Mitoxantrone (INN, BAN, USAN; also known as Mitozantrone in Australia; trade name Novantrone) is an anthracenedione antineoplastic agent.

[2] The combination of mitoxantrone and prednisone is approved as a second-line treatment for metastatic hormone-refractory prostate cancer.

In the absence of a cure, mitoxantrone is effective in slowing the progression of secondary-progressive MS and extending the time between relapses in both relapsing-remitting MS and progressive-relapsing MS.[4] Mitoxantrone, as with other drugs in its class, may cause adverse reactions of varying severity, including nausea, vomiting, hair loss, heart damage and immunosuppression, possibly with delayed onset.

Cardiomyopathy is a particularly concerning effect as it is irreversible; thus regular monitoring with echocardiograms or MUGA scans is recommended for patients.

Because of the risk of cardiomyopathy, mitoxantrone carries a limit on the cumulative lifetime dose (based on body surface area) in MS patients.