A Study to Assess the Efficacy and Safety of Efgartigimod IV in Adult Participants With Primary Immune Thrombocytopenia
NCT Number: NCT06544499
Acronym: advance NEXT
Status: NOT_YET_RECRUITING
Study Type: INTERVENTIONAL
Phases: PHASE3
Conditions: Primary Immune Thrombocytopenia (ITP)
Interventions: BIOLOGICAL: Efgartigimod IV|OTHER: Placebo IV
Sponsor: argenx
Sex: ALL
Age: ADULT, OLDER_ADULT
Enrollment: 63
Study Design: Allocation: RANDOMIZED|Intervention Model: PARALLEL|Masking: QUADRUPLE (PARTICIPANT, CARE_PROVIDER, INVESTIGATOR, OUTCOMES_ASSESSOR)|Primary Purpose: TREATMENT
Start Date: 2024-10
Completion Date: 2028-06

Summary:
The main purpose of this study is to look at the effect (efficacy) and safety of efgartigimod IV in participants with primary immune thrombocytopenia (ITP). After an up to 2 weeks screening period, eligible participants will be randomized in a 2:1 ratio to receive either efgartigimod IV or placebo IV, respectively during the double-blinded treatment period (DBTP). At the end of the treatment period (up to 24 weeks), all participants will receive efgartigimod IV during the first 52-week open-label treatment period (OLTP1). At the end of the first OLTP1, participants may begin a second 52-week OLTP2. After the OLTP2, the participants will enter a follow-up period (approximately 8 weeks) while off study drug. The participants will be in the study for up to 138 weeks.

Primary Outcome Measures: Extent of disease control, defined as the number of cumulative weeks during the Double-Blinded Treatment Period with platelet counts of at least 50 × 10^9/L, Up to 24 weeks
Secondary Outcome Measures: Proportion of participants achieving platelet counts of at least 50 × 10^9/L for at least 4 of the 6 study visits between study weeks 19 and 24 of the DBTP, Up to 6 weeks|Proportion of participants achieving platelet counts of at least 50 × 10^9/L for at least 6 of the 8 study visits between study weeks 17 and 24 of the DBTP, Up to 8 weeks|Proportion of participants achieving a platelet counts of at least 50 × 10^9/L for at least 8 of the 12 study visits between weeks 13 and 24 of the DBTP, Up to 12 weeks|Proportion of participants achieving a platelet count of at least 50 × 10^9/L on at least 4 occasions at any time until study week 12 during the DBTP, Up to 12 weeks|Time to response, defined as the time to achieve 2 consecutive platelet counts of at least 50 × 10^9/L at any time during the DBTP, up to 24 weeks|Proportion of participants with an IWG response during the DBTP, International Working Group (IWG), Up to 24 weeks|Proportion of participants with initial response, defined as a platelet count of at least 30 × 10^9/L and a 2-fold increase from baseline in platelet count from study week 5 of the DBTP, Up to 20 weeks|Time to achieve a platelet count of at least 30 × 10^9/L and a 2-fold increase from baseline in platelet count during the DBTP, Up to 24 weeks|Number of cumulative weeks during the DBTP with platelet counts of at least 30 × 10^9/L and ≥20 × 10^9/L above baseline, Up to 24 weeks|Number of cumulative weeks during the DBTP with platelet counts of at least 30 × 10^9/L and at least 20 × 10^9/L above baseline in participants with baseline platelet counts of <15 × 10^9/L, Up to 24 weeks|Extent of disease control, defined as the percentage of weeks with platelet counts of at least 50 × 10^9/L, Up to 76 weeks|Extent of disease control, defined as the number of cumulative weeks with platelet counts of at least 50 × 10^9/L, Up to 76 weeks|Overall platelet count response, defined as the proportion of participants achieving a platelet count of at least 50 × 10^9/L on at least 4 occasions during the first 52 weeks of treatment with efgartigimod IV, Up to 52 weeks|Mean change from baseline in platelet count at each study visit, Up to 76 weeks|The percentage of weeks with platelet counts of at least 30 × 10^9/L and at least 20 × 10^9/L above baseline, Up to 76 weeks|In participants with baseline platelet counts <15 × 10^9/L, the percentage of weeks with platelet counts of at least 30 × 10^9/L and at least 20 × 10^9/L above baseline, Up to 76 weeks|Proportion of participants who achieve a sustained platelet count response, defined as achieving platelet counts of at least 50 × 10^9/L for at least 4 occasions during 6-week intervals, Up to 76 weeks|Proportion of participants achieving a platelet counts of at least 50 × 10^9/L for at least 8 of the 12 study visits between weeks 13 and 24 of the OLTP1, Up to 12 weeks|In participants receiving placebo IV in the DBTP, proportion of participants who achieve sustained platelet count response, defined as achieving platelet counts of at least 50 × 10^9/L for at least 6 of 8 visits between weeks 17 and 24 of the OLTP1, Up to 8 weeks|In participants receiving placebo IV in the DBTP, the extent of disease control, defined as the number of cumulative weeks with platelet counts of at least 50 × 10^9/L during the first 24 weeks of treatment with efgartigimod IV, Up to 24 weeks|Occurrence rate of rescue ITP therapy, Up to 76 weeks|Proportion of participants with reduction in concurrent ITP therapy during the OLTP1, Up to 52 weeks|Incidence and severity of bleeding, assessed by the ITP Bleeding Scale (IBLS), Up to 76 weeks|Incidence of AEs of clinical interest, Up to 136 weeks|Incidence of antidrug antibodies (ADA) against efgartigimod in serum over time, Up to 136 weeks|Incidence of NAb against efgartigimod in serum over time, Up to 136 weeks|Efgartigimod Cmax over time, Up to 136 weeks|Percent change from baseline in total IgG levels in serum over time, Up to 136 weeks