Long-term results of Waldenström macroglobulinaemia treatment by bendamustine and rituximab: A study on behalf of the French Innovative Leukemia Organization (FILO).

The bendamustine-rituximab (BR) schedule is an efficient first-line therapy in Waldenström macroglobulinaemia (WM). A previous analysis of 69 patients who received this treatment confirmed a high response rate and good progression-free (PFS) and overall survival (OS). With a median follow-up of 76.1 months (95% confidence interval [CI] 69.9-80.6), 5-year outcome is still excellent at 66.63% (95% CI 56.09-79.17) for PFS and 80.01% (95% CI 70.82-90.41) for OS. The rate of secondary cancers is 17.66% (IQR 7.99-27.64) at 66 months. Relapsed patients who received ibrutinib as second-line clearly benefited from this schedule. This confirms current recommendations suggesting BR long-term efficacy as first-line option in WM.

Clinical and clonal characteristics of monoclonal immunoglobulin M-associated type I cryoglobulinaemia.

Monoclonal immunoglobulin M-associated type I cryoglobulinaemia is poorly characterised. We screened 534 patients with monoclonal IgM disorders over a 9-year period and identified 134 patients with IgM type I cryoglobulins. Of these, 76% had Waldenström macroglobulinaemia (WM), 5% had other non-Hodgkin lymphoma (NHL) and 19% had IgM monoclonal gammopathy of undetermined significance (MGUS). Clinically relevant IgM-associated disorders (including cold agglutinin disease [CAD], anti-MAG antibodies, amyloidosis and Schnitzler syndrome) coexisted in 31%, more frequently in MGUS versus WM/NHL (72% vs. 22%/29%, p < 0.001). The majority of those with cryoglobulins and coexistent CAD/syndrome had the molecular characteristics of a CAD clone (wild-type MYD88 in 80%). A half of all patients had active manifestations at cryoglobulin detection: vasomotor (22%), cutaneous (16%), peripheral neuropathy (22%) and hyperviscosity (9%). 16/134 required treatment for cryoglobulin-related symptoms alone at a median of 38 days (range: 6-239) from cryoglobulin detection. At a median follow-up of 3 years (range: 0-10), 3-year cryoglobulinaemia-treatment-free survival was 77% (95% CI: 68%-84%). Age was the only predictor of overall survival. Predictors of cryoglobulinaemia-related treatment/death were hyperviscosity (HR: 73.01; 95% CI: 15.62-341.36, p < 0.0001) and cutaneous involvement (HR: 2.95; 95% CI: 1.13-7.71, p = 0.028). Type I IgM cryoglobulinaemia is more prevalent than previously described in IgM gammopathy and should be actively sought.

A phase II study of ibrutinib in combination with ixazomib in patients with Waldenström macroglobulinaemia.

This phase II study evaluated time-limited (24 cycles) treatment with ibrutinib and ixazomib in newly diagnosed (NDWM; n = 9) and relapsed/refractory (RRWM; n = 12) Waldenström macroglobulinaemia (WM). The overall response rate (ORR) was 76.2% (n = 16) in 21 evaluable patients with no patient achieving a complete response (CR). The median duration of treatment was 15.6 months, and after a median follow-up time of 25.7 months, the median progression-free survival (PFS) was 22.9 months. While the primary end-point was not met (CR rate at any time) and 28.5% discontinued treatment due to toxicity, ibrutinib plus ixazomib led to a clinically meaningful ORR and PFS. Combined Bruton's tyrosine kinase (BTK) and proteasome inhibition merits further evaluation in WM.

Prognostic impact of nodal involvement in Waldenström macroglobulinaemia.

The clinical and prognostic implications of nodal involvement (NI) in Waldenström macroglobulinaemia (WM) are largely unknown. In this study, we explored the impact of NI on clinical presentation and outcome in a population-based cohort of 469 patients with WM, consecutively diagnosed between 2000 and 2022. NI was detected in 34% of patients and was associated with symptomatic disease, adverse prognostic factors, an increased risk of transformation, and lymphoma-related death. Our findings indicate that NI is of prognostic significance in WM, suggesting a need for enhanced surveillance in these patients.

PembroWM: A phase II trial to investigate the safety and efficacy of rituximab and pembrolizumab in relapsed/refractory Waldenström's Macroglobulinaemia.

