Superior efficacy of rituximab-based chemoimmunotherapy as an initial therapy in newly diagnosed patients with B cell indolent lymphomas: long-term results from a single center in China

Zengjun Li, Fei Li, Shuhua Yi, Zhimin Gu, Zhen Yu, Yan Xu, Xiaoyan Feng, Wei Liu, Dehui Zou, Junyuan Qi, Fenghuang Zhan, Lugui Qiu

Rituximab has been confirmed to improve the survival of patients with B cell indolent non-Hodgkin lymphomas (B-iNHLs) in Western world as previously reported, however, it is rarely reported in Chinese cohort. This study is to investigate the efficacy and safety of rituximab-based chemoimmunotherapy and select subpopulations most sensitive to the regimen in Chinese B-iNHL patients. 334 B-iNHL patients from our center were retrospectively assessed. Patients received R-based chemoimmunotherapy showed significantly higher rates of overall response (OR) (93.0 % vs. 53.4 %, P < 0.001) and complete response (CR) (63.3 % vs. 16.0 %, P < 0.001) compared with the patients received other therapies. Survival analysis showed that rituximab-based chemoimmunotherapy could obviously improve the progression-free survival (PFS) (110 vs. 49 months, P = 0.001) and overall survival (OS) (120 vs. 72 months, P < 0.001) in patients with B-iNHLs. Interestingly, in chronic lymphocytic leukemia (CLL) patients, we found that the patients with β2-microglobulin (β2-MG) < 3.5 mg/L, lactate dehydrogenase (LDH) < 220 U/L, zeta-chain-associated protein kinase 70 (ZAP-70) negative, and non high-risk genetic abnormality could achieve more benefits from R-based regimens with higher CR rate (P = 0.003, 0.029, 0.013 and 0.038, respectively). Meanwhile, more CLL patients achieved minimal residual disease (MRD) negative after rituximab-based treatment (46.5 % vs. 10.3 %, P < 0.001). Moreover, CLL patients with MRD < 1 %, LDH < 220 U/L, complete remission (CR) or partial remission (PR), β2-MG < 3.5 mg/L and non high-risk cytogenetic abnormality showed superior outcome compared to the controls (P = 0.001, 0.000, 0.000, 0.001 and 0.013, respectively). No other side-effects increased in chemoimmunotherapy group except the elevation of grade 3-4 neutropenia. Our results demonstrate the superior efficacy of rituximab-based chemoimmunotherapy as an initial therapy in Chinese cohort with newly diagnosed B-iNHLs and further identify subpopulations that are more sensitive to R-based chemoimmunotherapy in CLL group.