MIFAMURTIDE for Osteosarcoma | Relapsed/refractory osteosarcoma | High-grade osteosarcoma

Inclusion criteria

• {"criterion_text":"- Age ≥ 5 years and ≤ 30 years at the time of study enrollment.\n- Recovery from adverse effects of prior surgery and/or radiotherapy.\n- Consent to use effective contraception throughout the study period and for at least 1 year after discontinuation of study treatment in patients at pubertal and sexual maturity.\n- Osteosarcoma confirmed by histopathological examination based on previously performed tests.\n- Providing written, informed consent to participate in the study (including treatment with mifamurtide and sorafenib) in accordance with current legal regulations.\n- Patient classified as high-risk.\n- Life expectancy of at least 12 weeks from the date of signing the informed consent.\n- Patient deemed fit to receive systemic treatment.\n- Patient deemed able to swallow tablets.\n- Disease in complete remission or stable disease according to WHO criteria prior to randomization.\n- Completed surgery (major surgery ≥ 2 weeks) and radiotherapy (≥ 4 weeks) prior to IMP administration."}

Exclusion criteria

• {"criterion_text":"- Failure to meet any of the inclusion criteria.\n- Arterial or venous thrombotic or embolic events, such as stroke (including transient ischemic attacks), deep vein thrombosis, or pulmonary embolism, within the last 6 months before the first study drug administration.\n- Active hepatitis B or C infection or chronic hepatitis B or C infection requiring antiviral therapy.\n- Any bleeding or hemorrhagic event ≥ CTCAE v5 grade 3 within 4 weeks before the first study drug administration.\n- Diagnosis of other malignancies prior to study enrollment.\n- Planning to become pregnant, being pregnant, or breastfeeding.\n- Other acute or persistent disorders, behaviors, or abnormal laboratory test results that may increase the risks associated with participation in this clinical trial or with the study drug, or that may affect the interpretation of the study results, or that, in the opinion of the investigator, disqualify the patient from participating in the study.\n- Prior treatment with mifamurtide.\n- Hypersensitivity to the study drug or any of its components (including mifamurtide and sorafenib).\n- Concomitant treatment with other drugs that may interact with mifamurtide or sorafenib or other cytotoxic agents.\n- Persistent toxicity related to prior therapy precludes treatment with mifamurtide or sorafenib.\n- Significant cardiac conduction abnormalities, including known familial long QT syndrome or a screening corrected QT interval (QTc) >480 ms.\n- Symptoms of congestive heart failure or left ventricular ejection fraction <50%.\n- Requirement or likely need for corticosteroids at doses >10 mg prednisolone (or equivalent) daily or other immunosuppressive medications.\n- Uncontrolled blood pressure (blood pressure values ​​not maintained within the recommended range (≥140/90 mmHg) despite treatment)."}

Primary endpoints

• {"endpoint_text":"- EFS (Event-Free Survival) – the time from randomization to the first event, i.e., death, disease progression, or disease relapse, whichever occurs first. Assessment will be conducted from the date of randomization to the date of the event or to the date of the last available assessment.","definition_or_measurement_approach":"Time from randomization to first event (death, disease progression, or disease relapse); assessment from date of randomization to date of event or date of last available assessment."}

Secondary endpoints

• {"endpoint_text":"- OS (Overall Survival) – Overall survival will be measured from randomization to death from any cause; for patients alive at the end of follow-up, data will be censored at the date of last confirmed contact.","definition_or_measurement_approach":"Measured from randomization to death from any cause; censoring at date of last confirmed contact for survivors."}
• {"endpoint_text":"- PFS (Progression-Free Survival) – Progression-free survival will be measured from randomization to the date of disease progression or death, whichever occurs first.","definition_or_measurement_approach":"Measured from randomization to date of disease progression or death, whichever occurs first."}
• {"endpoint_text":"- ORR (Overall Response Rate) – Response rate, defined as the percentage of patients with the best documented complete response (CR) or partial response (PR), assessed according to RECIST v1.1 at the time points specified in the imaging schedule.","definition_or_measurement_approach":"Percentage of patients achieving CR or PR assessed by RECIST v1.1 at scheduled imaging time points."}
• {"endpoint_text":"- Evaluation of the safety of mifamurtide in patients with osteosarcoma. Safety will be assessed based on the number of serious adverse events (SAEs), the number of adverse events (AEs), a physical examination with analysis of recorded vital signs and laboratory abnormalities according to NCI CTCAE v5.0, from the start of treatment to the end of safety follow-up according to the study schedule.","definition_or_measurement_approach":"Safety assessed by counts of SAEs and AEs, physical exam, vital signs and laboratory abnormalities per NCI CTCAE v5.0 from treatment start to end of safety follow-up."}

Poland

Earliest CTIS Part Ii Submission Date

13-03-2026

Latest Decision Or Authorization Date

20-04-2026

Processing Time Days

38

Number Of Sites

2

Number Of Participants

40

Primary sponsor

Full Name

Instytut Matki I Dziecka

Organisation Type

Hospital/Clinic/Other health care facility

Country Of Registered Address

Poland

Third parties

• {"country":"","full_name":"Agencja Badań Medycznych","duties_or_roles":"Source of monetary support","organisation_type":""}