The optimal therapeutic approach for relapsed/refractory (R/R) Waldenström's Macroglobulinaemia (WM) has not been clearly defined, especially after treatment with chemoimmunotherapy (CIT) and covalent Bruton's tyrosine kinase inhibitors (cBTKi). The PembroWM trial is a multi-centre, phase II, single-arm study assessing the safety, tolerability and efficacy of rituximab with pembrolizumab in R/R WM patients who had received at least one prior line of treatment, with all having relapsed post-CIT and most also exposed to cBTKi. A total of 17 patients were enrolled, with a median age of 70, and median of three prior lines of therapy with 15 either refractory or intolerant of a cBTKi. A significant proportion was identified as genomically high risk with BTKC481, CXCR4 and MYD88 L265P wild-type aberrations. Twenty-four-week overall response rate was 50% (60% CI 39.3%-60.7%), and median duration of response was 11.6 months (IQR: 6.3-17). The median progression-free survival was 13.6 months (95% CI 3-19.8), and the median overall survival (OS) was not reached. Treatment was well tolerated, with minimal numbers of immune-mediated AEs typically seen with checkpoint inhibitors. PembroWM is the first study to evaluate the feasibility of PD-1 axis modulation in WM and has shown that in combination with Rituximab the combination is safe and deliverable.

ERK1/2 pro-survival signalling is suppressed by pirtobrutinib in ibrutinib-resistant MYD88-mutated lymphoma cells.

Covalent Bruton's tyrosine kinase-inhibitors (cBTK-i) are highly active in MYD88-mutated (MYD88Mut) Waldenstrom's macroglobulinaemia and suppress nuclear factor kappa-light-chain-enhancer of activated B cells and extracellular signal-regulated kinases-1/2 (ERK1/2)-related signalling. BTKCys481 mutations are associated with cBTK-i acquired resistance and are accompanied by reactivation of ERK1/2 that promotes inflammatory cytokine secretion and paracrine-mediated resistance of BTK wild-type (BTKWT) tumour cells. Pirtobrutinib is a non-covalent BTK-inhibitor that binds at non-BTKCys481 sites. We show that pirtobrutinib blocked p-ERK1/2, ERK1/2-driven inflammatory cytokines, and overcame paracrine-mediated resistance in MYD88Mut lymphoma cells expressing mutated BTKCys481. Our results provide important mechanistic insights for the activity of pirtobrutinib in MYD88Mut lymphomas carrying BTKCys481 mutations.

Serum CXCL13 level is related to treatment response and predicts disease prognosis in Waldenström macroglobulinemia.

Waldenström macroglobulinemia (WM) is a type of B-cell lymphoma that produces IgM. Our study aimed to investigate the role of CXCL13, a chemokine essential for B lymphocytes, in the evaluation of treatment response and prognosis in WM. We collected serum samples and clinical data from 72 WM patients, with 69 patients receiving systemic therapy and 3 patients opting not to receive treatment. Serum CXCL13 levels at baseline and after six months of treatments were measured by enzyme-linked immunosorbent assay. The median serum level of CXCL13 was 1 539.2 pg/ml (range 10.0-21 389.9) at baseline and significantly decreased to 123.1 pg/ml (range 0.0-6 741.5) after 6 months of treatments. At baseline, higher CXCL13 levels were associated with lower hemoglobin levels (p = 0.001), higher ß2-microglobulin levels (p = 0.001), lower albumin levels (p = 0.046), and higher IPSS-WM scores (p = 0.013). After 6 months of treatment, patients who achieved PR/VGPR had significantly lower CXCL13 levels compared to those with SD (70.2 pg/ml vs 798.6 pg/ml, p = 0.002). The median follow-up period was 40 months (range 4.2-188). Eight patients died during the follow-up period. Overall survival differed based on CXCL13 levels. When grouped by baseline CXCL13 levels, the median OS was 60.0 months in patients with serum CXCL13 > 2 000 pg/ml, while it was not reached in patients with low CXCL13 levels (p < 0.001). Based on CXCL13 levels after the treatments, the median OS was 74.0 months in patients with serum CXCL13 > 200 pg/ml, while it was not reached in patients with CXCL13 ≤ 200 pg/ml. In a subgroup of 28 patients with a series of serum samples, the increase of serum CXCL13 level was associated with disease progression or the start of next-line therapy (p < 0.001). Our study concludes that serum CXCL13 levels decrease in WM patients treated with various regimens and correlate with treatment response. Detecting serum CXCL13 at baseline or after treatment help in predicting prognosis.

