Preventing Nephrotoxicity and Ototoxicity From Osteosarcoma Therapy

Current osteosarcoma treatment regimens include cisplatin and high-dose methotrexate (HDMTX), which are nephrotoxic and ototoxic, and the damage to kidneys and cochlear hair cells may be irreversible. Preventing these toxicities will improve the outcome in long-term survivors and may also prevent short-term treatment delays and dose reductions that can compromise the efficacy of the treatment regimen and allow for administration of higher cumulative doses of cisplatin. This pilot study evaluates pharmacologically-based approaches to prevent the nephrotoxic effect of HDMTX by prolonging the infusion duration and thereby lowering the risk of drug precipitation in renal tubules; and to selectively block the uptake of cisplatin into renal tubular cells and cochlear hair cells by inhibiting the organic cation transporter 2 (OCT2) with the proton pump inhibitor (PPI), pantoprazole. Participants with previously untreated biopsy-proven, localized or metastatic osteosarcoma will receive six cycles of the standard Methotrexate, Adriamycin (doxorubicin),cisplatin (MAP) chemotherapy regimen, which includes high-dose methotrexate, doxorubicin and cisplatin. The first 2 cycles are administered neoadjuvantly followed by surgery to remove the primary tumor, when feasible.

A novel randomized, crossover, 2 x 2 factorial clinical trial design allows all patients to receive the new interventions to prevent toxicity and to serve as their own controls. New, sensitive urinary biomarkers of acute kidney injury serve as primary endpoints for evaluating treatment-related renal damage. Ototoxicity will be monitored using audiograms. The effect of these interventions on tumor response (radiographic and histologic) and toxicity (including a patient reported outcome survey and nutritional status) will be closely monitored. Other secondary objectives include evaluating bone-specific alkaline phosphatase as a biomarker of tumor burden and constructing a tissue microarray to evaluate expression of proteins that are responsible for resistance to the current drugs used to treat osteosarcoma and assess expression of proteins that are targeted by new anticancer drugs under development for childhood cancers.