Valrubicin.

Valrubicin (AD-32) is an N-trifluoroacetyl, 14-valerate derivative of the anthracycline doxorubicin. It has antineoplastic activity which probably results from interference with nucleic acid metabolism by the drug. Valrubicin entered individual cells more rapidly than doxorubicin in vitro. When valrubicin was administered intravesically to patients with bladder cancer, cytotoxic concentrations of the drug penetrated the superficial muscle layer of the bladder. Complete response rates were 18 and 29% in patients with carcinoma in situ of the bladder which was refractory to intravesical BCG in 2 non-comparative trials of prophylactic intravesical valrubicin. In patients with recurrent superficial papillary tumours, the complete response rate was 46%. Adverse events were generally transient in patients who received intravesical valrubicin. Bladder irritation occurred in 88% of patients. Systemic absorption of intravesically administered valrubicin was minimal. Accordingly, systemic adverse events generally occurred in < or =5% of patients. Valrubicin was less toxic to chick embryos and haematopoietic stem cells in vitro and produced a lower incidence of cardiotoxicity in rabbits, compared with doxorubicin.