Impact of the presence and number of chromosomal abnormalities on the clinical outcome in Waldenström Macroglobulinemia: a monocentric experience.

The prognostic and predictive role of specific gene mutations in Waldenström Macroglobulinemia (WM) is well-ascertained whereas the clinical impact of chromosome aberrations is far less known. Recent work has provided initial evidence for an adverse prognostic impact of some aberrations, such as del(6q), while other studies suggest a possible relationship between some clinical features (e.g. advanced age and/or inflammatory status) and specific cytogenetic abnormalities. To add to the still limited knowledge on WM cytogenetics and its clinical implications, we herein report our experience in a cohort of WM patients across 23 years. Based on our retrospective study, we found that abnormal karyotype was more represented in older patients and maintained a statistically significant independence from other molecular, clinical, and biological features related to WM. The presence and number of cytogenetic aberrations correlated with inferior overall and progression-free survival outcomes regardless of the type of single chromosome aberration. Our data suggests that the role of the altered karyotype deserves to be further clarified especially in elderly WM patients, in whom cytogenetic abnormalities and disease biology appear to be characterized by a higher degree of complexity.

Impact of chromosomal aberrations detected by chromosome banding analysis in symptomatic Waldenström's macroglobulinemia.

The clinicopathologic features and prognostic impact of MYD88 L265P (MYDL265P) and CXCR4 mutations (CXCR4Mut) have been well reported, although little is known regarding the impact of chromosomal aberrations (CA) detected by chromosome banding analysis (CBA) in symptomatic Waldenström's macroglobulinemia (sWM). Thus, we investigated the clinicopathologic features and prognostic impact in sWM with CAs identified by CBA. We retrospectively analyzed the clinicopathologic results and genomic alterations by droplet digital PCR, fluorescence in situ hybridization (FISH), and CBA using the G-banding method in bone marrow samples from sWM patients collected between April 2010 and March 2024 at our institute. The relationship between CAs and clinicopathologic features was evaluated, as well as the time to next treatment (TTNT). Thirty-five patients were enrolled. The median age was 71 years, and the median hemoglobin level was 10.1 g/dL. The median serum IgM and M-protein levels were 3,009 mg/dL and 2.95 g/dL, respectively. MYDL265P was found in 30/35 patients (85.7%), whereas CXCR4Mut was found in 3/35 patients (8.6%). Deletion 6q identified by FISH in 5/18 patients (28%), and CAs using CBA in 9/34 patients (26%), including 4/34 (12%) complex karyotypes. sWM with CAs had more anemia (p = 0.04) and hypoalbuminemia (p = 0.007), in addition to higher serum M-protein and IgM levels (p = 0.03). With a median follow-up of 73 months, the median TTNT in patients with and without CAs was 27 and 68 months, respectively. CAs with CBA may be associated with clinical aggressiveness and shorter TTNT in sWM.

Health-related quality of life in patients with Waldenström macroglobulinemia: results from the ASPEN trial.

Aim ASPEN is a randomized, open-label, Phase III study comparing zanubrutinib and ibrutinib in patients with Waldenström macroglobulinemia (WM).Materials & methods: Patient-reported outcomes were exploratory end points assessed using the EORTC QLQ-C30 and EQ-5D-5L VAS scores.Results: Overall, 201 patients (102 zanubrutinib; 99 ibrutinib) were enrolled. Clinically meaningful differences were observed in diarrhea and nausea/vomiting in both the intent-to-treat population and in patients attaining very good partial response (VGPR) in earlier cycles of treatment, as well as in long-term physical functioning and fatigue in patients achieving VGPR.Conclusion: Treatment with zanubrutinib was associated with greater improvements in health-related quality of life compared with ibrutinib in patients with WM and MYD88 mutations.Clinical Trial Registration: NCT03053440 (ClinicalTrials.gov).

