Lu-TARGO (177Lu-TARGeted Osteosarcoma Therapy)

A Phase 1/2, Multi-Center, Open-Label Study to Evaluate the Safety, Tolerability, Pharmacokinetics, -Radiation Dosimetry, and Preliminary Anti-Neoplastic Activity of LNTH-2403, a LRRC15-targeted 177Lutetium-labeled Monoclonal Antibody, in Participants With Relapsed / Refractory Osteosarcoma

Lu-TARGO (177Lu-TARGeted Osteosarcoma Therapy) (NCT07357519) is a Phase 1 / Phase 2 interventional studying Relapsed / Refractory Osteosarcoma, sponsored by Lantheus Medical Imaging. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

What Stage of Research Is This?

Phase 1 trials test a new treatment for the first time in humans, focusing on safety, dosing, and how the body processes the drug. For Relapsed / Refractory Osteosarcoma, a Phase 1 study typically enrolls a small number of participants — often healthy volunteers or patients who have exhausted standard treatment options. Phase 1 results determine whether a treatment moves into larger Phase 2 efficacy studies.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

Target enrollment of 55 participants puts this in the typical range for a Phase 2-style efficacy study or a moderate Phase 3 trial in a focused Relapsed / Refractory Osteosarcoma subpopulation. At this scale, the study has enough statistical power to detect a clear treatment effect but is not the largest cohort in the field.

Who May Be Eligible (Plain English)

Who May Qualify: Participants must meet all the following criteria to be enrolled in the study 1. Histopathologic documented diagnosis of R/R osteosarcoma 2. 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). 1. Measurable as defined in RECIST 1.1 2. Evaluable non-measurable disease as per RECIST 1.1 3. Bone only without a soft tissue component: must be 18F-FDG-PET avid and evaluable by serial 18F-FDG-PET imaging studies. 3. 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. 4. Performance Status: 1. Eastern Cooperative Oncology Group (ECOG) Performance Score (PS): 0 - 2 2. Lansky PS ≥ 50. 5. Body weight: ≥ 30 kg. 6. Tumor biopsies; Fresh or Archival 7. Progression following at least one course of chemotherapy, which includes neoadjuvant / perioperative systemic therapy. 8. All adverse events (AEs) related to prior therapies (chemotherapy / systemic therapies, radiation, surgery) must have resolved to Grade 1 or baseline 9. Organ Function 10. Pregnancy Women of Child-Bearing Potential (WOCBP) must have a negative serum pregnancy test result at screening 11. Contraception- Male participants with a WOCBP partner must use 2 forms of acceptable contraception 12. Written willing to sign a consent form and/or assent must be obtained according to local guidelines and signed and dated by the participant, parent, and/or legal guardian prior to the performance of any study-specific procedures, sampling, or analyses Who Should NOT Join This Trial: Participants meeting any of the following criteria will be excluded from the study 1. Known allergies, hypersensitivity, or intolerance to LNTH-2403 and/or its excipients ...See full criteria on ClinicalTrials.gov Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language

Inclusion Criteria: Participants must meet all the following criteria to be enrolled in the study 1. Histopathologic documented diagnosis of R/R osteosarcoma 2. 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). 1. Measurable as defined in RECIST 1.1 2. Evaluable non-measurable disease as per RECIST 1.1 3. Bone only without a soft tissue component: must be 18F-FDG-PET avid and evaluable by serial 18F-FDG-PET imaging studies. 3. 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. 4. Performance Status: 1. Eastern Cooperative Oncology Group (ECOG) Performance Score (PS): 0 - 2 2. Lansky PS ≥ 50. 5. Body weight: ≥ 30 kg. 6. Tumor biopsies; Fresh or Archival 7. Progression following at least one course of chemotherapy, which includes neoadjuvant / perioperative systemic therapy. 8. All adverse events (AEs) related to prior therapies (chemotherapy / systemic therapies, radiation, surgery) must have resolved to Grade 1 or baseline 9. Organ Function 10. Pregnancy Women of Child-Bearing Potential (WOCBP) must have a negative serum pregnancy test result at screening 11. Contraception- Male participants with a WOCBP partner must use 2 forms of acceptable contraception 12. Written informed consent and/or assent must be obtained according to local guidelines and signed and dated by the participant, parent, and/or legal guardian prior to the performance of any study-specific procedures, sampling, or analyses Exclusion Criteria: Participants meeting any of the following criteria will be excluded from the study 1. Known allergies, hypersensitivity, or intolerance to LNTH-2403 and/or its excipients 2. 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 3. Concurrent treatment with any other anti-neoplastic agents, including localized radiation therapy 4. Known active infection 5. Participation in an interventional study of another investigational agent 6. Prior therapies or diagnostics 7. Active prior or concurrent malignancy: immunoglobulin), 8. Known active liver disease from any cause, Hepatitis A Virus 9. Known to be human immunodeficiency virus (HIV) positive 10. Clinically relevant cardiovascular disease 11. Receipt of live vaccine within the 30 days prior to the first dose o 12. A female participant who is pregnant or breastfeeding 13. Major surgical procedure within 28 days of the first dose of LNTH-2403. 14. Participant is unwilling or unable to comply with the scheduled visits, drug administration plan, laboratory tests, or other study procedures and study restrictions

Treatments Being Tested

DRUG

LNTH2403 Phase 1 dose

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

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

Once the RP2D is selected, phase 2 will commence

Locations (2)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

UCLA

Los Angeles, California, United States

Dana Farber Cancer Institute

Boston, Massachusetts, United States

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT07357519), the sponsor (Lantheus Medical Imaging), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT07357519 clinical trial studying?

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. The full protocol is registered on ClinicalTrials.gov and includes the primary outcome measures, eligibility criteria, and study endpoints.

Who can participate in NCT07357519?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT07357519?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT07357519. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT07357519. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.