy • Absolute neutrophil count below 1.0 G/L at randomization • Participants with concurrent coagulation disorders and/or receiving anti-platelet or anticoagulant medication with an exemption of low dose of acetylsalicylic acid (see Prohibited Medication in Protocol Section 6.8.2 ) • Active viral, bacterial or other infections (including tuberculosis -TB) requiring systemic treatment or SARS-CoV-2 infection during the screening period, or history of recurrent clinically significant infection (eg. bacterial infections with encapsulated organisms). • Participants with positive hepatitis C virus antibody (HCV Ab) antibody, hepatitis B surface antigen (HBsAg) are excluded. Participants who are hepatitis B core antibody (HBcAb) are excluded unless all the following criteria are met: • HBsAG (irrespective of anti-HBs status) and HBV DNA are negative • Participant has no pre-existing liver fibrosis • Hepatitis B monitoring is implemented, including regular ALT testing and HBV DNA testing • Antiviral prophylaxis with Entecevir must be initiated prior to randomization and must continue during treatment period and at least 12 months after last dose (If antiviral prophylaxis with entecavir is not allowed as per local guidelines or local clinical practice, clinically contraindicated or not accepted by the patient, participants who are HBsAg negative and HBcAb positive are not eligible)

Study ID

More information available at ClinicalTrials.gov: NCT05653349