108P Safety and efficacy of fruquintinib (FRU)-based therapy in patients (Pts) with advanced or metastatic osteosarcoma: A real-world study

Pts with advanced or metastatic osteosarcoma may have a promising anti-tumor response to tyrosine kinase inhibitors (TKIs). This study aims to evaluate the efficacy and safety of FRU-based therapy for pts with advanced or metastatic osteosarcoma. Pts with pathologically confirmed advanced or metastatic osteosarcoma were eligible. One group received FRU, while the other group received a combination of FRU with chemotherapy, bio-targeted therapy, or immune checkpoint inhibitors (ICIs). On day 1– 21 of a 28-day cycle, pts received a once-daily oral dosage of 5 mg FRU for adults or 4mg FRU for pts < 18 years old. Safety and efficacy of FRU based therapy were reviewed retrospectively. From 2021/10 to 2023/05, this retrospective study involved 26 pts, with a median follow-up duration of 7.5 months (mon). Among them, 6 were in the FRU monotherapy group and the other 20 in the combination therapy group. The median age of the participants was 25.8 years, (range: 8-63). A majority of 92.3% were diagnosed at stage IV, all of whom experienced lung metastasis. 84.6% having an ECOG performance status of 0-1 and 15.4% scoring 2. 80.8% had not received prior targeted therapy, and 42.3% treated as a second-line treatment or above (2L+). The overall response rate was 11.5%, with a disease control rate of 96.2%. The median progression-free survival was 10.0 mon (95% CI: 5.9 mon–NA) overall, extending to 14.3 mon (95% CI: 5.9 mon–NA) with combination therapy, and 10 mon (95% CI: 1.3 mon-NA) with FRU monotherapy. Overall Survival data are still immature (not presented). 11 pts underwent surgery, with 10 (91%) achieving R0 resection and 1 (9%) having R1 resection, despite both were being initially deemed unresectable before the FRU-based therapy. In the combination therapy group, the most common grade 3 (G3) or higher adverse events (AEs) included leukopenia (40.0%), thrombocytopenia (15.0%), pneumothorax (5.0%), and anemia (5.0%). Conversely, pts in the monotherapy group experienced no G3 or higher AEs, with no severe AEs reported. This real-world study revealed that FRU-based therapy is effective and safe for pts with advanced or metastatic osteosarcoma, including as a tumor conversion therapy.