Pattern of Rituximab Use Among Patients with B-Cell Non-Hodgkin's Lymphoma: A Report from China Lymphoma Patient Registry (CLAP)

Introduction: Rituximab is a chimeric monoclonal antibody against the protein CD20 and has been wildly used in the treatment of CD20-positive, B-cell Non-Hodgkin's Lymphoma (NHL). Many studies have demonstrated the effect and safety of Rituximab both in China and international. However, the pattern of real-world Rituximab use in China still remains unclear, although the country is trying very hard to lower the barrier of anti-cancer drug access. In this study, we reported the pattern of Rituximab use during initial treatment and factors associated with Rituximab use among B-cell NHL patients in China Lymphoma Patient Registry (CLAP) study (NCT03313271). Method: CLAP is a multi-center observational bi-directional cohort study based on medical records of hospitalized lymphoma patients and was launched in early 2017 in five hospitals. Medical records of the eligible patients in participating hospitals were systematically reviewed and study data were manually entered or directly transferred into a predesigned electronic database with the support of Medbanks Network Technology Co., Ltd. Its inclusion criteria include: 1) newly diagnosed as lymphoma in participating hospitals; 2) age >=18 yrs old at time of disease diagnosed; 3) given informed consent if prospective follow-up is needed. In order to be eligible for this particular report, three additional criteria were applied: 1) diagnosis was made after July 2015; 2) with clear diagnosis of one of B-cell NHL subtypes, including diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), small lymphocytic lymphoma/chronic lymphocytic leukemia (SLL/CLL), mantle cell lymphoma (MCL) and marginal zone lymphoma (MZL); 3) with recorded initial treatment. Frequency analysis was used to describe the distribution of patient demographics and disease characteristics, stratified by if Rituximab was used. Rituximab use was defined as YES if at least one prescription was made regardless of number of cycles and duration of treatment. Percentage of Rituximab use was also reported by histology subtypes and first prescription time (every 6 months). Multiple logistic regression was used to explore factors associated with Rituximab use during initial treatment. Result: A total of 1634 study subjects were included in this analysis and 1258 of them were treated with Rituximab contained regimen. Among all study subjects, male was slightly more than female (52.4% vs 47.6%) and 85.7% of them were older than 40 yrs. Majority of study subjects (84.9)% had a ECOG score between 0-1 at time of disease diagnosis. The distribution of demographic and disease characteristics was similar between the two groups (Table1). Among the five subtypes, patients with FL had the highest rate of Rituximab use (80.8%), followed by DLBCL (77.2%), MZL (74.3%), MCL (73.3%) and CLL/SLL (57.1%) (Figure1). Using every 6 months as a time period, Rituximab use rate between July 2015 and March 2018 was 71.8%, 77.9%, 70.6%, 78.8%, 87.9% and 93.8% , p-value for trend test was 0.0002(figure2). In multiple logistic regression, CLL/SLL was associated with less Rituximab use comparing with DLBCL (OR=0.439; 95% CI=0.228-0.846) and later time of first prescription was associated with more Rituximab use (OR=1.192; 95% CI=1.088-1.305). Conclusion Closed to 77% B-cell NHL patients received Rituximab contained regimen as their initial treatment, demonstrating the well recognition of the efficacy and safety of Rituximab among doctors in CLAP hospitals. Compared with other subtypes, patients with CLL/SLL had lower Rituximab use rate, which might be contributed to its lower CD20 express (Beum et.al, J Immunol 2006) and suboptimal clinical effect (Robak et.al, J Clin Oncol 2010). In September 2017, Rituximab was covered by the National Basic Medical Insurance and the price was also dropped. Therefore, as a proxy of payment policy improvement and lower access barrier, later time of diagnosis was associated with higher Rituximab use rate. Although not statistical significant, patients with poorer health status (ECOG>=2) was more likely to be prescribed with Rituximab. In conclusion, NHL subtypes and economic reason are two main driven factors that influence the use of Rituximab as initial treatment in real world practice in China. Disclosures Song: Peking University Cancer Hospital (Beijing Cancer Hospital): Employment. Zhu:Beijing Cancer Hospital: Employment.