Attainment of complete/very good partial response following rituximab‐based therapy is an important determinant to progression‐free survival, and is impacted by polymorphisms in FCGR3A in Waldenstrom macroglobulinaemia

Summary The incorporation of rituximab into various regimens has improved depth of response in Waldenstrom macroglobulinaemia (WM), though the impact of achieving better responses remains to be determined. We examined response depth on progression‐free survival (PFS) in 159 rituximab‐naïve WM patients who received rituximab‐based therapy. The median follow‐up was 33·5 months, and categorical responses were as follows: complete response (CR, 8·8%); very good partial response (VGPR, 13·2%); partial response (50%); minor response (18·9%); Non‐Responders (8·8%). Sequencing for polymorphic variants of FCGR2A, FCGR2B, and FCGR3A was performed, and impact on response depth determined. Achievement of better categorical responses was incrementally associated with improved PFS (P