Rituximab addition benefits adult ALL patients
medwireNews: Addition of rituximab to a standard chemotherapeutic regimen boosts outcomes for adult patients with B-lineage, CD20-positive acute lymphoblastic leukaemia (ALL), trial findings indicate.
An event – defined as failure to induce complete remission, relapse or death – was a significant 34% less likely to occur in participants given the anti-CD20 antibody during all stages of chemotherapy, including maintenance, versus those who were not.
And the estimated event-free survival rates at 2 years were 65% and 52%, respectively, report Hervé Dombret (Université Paris Diderot, France) and fellow researchers.
This improvement was mainly driven by a significant decrease in the incidence of relapse among rituximab-treated patients, with a 2-year cumulative incidence of 18% compared with 32% for the control arm.
By contrast, the cumulative incidence of death during the first remission did not differ significantly between groups.
Multivariate analysis showed that allocation to the control arm was a significant predictor of worse event-free survival, as was older age, central nervous involvement and higher white cell count at diagnosis.
The Group for Research on Adult Acute Lymphoblastic Leukemia 2005 Rituximab (GRAALL-2005/R) trial recruited 209 newly diagnosed adult ALL patients with Philadelphia chromosome-negative, CD20-positive (antigen expressed in >20% of leukaemic cells at baseline) disease.
Participants were randomly assigned to receive standard chemotherapy either with or without rituximab 375 mg/m2 for a total of 16–18 infusions, and were followed-up for a median of 30 months.
Dombret et al summarise that their findings “provide evidence of a beneficial effect of the addition of rituximab to chemotherapy” in this patient population.
However, it remains unclear whether individuals with CD20 levels below the 20% cutoff may also benefit from treatment with the anti-CD20 antibody, they write in The New England Journal of Medicine.
The authors note that a trial is currently underway to evaluate the role of rituximab addition regardless of the CD20 expression level.
Moreover, “[i]n patients with low or very low CD20 expression levels at baseline, the use of higher-affinity anti-CD20 antibodies, such as obinutuzumab or ofatumumab, might offer an attractive alternative”, they conclude.
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