Given that osteosarcoma typically presents at an early age and predominantly affects pediatric and adolescent populations, early control of disease progression and the opportunity for complete tumor resection are particularly crucial. Postoperatively, patients can regain functional mobility through prosthetic implantation and artificial joint reconstruction, thereby preventing premature loss of mobility in young patients. This study aims to explore the efficacy and safety of neoadjuvant treatment with the PD-L1 antibody envafolimab in combination with standard chemotherapy in patients with resectable stage IIb osteosarcoma, and to assess whether this combined regimen can increase the proportion of patients achieving complete tumor resection.
Patients voluntarily participate in the study and have good compliance, signing a written informed consent form before enrollment.
Age between 12 and 70 years, with no gender restrictions.
Patients diagnosed with non-metastatic, resectable osteosarcoma by pathology and clinical physician assessment.
Have measurable disease (according to RECIST 1.1 criteria, non-nodal lesions with a CT scan longest diameter ≥10 mm, and nodal lesions with a CT scan shortest diameter ≥15 mm).
Participants with a history of or concurrent diagnosis of other malignant tumors (except for cured cutaneous basal cell carcinoma and in situ cervical carcinoma).
Patients with recurrent postoperative or previously treated osteosarcoma with local or systemic anti-tumor therapy, or with metastasis.
Participants who have received the following treatments within 4 weeks prior to study initiation: radiation therapy for tumors, surgical procedures, chemotherapy, immunotherapy, or other investigational drugs.
Known allergies to any component of the study medication in participants. Participants with uncontrolled clinical symptoms or diseases of the heart, such as: (1) NYHA Class II or higher heart failure, (2) unstable angina pectoris, (3) myocardial infarction within the past year, (4) clinically significant supraventricular or ventricular arrhythmias requiring treatment or intervention.