3D-printed tri-element-doped hydroxyapatite/ polycaprolactone composite scaffolds with antibacterial potential for osteosarcoma therapy and bone regeneration

The resection of malignant osteosarcoma often results in large segmental bone defects, and the residual cells can facilitate recurrence. Consequently, the treatment of osteosarcoma is a major challenge in clinical practice. The ideal goal of treatment for osteosarcoma is to eliminate it thoroughly, and repair the resultant bone defects as well as avoid bacterial infections. Herein, we fabricated a selenium/strontium/zinc-doped hydroxyapatite (Se/Sr/Zn-HA) powder by hydrothermal method, and then employed it with polycaprolactone (PCL) as ink to construct composite scaffolds through 3D printing, and finally introduced them in bone defect repair induced by malignant osteosarcoma. The resultant composite scaffolds integrated multiple functions involving anti-tumor, osteogenic, and antibacterial potentials, mainly attributed to the anti-tumor effects of SeO32-, osteogenic effects of Sr2+ and Zn2+, and antibacterial effects of SeO32- and Zn2+. In vitro studies confirmed that Se/Sr/Zn-HA leaching solution could induce apoptosis of osteosarcoma cells, differentiation of MSCs, and proliferation of MC3T3-E1 while showing excellent antibacterial properties. In vivo tests demonstrated that Se/Sr/Zn-HA could significantly suppress tumors after 8 days of injection, and the Se/Sr/Zn-HA-PCLs scaffold repaired femoral defects effectively after 3 months of implantation. Summarily, the Se/Sr/Zn-HA-PCLs composite scaffolds developed in this study were effective for tumor treatment, bone defect repair, and post-operative anti-infection, which provided a great potential to be a facile therapeutic material for osteosarcoma resection.

A phase II trial of sorafenib in relapsed and unresectable high-grade osteosarcoma after failure of standard multimodal therapy: an Italian Sarcoma Group study

PURPOSE

After standard multimodal therapy, the prognosis of relapsed and unresectable high-grade osteosarcoma is dismal and unchanged over the last decades. Recently, mitogen-activated protein kinases were shown to be activated in osteosarcoma specimens, suggesting, therefore, they are suitable targets for the multikinase inhibitor sorafenib. Thus, we explored sorafenib activity in patients with relapsed and unresectable osteosarcoma.

EXPERIMENTAL DESIGN

Patients > 14 years, progressing after standard treatment, were eligible to receive 400 mg of sorafenib twice daily until progression or unacceptable toxicity. The primary end point was progression-free survival (PFS) at 4 months. Secondary objectives were PFS, overall survival (OS), clinical benefit rate (CBR), defined as no progression at 6 months and safety. This nonrandomized phase II study used a Simon two-stage design. PFS and OS at 95% confidence intervals (95% CIs) were calculated by the Kaplan-Meier method. All tests were two sided.

RESULTS

Thirty-five patients were enrolled. PFS at 4 months was 46% (95% CI 28% to 63%). Median PFS and OS were 4 (95% CI 2-5) and 7 (95% CI 7-8) months, respectively. The CBR was 29% (95% CI 13% to 44%). We observed 3 (8%) partial responses (PRs), 2 (6%) minor responses (< 30% tumor shrinkage) and 12 (34%) stable diseases (SDs). For six patients (17%), PR/SD lasted ≥ 6 months. Noteworthy, tumor density reduction and [(18)F]2-fluoro-2-deoxy-d-glucose-positron emission tomography responses were observed among SD patients. Sorafenib was reduced or briefly interrupted in 16 (46%) patients and permanently discontinued in one (3%) case due to toxicity.

CONCLUSIONS

Sorafenib demonstrated activity as a second- or third-line treatment in terms of PFS at 4 months with some unprecedented long-lasting responses. Sorafenib, the first targeted therapy showing activity in osteosarcoma patients, deserves further investigations.