At a median follow-up of 22.6 months, two isolated CNS relapses occurred, although the small number of events and absence of a randomized comparison make the findings hypothesis-generating rather than proof that the regimen prevents CNS recurrence. The study enrolled adults with newly diagnosed, histologically confirmed CD20-positive diffuse large B-cell lymphoma, including transformed disease, and a CNS International Prognostic Index score of 4 to 6. This index combines age, lactate dehydrogenase level, performance status, number of extranodal sites and Ann Arbor stage to estimate CNS recurrence risk.

Participants had not received prior anti-lymphoma therapy, apart from corticosteroids for symptom control, and had adequate organ function. Patients with evidence of CNS involvement on imaging or cytology were excluded. In the evaluable group, 34 of 37 patients underwent contrast-enhanced brain MRI and three underwent contrast-enhanced brain CT because MRI was contraindicated.

Lumbar puncture was performed in 29 of 37, and cerebrospinal-fluid cytology was negative in all patients with evaluated samples. CSF flow cytometry was available for 18 patients and showed no evidence of CNS involvement. The median age of the evaluable cohort was 63 years, with a range of 41 to 89 years, and 13 patients were older than 70.

Most participants were men, and 29 of 37 had an Eastern Cooperative Oncology Group performance status from 0 to 2. Immunohistochemical analysis identified 24 patients, or 64.9%, with double-expressor lymphoma involving MYC and BCL-2, while 26, or 70.3%, were classified as non-germinal-center B-cell-like. CNS-IPI scores were 4 in 15 patients, 5 in 16 and 6 in six.

Nine patients had high-risk extranodal sites, including the testis, breast, adrenal gland, kidney, uterus or ovary, and epidural space. The cohort therefore included a substantial number of patients with recognized high-risk features for CNS relapse. Each patient received six 21-day cycles of orelabrutinib, administered orally at 150 mg once daily, alongside R-CDOP.

The chemotherapy backbone comprised rituximab, cyclophosphamide, liposomal doxorubicin, vinorelbine and prednisone. Liposomal doxorubicin replaced conventional doxorubicin and vinorelbine replaced vincristine as part of a rationale aimed at reducing cardiotoxicity and neurotoxicity. Age-stratified reductions in cyclophosphamide and liposomal doxorubicin were prespecified for older adults, while granulocyte colony-stimulating factor support followed institutional guidelines.

Response was assessed by CT or PET-CT at baseline, after cycles two and four, and at the end of induction using Lugano 2014 criteria. Seven patients in complete response subsequently underwent autologous stem-cell transplantation as consolidation rather than salvage treatment. The primary efficacy analysis included all 44 enrolled patients in the intention-to-treat population, with early withdrawals for progressive or stable disease counted as nonresponses.

Objective response at the end of induction occurred in 31 patients, giving an intention-to-treat rate of 70.5% with a 95% confidence interval of 55.3% to 82.1%; 22 patients, or 50.0%, achieved complete response, with a 95% confidence interval of 35.1% to 64.9%. The per-protocol analysis of 37 evaluable patients produced an objective response rate of 75.7%, with a 95% confidence interval of 59.9% to 86.9%, and a complete-response rate of 59.5%, with a 95% confidence interval of 43.4% to 73.9%. Complete response increased across successive assessments, from 13.5% after cycle two to 48.6% after cycle four and 59.5% after cycle six.

Because five of the seven excluded patients withdrew with early progressive disease and had numerically poorer baseline characteristics, the per-protocol results may overestimate efficacy relative to the intention-to-treat estimate. Median progression-free survival had not been reached at the median follow-up of 22.6 months, with a 95% confidence interval of 22.1 months to not estimable. Estimated one- and two-year progression-free survival was 77.6% and 57.4%, respectively.

Sixteen progression-free survival events occurred: 12 systemic progressions, two isolated CNS relapses and two combined CNS and systemic progressions. The CNS relapses occurred 8.2 and 19.4 months after treatment began; both involved the brain parenchyma, and one also included leptomeningeal involvement. Median overall survival was 38.1 months, with a 95% confidence interval of 30.1 months to not estimable.

Estimated one- and two-year overall survival was 93.8% and 90.2%, respectively. The divergence between progression-free and overall survival reflects partly on salvage treatment after relapse, including CAR-T therapy, lenalidomide-based regimens, platinum-based chemotherapy and radiotherapy, rather than establishing the independent effect of first-line orelabrutinib. In an analysis with a median follow-up of 19.1 months, two of the 37 evaluable patients experienced CNS relapse, a proportion of 5.4%.

Estimated cumulative CNS-relapse incidence was 0% at one year and 9.3% at two years, with a 95% confidence interval of 0% to 21.5% at two years. The authors emphasized that this estimate was imprecise because only two CNS events were observed. Orelabrutinib was selected partly because earlier pharmacokinetic studies reported a median cerebrospinal-fluid concentration of 28.7 ng/mL and a median unbound CSF-to-plasma ratio of 59.8%, giving it measurable CNS penetration.

