A Phase 2/3 interventional study of Efgartigimod IV and Placebo IV in Immune Thrombocytopenia (ITP), ITP - Immune Thrombocytopenia and ITP, sponsored by argenx. Recruiting at 26 sites in 10 countries. Open to participants aged 12 Years to 17 Years. Per ClinicalTrials.gov, last updated 2026-10-16.
Sponsored by argenx · Phase 2/3, Interventional, and Treatment
The main purpose of this study is to confirm the correct dose of efgartigimod IV for treating patients aged 12 to younger than 18 years with chronic immune thrombocytopenia (ITP).
The study consists of a double-blinded treatment period (DBTP) in which the participants will be randomized in a 2:1 ratio to receive either efgartigimod IV or placebo IV. At the end of the treatment period (up to 24 weeks), all participants will receive efgartigimod IV during the first year open-label treatment period (OLTP1). At the end of the first OLTP1, participants may begin a second year (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.
More information can be found here: https://clinicaltrials.argenx.com/advancejunior
503 studies on the registry are indexed under Purpura, Thrombocytopenic, Idiopathic; 158 are open to participants now.
This study's planned enrollment of 24 is below the median of 58 across 376 interventional studies indexed under Purpura, Thrombocytopenic, Idiopathic.
Browse Purpura, Thrombocytopenic, Idiopathic studies →argenx is the lead sponsor of 87 studies on the registry; 29 are open to participants now.
Of its 22 completed or terminated interventional studies of FDA-regulated products, 16 (73%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants receiving efgartigimod IV during the double-blinded treatment period and the open-label treatment period(s)
Biological: Efgartigimod IV
Participants receiving placebo IV during the double-blinded treatment period and receiving efgartigimod IV during the open-label treatment period(s)
Biological: Efgartigimod IV · Other: Placebo IV
Intravenous infusion of efgartigimod
Intravenous infusion of placebo
Efgartigimod serum concentrations in the DBTP
Time frame: Up to 24 weeks
Total IgG levels in the DBTP
Time frame: Up to 24 weeks
Efgartigimod serum concentrations over time during the DBTP
Time frame: Up to 24 weeks
Percent change from baseline in total IgG levels in serum over time during the DBTP
Time frame: Up to 24 weeks
Incidence of AEs, SAEs and AEs leading to IMP discontinuation
SAE: Serious adverse event; AE: adverse event
Time frame: Up to 136 weeks
Sustained platelet count response between study weeks 19 and 24 of the DBTP and in OLTP1 for participants receiving placebo in the DBTP
Sustained platelet count defined as achieving platelet counts of ≥50 × 10\^9/L for at least 4 of the 6 study visits
Time frame: Up to 48 weeks
Extent of disease control during the DBTP and during the first 24 weeks of OLTP1 for those participants receiving placebo in the DBTP
Extend of disease defined as the number of cumulative weeks with a platelet count of ≥50 × 10\^9/L
Time frame: Up to 48 weeks
Changes from baseline for platelet counts over time
Time frame: Up to 76 weeks
Incidence of bleeding, assessed by the Modified Buchanan and Adix Bleeding Score for pediatric ITP
The Modified Buchanan and Adix Bleeding Score for pediatric ITP is a semiquantitative assessment tool that measures bleeding signs and symptoms, comprising a score based on a scale of 0 to 5, each representing a different level of severity (0 = no risk; 5 = highest severity).
Time frame: Up to 76 weeks
Incidence of ADA and Nab against efgartigimod in serum
ADA: anti-drug antibodies; Nab: neutralizing antibodies
Time frame: Up to 76 weeks
Change from baseline in EQ-5D-5L
The European Quality of Life 5 Dimensions 5 Level (EQ-5D-5L) is a questionnaire comprised of 5 dimensions. Participants are asked to select the statement in each dimension which best describes their health on the day they complete the questionnaire. Responses in each dimension are coded as a 1-digit number ranging from 1 (no problems) to 5 (extreme problems).
Time frame: Up to 76 weeks
Change from baseline in KIT Child Self-Report and KIT Parent Impact Report
The Kids' ITP Tools (KIT) comprises two disease- specific tools: a self-report form for children aged 12 and older, and a parent impact form. Respondents provide insights into their disease experience using a 1-week recall period. The instrument generates a total score, calculated by summing the items and converting them to a scale of 0 to 100, where higher scores reflect a better disease-specific quality of life (QoL).
Time frame: Up to 76 weeks
Change from baseline in peds FACIT-F
In all participants, the pediatric Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) will use to assess health-related quality of life (HRQoL) before and after treatment. The FACIT-F questionnaire has a score range of 0 to 52, where 0 represents the worst possible fatigue and 52 indicates no fatigue.
Time frame: Up to 76 weeks
Plan to share: No
Started Oct 2025 (actual). Primary completion is estimated for Oct 2028, 36 months after the start.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Studies of the drug tested here: Efgartigimod alfa
Purpura, Thrombocytopenic, Idiopathic →