The off-label use of targeted therapies in sarcomas: The OUTC'S program

Background: Few targeted therapies (TTs) are registered for sarcoma treatment despite numerous phase II studies and yet there are potential treatment options for patients after standard treatment escape. The French Sarcoma Group - Bone Tumor Study Group (GSF-GETO) created a national registry to evaluate the outcome of patients treated with off-label TTs. Methods: Every consecutive sarcoma-patient receiving an off-label TT outside a clinical trial was included. The objective was to describe this patient efficacy and safety data in routine practice. Results: From October 2008 to October 2011, 249 patients in 24 centers received 278 treatment lines with TTs. Twenty-five histological subtypes were included: most frequent were leiomyosarcoma (n = 48, receiving sorafenib in 63%, and sunitinib in 27%), GIST (n = 39, receiving sorafenib in 79%), and angiosarcoma (n =18, receiving sorafenib in 78%). The overall response rate to TTs was 15% (95% CI [10,6-20,2]), the disease control rate at 2 months was 59%. The median progression-free survival was 4,1 months (IC 95% [3,2-4,8]). Three complete responses were observed. No toxic death occurred, grade 3 and 4 toxicities were reported in 74 (27%) and 14 patients (5%) respectively. Conclusion: Off-label TTs can be used for sarcoma patients in routine practice with an acceptable toxicity profile and efficacy similar to that reported in non-randomized clinical trials.