Patient quality of life is importantWhat is this article about? This article talks about a study called the ASPEN trial, which compares two medicines used for treating a rare blood cancer that doctors call Waldenström macroglobulinemia. The medicines are called zanubrutinib (ZAN) and ibrutinib (IBR). They work in the same way, by blocking a protein called Bruton tyrosine kinase. When patients take medicines for an illness, it is important to learn about their physical, social, emotional and mental well-being (quality of life). In this study, we asked patients to fill out questionnaires about their well-being before starting the study treatment for their blood cancer, and again a few times while taking the medication, to see if there were any changes.What were the results of the study? There were two groups of patients. One group took ZAN and the other took IBR. The patients could not choose which medicine they were going to take. Results from both groups of patients were compared. Patients taking ZAN did not feel worse or better about their diarrhea and sickness, but those taking IBR said these symptoms had become worse. Both medicines improved how patients were feeling. However, improvement in tiredness and physical ability was larger in patients taking ZAN than those on IBR, especially for the patients whose cancer was getting better.What do the results mean? For patients with a rare blood cancer in this study, those taking ZAN had a better quality of life than those taking IBR.

Antineutrophil cytoplasmic antibody-negative pauci-immune glomerulonephritis in a patient with Waldenstrom macroglobulinaemia.

Waldenstrom macroglobulinaemia (WM), the predominant subtype of lymphoplasmacytic lymphoma with bone marrow involvement and serum IgM paraprotein, is a haematological condition commonly associated with renal parenchymal involvement. However, antineutrophil cytoplasmic antibody (ANCA)-negative pauci-immune crescentic glomerulonephritis (PICGN) in kidney infiltrated by lymphoma is very rare, with only two cases described in chronic lymphocytic leukaemia in English literature so far. We herein report the first patient with WM developing ANCA-negative PICGN. He was a 76-year-old male who presented with elevated serum globulin level and bilateral groin lymph node enlargement, subsequently diagnosed to have WM after pathologic examination of the bone marrow and groin lymph node. One month later, he was found to have acute kidney injury and proteinuria. Renal biopsy confirmed the presence of parenchymal involvement by WM accompanied by PICGN; while ANCA testing was negative. He was treated with pulse methylprednisolone followed by oral prednisolone. In addition, six courses of intravenous rituximab and oral cyclophosphamide were given. There was significant improvement in both his renal and haematological conditions. The clinical course of this case suggested that ANCA-negative PICGN may represent a paraneoplastic syndrome and a rare manifestation of WM-associated renal lesion. Early kidney biopsy and prompt treatment may improve the outcome of patients.

Invasive fungal infection incidence and risk factors in patients receiving ibrutinib in real-life settings: A nationwide population-based cohort study.

BACKGROUND: Data on the risk of invasive fungal infections (IFI) with ibrutinib treatment are scarce. OBJECTIVES: This study aimed to determine IFI incidence and risk factors in ibrutinib-treated patients in real-life settings. METHODS: We constituted a cohort of ibrutinib incident users in the French National Healthcare Database. All patients ≥18 years with a first dispensing of ibrutinib between 21 November 2014 and 31 December 2019 were included. Patients were followed from the cohort entry date until IFI, ibrutinib discontinuation, death, or 31 December 2020, whichever came first. The cumulative incidence function method was used to estimate the probability of IFI accounting for competing risk of death. A multivariate cause-specific Cox proportional hazards model was used to assess independent IFI risk factors. RESULTS: Among 6937 ibrutinib-treated patients, 1-year IFI cumulative incidence was 1.3%, with invasive aspergillosis being the most frequent. Allogenic or autologous stem cell transplantation (ASCT) (hazard ratio [HR] 3.59, 95% confidence interval [1.74; 7.41]), previous anticancer treatment (HR 2.12, CI 95% [1.34; 3.35]) and chronic respiratory disease (HR 1.66, [1.03; 2.67]) were associated with higher risk of IFI. Besides neutropenia and corticosteroids, use of anti-CD20 agents was significantly more frequent in patients having experienced IFI (HR 3.68, [1.82; 7.45]). CONCLUSIONS: In addition to patients with ASCT history, severe neutropenia or treated with corticosteroids, our findings support active surveillance of IFIs in those with chronic respiratory disease, previously treated, or treated with anti-CD20 agents in combination with ibrutinib. Further studies are needed to optimise IFI prophylaxis in these patient subgroups.

Infection as a trigger of acute, transient glomerular deposition of clonal immunoglobulins.

Glomerular deposition of monoclonal IgM, frequently in the form of intracapillary pseudothrombi, can be seen in Waldenström macroglobulinemia (WM) and type I cryoglobulinemia (CG). They are typically associated with plasma cell or B-lymphoid neoplasms, particularly lymphoplasmacytic lymphoma (LPL). While infection is a frequent trigger of mixed (type II and III) CG, its association with type I CG is uncommon. We report two cases in which striking lambda-chain-restricted IgM deposits and acute kidney injury (AKI) occurred in the setting of known or suspected systemic infections, with prompt resolution on treatment of the infection.

