Waldenström's Macroglobulinemia Clinical Trials — 2026 Pipeline

Active Phase 2 and Phase 3 recruiting trials — Waldenström's macroglobulinemia / lymphoplasmacytic lymphoma (March 2026)

The table below reflects key recruiting and active trials on ClinicalTrials.gov for Waldenström's macroglobulinemia as of March 2026, organized by treatment setting. DataLookout monitors for new registrations and status changes daily.

Sources: ClinicalTrials.gov. DataLookout monitors for new registrations and status updates daily. Table reflects recruiting and active trials as of March 2026.

Waldenström's macroglobulinemia: a molecularly defined disease with a rapidly maturing BTK inhibitor landscape

Waldenström's macroglobulinemia is biologically unique among B-cell malignancies. Its dual identity — simultaneously a lymphoma (lymphoplasmacytic lymphoma) and a plasma cell dyscrasia (IgM secreting) — means it draws on biology from both CLL and multiple myeloma while responding to neither paradigm completely. The discovery of MYD88 L265P in ~90–95% of patients in 2012 (Hunter et al., NEJM) transformed WM from an orphan disease with chemoimmunotherapy as its only option to one of the most molecularly tractable rare hematologic malignancies.

The clinical trial landscape in WM has accelerated around three converging themes: (1) BTK inhibitor optimization — moving from ibrutinib to more selective agents and addressing acquired resistance via non-covalent BTK inhibitors; (2) rational combination therapy — dual targeting of BTK + BCL-2, BTK + CXCR4, or BTK + anti-CD20 to achieve MRD negativity; and (3) emerging immunotherapy — CAR-T and bispecific antibodies adapted from lymphoma/myeloma platforms but requiring target and dosing adjustment for WM biology.

Standard front-line regimens: BCD, BR, and DRC

Chemoimmunotherapy backbone: BR, BCD, DRC

Before BTK inhibitors, WM was treated with rituximab-based chemoimmunotherapy regimens. Three regimens remain widely used, particularly when continuous oral BTK therapy is not feasible: BR (bendamustine + rituximab), BCD (bendamustine + cyclophosphamide + dexamethasone), and DRC (dexamethasone + rituximab + cyclophosphamide). BR achieves ORR ~90%, major response rate ~80%, and median PFS ~69 months in treatment-naive WM — comparable to or slightly superior to ibrutinib monotherapy in front-line disease, though without head-to-head Phase 3 data. These regimens are time-limited (typically 6 cycles), avoiding the indefinite dosing and cumulative toxicity of continuous BTK inhibitor therapy. DRC is preferred in patients where avoiding cytopenias is prioritized. In clinical trial design, BR and BCD are the most common chemoimmunotherapy comparators or combination backbone agents.

BTK inhibitor landscape: ibrutinib, zanubrutinib, and pirtobrutinib

Ibrutinib (Imbruvica) — the iNNOVATE data and long-term follow-up

Ibrutinib was the first BTK inhibitor FDA-approved in WM (August 2015 for R/R disease; October 2018 for combination ibrutinib + rituximab in treatment-naive and R/R WM). The pivotal iNNOVATE Phase 3 trial (NCT01691898) demonstrated the combination superiority over placebo + rituximab: ORR 92% vs. 47%, PFS not reached vs. ~21 months at 30-month follow-up, with consistent benefit across MYD88 L265P-mutant and MYD88 wild-type subgroups. Long-term iNNOVATE follow-up data (5-year analysis) showed ~70% of patients remained progression-free on ibrutinib + rituximab, establishing the combination as a front-line standard of care for symptomatic WM.

However, ibrutinib's toxicity profile has limited its use. The off-target inhibition of ITK, TEC, and EGFR-family kinases drives a distinctive adverse event profile: atrial fibrillation (~16–20% in WM-relevant long-term follow-up), ventricular arrhythmias, hypertension requiring antihypertensives, bleeding (particularly relevant in patients on anticoagulation for AF), arthralgias, and rash. Real-world WM series show that approximately 30–40% of patients discontinue ibrutinib within 3 years due to adverse events — not disease progression — a discontinuation profile that directly motivated the development of more selective next-generation BTK inhibitors.

