Rituximab plus bendamustine or chlorambucil for chronic lymphocytic leukemia: primary analysis of the randomized, open-label MABLE study.

MABLE investigated the efficacy and safety of rituximab plus bendamustine or rituximab plus chlorambucil in fludarabine-ineligible patients with chronic lymphocytic leukemia. Patients received rituximab plus bendamustine or rituximab plus chlorambucil every four weeks for six cycles. Rituximab plus chlorambucil-treated patients without a complete response after Cycle 6 received chlorambucil monotherapy for at least six additional cycles or until complete response. The primary endpoint was complete response rate (confirmed by bone marrow biopsy) after Cycle 6 in first-line patients. Secondary endpoints included progression-free survival, overall survival, minimal residual disease, and safety. Overall, 357 patients were randomized (rituximab plus bendamustine, n=178; rituximab plus chlorambucil, n=179; intent-to-treat population), including 241 first-line patients (n=121 and n=120, respectively); 355 patients received treatment (n=177 and n=178, respectively; safety population). In first-line patients, complete response rate after Cycle 6 (rituximab plus bendamustine, 24%; rituximab plus chlorambucil, 9%; P=0.002) and median progression-free survival (rituximab plus bendamustine, 40 months; rituximab plus chlorambucil, 30 months; P=0.003) were higher with rituximab plus bendamustine than rituximab plus chlorambucil. Overall response rate and overall survival were not different. In first-line patients with a complete response, minimal residual disease-negativity was higher with rituximab plus bendamustine than rituximab plus chlorambucil (66% vs 36%). Overall adverse event incidence was similar (rituximab plus bendamustine, 98%; rituximab plus chlorambucil, 97%). Rituximab plus bendamustine may be a valuable first-line option for fludarabine-ineligible patients with chronic lymphocytic leukemia.

Treatment of myelodysplastic syndromes with valproic acid alone or in combination with all-trans retinoic acid.

Valproic acid (VPA) has been shown to inhibit histone deacetylase activity and to synergize with all-trans retinoic acid (ATRA) in the differentiation induction of acute myelogenous leukemia (AML) blasts in vitro. We treated 18 patients with myelodysplastic syndromes (MDS) and AML secondary to MDS (sAML/MDS) with VPA monotherapy (serum concentrations 346-693 microM [50-100 microg/mL]). Five patients received VPA and ATRA (80 mg/m(2)/d, days 1-7, every other week). Response according to international working group (IWG) criteria was observed in 8 patients (44%) on VPA monotherapy, including 1 partial remission. Median response duration was 4 months (range, 3-9 months). Four of 5 patients relapsing were treated with VPA + ATRA, 2 of them responding again. Among 5 patients receiving VPA + ATRA from the start, none responded according to IWG criteria, but 1 patient with sAML/MDS achieved a marked reduction in peripheral and marrow blasts. Thus, VPA is of therapeutic benefit for patients with MDS, and ATRA may be effective when added later.

Levels of minimal residual disease detected by quantitative molecular monitoring herald relapse in patients with multiple myeloma.

BACKGROUND AND OBJECTIVES: Detection of minimal residual disease (MRD) has helped to improve the treatment of patients with leukemia. At present MRD testing in patients with multiple myeloma (MM) is not applied as a standard diagnostic or prognostic method. DESIGN AND METHODS: Immunoglobulin heavy chain (IgH) polymerase chain reaction (PCR) using patient-specific TaqMan probes together with LightCycler technology was performed to quantify minimal residual disease in MM. Relative levels of clonotypic cells were assessed as IgH/2beta-actin ratios with a sensitivity of 10(-4) to 10(-5). RESULTS: Following stem cell transplantation, a significant reduction of clonotypic cells was observed in bone marrow (BM) and peripheral blood (PB) samples of 11 patients, comparing pre-treatment values with those of best response (median: 13% to 0.09% and 0.03% to 0%, respectively). In 5 patients with ongoing clinical remission IgH/2beta-actin ratios remained stable at a low level, while in 6 patients an increase to 2% in BM and 0.4% in PB was associated with progression of the disease. In 4 of these 6 patients the increase of clonotypic cells in PB was detectable a median of 3 months (range: 0.5-6) before relapse. Furthermore, time-to-progression of patients with pre-transplantation IgH/2b-actin ratios > 0.03% in BM was significantly shorter than that of patients with lower MRD levels. INTERPRETATION AND CONCLUSIONS: MRD in patients with MM can be quantified reliably using TaqMan chemistry adapted to the LightCycler system. Residual tumor cell levels before transplantation as well as results of sequential molecular monitoring are predictive of relapse.