Ph. I/II Sodium Thiosulfate for OtoProtection During Cisplatin (STOP-CIS)

Inclusion Criteria: * Participants have provided informed consent prior to initiation of any study-specific activities. * At least 18 years of age, male or female, at the time of signing the informed consent. * ECOG Performance Status 0-1 * Histologically or cytologically confirmed treatment-naïve cancer. * Scheduled to receive an FDA-approved, on-label indication, standard of care systemic cisplatin-based regimen (at least 200 mg/m2 cumulative dose) for any untreated any solid malignancy deemed by the treating physician Exclusion Criteria: * Prior cisplatin exposure due to a cancer treatment history * Concurrent ototoxic medication unable to be safely discontinued or switched to a non-toxic alternative * Planned radiation to the head or neck prior to, during, or within 3 months of completion of cisplatin * History of severe hypersensitivity to sulfite, sodium thiosulfate, or any components * Baseline serum sodium \> 145 mmol/L or any grade ≥ 3 electrolyte abnormality * Cisplatin infusion duration greater than 6 hours * Females during pregnancy or breastfeeding, and childbearing potential, unwilling to use a method of contraception during treatment * Male subjects with a pregnant partner who are unwilling to practice abstinence or use a condom during treatment * Subject likely not to be available to complete all protocol-required study visits or procedures, and/or to comply with all required study procedures (i.e., Clinical Outcome Assessments) to the best of the subject's and investigator's knowledge. * History or evidence of any other clinically significant disorder, condition, or disease (with the exception of those outlined above) that, in the opinion of the investigator, if consulted, would pose a risk to subject safety or interfere with the study evaluation, procedures, or completion.