Zanubrutinib (Brukinsa) — the ASPEN safety advantage

Zanubrutinib (BeiGene) is a highly selective, covalent BTK inhibitor engineered to minimize off-target kinase activity. The Phase 3 ASPEN trial (NCT03053440) compared zanubrutinib versus ibrutinib in 229 patients with MYD88 L265P-mutant WM (both treatment-naive and R/R). The primary endpoint — CR + VGPR rate — was not statistically superior at the initial 18-month analysis (28.4% vs. 19.2% for zanubrutinib vs. ibrutinib; p=0.09), though the numerical advantage favored zanubrutinib. The key differentiator was safety: atrial fibrillation rate was dramatically lower with zanubrutinib (2.6% vs. 15.5%), as was the rate of dose reductions (13% vs. 26%) and cardiac events overall. Updated long-term ASPEN follow-up demonstrated deepening responses over time with zanubrutinib and confirmed the sustained safety advantage. Zanubrutinib received FDA approval in WM in August 2021 and is now widely considered the preferred BTK inhibitor for most WM patients, particularly those at cardiovascular risk or requiring anticoagulation.

Pirtobrutinib (Jaypirca) — the BTK-resistant setting and BRUIN data

Pirtobrutinib (Eli Lilly) is a non-covalent, reversible BTK inhibitor that targets the ATP-binding site rather than forming a covalent bond with BTK cysteine-481. This mechanism confers activity against the BTK C481S mutation — the most common acquired resistance mechanism to ibrutinib and zanubrutinib, arising in approximately 20–30% of WM patients who progress on covalent BTKi therapy. In the BRUIN Phase 1/2 trial (NCT03740529), pirtobrutinib demonstrated an ORR of approximately 68% in the WM cohort, including patients with confirmed BTK C481S mutations and those who progressed on prior covalent BTKi therapy. Response rates were consistent across CXCR4-mutant and wild-type patients — in contrast to covalent BTKi, where CXCR4 mutations reduce efficacy. Pirtobrutinib received FDA Breakthrough Therapy Designation in R/R WM based on BRUIN data and is in registration-intent trials as of 2026. For BD teams tracking the WM pipeline, pirtobrutinib represents the dominant near-term regulatory event in the space.

BCL-2 targeting: venetoclax in WM

Venetoclax monotherapy and combination strategies

WM cells express high levels of BCL-2, the anti-apoptotic protein that is venetoclax's target. Phase 2 data for venetoclax monotherapy in R/R WM (NCT02471261) demonstrated an ORR of ~80% and major response rate (MRR, defined as at least partial response achieving IgM reduction) of ~70%, with responses seen across MYD88-mutant and MYD88 wild-type patients. This is clinically significant because venetoclax represents one of the most active single agents available for MYD88 wild-type WM — a subgroup with worse prognosis and inferior BTK inhibitor response where alternative mechanisms are urgently needed.

The combination of venetoclax + ibrutinib is being evaluated in WM based on CLL precedent (CAPTIVATE, GLOW), where dual BTK + BCL-2 inhibition achieves high rates of MRD negativity and enables time-limited therapy. Phase 2 data from venetoclax + ibrutinib in R/R WM show VGPR rates significantly higher than BTKi monotherapy, with acceptable tolerability. The key question for future trial design is whether time-limited venetoclax + BTKi combination therapy can achieve durable MRD-negative remissions in WM — analogous to what has been demonstrated in CLL — potentially enabling treatment discontinuation in some patients for the first time.

CXCR4 mutations and pathway-directed therapy

WHIM pathway and BTK inhibitor resistance mechanisms

CXCR4 mutations (~30–35% of WM) create a distinct disease subgroup with reduced BTK inhibitor efficacy and shorter progression-free survival. CXCR4 gain-of-function mutations activate PI3K/AKT and ERK signaling independent of BTK, providing a survival escape route for WM cells during BTK inhibitor therapy. Clinically, CXCR4-mutant WM patients treated with ibrutinib have lower major response rates and shorter time to progression compared to CXCR4 wild-type patients, despite similar MYD88 L265P mutation rates.

Ulocuplumab (BMS-936564), a fully human IgG4 anti-CXCR4 antibody, has been evaluated in Phase 1b/2 trials in combination with ibrutinib specifically in CXCR4-mutant WM (NCT02975648). Early data show improved response depth compared to ibrutinib historical controls in this subgroup, with manageable tolerability. CXCR4 inhibitors represent a biologically rational strategy for the CXCR4-mutant subgroup and are an active area of clinical investigation. For BD teams, CXCR4-directed combination development represents a focused rare disease opportunity where patient selection via mutation status provides a clean clinical development path.

