A clinical trial of ifinatamab deruxtecan in people under age 18 who have certain types of cancer (MK-9999-01D)

Overview

Sponsor-declared trial summary

Key facts

Sponsor

Merck Sharp & Dohme LLC

Participant type

Pediatric, Patients

Age range

0-17 years

Gender

Male and Female

Therapeutic area

Diseases [C] - Neoplasms [C04]

Decision date (initial)

2026-05-27

Transition trial

No

Low-intervention

No

Rare-disease indication

Yes

Vulnerable population

No

Funding sources

Daiichi Sankyo · Merck Sharp & Dohme LLC

External identifiers

EU CT number

2025-522339-32-00

WHO UTN

U1111-1322-6561

Trial design

CTIS Part I — objectives, methods, condition coding

Main objective

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

1. Part 1: To evaluate the safety and tolerability and to determine the RDE of ifinatamab deruxtecan (I-DXd) in pediatric participants aged ≥1 month to <12 years with relapsed, refractory solid tumors (excluding primary CNS)
2. Part 1 and Part 2: To evaluate the preliminary antitumor effect of I-DXd in terms of ORR (NBL, RMS, or WT) and DCS-4 (OST) in participants with NBL, RMS, WT, or OST per investigator assessment by tumor type

Secondary objectives 5

1. Part 1 and Part 2: To evaluate the preliminary antitumor effect of I-DXd in terms of DOR, DCR, TTR, PFS in participants with NBL, RMS, WT, or OST and ORR in OST per investigator assessment by tumor type
2. Part 1 and Part 2: To evaluate OS by tumor type
3. Part 1 and Part 2: To describe the safety and tolerability of I-DXd in participants with NBL, RMS, WT, or OST
4. Part 1 and Part 2: to characterize the PK of I-DXd and DXd
5. Part 1 and Part 2: to assess the immunogenicity of I-DXd

Conditions and MedDRA coding

Neoplasm malignant

Eligibility criteria

Principal inclusion / exclusion criteria as submitted by sponsor

Inclusion criteria 3

1. In Part 1, participant has recurrent or relapsed, refractory solid tumors (excluding primary central nervous system (CNS)); and in Part 2, participant has recurrent or relapsed, refractory and histologically confirmed diagnosis of osteosarcoma (OST), neuroblastoma (NBL), rhabdomyosarcoma (RMS), or Wilms tumor (WT). All participants must meet the following criteria: Has documented radiological disease progression after at least 1 line of prior therapy in the locally advanced/metastatic setting and who has no satisfactory alternative treatment option (ie, is ineligible for other standard treatment regimens)
2. Is an individual of any sex/gender, ≥1 month to <12 years of age for Part 1 and ≥1 month to <18 years for Part 2 at the time of providing the informed consent or assent, as applicable
3. Participants who have AEs due to previous anticancer therapies must have recovered to ≤Grade 1 or baseline. Participants with endocrine-related AEs who are adequately treated with hormone replacement or participants who have ≤Grade 2 neuropathy are eligible. Participants with ≤Grade 2 alopecia are also eligible

Exclusion criteria 14

1. Clinically significant corneal disease
2. History of cerebrovascular accident, transient ischemic attack, or another arterial thromboembolic event within 6 months before screening
3. Uncontrolled or significant cardiovascular disease, including conduction abnormalities, hypertension, ischemic heart disease, heart failure, and peripheral vascular disease
4. History of ILD/pneumonitis (including drug-induced ILD/pneumonitis), current ILD/pneumonitis, or suspected ILD/pneumonitis that cannot be ruled out by imaging at screening
5. Has clinically severe respiratory compromise resulting from intercurrent pulmonary illnesses
6. Has an active, known or suspected autoimmune disease
7. History of solid organ transplant
8. History of allogeneic stem cell transplant (SCT)
9. Known active CNS metastases and/or carcinomatous meningitis/leptomeningeal disease/spinal cord compression. Participants with untreated and asymptomatic brain metastases or previously treated brain metastases may participate provided they are radiologically stable, (ie, without evidence of progression) for at least 4 weeks
10. History of human immunodeficiency virus (HIV) infection
11. Known additional malignancy that is progressing or has required active treatment within the past 1 year
12. Active infection requiring systemic therapy
13. Has known hypersensitivity or contraindication to either the study intervention substance or inactive ingredients in the study intervention product
14. Participants who have not adequately recovered from major surgery or have ongoing surgical complications

