177Lu targeted therapy for relapsed or refractory osteosarcoma

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

This trial will test LNTH-2403, a radioactive targeted drug using lutetium-177, to see if it can shrink or control tumors in people with relapsed or refractory osteosarcoma.

Quick facts

• Phase: Phase1; Phase2
• Study type: Interventional
• Enrollment: 55 (estimated)
• Ages: 12 Years and up
• Sex: All
• Sponsor: Lantheus Medical Imaging (Industry-sponsored)
• Drugs / interventions: chemotherapy, radiation
• Locations: 2 sites (Los Angeles, California and 1 other locations)
• Trial ID: NCT07357519 on ClinicalTrials.gov

What this trial studies

Lu-TARGO is a multicenter, open-label study that uses dosimetry and a dose-escalation design followed by a cohort-expansion phase to find a recommended phase 2 dose (RP2D) of LNTH-2403. Participants will receive LNTH-2403 and undergo imaging and dosimetry to measure how the drug targets tumors and what radiation doses organs receive. The trial enrolls adolescents (≥12 years) and adults, with the first cohort limited to adults (≥18 years) for initial safety evaluation. Key eligibility includes histologically confirmed relapsed/refractory osteosarcoma with measurable disease, PET-avid bone-only disease, adequate performance status, and minimum body weight.

Who should consider this trial

Good fit: Ideal candidates are patients aged 12 or older (18+ for the initial cohort) with histologically confirmed relapsed or refractory osteosarcoma who have measurable or 18F-FDG–avid bone disease and an ECOG performance status of 0–2.

Not a fit: Patients who lack PET-avid disease, who have performance status worse than the study limits, or who have medical contraindications to radioligand therapy are unlikely to benefit from this treatment.

Why it matters

Potential benefit: If successful, this approach could provide a new targeted treatment option that shrinks tumors or delays progression for patients with relapsed/refractory osteosarcoma.

How similar studies have performed: 177Lu-based radioligand therapies have proven effective in other cancers (for example neuroendocrine tumors and prostate cancer), but using a 177Lu-targeted approach specifically for osteosarcoma is early and not yet established.

Eligibility criteria

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

Where this trial is running

Los Angeles, California and 1 other locations

• UCLA — Los Angeles, California, United States (Recruiting)
• Dana Farber Cancer Institute — Boston, Massachusetts, United States (Recruiting)

Study contacts

• Study coordinator: Kerri Sforzo

Conditions Relapsed / Refractory Osteosarcoma