Led by Dr Michael Lubbert, of the University of Freiburg Medical Center in Freiburg, Germany, researchers assessed the efficacy of decitabine retreatment on relapsing high-risk myelodysplastic syndrome (MDS) patients who received initial treatment with decitabine.
MDS generally afflicts adults over 50 years of age, and therapy is supportive rather than curative. However, a subset of MDS patients will develop blood cell cancer, or leukemia. These high-risk patients have been shown to benefit from a new DNA hypomethylating agent, decitabine, which is currently undergoing clinical trials.
Little is known about the optimal duration of treatment with decitabine and the effect of retreatment for relapse. Led by Dr Michael Lubbert, of the University of Freiburg Medical Center in Freiburg, Germany, researchers assessed the efficacy of decitabine retreatment on relapsing high-risk MDS patients who received initial treatment with decitabine.
According to the researchers, the study found that 45% of patients with MDS who relapse did respond to a second course of treatment, but that the quality and duration of the second response was inferior to the initial treatment, leading researchers to believe that longer initial treatments may be more beneficial to patient outcome.
Study results were published in the journal Cancer. The researchers found that retreatment with a median of three courses of decitabine resulted in 10 patients out of 22 (45%) achieving any response. Three of the patients achieved a partial or complete response in all three cell lines, while the other seven patients experienced hematologic improvements of an at least 50% drop in transfusion requirements and higher counts in one or two blood cell lines.
The median overall survival of all patients from the start of the first decitabine course was 28 months. Decitabine-retreated patients had a median survival of 13 months from relapse
Decitabine retreatment in the 12 patients (55%) not achieving a second response either suppressed the abnormal cells without bone marrow repopulation with normal cells, resulting in cytopenia (blood cell deficiency), or had no effect on normal or abnormal cell lines. Of these 12 retreatment failures, four patients developed acute leukemia and three patients died of complications due to pathological deficiencies in cell lines.
“Results of the present analysis point to the importance of extending therapy with low-dose decitabine beyond the point of first response, and strongly support institution of a maintenance treatment,” the study authors conclude.