Endpoints

Primary and secondary outcome measures (English text)

Primary endpoints 6

1. Part 1: Number of Participants From ≥1 Month to <12 Years Who Experience a Dose-limiting Toxicity (DLT)
2. Part 1: Number of Participants From ≥1 Month to <12 Years Who Experience One or More Adverse Events (AEs)
3. Part 1: Number of Participants From ≥1 Month to <12 Years Who Discontinue Study Intervention Due to an AE
4. Part 1: Number of Participants From ≥1 Month to <12 Years Who Receive Dose Modifications Due to AEs
5. Part 1 and Part 2: Objective Response Rate (ORR) for Participants with neuroblastoma (NBL), rhabdomyosarcoma (RMS), and Wilms tumor (WT)
6. Part 1 and Part 2: Disease Control Success at 4 Months (DCS-4) for Participants with osteosarcoma (OST)

Secondary endpoints 16

1. Part 1 and Part 2: Duration of Response (DOR) For Participants With NBL, RMS, WT, or OST
2. Part 1 and Part 2: Disease Control Rate (DCR) For Participants With NBL, RMS, WT, or OST
3. Part 1 and Part 2: Time to Response (TTR) For Participants With NBL, RMS, WT, or OST
4. Part 1 and Part 2: Progression-free Survival (PFS) For Participants With NBL, RMS, WT, or OST
5. Part 1 and Part 2: ORR for Participants With OST
6. Part 1 and Part 2: Overall Survival (OS)
7. Part 1 and Part 2: Number of Participants With NBL, RMS, WT, or OST Who Experience One or More AEs
8. Part 1 and Part 2: Number of Participants With NBL, RMS, WT, or OST Who Discontinue Study Treatment Due to an AE
9. Part 1 and Part 2: Number of Participants With NBL, RMS, WT, or OST Who Receive Dose modifications due to AEs
10. Part 1 and Part 2: Maximum Plasma Concentration (Cmax) of Ifinatamab Deruxtecan (I-DXd)
11. Part 1 and Part 2: Area Under the Concentration-Time Curve from Time 0 to the End of the Dosing Period (AUC-tau) of I-DXd
12. Part 1 and Part 2: Plasma Trough Concentration (Ctrough) of I-DXd
13. Part 1 and Part 2: Maximum Plasma Concentration (Cmax) of DXd
14. Part 1 and Part 2: Area Under the Concentration-Time Curve from Time 0 to the End of the Dosing Period (AUC-tau) of DXd
15. Part 1 and Part 2: Plasma Trough Concentration (Ctrough) of DXd
16. Part 1 and Part 2: Number of Participants with Antidrug Antibodies (ADA) Against I-DXd

Investigational products

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

Test 1

Sponsors and contacts

Sponsor organisations, regulatory contacts, third parties

Merck Sharp & Dohme LLC

Sponsor organisation

Merck Sharp & Dohme LLC

Address

126 East Lincoln Avenue, P. O. Box 2000 P. O. Box 2000

City

Rahway

Postcode

07065-4607

Country

United States

Scientific contact point

Organisation

Merck Sharp & Dohme LLC

Contact name

Arpan Sinha

Public contact point

Organisation

Merck Sharp & Dohme LLC

Contact name

Arpan Sinha

Third parties 7

Locations

7 EU/EEA countries · 18 investigational sites

By country

Investigational sites

Results and documents

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

Documents 79 files

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

Application history

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