Sustained Response of Ibrutinib in a Patient with Waldenstrom Macroglobulinemia Presenting with Myasthenic Crisis as a Paraneoplastic Neurological Syndrome: A Case Report and Review of Literature.

Paraneoplastic syndrome is a broad spectrum of signs and symptoms due to neoplasm, attributed to substances produced by tumor cells, or in response to it. Myasthenia gravis (MG) is a well-known paraneoplastic neurological syndrome (PNS), frequently associated with thymic abnormalities, but rarely reported in patients with lymphoplasmacytic lymphoma.This study presents the case of a 52-year-old Indonesian male patient who was diagnosed with Waldenstrom macroglobulinemia (WM), a rare B-cell neoplasm, after developing a new onset of MG with myasthenic crisis. the patient's MG features improved with Ibrutinib as a treatment targeted toward cancer. This is the first case report presenting the treatment response of Ibrutinib in WM with myasthenic crisis. The literature was reviewed to explain the possibility of MG as a paraneoplastic syndrome of WM and the treatment response of Ibrutinib for this patient, as well as summarizing previous case reports of concomitant MG and WM.MG should be considered a paraneoplastic malignancy syndrome, including WM, during diagnostic workup. Ibrutinib should also be considered when available to patients, due to its adequate response in both previously treated and treatment naïve patients.

Dysfunctions of innate and adaptive immune tumor microenvironment in Waldenström macroglobulinemia.

Waldenström macroglobulinemia (WM) is a rare subtype of non-Hodgkin lymphoma characterized by malignant lymphoplasmacytic cells in the bone marrow (BM). To dissect the pathophysiology of WM, we evaluated clonal cells by mapping of B cell lymphomagenesis with adaptive and innate immune tumor microenvironment (TME) in the BM of WM patients using mass cytometry (CyTOF). In-depth immunophenotypic profiling of WM cells exhibited profound expansion of clonal cells in both unswitched and switched memory B cells and also plasma cells with aberrant expression variations. WM B lymphomagenesis was associated with reduction of most B cell precursors assessed with the same clonally restricted light chain and phenotypic changes. The immune TME was infiltrated by mature monocytes, neutrophils and adaptive T cells, preferentially subsets of effector T helper, effector CTL and effector memory CTL cells that were associated with superior overall survival (OS), in contrast to progenitors of T cells and myeloid/monocytic lineage subsets that were suppressed in WM cohort. Moreover, decrease in immature B and NKT cells was related to worse OS in WM patients. Innate and adaptive immune subsets of WM TME were modulated by immune checkpoints, including PD-1/PD-L1&PD-L2, TIGIT/PVR, CD137/CD137-L, CTLA-4, BTLA and KIR expression. The response of ibrutinib treatment to the reduction of clonal memory B cell was associated with high levels of immature B cells and effector memory CTL cells. Our study demonstrates that CyTOF technology is a powerful approach for characterizing the pathophysiology of WM at various stages, predicting patient risk and monitoring the effectiveness of treatment strategies.

Dose reductions in patients with Waldenström macroglobulinaemia treated with ibrutinib.

Waldenström macroglobulinaemia (WM) is characterized by the presence of a MYD88L265P mutation. This mutation promotes growth and survival of malignant cells through Bruton tyrosine kinase (BTK) activation. Ibrutinib was the first BTK inhibitor approved for WM. Intolerance to ibrutinib frequently leads to dose reductions, though the impact of reducing ibrutinib dosing has not been systematically studied. We performed a retrospective study to determine the frequency and impact of reducing ibrutinib dosing in WM patients. With a median treatment time of 64 months, 96 (27%) of 353 WM patients required a dose reduction due to adverse events such as musculoskeletal symptoms, cardiac events, dermatologic symptoms, cytopenias, and gastrointestinal symptoms. The median time to initial dose reduction was 9.3 months (range, 0.5-74). Dose reductions were more common in those 65 years of age or older versus under 65 [hazard ratio (HR) 2.46, 95% confidence interval (CI) 1.55-3.90; p < 0.001], and in females versus males (HR 2.20, 95% CI 1.41-3.28, p < 0.001). Most patients (65%) had improvement or resolution of adverse effects after initial dose reduction. With a median follow-up of three years from dose reduction, hematologic response sustained or deepened in 79% of patients. These data suggest that dose reduction of ibrutinib is a reasonable treatment approach for patients with intolerable side effects.

