Clinical trial NCT06544499: A Study to Assess the Efficacy and Safety of Efgartigimod IV in Adult Participants With Primary Immune Thrombocytopenia
Official title: A Phase 3, Multicenter, Randomized, Double-Blinded, Placebo-Controlled, Parallel-Arm Study Followed by an Open-Label Arm to Evaluate the Efficacy and Safety of Efgartigimod IV in Adult Participants With Primary Immune Thrombocytopenia
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: PHASE3
Conditions: Primary Immune Thrombocytopenia (ITP)
Lead sponsor: argenx
Sponsor class: INDUSTRY
First posted: 2024-08-09
Enrollment: 63
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief 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.


Eligibility criteria: Inclusion Criteria:

* Is at least 18 years of age and the local legal age of consent for clinical studies when signing the informed consent form (ICF).
* Has documented baseline mean platelet count of \<30 x 10\^9/L before randomization
* Has a documented duration of primary immune thrombocytopenia (ITP) of more than 12 months on the date of informed consent form (ICF) signature.
* Has documented prior ITP treatment with at least 1 of the following treatments: corticosteroids, intravenous immunoglobulin (IVIg), anti-D immunoglobulin, thrombopoietin receptor agonist (TPO-RAs), or rituximab.
* Has documented insufficient response to a prior ITP treatment (the specific criteria can be found in the protocol).
* Has documented prior response defined as 1 platelet count of ≥50 × 109/L to at least 1 of the following ITP treatments in the 3 years before the date of ICF signature: prednisone, dexamethasone, other or nonspecified corticosteroids, IVIg, or anti-D immunoglobulin

Exclusion Criteria:

* Other than the indication under study, known autoimmune disease or any medical condition that would interfere with an accurate assessment of clinical symptoms of ITP, confound the results of the study or put the participant at undue risk.
* Secondary ITP
* Nonimmune thrombocytopenia
* Autoimmune hemolytic anemia
* ITP-associated critical or severe bleeding The complete list of criteria can be found in the protocol.

Primary outcomes:
measure: 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
timeFrame: Up to 24 weeks
Secondary outcomes:
measure: 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
timeFrame: Up to 6 weeks
measure: 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
timeFrame: Up to 8 weeks
measure: 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
timeFrame: Up to 12 weeks
measure: 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
timeFrame: Up to 12 weeks
measure: 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
timeFrame: up to 24 weeks
measure: Proportion of participants with an IWG response during the DBTP
timeFrame: Up to 24 weeks
measure: 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
timeFrame: Up to 20 weeks
measure: 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
timeFrame: Up to 24 weeks
measure: Number of cumulative weeks during the DBTP with platelet counts of at least 30 × 10^9/L and ≥20 × 10^9/L above baseline
timeFrame: Up to 24 weeks
measure: 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
timeFrame: Up to 24 weeks
measure: Extent of disease control, defined as the percentage of weeks with platelet counts of at least 50 × 10^9/L
timeFrame: Up to 76 weeks
measure: Extent of disease control, defined as the number of cumulative weeks with platelet counts of at least 50 × 10^9/L
timeFrame: Up to 76 weeks
measure: 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
timeFrame: Up to 52 weeks
measure: Mean change from baseline in platelet count at each study visit
timeFrame: Up to 76 weeks
measure: The percentage of weeks with platelet counts of at least 30 × 10^9/L and at least 20 × 10^9/L above baseline
timeFrame: Up to 76 weeks
measure: 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
timeFrame: Up to 76 weeks
measure: 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
timeFrame: Up to 76 weeks
measure: 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
timeFrame: Up to 12 weeks
measure: 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
timeFrame: Up to 8 weeks
measure: 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
timeFrame: Up to 24 weeks
measure: Occurrence rate of rescue ITP therapy
timeFrame: Up to 76 weeks
measure: Proportion of participants with reduction in concurrent ITP therapy during the OLTP1
timeFrame: Up to 52 weeks
measure: Incidence and severity of bleeding, assessed by the ITP Bleeding Scale (IBLS)
timeFrame: Up to 76 weeks
measure: Incidence of AEs of clinical interest
timeFrame: Up to 136 weeks
measure: Incidence of antidrug antibodies (ADA) against efgartigimod in serum over time
timeFrame: Up to 136 weeks
measure: Incidence of NAb against efgartigimod in serum over time
timeFrame: Up to 136 weeks
measure: Efgartigimod Cmax over time
timeFrame: Up to 136 weeks
measure: Percent change from baseline in total IgG levels in serum over time
timeFrame: Up to 136 weeks
Other outcomes:
Locations:
city: Los Angeles
country: United States
facility: University of Southern California Norris Comprehensive Cancer Center
state: California
city: Little Silver
country: United States
facility: Regional Cancer Care Associates, LLC (RCCA)
state: New Jersey
city: Westbury
country: United States
facility: Clinical Research Alliance Inc.
state: New York
city: Linz
country: Austria
facility: Krankenhaus der Elisabethinen Linz GmbH
city: Stara Zagora
country: Bulgaria
facility: University Hospital Prof. Dr. Stoyan Kirkovich AD
city: Dublin
country: Ireland
facility: St James's Hospital - Cancer Clinical Trials Office
city: Bassano del Grappa
country: Italy
facility: Azienda ULSS 7 Pedemontana
city: Firenze
country: Italy
facility: Universita Degli Studi Di Firenze - Azienda Ospedaliero-Universitaria Careggi (AOUC)
city: Novara
country: Italy
facility: AO Maggiore Della Carita
city: Ravenna
country: Italy
facility: U.O.C. Ematologia Ospedale Santa Maria delle Croci
city: Torino
country: Italy
facility: AO Ordine Mauriziano di Torino
city: Trieste
country: Italy
facility: Azienda Sanitaria Universitaria Integrata
city: Katowice
country: Poland
facility: Pratia Onkologia Katowice
city: La Coruna
country: Spain
facility: Complejo Hospitalario Universitario A Coruna
city: Madrid
country: Spain
facility: Hospital Universitario Ramon y Cajal
city: Murcia
country: Spain
facility: Hospital General Universitario Morales Meseguer
city: Pozuelo de Alarcon
country: Spain
facility: University Hospital Quironsalud Madrid
city: Valencia
country: Spain
facility: Hospital Clinico Universitario - University of Valencia
city: Coventry
country: United Kingdom
facility: University Hospitals Coventry and Warwickshire NHS Trust
city: Glasgow
country: United Kingdom
facility: Glasgow Royal Infirmary - North Glasgow University Hospital Division
city: London
country: United Kingdom
facility: Barts and the London Pathology & Pharmacy Building - Barts Health NHS Trust
city: London
country: United Kingdom
facility: Hammersmith Hospital, Imperial College School Of Medicine - Imperial College Healthcare NHS Trust
city: Truro
country: United Kingdom
facility: Royal Cornwall Hospital (RCH)
Study officials:
References: