PF621 REAL WORLD EXPERIENCE IN THE MANAGEMENT OF WALDENSTRÖM'S MACROGLOBULINAEMIA FROM ANALYSIS OF THE RORY MORRISON REGISTRY

Background: Waldenström's Macroglobulinaemia (WM) is characterised by the presence of an IgM paraprotein and bone marrow infiltration by lymphoplasmacytic lymphoma (Owen et al. 2003); patients present in a variable manner (Castillo et al 2016). A variety of treatments are used at front line and relapse. Current guidelines advocate chemoimmunotherapy in both settings (Owen et al. 2014). Novel agents are also effective spurred on by biological discoveries, including the somatic mutations in MYD88 and CXCR4 genes, but their precise role remains to be determined. Ibrutinib became available in the UK in 2017 via the Cancer Drugs Fund (CDF) for WM in the relapsed setting (NICE TA491). Aims: To describe the natural history of WM, monitor usage and impact of treatments including emerging therapies on outcomes in the UK Methods: The Rory Morrison Registry (RMR) collects data from existing and new patients with WM & related conditions from (so far) 14 centres across the UK using entry on to a web‐based platform. 701 patients are registered including 560 with a confirmed WM diagnosis. We describe treatment trends from across the UK at front line and first relapse. To facilitate analysis, we grouped the regimens. Results: 383 patients have received front line therapy with at least 29 different regimens since 1984, and 215 second line therapy with at least 32 different regimens. The most common categories were DRC (90 patients; 23%), Alkylator based (75, 20%), R‐Bendamustine (50; 13%) and CHOP‐based (42; 11%), Other (37, 10%), Purine analogue (PA)‐based therapy (35; 9%), Rituximab monotherapy (R‐mono) (34, 9%), Bortezomib‐based (17; 4%) and BTK inhibitors (3, 1%). The use of each treatment has noticeably changed over time (See graph). The peak treatment choices in the early 2000 s were Alkylator‐ or CHOP‐based therapies. This has been superseded by DRC (since 2007) and R‐Bendamustine (since 2011). There has been a stable role for R‐mono and PA‐based therapy. Regimens used at first relapse have been highly variable till 2017 when Ibrutinib became available. Treatments from 209 patients at first relapse since 1984 show that the most common category was ‘Other’ (52; 25%), followed by BTK Inhibitors (41; 21%), R‐mono (including maintenance rituximab) (22; 11%), Alkylator‐based (21; 10%), PA‐based (19; 9%), DRC (19, 9%), Bendamustine‐based (17, 8%), CHOP‐based (13; 6%) and Bortezomib‐based (5; 2%). Notably, since 2017, of the 58 patients having 2 nd line therapy 34 (58%) received BTK inhibitors. Summary/Conclusion: Observations from the Rory Morrison Registry demonstrate the evolving trends in WM treatment in the UK, including the emergence of DRC and R‐Bendamustine as standard frontline therapy and a preference for BTK inhibition as 2 nd line therapy, since their availability. Further analysis is planned to assess the ‘real world’ impact of the emerging treatments.