Schering-Plough Corp. has announced results from a phase III study that showed maintenance chemotherapy with Caelyx (pegylated liposomal doxorubicin hydrochloride) significantly prolonged time to progression (TTP) in patients with metastatic breast cancer with infrequent and manageable clinical toxicity after first-line chemotherapy. These data were presented at the 43rd Annual Meeting of the American Society of Clinical Oncology.

"While standard chemotherapy has proven effective for patients with metastatic breast cancer, their response is short-lived and the time to progression is brief," said Emilio Alba, M.D., professor at Hospital U Virgen de la Victoria, in Malaga, Spain and lead investigator for the study. "The results from this study showed a significantly improved time to progression (13.2 months) in patients treated with Caelyx versus the observational arm (10.2 months)."

The Spanish Cooperative Group, Grupo Espanol de Investigacion en Cancer de Mama (GEICAM) conducted the multi-centre, phase III study at seven different sites throughout Spain. Of the 288 patients with metastatic breast cancer registered for the trial, 155 subjects who had responded to initial therapy or had stable disease were randomised either to receive Caelyx or to observation. Patients receiving therapy were given a regimen of Caelyx at 40 mg/m2 once every four weeks for six cycles of therapy. Patients in the Caelyx arm experienced a median improvement in time to progression of three months.

The patients in the study had a median age of 57, and had adequate bone marrow, renal, hepatic and cardiac function. These patients had experienced either complete response, partial response or had stable disease. Patients received induction chemotherapy with three cycles of anthracycline followed by three cycles of taxane, and were then randomly assigned to either the Caelyx or the observation arm. The incidence of nausea/vomiting and alopecia were low and manageable; 21 per cent of patients experienced grade 1 or 2 nausea/vomiting and 29 per cent experienced alopecia. Importantly, neither clinically relevant left ventricular ejection fraction (decrease heart function) nor clinical congestive heart failure was observed.

"The study results are promising and suggest the potential value of Caelyx in the management of metastatic breast cancer," said Robert J Spiegel, chief medical officer and senior vice president, Schering-Plough Research Institute. "Further evaluation is indicated to confirm that Caelyx is effective and safe for select metastatic breast cancer patients who are at increased cardiac risk."

The current approved dosage of Caelyx in metastatic breast cancer is 50 mg/m2, every 4 weeks. To manage certain adverse events, such as palmar-plantar erythrodysesthesia (PPE), the dose may be reduced.