An observational study in High-Grade Osteosarcoma, sponsored by MedPacto, Inc.. Recruiting at 4 sites in South Korea. Open to participants aged 12 Years and older. Per ClinicalTrials.gov, last updated 2026-10-16.
Sponsored by MedPacto, Inc. · Observational
This is a multicenter, medical-record-based, retrospective observational study of approximately 400 patients with high-grade osteosarcoma treated at four sites in the Republic of Korea. The study describes treatment patterns and survival outcomes (event-free survival [EFS], progression-free survival [PFS], and overall survival [OS]) in patients who completed or discontinued first-line treatment for high-grade osteosarcoma, irrespective of complete remission status. The primary objective is to retrospectively estimate the 12-month EFS rate, calculated from the date of diagnosis, in the full cohort of high-grade osteosarcoma patients. Key secondary objectives evaluate EFS and OS from the date of confirmed complete remission/no evidence of disease (CR/NED) in the subset of clinically high-risk patients who achieve CR/NED, in order to establish a historical reference data supporting the design and interpretation of a future prospective clinical trial of vactosertib as maintenance therapy.
High-grade osteosarcoma is the most common primary malignant bone tumor in children, adolescents, and young adults and is treated as a systemic disease requiring multimodal therapy (neoadjuvant chemotherapy, wide surgical resection, and adjuvant chemotherapy). Despite standard multimodal treatment established by trials such as the Multi-Institutional Osteosarcoma Study (MIOS), approximately 30-40% of patients relapse within 2 years, and outcomes remain particularly poor among patients with predefined clinically high-risk features: (1) primary tumor of the axial skeleton, (2) age ≥40 years at diagnosis, (3) pulmonary metastasis (M1a, AJCC 8th edition) at diagnosis, and (4) tumor necrosis rate \<90% after neoadjuvant chemotherapy.
No maintenance therapy is currently established for high-risk osteosarcoma patients who achieve complete remission, and an appropriate historical control cohort for designing and interpreting a single-arm maintenance-therapy trial is lacking. This study addresses that gap by retrospectively characterizing survival outcomes in the overall high-grade osteosarcoma population and, separately, in the clinically high-risk subset that achieves CR/NED, anchored to the CR/NED confirmation date. Data will be abstracted from electronic medical records at each site by trained personnel, pseudonymized, and entered into a standardized electronic case report form (eCRF). Two independent reviewers will verify eligibility and key survival-related data. Kaplan-Meier methodology will be used for time-to-event estimates, with 95% confidence intervals derived via the Greenwood formula and log(-log) transformation; Multivariable Cox proportional hazards modeling will be used for exploratory prognostic factor analysis. No formal hypothesis testing against a prespecified benchmark is performed, as this is a descriptive, non-comparative retrospective cohort study.
446 studies on the registry are indexed under Osteosarcoma; 117 are open to participants now.
This study's planned enrollment of 400 is above the median of 100 across 91 observational studies indexed under Osteosarcoma.
Browse Osteosarcoma studies →MedPacto, Inc. is the lead sponsor of 11 studies on the registry; 2 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Patients diagnosed with pathologically confirmed high-grade osteosarcoma who completed or ended first-line treatment at one of the four participating institutions on or before 2021-06-30, identified via retrospective EMR review.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Retrospectively identified patients with high-grade osteosarcoma who meet the study eligibility criteria.
12-month Event-Free Survival (EFS) rate
Estimated by the Kaplan-Meier method in the Full Cohort Set (FCS), calculated from the date of pathological diagnosis regardless of complete-remission status. An event is defined as relapse, new metastasis, disease progression, or death from any cause, whichever occurs first; patients without an event are censored at the date of last confirmed event-free status. 95% CI derived via the Greenwood formula with log(-log) transformation. No hypothesis testing against a prespecified threshold is performed.
Time frame: From date of diagnosis to 12 months
12-month EFS rate in CR/NED Set
Kaplan-Meier EFS rate anchored to CR/NED confirmation date, in CHRS patients achieving CR/NED after first-line or ≥2nd-line treatment.
Time frame: From CR/NED confirmation date to 12 months
EFS rate at additional timepoints in CR/NED Set
Kaplan-Meier EFS rate at 6, 24, and 36 months from CR/NED confirmation date.
Time frame: 6, 24, 36 months from CR/NED confirmation date
Overall Survival (OS) in CR/NED Set
Time from CR/NED confirmation date to death from any cause; median OS with 95% CI (Brookmeyer-Crowley method) where estimable.
Time frame: From CR/NED confirmation date until death or last confirmed alive date, assessed up to 17 years.
OS rate at multiple timepoints in CR/NED Set
Kaplan-Meier OS rate at 12, 24, 36, 48, and 60 months from CR/NED confirmation date.
Time frame: 12, 24, 36, 48, 60 months from CR/NED confirmation date
Progression-Free Survival (PFS) in FCS
Time from diagnosis to disease progression or death from any cause in the Full Cohort Set; median PFS with 95% CI where estimable.
Time frame: From diagnosis until progression, death, or last confirmed alive date, assessed up to 17 years.
PFS rate at multiple timepoints in FCS
Kaplan-Meier PFS rate at 6, 12, 24, 36, 48, and 60 months from diagnosis.
Time frame: 6, 12, 24, 36, 48, 60 months from diagnosis
Overall Survival (OS) in FCS
Time from diagnosis to death from any cause in the Full Cohort Set; median OS with 95% CI where estimable.
Time frame: From diagnosis until death or last confirmed alive date, assessed up to 17 years.
OS rate at multiple timepoints in FCS
Kaplan-Meier OS rate at 6, 12, 24, 36, 48, and 60 months from diagnosis.
Time frame: 6, 12, 24, 36, 48, 60 months from diagnosis
Exploratory prognostic factor analysis
Multivariate Cox proportional hazards modeling of independent prognostic effects of high-risk factors, remission status, stage, age, tumor site, and number of relapses on EFS/PFS/OS; performed in FCS with optional subgroup analyses in CHRS and/or CR/NED Set.
Time frame: From diagnosis or CR/NED confirmation date to the applicable event or censoring date, assessed up to 17 years.
Plan to share: No — Results are planned for presentation at international scientific conferences (poster or oral) and subsequent submission to a peer-reviewed journal in the field. All presentation and manuscript materials will undergo institutional review prior to submission. Anonymized data may be used to support future meta-analyses or the design of a subsequent maintenance-therapy study.
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
MedPacto, Inc.