CAR-T cell therapy and bispecific antibodies in WM

CD19/CD20 CAR-T: the target rationale in WM vs. myeloma

CAR-T cell therapy in WM differs fundamentally from multiple myeloma because of target antigen biology. Myeloma CAR-T programs predominantly target BCMA (B-cell maturation antigen), which is highly expressed on myeloma plasma cells. WM cells, however, are lymphoplasmacytic — they express surface B-cell markers (CD19, CD20, CD22) much more consistently than terminal plasma cell markers (BCMA, CD38). This makes CD19 and CD20 more compelling CAR-T targets in WM than BCMA. CD20 is uniformly expressed on WM cells (it is the therapeutic target of rituximab) and is a rational CAR-T target, though antigen loss after prior anti-CD20 therapy can occur. Early-phase CD19-directed and CD19/CD20 bispecific CAR-T programs (NCT05169489 and investigator-initiated series) have demonstrated feasibility and early activity in heavily pretreated WM, though the extreme rarity of the disease limits trial accrual and definitive Phase 3 development is distant.

Bispecific antibodies: mosunetuzumab and epcoritamab in exploratory WM cohorts

CD20×CD3 bispecific antibodies including mosunetuzumab (Genentech/Roche) and epcoritamab (AbbVie/Genmab) are approved in R/R follicular lymphoma and diffuse large B-cell lymphoma, respectively. Given CD20 expression in WM, both agents are being explored in WM expansion cohorts within their broader B-cell lymphoma programs. Data in WM specifically are limited to small case series and single-arm cohort publications as of early 2026, with ORR in the 50–70% range in heavily pretreated patients. The hyperviscosity management challenge (bispecific antibodies can cause rapid IgM mobilization), cytokine release syndrome risk in older WM patients, and lack of dedicated WM Phase 2/3 development make bispecific antibodies an emerging option rather than a near-term standard.

Who uses DataLookout for WM trial intelligence

Waldenström's macroglobulinemia's rarity makes pipeline intelligence disproportionately valuable — there are few active competitive programs, and every new trial registration or data update materially shifts the competitive landscape. DataLookout users tracking WM include:

• Pharma and biotech BD teams evaluating WM as an indication extension for BTK inhibitors, BCL-2 inhibitors, or novel immunotherapy platforms — particularly for assets that have demonstrated activity in CLL or indolent B-cell lymphoma
• Hematology-oncology medical affairs and clinical teams at institutions with dedicated WM programs (Dana-Farber, Mayo Clinic, Memorial Sloan Kettering) monitoring competitive trials for patient enrollment decisions
• Rare disease investors and equity analysts tracking the pirtobrutinib (Eli Lilly) regulatory pathway in WM, BeiGene's zanubrutinib market share expansion, and emerging venetoclax combination trial data
• Patient advocacy organizations such as the International Waldenstrom's Macroglobulinemia Foundation (IWMF) that support patients in identifying open trials

Related clinical trials and monitoring resources

Waldenström's macroglobulinemia shares mechanistic overlap with several B-cell malignancy programs. DataLookout monitors related areas including:

• Multiple myeloma clinical trials — plasma cell biology overlap; BCMA CAR-T, daratumumab, and venetoclax programs relevant to MYD88 wild-type WM
• CLL clinical trials — BTK inhibitors and BCL-2 inhibitor combination strategies directly translate to WM; CAPTIVATE and GLOW venetoclax + ibrutinib data inform WM trial design
• Non-Hodgkin lymphoma clinical trials — WM is classified under NHL; CD20-directed CAR-T and bispecific antibody programs include WM expansion cohorts
• Follicular lymphoma clinical trials — indolent B-cell lymphoma framework; PI3K inhibitor and bispecific antibody data from FL informs WM exploratory programs

Frequently asked questions

What is Waldenström's macroglobulinemia and how does it differ from CLL and multiple myeloma?

Waldenström's macroglobulinemia (WM) is a rare, indolent B-cell lymphoproliferative malignancy classified as lymphoplasmacytic lymphoma (LPL) in the WHO classification, defined by bone marrow LPL and a serum IgM paraprotein of any level. It is distinct from CLL — a pure mature B-cell neoplasm without significant immunoglobulin secretion or plasma cell differentiation — and from multiple myeloma, which secretes IgG/IgA/light chains, causes lytic bone lesions, and has high BCMA expression suitable for targeting. WM cells occupy the lymphoplasmacytic differentiation stage between mature B cells and plasma cells, producing IgM that causes disease through hyperviscosity, cryoglobulinemia, cold agglutinin hemolysis, and IgM-related peripheral neuropathy. The cardinal molecular hallmark of WM is MYD88 L265P (~90–95%), absent in myeloma and CLL, which drives BTK-dependent survival signaling and explains the dramatic BTK inhibitor activity unique to WM.

