Chondrosarcomas (CHS) represent 25% of bone sarcomas and are the second most frequent primary malignant type of bone tumor. No effective systemic treatment has been identified in advanced or adjuvant phases for CHS. As CHS are relatively resistant to chemo- and radiotherapy, surgery remains the primary treatment of this tumor type. The aim of tumor resection is to obtain complete removal of the malignant lesion with adequate margins taking into account tumor control and functional reconstruction. However, considering the particular localizations of CHS, a wide resection (i.e. R0 clear margins) is rarely achieved. Unfortunately, therapeutic options are limited for patients with incomplete resection. In this context, new therapeutic strategies are needed to slow down tumor progression and to reduce tumor size before surgery.

Increasing knowledge of the signal transduction pathways involved in oncogenesis has led to speculation that components of signalling pathways could be envisaged as novel targets for cancer therapy. Mammalian Target of Rapamycin (mTOR), which lies downstream of the Phosphatidylinositol 3-kinase/B kinase protein (PI3K/Akt) pathway, plays a central role in the regulation of cancer cell growth, suggesting that mTOR could be an attractive target for anti-cancer therapy. The PI3K-Akt-mTOR signaling pathway is intimately implicated in sarcoma development and progression. Indeed, mutations and/ or overexpression of one or several components of the PI3K-Akt-mTOR pathway are often observed in sarcoma. These alterations, located both upstream and downstream of mTOR, lead to dysregulation of the mTOR pathway. mTOR inhibitor evaluation as anticancer agents has began with rapamycin analogues (called rapalogs). Currently, mTOR inhibitors under clinical development include temsirolimus (CCI-779, Torisel®, Wyeth Pharmaceuticals), everolimus (RAD001, Afinitor®, Novartis Pharmaceuticals), and ridaforolimus (AP23573, ARIAD Pharmaceuticals). mTOR inhibitors were found to be efficient in various preclinical cancer models, for example in a preclinical mouse model of follicular thyroid cancer, everolimus induced a significant decrease in proliferation of cancer cells.

Two sets of recent data suggest that inhibition of mTOR pathway could be an effective systemic treatment for chondrosarcoma. The first one is a case report describing an impressive tumor response in a patient with myxoid chondrosarcoma treated by rapamycin in combination with cyclophosphamide. The second one concerns nonclinical data generated by our institution. Using an orthotopic rat chondrosarcoma model, we have shown that monotherapy with everolimus inhibits chondrosarcoma proliferation as evaluated by Ki67 expression and significantly reduced tumor volume. Importantly, when given in a "pseudo-adjuvant" setting following R1 resection of the implanted tumor, everolimus significantly delayed tumor recurrence. These preclinical data provide a strong rationale to evaluate the therapeutic potential of everolimus in both the neo-adjuvant and adjuvant settings in patients with chondrosarcoma.

In this context, the proposal of the investigators is to perform a multicenter, randomized, Phase II study in patients with a primary or relapsed chondrosarcoma in neo-adjuvant setting