CLINICAL AND BIOLOGICAL FEATURES AND OUTCOMES OF PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKEMIA: A REAL‐WORLD STUDY OF 2005 PATIENTS IN CHINA

Abstract

Introduction: Chronic lymphocytic leukemia (CLL) is less common in Han Chinese compared with persons of Europeans. The data about the clinical and biological features and outcomes of Chinese with CLL are limited, thus promoting us to perform this analysis on a large cohort of 2005 patients with CLL in China. Methods: Clinical data of 2005 patients with CLL were analyzed in Blood Diseases Hospital, Chinese Academy of Medical Sciences from February 2000 to December 2020. Results: In this cohort, the median age of patients at diagnosis was 61(20-92) years, which was younger than that for Western CLL patients (65-70 years). Patients showed similar male predominance as Europeans with CLL with an M:F ratio of about 1.8. 69.3% of patients had Binet stage B or C at diagnosis, higher than those of predominately European descent (20%-40%). A higher proportion of mutated immunoglobulin heavy chain variable region (IGHV) (64.0%) was shown in patients with CLL in this cohort than Europeans. IGHV4-34 rather than IGHV1-69 was the most commonly used fragment. Compared with Europeans, patients in this cohort had a higher proportion of subset eight stereotype and a lower proportion of subset two. The most frequent abnormality detected by FISH was RB1 deletion (21.1%), followed by trisomy 12 (20.4%), IGH translocation (16.8%), del(17p) (11.4%) and del(11q) (10.9%), respectively. It was shown that the frequencies of the chromosomal abnormalities in this study population were similar to the frequencies in Western countries. Of the 1476 patients for whose treatment data were available, 1191 (80.7%) received treatment. Median time to first treatment (TTFT) for CLL patients was 7 months. Among patients treated, chemotherapy, immunochemotherapy and targeted therapy accounted for 69.6%, 14.1% and 16.3% of first line, yielding 68.4%, 90.0% and 94.2% of overall response rate (ORR), respectively. After median 75-month follow up, median progression free survival (PFS) was 42 months, 5-year and 10-year PFS rate was 35.5% and 12.5%, respectively. Median overall survival (OS) was 130 months, 5-year and 10-year OS rate was 74.9% and 52.3%, respectively. The outcomes were similar to those reported in previous Chinese and Western studies. As expected, PFS and OS were better in CLL patients receiving immunochemotherapy and targeted therapy than those receiving chemotherapy. In addition, patients who achieved partial remission (PR) or complete remission (CR) after first-line treatment had a longer PFS and OS. Interestingly, females with CLL had a longer OS than males. Conclusions: This is the largest real-world study involving Chinese patients with CLL so far, which might lay a foundation for clinical investigation of Chinese CLL in future. Although the patients were younger, had a later stage at diagnosis and had different genetic backgrounds compared with Europeans, the outcomes were not different from those reported in Western studies. Keyword: chronic lymphocytic leukemia (CLL) No conflicts of interests pertinent to the abstract.