Phase II study of dexamethasone, ascorbic acid, thalidomide and arsenic trioxide (DATA) in high risk previously untreated (PU) and relapsed/refractory (RR) multiple myeloma (MM)

Abstract

17535 Background: The combination of Thalidomide (T) and Dexamethasone (D) is often used first line in patients with MM. Arsenic trioxide (ATO) is active and well tolerated in patients with RR MM. ATO, D and T have non-overlapping toxicity. We therefore initiated a phase II study to assess the efficacy and toxicity of this combination in patients with high risk PU MM (serum B2 microglobulin>5.5, chromosome 13 or 14 abnormalities by FISH or the presence of peripheral plasma cells) and RR MM. Methods: On week 1, ATO was given at a dose of 0.25mg/kg IV on days 1–5. On weeks 2–12, ATO was given at the same dose twice weekly. On weeks 13–16, the patients did not receive treatment. Ascorbic acid 1000mg IV was given after each ATO infusion. D was given at a dose of 20mg orally on days 1–4 of a 28 days cycle, and T was started at a dose of 50mg daily and increased as tolerated to a dose of 100mg daily. A similar 16 weeks consolidation course was given. Maintenance included ATO 0.25mg/kg on days 1,8,15 and 22 every 12 weeks in addition to the above schedule for D, T and Ascorbic acid. Results: Sixteen patients were enrolled (3 with PU and 13 RR), 13 are evaluable for response. The median age was 57 years and 62% were males. The median number of prior chemotherapy regimen is 2 (range 0–6), 7 patients had received a prior T containing regimen, and 2 patients had received an ATO-containing regimen. Seven, seven and two patients had SWOG stages 2, 3 and 4 respectively. The mean serum B2 microglobulin was 7.1-mg/dL (s.d. 4.4). After a median follow up of 9.5 months (range 1–12), 9 patients progressed and 5 died. The median progression free survival was 9.4 months. The median progression free survival for responder has not been reached. Four patients had a PR (31%), 8 had stable disease (62%), and 1 had progressive disease. No patient had a QT>500 or a cardiac arrhythmia. Grade 3 leukopenia, anemia, neuropathy and renal failure occurred in 3, 2, 1 and 1 patients respectively. Three patients had a venous thromboembolic event (2 DVT and 1 PE). Conclusions: The addition of T to the combination of ATO, Ascorbic acid and D is safe, well tolerated and results in 30% PR and 61% stable disease in patients with poor risk MM. [Table: see text]