Outcome of CD20-positive Adult B-cell Acute Lymphoblastic Leukemia and the Impact of Rituximab Therapy

Background In adult B cell precursor acute lymphoblastic leukemia (BCP-ALL), CD20 expression has generally been associated with an adverse prognosis. Incorporating rituximab to standard of care is found to improve the outcome of CD20+ BCP-ALL. The aim of this study is to estimate the prognostic effect of CD20 expression and the impact of rituximab in BCP-ALL in Saudi Arabia. Patients and Methods We performed a retrospective study of 55 Saudi adult patients with BCP-ALL in King Fahad Specialist Hospital in Dammam from 2008 to 2017. Results The proportion of CD20+ cases was approximately 55%. Excluding rituximab-treated patients, the 5-year overall survival (OS) rate of CD20+ patients was lower than CD20− patients (56% vs. 66%; P = .62). Among CD20+ patients, the proportion that received rituximab was approximately 27%. Comparing CD20+ patients with and without rituximab, all patients who received rituximab achieved complete remission (CR) 4 weeks post-induction. The 3-year OS rate (88% vs. 63%; P = .35) and the 2-year event-free survival rate (70% vs. 68%; P = .75) were in favor of rituximab. In univariate and multivariate analyses, CR 4 weeks post-induction is recognized as an independent predictor of outcome. However, differences in survival rates did not have a statistical significance. Conclusion CD20 expression in adult patients with BCP-ALL seems to be higher in Saudi Arabians than in Caucasians, and it seems to have a tendency towards an inferior outcome in terms of OS. Incorporating rituximab to standard of care seems to improve the outcome in terms of CR, OS, and event-free survival.