PRIMARY OBJECTIVE:~I. Find maximum tolerated doses (MTDs) for the combination therapy of ixazomib (ixazomib citrate) and gemcitabine (gemcitabine hydrochloride)/doxorubicin (doxorubicin hydrochloride) (i.e. dose pairs of ixazomib and gemcitabine/doxorubicin that have an acceptable target toxicity rate of 30%). (Phase I)~SECONDARY OBJECTIVES:~I. Define the dose-limiting toxicities of the dose pairs found. II. Choose a dose pair for phase II expansion in patients with locally advanced or metastatic urothelial cancer.~III. Determine the objective response rate and median survival for patients treated on the phase II expansion.~OUTLINE: This is a phase I, dose-escalation study followed by a phase II study.~Patients receive ixazomib citrate orally (PO), gemcitabine hydrochloride intravenously (IV) over 90 minutes, and doxorubicin hydrochloride IV over 15-30 minutes on day 1. Cycles repeat every 14 days in the absence of disease progression or unacceptable toxicity.
This phase I/II trial studies the side effects and best dose of ixazomib citrate, gemcitabine hydrochloride, and doxorubicin hydrochloride when given together in treating patients with urothelial cancer that has spread to other places in the body (metastatic) or cannot be removed by surgery. Ixazomib citrate may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Chemotherapy drugs, such as gemcitabine hydrochloride and doxorubicin hydrochloride, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Giving ixazomib citrate together with gemcitabine hydrochloride and doxorubicin hydrochloride may be a better treatment for urothelial cancer.