Lu-TARGO (177Lu-TARGeted Osteosarcoma Therapy)

NCT07357519 | Recruiting Phase 1 FDA Drug

• 1 other identifier: LNTH2403-1301
• Study Type: interventional
• Target: 55
• Locations: 1 country
• Sites: 2

Brief Summary

This is a multi-center, non-randomized, open-label, dosimetry and dose-escalation, cohort-expansion study of LNTH-2403 administered to subjects with relapsed / refractory (R/R) osteosarcoma. This study consists of 2 phases: (1) a dosimetry and dose escalation phase; and (2) a cohort expansion phase.

Conditions

Relapsed / Refractory Osteosarcoma

Outcome Measures

Primary Outcomes (3)

• To identify the maximum tolerated dose (MTD) of LNTH-2403 in participants with R/R osteosarcoma (Ph1)

  Incidence of DLTs during the first 8 weeks (DLT evaluation window) after the first dose of LNTH-2403

  From enrollment to the end of treatment at 8 weeks

• To evaluate the safety and tolerability profile of LNTH-2403 in participants with R/R osteosarcoma (Ph1)

  Type, frequency, severity, timing, and relationship to LNTH-2403 of all Treatment-emergent adverse event, (TEAEs) and Serious adverse events, (SAEs)

  From enrollment to the end of treatment at 8 weeks

• To assess the preliminary anti-neoplastic activity of LNTH-2403 in participants with R/R osteosarcoma (Ph2)

  Event-Free Survival (EFS) at 4 months

  From enrollment to Event-Free Survival (EFS) at 4 months

Secondary Outcomes (2)

• To assess the preliminary anti-neoplastic activity of LNTH-2403 in participants with R/R osteosarcoma (Ph1)

  8 weeks

• To describe the safety and tolerability profile of LNTH-2403 in participants with R/R osteosarcoma (Ph2)

  4 months

Study Arms (2)

Phase 1- Escalating doses of LNTH-2403 administered once every 8 weeks

EXPERIMENTAL

Phase 1 will evaluate escalating doses of LNTH-2403 administered once every 8 weeks, with the potential to explore other dosing schedules based on observed radiation dosimetry and PK parameters and safety and tolerability data.

Drug: LNTH2403 Phase 1 dose

Phase 2 will evaluate LNTH-2403 as a single agent at the recommended phase 2 dose

EXPERIMENTAL

Phase 2 will evaluate LNTH-2403 as a single agent in participants with R/R osteosarcoma at the recommended phase 2 dose (RP2D).

Drug: Phase 2; LNTH2403 a single agent recommended phase 2 dose (RP2D).

Interventions

LNTH2403 Phase 1 dose DRUG

LNTH-2403 administered once every 8 weeks, with the potential to explore other dosing schedules based on observed radiation dosimetry and PK parameters and safety and tolerability data.

Phase 1- Escalating doses of LNTH-2403 administered once every 8 weeks

Phase 2; LNTH2403 a single agent recommended phase 2 dose (RP2D). DRUG

Once the RP2D is selected, phase 2 will commence

Phase 2 will evaluate LNTH-2403 as a single agent at the recommended phase 2 dose

Eligibility Criteria

• Age: 12 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)

You may qualify if:

• Histopathologic documented diagnosis of R/R osteosarcoma
• Must have disease characterized by at least one of the following (Participants meeting only (b.), only (c.), or only (b. and c.) must be discussed with and receive written approval from the Sponsor to qualify).
• Measurable as defined in RECIST 1.1
• Evaluable non-measurable disease as per RECIST 1.1
• Bone only without a soft tissue component: must be 18F-FDG-PET avid and evaluable by serial 18F-FDG-PET imaging studies.
• Age: a. First Cohort in Phase 1: ≥ 18 years-of-age at the time of signature of the main study ICF. b. Second and subsequent cohorts, in Phase 1 and all participants in Phase 2: ≥12years-of-age at the time of signature of the main ICF.
• Performance Status:
• Eastern Cooperative Oncology Group (ECOG) Performance Score (PS): 0 - 2
• Lansky PS ≥ 50.
• Body weight: ≥ 30 kg.
• Tumor biopsies; Fresh or Archival
• Progression following at least one course of chemotherapy, which includes neoadjuvant / perioperative systemic therapy.
• All adverse events (AEs) related to prior therapies (chemotherapy / systemic therapies, radiation, surgery) must have resolved to Grade 1 or baseline
• Organ Function
• Pregnancy Women of Child-Bearing Potential (WOCBP) must have a negative serum pregnancy test result at screening

You may not qualify if:

• Participants meeting any of the following criteria will be excluded from the study
• Known allergies, hypersensitivity, or intolerance to LNTH-2403 and/or its excipients
• Prior or ongoing clinically significant illness, medical condition, surgical history, physical finding, or laboratory abnormality that, in the investigator's opinion, may affect the participant's safety, compliance with the study, or otherwise impair the assessment of study results
• Concurrent treatment with any other anti-neoplastic agents, including localized radiation therapy
• Known active infection
• Participation in an interventional study of another investigational agent
• Prior therapies or diagnostics
• Active prior or concurrent malignancy: immunoglobulin),
• Known active liver disease from any cause, Hepatitis A Virus
• Known to be human immunodeficiency virus (HIV) positive
• Clinically relevant cardiovascular disease
• Receipt of live vaccine within the 30 days prior to the first dose o
• A female participant who is pregnant or breastfeeding
• Major surgical procedure within 28 days of the first dose of LNTH-2403.
• Participant is unwilling or unable to comply with the scheduled visits, drug administration plan, laboratory tests, or other study procedures and study restrictions

Sponsors & Collaborators

• Lantheus Medical Imaging: lead

Study Sites (2)

UCLA

Los Angeles, California, 90095, United States

RECRUITING

Dana Farber Cancer Institute

Boston, Massachusetts, 02115, United States

RECRUITING

MeSH Terms

Conditions

Osteosarcoma

Interventions

Clinical Trials, Phase II as Topic

Condition Hierarchy (Ancestors)

Neoplasms, Bone Tissue; Neoplasms, Connective Tissue; Neoplasms, Connective and Soft Tissue; Neoplasms by Histologic Type; Neoplasms; Sarcoma

Intervention Hierarchy (Ancestors)

Clinical Trials as Topic; Clinical Studies as Topic; Epidemiologic Study Characteristics; Epidemiologic Methods; Investigative Techniques; Health Care Evaluation Mechanisms; Quality of Health Care; Health Care Quality, Access, and Evaluation; Public Health; Environment and Public Health

Central Study Contacts

Kerri Sforzo

CONTACT

978-671-8886; clinicaltrials@lantheus.com

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: Phase 1 will evaluate escalating doses of LNTH-2403 administered once every 8 weeks, with the potential to explore other dosing schedules based on observed radiation dosimetry and PK parameters and safety and tolerability data. Phase 2 will evaluate LNTH-2403 as a single agent in participants with R/R osteosarcoma at the recommended phase 2 dose (RP2D).

Study Record Dates

• First Submitted: January 14, 2026
• First Posted: January 22, 2026
• Study Start: February 3, 2026
• Primary Completion (Estimated): August 1, 2027
• Study Completion (Estimated): May 1, 2032
• Last Updated: May 1, 2026

Record last verified: 2026-01

Locations

US (2)