Regarding haematologic AEs, the risk of grade 3 or higher neutropenia was significantly increased in the combined BTK inhibitor with anti-CD20 treatment arm versus the BTK inhibition treatment arm, 119/522 (23%) versus 64/521 (12%) (RR, 1.80; 95% CI 1.03–3.17; I2 = 37%; p = 0.19; 1043 patients; four RCTs). This evidence concerns the gene BTK and neutropenia.