Amrubicin, a topoisomerase II inhibitor, shows significant activity against small-cell lung cancer (SCLC), according to the findings of a phase II trial. Amrubicin appeared more potent than doxorubicin in preclinical studies, the authors explain, and it showed high activity as a single agent in untreated patients with extensive disease SCLC in an earlier study. Dr. Noriyuki Masuda from Kitasato University School of Medicine, Kanagawa, Japan and colleagues investigated the antitumor activity and toxicity of amrubicin in 60 previously treated patients with SCLC.
Two patients (3%) achieved a complete response and 29 (48%) had a partial response, the authors report in the December 1st issue of the Journal of Clinical Oncology, for an overall response rate of 52%.Response rates were similar between patients who were sensitive to their initial therapy but who relapsed and patients refractory to first-line therapy, the results indicate.The median time to progression was 4.2 months among sensitive patients and 2.6 months among refractory patients, the researchers note.Median survival time from enrolment was 11.2 months, the report indicates, and 1-year actuarial survival was 45.5% in patients with sensitive disease, 40.3% in patients with refractory disease, and 44.1% overall.Myelosuppression affecting primarily leukocytes was the most frequent toxicity, requiring G-CSF administration to 42 patients (70%), the investigators note. Nonhematologic toxicity was generally mild, and the only case of cardiotoxicity was transient atrial fibrillation."Given the greater activity of single-agent amrubicin, additional studies in previously treated patients with SCLC are warranted, especially for the patients who are refractory to previous therapy, either as a single agent or in combination with cytotoxic agents or target-based agents," the authors suggest."The incorporation of amrubicin instead of doxorubicin in anthracycline-containing regimens might decrease the incidence of cardiotoxicity, thereby improving the therapeutic index of doxorubicin-containing regimens in future trials," the researchers add.(Source: Journal of Clinical Oncology : Kitasato University School of Medicine : January 2007.)