Dose of ibrutinib in Waldenström macroglobulinaemia: Less can be more.

Ibrutinib changed the landscape of treatment in Waldenström macroglobulinaemia (WM) with excellent responses; however, there are high rates of dose reduction due to adverse events. The impact of this reduced dosing is unclear with regards to outcomes. Sarosiek and colleagues provide valuable data in a very large retrospective study demonstrating that dose reduction is effective in managing adverse events in the majority, with equivalent, if not better, outcomes than those without dose reductions.

The Rory Morrison WMUK Registry for Waldenström macroglobulinaemia: The growth of a national registry for a rare disorder.

National registries are used globally to characterise patient demographics, treatment choices and mortality to inform and improve clinical management. Waldenström macroglobulinaemia (WM) is a rare, treatment-responsive B-cell lymphoproliferative disorder with diverse clinical features and variable outcomes. To prospectively chart changes in the management of WM in the UK, the Rory Morrison Registry (RMR) was developed to systematically collect real-world data. Here we describe the development of the RMR, demonstrate its feasibility and describe preliminary observations. The RMR was devised as a collaborative project between patients and clinicians, under the auspices of the UK Charity for WM in 2016. Patients may be registered after the point of diagnosis and those with historic diagnosis were also eligible. Data collection fields were compiled by focus groups of clinicians, patients, industry and commissioning partners. The RMR launched in November 2017 and as of March 2022, there were 22 participating centres and 1305 patients registered. Median follow-up was 6.4 years, five-year overall survival 90.7% (95% confidence interval [CI] 88.4%-92.5%) and 10-year overall survival 79.3% (95% CI 75.7%-82.4%). There has been a clear evolution in treatments including a rapid growth in the use of Bruton's tyrosine kinase inhibitors in relapsed disease since their availability in the UK.

Prognostic impact of MYD88 and CXCR4 mutations assessed by droplet digital polymerase chain reaction in IgM monoclonal gammopathy of undetermined significance and smouldering Waldenström macroglobulinaemia.

Waldenström macroglobulinaemia (WM) is characterized by recurrent somatic mutations in MYD88 and CXCR4 genes. However, limitations arise when analysing these mutations in IgM monoclonal gammopathy of undetermined significance (MGUS) or smouldering WM (SWM) given the lower tumour load. Here, we used droplet digital polymerase chain reaction (ddPCR) to analyse MYD88 L265P and CXCR4 S338* mutations (C1013G and C1013A) in unsorted bone marrow (BM) or cell-free DNA (cfDNA) samples from 101 IgM MGUS and 69 SWM patients. ddPCR was more sensitive to assess MYD88 L265P compared to allele-specific PCR, especially in IgM MGUS (64% vs 39%). MYD88 mutation burden correlated with other laboratory biomarkers, particularly BM infiltration (r = 0.8; p < 0.001). CXCR4 C1013G was analysed in MYD88-mutated samples with available genomic DNA and was detected in 19/54 (35%) and 18/42 (43%) IgM MGUS and SWM cases respectively, also showing correlation with BM involvement (r = 0.9; p < 0.001). ddPCR also detected 8 (38%) and 10 (63%) MYD88-mutated cfDNA samples in IgM MGUS and SWM respectively. Moreover, high BM mutation burden (≥8% MYD88 and ≥2% CXCR4) was associated with an increased risk of progression to symptomatic WM. We show the clinical applicability of ddPCR to assess MYD88 and CXCR4 in IgM MGUS and SWM and provide a molecular-based risk classification.

Born in the UK: A registry to improve and broadcast knowledge on Waldenström macroglobulinaemia.

Registries constitute an interesting source of real-world data and bring complementary information to randomised controlled trials. They are of particular importance in rare diseases such as Waldenström macroglobulinaemia (WM), which can present with various clinical and biological features. In their paper Uppal and colleagues describe the development of the Rory Morrison Registry, the UK registry for WM and IgM-related disorders and highlight the profound changes in therapies both at first-line and relapsed settings in the recent years. Commentary on: Uppal E. et al. The WMUK Rory Morrison Registry for Waldenström Macroglobulinaemia: the growth of a national registry for a rare disorder. Br J Haematol. 2023;201:905-912.