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Budoprutug for adults with immune thrombocytopenia (ITP)

A Phase 1b/2a, Open-Label, Sequential-Cohort, Dose Escalation and Expansion Study to Evaluate Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Preliminary Clinical Effectiveness of Budoprutug (TNT119) in Subjects With Immune Thrombocytopenia (ITP)

Phase1; Phase2 Interventional Climb Bio, Inc. · NCT07043946

This trial will test whether two IV doses of budoprutug are safe and can help raise platelet counts in adults with ITP who still have platelets under 30,000/µL after prior treatment.

Quick facts

PhasePhase1; Phase2
Study typeInterventional
Enrollment24 (estimated)
Ages18 Years and up
SexAll
SponsorClimb Bio, Inc. Industry-sponsored
Drugs / interventionsrituximab
Locations20 sites (Plovdiv and 19 other locations)
Trial IDNCT07043946 on ClinicalTrials.gov

What this trial studies

This open-label, sequential-cohort Phase 1b/2a dose-escalation and expansion study gives budoprutug as two IV infusions 14 days apart to adults with ITP and platelet counts below 30,000/µL. The primary focus is on safety and tolerability, with secondary evaluations of pharmacokinetics, pharmacodynamics, and preliminary clinical efficacy such as platelet response. Dosing will proceed in ascending cohorts to identify tolerable dose levels and characterize biological effects on CD19+ B cells. Eligible patients must have confirmed low platelet counts despite prior therapy and meet baseline coagulation and laboratory criteria.

Who should consider this trial

Good fit: Adults (18+) with diagnosed ITP who have platelet counts under 30,000/µL despite at least one prior therapeutic attempt, acceptable coagulation labs, and sufficient CD19+ B-cell counts are the intended candidates.

Not a fit: Patients with very low or absent CD19+ B cells, recent or planned B-cell depleting therapy, other bleeding disorders, or chronic use of anticoagulant/antiplatelet drugs are unlikely to be eligible or to benefit from this treatment.

Why it matters

Potential benefit: If successful, budoprutug could become a new B-cell–targeted option to increase platelet counts and reduce bleeding risk in adults with refractory ITP.

How similar studies have performed: B-cell–depleting therapy with anti-CD20 agents like rituximab has shown benefit in ITP, but anti-CD19 monoclonal approaches are less well studied and have only limited early evidence so far.

Eligibility criteria

Show full inclusion / exclusion criteria 
Inclusion Criteria:

1. Aged 18 years at the time of consent.
2. Platelet count \< 30,000/µL despite an adequate trial of at least one prior therapeutic attempt. Platelet counts of \< 30,000/µL must be confirmed on 2 occasions at least 5 days apart, but no more than 14 days apart.
3. Partial thromboplastin time \< 1.5 x upper limit of normal (ULN), prothrombin time \< 1.5 x ULN, total bilirubin \< 1.5 x ULN unless due to Gilbert's syndrome, or an international normalized ratio \< 1.5 at screening.

Exclusion Criteria:

1. CD19+ B cell count \< 80 cells/µL at Screening, or \< 40 cells/µL if B-cell depleting therapy was received within 24 weeks to 2 years prior.
2. Diagnosis of paroxysmal nocturnal hemoglobinuria, Evan's Syndrome, or other bleeding disorders affecting safety or data integrity.
3. Prior B-cell depleting therapy (e.g., rituximab) within 24 weeks before first dose or planned during the study.
4. Chronic use of anticoagulants or antiplatelet agents (e.g., aspirin, NSAIDs, thienopyridines) within 14 days before dosing through follow-up. Intermittent NSAID use is allowed.
5. Immunosuppressants (excluding corticosteroids) within 30 days or 5× half-life before Screening; alkylating agents within 180 days.
6. IVIg treatment within 90 days prior to Screening.
7. Active ITP treatment (other than steroids or TPO agonists) within 30 days or 5× half-life before first dose, unless approved by Medical Monitor.
8. Active, chronic, or latent infections including hepatitis B/C or HIV.
9. Active TB or high TB risk.

Where this trial is running

Plovdiv and 19 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Immune ThrombocytopeniaITPBiologicsMonoclonalAnti-CD19
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.