Clinical Outcomes of Lymphoplasmacytic Lymphoma / Waldenstrom Macroglobulinemia (LPL/WM) in the Targeted Therapy Era: A US Multicenter Retrospective Analysis

• Published in: Blood 2024-11, Vol.144 (Supplement 1), p.4392-4392
• Main Authors: Tariq, Muhammad Junaid, Attwood, Kristopher, Anampa-Guzmán, Andrea Carolina, Hamid, Showkat, Niu, Alex, Kaldas, David, Thapa, Shrinjaya B, Leng, Jessica, Youssef, Youssef, Carroll, Keegan, Treitman, Rachel, Rafae, Abdul, Singhal, Sachi, Nakhoda, Shazia K., Al Hadidi, Samer, Bair, Steven M., Voorhees, Timothy, Epperla, Narendranath, Caimi, Paolo F., Grajales-Cruz, Ariel F., Hernandez-Ilizaliturri, Francisco, Cortese, Matthew J
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2024-199278

Background: Lymphoplasmacytic lymphoma (LPL) is a rare indolent disease characterized by malignant proliferation of B-lymphocytes with plasmacytic differentiation and typically has MYD88 mutation. An IgM monoclonal gammopathy and bone marrow involvement defines Waldenstrom Macroglobulinemia (WM), and non-IgM LPL is rare. Treatments for LPL/WM have evolved over the past decade with the availability of targeted therapies, especially Bruton's kinase inhibitors (BTKi). We reviewed over 20 years of data to assess how patient and disease characteristics, treatment choices, and key mutations (TP53 and CXCR4) affect clinical outcomes. Methods: We conducted a multicenter retrospective analysis of patients (age ≥18 years) diagnosed with LPL/WM between January 1, 2003, and March 31, 2024 at 7 academic centers in USA. The outcomes of the study included objective response rate (ORR), time to next treatment (TTNT), and overall survival (OS). ORR (CR, VGPR, PR and MR) was calculated according to response criteria per the 6th International Workshop for WM. Associations between baseline characteristics and survival outcomes were evaluated using Cox regression models. Results: A total of 709 patients were included in this analysis. Patients had a median age of 68 years, with a male predominance (60%), were largely white (91%) and generally had good performance status (53% ECOG 0). An IgM monoclonal gammopathy was present in 98% (n=692) of all patients, followed by IgG in 1% (n=9) and IgA in 0.4% (n=3). An IgM monoclonal protein of ≥3000 mg/dl was present in 33% (n=232) patients and the median M-protein concentration was 1.56 g/dL at diagnosis. Only 6% patients (n=46) required plasmapheresis at some point in their treatment course. MYD88 mutation was present in 85% (448 of 529) patients with available MYD88 results. Mutations in CXCR4 and TP53 were present in 5% (11 of 130) and 14% (41 of 303) of patients respectively at diagnosis. Twenty percent (n=143) patients were observed with no treatment required. Frontline treatment (1L) with chemo-immunotherapy (CIT) was the most common treatment modality (34%, n=242), with bendamustine-rituximab being the most prescribed CIT (23%, n=160) followed by cyclophosphamide-rituximab combinations (9%, n=60). After CIT, single agent rituximab (R) was used in 22% (154) patients, followed by BTKi with or without anti-CD20 therapies in 11% (81), then proteasome inhibitor (PI) based regimens (8%, 59 patients), and finally chemotherapy without a