Abstract 108P
Background
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.
Methods
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.
Results
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.
Conclusions
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.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
This study was funded by the Shanghai Pujiang Program (grant number 21PJD050); the National Natural Science Foundation of China (grant numbers 82272835); the Retrospective Clinical Study of the Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine (grant numbers ynhg202110).
Disclosure
All authors have declared no conflicts of interest.