Cardiac evaluation of mitoxantrone.

Mitoxantrone is a synthetic anthraquinone that was developed through the doxorubicin analog program in hopes of retaining anticancer activity with less cardiotoxicity. This study evaluated 18 patients receiving mitoxantrone with serial noninvasive tests of left ventricular function and with endomyocardial biopsy. The echocardiograms and systolic time intervals demonstrated a trend to deterioration that did not achieve statistical significance. However, the nuclear angiographic ejection fraction significantly decreased from 61% +/- 6% (means +/- SD) at baseline to 58% +/- 5% (P less than 0.05) after 48 mg/m2 of mitoxantrone. The endomyocardial biopsies revealed tubular swelling, degeneration of mitochondria, minimal chromatin clumping, and myofibrillar lysis. This study has revealed mild but definite impairment of cardiac function and mild changes of myocardial morphology during mitoxantrone therapy. Although mitoxantrone is an effective chemotherapeutic agent, a direct comparison of mitoxantrone with doxorubicin is necessary to compare relative therapeutic to cardiotoxic ratios.