What is MYD88 L265P and why does it matter in WM?

MYD88 L265P is a somatic gain-of-function mutation present in ~90–95% of WM patients — the most disease-defining molecular alteration in any hematologic malignancy. It causes constitutive homodimerization of MYD88, activating IRAK4/IRAK1 kinases and downstream NF-kB and MAPK pathways that promote WM cell survival. MYD88 L265P has diagnostic significance (distinguishing WM from IgM myeloma, IgM MGUS, and MZL), prognostic significance (wild-type cases have worse prognosis and different biology), and therapeutic significance (MYD88-mutant WM cells are more dependent on BTK signaling — BTK is recruited to the MYD88 signaling complex — explaining the ~90% ORR with ibrutinib in MYD88-mutant vs. ~25–60% in wild-type WM).

How do BTK inhibitors compare in WM — ibrutinib vs. zanubrutinib vs. pirtobrutinib?

Ibrutinib (iNNOVATE trial, ORR 92% + rituximab in TN/R/R WM) established BTK inhibition in WM but carries significant cardiac toxicity — atrial fibrillation in ~16–20% of patients, driving ~30–40% discontinuation rates over 3 years. Zanubrutinib (ASPEN Phase 3) demonstrated far lower atrial fibrillation (~2% vs. ~15%) with comparable or numerically superior response rates, establishing it as the preferred first-line BTK inhibitor for most WM patients, with FDA approval in 2021. Pirtobrutinib (BRUIN Phase 1/2, ORR ~68% in BTKi-pretreated WM including BTK C481S-mutant) is the key agent for BTK-resistant disease. Unlike covalent BTKi, pirtobrutinib also shows activity across CXCR4 mutation strata, making it particularly relevant for the ~30–35% of WM patients whose CXCR4 mutations reduce covalent BTKi efficacy.

What are CXCR4 mutations and how do they affect BTK inhibitor response in WM?

CXCR4 gain-of-function mutations occur in ~30–35% of WM patients and cause constitutive CXCR4 signaling through the WHIM pathway, promoting WM cell homing to bone marrow niches and activating PI3K/AKT/ERK signaling independent of BTK. Clinically, CXCR4-mutant WM patients have lower major response rates and shorter PFS on BTK inhibitor monotherapy. Ulocuplumab (anti-CXCR4) + ibrutinib combination therapy is in Phase 1b/2 development specifically for this subgroup. Pirtobrutinib appears to overcome CXCR4-mediated BTKi resistance, showing consistent ORR regardless of CXCR4 status — a potential advantage over covalent BTKi in this biomarker-defined subgroup.

What is the role of venetoclax in WM?

Venetoclax (BCL-2 inhibitor) has demonstrated compelling single-agent activity in R/R WM (ORR ~80%, MRR ~70%) and is being evaluated in combination with ibrutinib for dual BTK + BCL-2 targeting. It is particularly relevant in: (1) BTKi-intolerant patients who need an alternative mechanism; (2) CXCR4-mutant WM where BTKi monotherapy is less effective; and (3) MYD88 wild-type WM (~5–10% of cases), where BTK inhibitors have inferior activity and the plasma cell-like biology predicts BCL-2 dependence. Venetoclax + BTKi combinations may enable time-limited, MRD-negative remissions in WM analogous to CLL — a potential paradigm shift for a disease currently managed with indefinite continuous therapy.

How can I track WM clinical trials?

DataLookout monitors ClinicalTrials.gov daily and sends email digests filtered by condition and drug target. For WM, configure alerts for 'Waldenstrom', 'Waldenström', 'lymphoplasmacytic lymphoma', 'LPL', 'zanubrutinib', 'pirtobrutinib', 'venetoclax WM', 'CXCR4 WM', or 'MYD88 L265P'. The free plan covers one search profile with weekly alerts; Starter ($29/month) supports up to three watchlists with daily alerts; Pro ($99/month) is unlimited with CSV export for full pipeline coverage.