Is There a Role for Mifamurtide in Nonmetastatic High‑Grade Osteosarcoma? Results From the Italian Sarcoma Group (ISG/OS‑2) and Spanish Sarcoma Group (GEIS‑33) Trials

Cancer research · Osteosarcoma

Mifamurtide, when added to adjuvant chemotherapy in Pgp‑positive patients with nonmetastatic high‑grade extremity osteosarcoma, improves 5‑year event‑free survival compared with chemotherapy alone.

This pooled analysis combined data from the Italian ISG/OS‑2 and Spanish GEIS‑33 phase II/IV prospective trials comprising 398 patients with nonmetastatic high‑grade extremity osteosarcoma. Patients were stratified by P‑glycoprotein (Pgp) expression from baseline biopsies. Pgp‑positive patients received postoperative mifamurtide, combined with high‑dose ifosfamide (HDIFO) in poor responders or MAP in good responders; Pgp‑negative patients received MAP alone. With a median follow‑up of 70 months, the 5‑year event‑free survival (EFS) was 71.4% (95% CI 64.5–77.1) for the mifamurtide group versus 58.3% (95% CI 50.6–65.3) for the MAP‐only group (P = .0131). This benefit was also seen in poor responders (P = .0359). Overall survival was higher in the mifamurtide group (74.8% vs 68.5% at 5 years). These findings suggest that mifamurtide may provide a survival advantage for patients with high‑risk osteosarcoma defined by Pgp expression.

Improved survival in a high‑risk osteosarcoma population would provide an evidence‑based adjuvant therapeutic option that could be tailored to patients most likely to benefit, thereby optimizing outcomes in this historically poor‑prognosis disease.

Evidence level: Állatkísérletes. Állatmodellben vizsgálták.

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