Correction to: Thalidomide maintenance therapy in Japanese myeloma patients: a multicenter, phase II clinical trial (COMET study).

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Thalidomide maintenance therapy in Japanese myeloma patients: a multicenter, phase II clinical trial (COMET study).

A prospective, multicenter, phase II study was performed to assess the efficacy and safety of thalidomide maintenance therapy at different doses in Japanese multiple myeloma (MM) patients. This study included 34 patients (median age, 74 years) who were previously treated with not more than three prior therapies and whose response status was evaluated as at least stable disease. They were randomized into Group A (no maintenance; 12 patients), Group B (50 mg thalidomide maintenance; 12 patients), and Group C (100 mg thalidomide maintenance; 10 patients), respectively. Thalidomide maintenance therapy resulted in improved depth of response in three cases (13.6%) and sustained response after induction therapy in eight cases (36.4%). Two-year progression-free survival (PFS) was 25.0%, 33.3%, and 77.8% in Groups A, B, and C, respectively, and was significantly higher in Group C than in Group A (p = 0.005). There was no difference in the incidence of hematological or non-hematological adverse events between Groups B and C. The current study demonstrates that maintenance with daily thalidomide at 100 mg, but not 50 mg, improved depth of response and prolonged PFS, and that this treatment was feasible for use in Japanese MM patients.

Clinical significance of minimal residual disease in patients with t(8;21) acute myeloid leukemia in Japan.

To examine the prognostic significance of minimal residual disease (MRD) in t(8;21) acute myeloid leukemia (AML), 96 bone marrow samples from 26 Japanese patients in complete remission (CR) were analyzed regarding the RUNX1/MTG8 transcript using real-time reverse transcriptase polymerase chain reaction assay. All patients were treated with intensive chemotherapy. The median copy number of the RUNX1/MTG8 transcript, measured after each treatment course decreased over time. However, an increase in the MRD level was documented in three patients after the second consolidation, and all of them subsequently relapsed. The relapse-free survival (RFS) did not differ between the patients whose MRD levels were below or above 1,000 copies/microg after the first consolidation, with respective 2-year rates of 62 and 86% (P = 0.21). With respect to the MRD level after induction therapy, our data also failed to show any favorable effect of a lower MRD on RFS. Although these findings need to be confirmed with a larger number of patients, our data indicate that the MRD level at a given time during the early course in CR does not predict the outcome in Japanese patients.

Multiplex real-time RT-PCR for prospective evaluation of WT1 and fusion gene transcripts in newly diagnosed de novo acute myeloid leukemia.

Prognostic assessment is crucial for the management of AML. Although the use of karyotype analysis for risk-stratification is widely accepted, prognosis of AML remains ambiguous, particularly for patients categorized into the intermediate cytogenetic risk group and additional markers are required for an accurate prediction of outcome. For this study, we used multiplex real-time RT-PCR, which can simultaneously quantify WT1 and 10 distinct fusion gene transcripts, to prospectively evaluate the pre-treatment bone marrow findings of 53 de novo AML patients. Five patients with normal karyotype or insufficient metaphases detected by conventional karyotype analysis proved to have AML1-MTG8, CBFbeta-MYH11 or PML-RARalpha fusion transcripts. WT1 overexpression was observed in 92% of the patients, and the levels were significantly higher in the cytogenetic favorable risk group, especially patients with PML-RARalpha. WT1 levels also correlated with the percentage of blasts in bone marrow, especially in cases of core-binding factor leukemia. There was no association between initial WT1 levels and outcome in terms of event-free survival or overall survival. These results suggest that multiplex real-time RT-PCR is rapid and useful for the precise cytogenetic stratification of AML, and that WT1 levels at presentation correlate with several biologic features of leukemia, but have no prognostic significance.