Purpose: On May 17, 2007, doxorubicin HCl liposome injection (Doxil) in combination with bortezomib (Velcade) received approval from the US Food and Drug Administration (FDA) for the treatment of relapsed or refractory multiple myeloma after at least one prior therapy that has not included bortezomib. Liposomal doxorubicin's efficacy and safety were demonstrated in a phase III, randomized, multicenter, international trial comparing the combination of this agent plus bortezomib vs bortezomib alone in multiple myeloma patients who had not previously received bortezomib and had received at least one prior therapy. Here we summarize the FDA review of the data that support this approval.
Experimental design and results: An interim analysis of time to disease progression (TTP), the primary endpoint, was conducted after 249 TTP events in this study that randomized 324 patients to liposomal doxorubicin plus bortezomib treatment and 322 patients to bortezomib monotherapy. Time to progression was significantly prolonged in the combination arm (median TTP = 9.3 months) compared with bortezomib monotherapy (median TTP = 6.5 months), P < .0001 (log-rank test); hazard ratio = 0.55 (95% confidence interval = 0.43-0.71). The response rates were similar between the two arms and not statistically different; however, among responding patients, the median duration of response was longer with the combination--10.2 months compared to 7.0 months in the monotherapy arm. Adverse reactions occurred more frequently with the combination therapy. As compared to the monotherapy, frequent grade 3/4 adverse reactions with the combination were neutropenia and thrombocytopenia.
Conclusions: Liposomal doxorubicin received FDA approval for use in combination with bortezomib in patients with multiple myeloma who have not previously received bortezomib and have received at least one prior therapy.