A study to find how well budoprutug (TNT119) works and how safe it is in participants with immune thrombocytopenia

Overview

Sponsor-declared trial summary

Key facts

Sponsor

Climb Bio Inc.

Participant type

Patients

Age range

18-64 years, 65+ years

Gender

Male and Female

Therapeutic area

Diseases [C] - Immune System Diseases [C20], Diseases [C] - Hemic and Lymphatic Diseases [C15]

Trial duration

19 Dec 2025 → ongoing

Decision date (initial)

2025-11-03

Transition trial

No

Low-intervention

No

Rare-disease indication

Yes

Vulnerable population

No

Funding sources

Climb Bio, Inc.

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

Scope: Pharmacokinetic, Dose response, Therapy, Safety, Pharmacodynamic, Efficacy, Others

To evaluate the safety and tolerability of ascending doses of budoprutug in subjects with ITP.

Secondary objectives 4

1. 1. To investigate potential doses for subsequent dose-finding studies in subjects with ITP.
2. 2. To characterize the pharmacokinetic (PK) profile of budoprutug in subjects with or ITP.
3. 3. To evaluate the effects of budoprutug on B-cell depletion (pharmacodynamic [PD] response).
4. 4. To evaluate the effects of budoprutug on platelet counts (ITP clinical response).

Conditions and MedDRA coding

Immune Thrombocytopenia (ITP)

Study design 6 periods

Regulatory references

Plan to share IPD

No

IPD plan description

N/A

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 6

1. 1. Aged > 18 years at the time of informed consent.
2. 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. 3. Partial thromboplastin time < 1.5 × upper limit of normal (ULN), prothrombin time < 1.5 × ULN, total bilirubin < 1.5 × ULN unless due to Gilbert’s syndrome, or an international normalized ratio < 1.5 at screening.
4. 4. Adequate hematologic, hepatic, and renal function
5. 5. If being treated with corticosteroids or thrombopoietin (TPO) agonists, subjects must be on a stable dose (< 20% change in dose over the 14 days prior to the first dose of study drug). Corticosteroid treatment should not be > 1 mg/kg methylprednisolone (or equivalent) for 2 weeks prior to the first dose of study drug.
6. 6. Diagnosed with primary ITP

Exclusion criteria 9

1. 1. CD19+ B-cell count < 80 cells/μL at Screening or < 40 cells/μL if B-cell depleting treatment was received within 24 weeks to 2 years prior to Screening.
2. 2. Diagnosis of paroxysmal nocturnal hemoglobinuria, Evan’s Syndrome, or any other bleeding disorder that could confound results and impact patient safety.
3. 3. Prior treatment with rituximab or other B-cell depleting agents within 24 weeks prior to the first dose of study drug or plan to receive B-cell depleting agents during the study.
4. 4. Current or planned treatment with any chronic anticoagulants or platelet aggregation-inhibiting drugs such as aspirin, nonsteroidal anti-inflammatory drugs, or thienopyridines within 14 days of planned dosing through the end of follow-up. Symptom-based intermittent dosing of nonsteroidal anti-inflammatory drugs is permitted.
5. 5. Prior treatment with immunosuppressants (other than corticosteroids) within 30 days or 5 times the elimination half-life (whichever is longer) of the Screening Visit (e.g., calcineurin inhibitors, mycophenolate mofetil, azathioprine), or alkylating agents within 180 days of the Screening Visit.
6. 6. Active or uncontrolled infection at the time of informed consent or study drug initiation.
7. 7. Recent hospitalization for any reason within 14 days prior to Screening, unless approved by the Medical Monitor.
8. 8. Receipt of a live vaccine within 28 days prior to the first dose of study drug or during the study. All other vaccines must be completed within 21 days prior to the first dose of study drug.
9. 9. Secondary cause of ITP (e.g., malignancy, hepatitis B or C, HIV, or other autoimmune diseases [e.g., thyroiditis], or drug-induced ITP).

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 1

1. 1. Incidence, relatedness, severity, and duration of treatment-emergent adverse events (TEAEs) and dose-limiting toxicities (DLTs).

Secondary endpoints 7

1. 1. Budoprutug PK parameters (including area under the concentration-time curve, maximum observed concentration, time to maximum observed concentration, terminal half-life, apparent clearance, and volume of distribution).
2. 2. The change from baseline in absolute peripheral cluster of differentiation (CD)20+ B-cell count.
3. 3. The change in platelet count observed with budoprutug over time in subjects with ITP.
4. 4. The percentage of subjects with ITP who achieve a stable, partial, and complete response by Week 12. Note: A stable, partial, and complete response is defined as a platelet count ≥ 30,000/μL, ≥ 50,000/μL, or ≥ 100,000/μL, respectively, on at least 2 occasions at least 7 days apart within a 30-day time frame.
5. 5. The change in serum IgG, IgM, and IgA from baseline over time.
6. 6. The incidence of subjects who develop ADAs at any time after study drug administration.
7. 7. The percentage of subjects on a steroid at baseline who are able to stop steroid treatment.

Investigational products

Investigational medicinal products (IMPs), comparators, placebo, auxiliary

Test 1

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

Climb Bio Inc.

Sponsor organisation

Climb Bio Inc.

Address

20 William Street Suite 145

City

Wellesley Hills

Postcode

02481-4124

Country

United States

Scientific contact point

Organisation

Climb Bio Inc.

Contact name

Janaki Subramanyam

Public contact point

Organisation

Climb Bio Inc.

Contact name

Janaki Subramanyam

Third parties 11

Locations

3 EU/EEA countries · 12 investigational sites

By country

Investigational sites

Country notifications

Trial-start, recruitment-start, end and early-termination notifications submitted per Member State

Results and documents

Annex IV summary of results, Annex V layperson summary, and all documents registered in CTIS for this trial

Documents 22 files

Public protocol annexes, IB summaries, regulatory submissions and post-authorisation documents registered in CTIS.

Application history

6 submissions — initial application plus substantial / non-substantial modifications