Abstract 1645P
Background
Advanced osteosarcoma (OS) and Ewing sarcoma (ES) have a bad prognosis and exhibit low response rates to the available chemotherapeutic agents. Angiogenesis and MET signaling have been shown to play an important role in these neoplasm and anti-angiogenic drugs (sorafenib, regorafenib, lenvatinib and cabozantinib have been tested in phase II trials in bone sarcomas. Cabozantinib, which is currently approved for renal cell carcinoma, medullary thyroid carcinoma and dhepatocellular carcinoma, led to the most promising results, as reported recently by the French Sarcoma Group.
Methods
We retrospectively analyzed clinical data of adult patients who were treated with cabozantinib for advanced OS and ES in 2 centers of the Hellenic Group of Sarcoma and Rare Cancers. Diagnosis of OS and ES was confirmed histologically and for ES patients molecular biology was also performed. This study was realized in order to register our real-world experience of the off-label use of the drug in this rare group of patients, with few therapeutic options.
Results
Between April 23, 2019, and May 19, 2020, 9 patients (1 female and 8 male) received cabozantinib for advanced bone sarcoma, 2 with ES and 7 with OS. Median age at cabozantinib initiation was 31 years (17-83). All patients had received peri-operative chemotherapy for primary sarcoma and between 0 and 3 lines of treatment (median value 1) for advanced disease. Previous lines of treatment included mainly ifosfamide/etoposide and gemcitabine/docetaxel. Lung metastases were the most common metastatic sites. In 4 patients disease progression was noted and 3 of them died from the disease. The remaining 5 patients are still receiving the drug. The progression-free survival varied from 1 to 8 months. The most common side-effects include anorexia, fatigue, hypertransaminasemia, weight loss and diarrhea. One patient with subpleural lesions presented hemothorax. In 2 patients a dose reduction to 40 mg was undertaken due to toxicity.
Conclusions
Cabozantinib is a new promising therapy for advanced OS and ES, with a manageable safety profile.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.