However, the trial itself did not measure CSF drug concentrations, so the treatment’s achieved CNS exposure and its contribution to the relapse estimate remain unconfirmed. Treatment toxicity was frequent, particularly hematologic toxicity, but no treatment-related deaths or permanent discontinuations because of adverse events were reported. All 37 patients assessed for safety experienced at least one treatment-related adverse event.

Any-grade neutropenia occurred in 100%, anemia in 91.9% and thrombocytopenia in 75.7%. Grade 3 or 4 treatment-related events occurred in 25 patients, or 67.6%, led by neutropenia at 59.5%, anemia at 24.3% and thrombocytopenia at 16.2%. Common nonhematologic events included nausea in 64.9%, fatigue in 59.5% and elevated aminotransferases in 43.2%.

Investigators reported managing the severe hematologic events with granulocyte colony-stimulating factor and blood-component transfusions. No atrial fibrillation or flutter, clinical tumor-lysis syndrome, fatal toxicity or unexpected toxicity pattern was observed. Several features prevent the results from being interpreted as a direct comparison with standard care.

The study had no concurrent randomized control group, making historical comparisons vulnerable to selection bias, changes in staging and evolving supportive treatment. Lumbar puncture and CSF flow cytometry were not completed in every patient, so occult baseline CNS involvement cannot be completely excluded. Dose reductions in older adults also introduced variation in treatment intensity, while incomplete retrospective collection of post-progression therapies prevents separation of salvage effects from the first-line regimen’s contribution to survival.

Accordingly, the phase II results support further investigation of a methotrexate-free approach but do not establish CNS-prophylactic efficacy or superiority over R-CHOP or R-CDOP. Randomized controlled validation is required.

Subject of Research: Single-arm phase II trial of orelabrutinib plus R-CDOP in untreated diffuse large B-cell lymphoma with high CNS-relapse risk

Article Title: Efficacy and safety of orelabrutinib plus R-CDOP as first-line therapy in diffuse large B-cell lymphoma with high-risk CNS-IPI: a prospective, multicenter, single-arm, phase II study

Article References: Guo, Y., Wang, J., Lei, H., Bao, C., Chen, P., Shou, L., Guo, Q., Hu, B., Xie, Y., Zhong, S., Qian, W., & Xiao, X. (2026). Efficacy and safety of orelabrutinib plus R-CDOP as first-line therapy in diffuse large B-cell lymphoma with high-risk CNS-IPI: a prospective, multicenter, single-arm, phase II study. Frontiers in Oncology, 16, Article 1976858. https://doi.org/10.3389/fonc.2026.1976858

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DOI: 10.3389/fonc.2026.1976858

Keywords: orelabrutinib, diffuse large B-cell lymphoma, CNS relapse, CNS-IPI, BTK inhibitor, R-CDOP, phase II trial, blood-brain barrier, chemotherapy, lymphoma prognosis, Efficacy, safety

The technical architecture of the MyD88 pathway explains why it carries such weight. Toll-like receptors are pattern recognition receptors that detect pathogen-associated molecular patterns and damage-associated molecular patterns. Humans possess ten TLRs and mice twelve, distributed between the cell membrane and intracellular organelles. Structurally, TLRs are type I transmembrane proteins with an extracellular leucine-rich domain, a transmembrane segment, and an intracellular Toll/IL-1 receptor (TIR) domain. When a ligand engages the receptor, the TIR domain changes conformation and recruits MyD88, whose own C-terminal TIR domain forms heterodimers with the receptor and homodimerizes with itself, a step considered critical for signal transduction. The sole exception is TLR3, which signals independently of MyD88 through the TRIF adaptor. MyD88’s N-terminal death domain then attracts the kinases IRAK1 and IRAK4; IRAK4 phosphorylates IRAK1, which activates TRAF6 and, in turn, the NF-κB, MAPK, and PI3K-Akt cascades.

Nowhere is the oncogenic potential of this pathway clearer than in hematologic malignancy. The missense mutation L265P, which swaps a leucine for a proline at position 265 of MyD88, is found in roughly 90 percent of cases of Waldenström’s macroglobulinemia (WM), as well as in a large proportion of activated diffuse large B-cell lymphoma and IgM monoclonal gammopathy of undetermined significance. The review emphasizes how unusual this is in cancer: a single amino acid change acting as a dominant driver of disease, making WM a paradigm for treating disorders caused by one genetic alteration. Mechanistically, the L265P mutation renders the TIR domain hyperactive, strengthening binding to IRAK4 and phosphorylated IRAK1 so that the myddosome complex assembles even without external stimuli. The result is constitutive NF-κB signaling that sustains the survival and proliferation of malignant B cells.

The mutation also rewires cooperating pathways. In WM cells carrying L265P, MyD88 complexes with phosphorylated Bruton’s tyrosine kinase (pBTK) within the B-cell receptor signaling cascade, and disrupting this complex triggers apoptosis. MyD88 additionally activates transcription of the hematopoietic cell kinase HCK through NF-κB, and reducing HCK diminishes WM cell survival. Phelan and colleagues identified a MyD88-TLR9-BCR super-complex that engages the mTOR and CBM complexes to promote lymphomagenesis. