Arsenic Trioxide (Trisenox® ATO), Ascorbic Acid (AA) and Dexamethasone (Dex) Pulses (TAD) for Relapsed Refractory Progressive Multiple Myeloma (MM) Patients (pts); a Final Report.
ATO is a novel anticancer agent whose unique multifaceted mechanisms of action offer a scientific rationale for investigation in different hematologic malignancies. 2 phase II studies of ATO in advanced, heavily treated MM reported ≥25% decrease(40–50% of treated pts) in serum M-protein concentrations. Data from both studies suggest that long term therapy might result in enhanced quality of responses. It has been shown that ATO sensitizes myeloma cells to Dex in-vitro and AA potentiates the effect of ATO on different myeloma and human cell lines. We therefore initiated a phase II trial combining ATO with Dex & AA. MM pts with active, progressive disease who failed 50% reduction of the m-protein following cycle 1 of therapy;2CR,1NCR,5PR,10SD & 3PD. None of the pts but 1 showed further improvement in the m-protein after the1st cycle of therapy. Mean duration of therapy was 1.9 years. TAD results in an over all response rate of 45% & 85% SD or better with a mean survival of 18.3 months. Further expansion of the study to confirm this data is warranted, and utilizing the complementary mechanism of action of other immunomodulatory agents such as thalidomide with this regimen is ongoing.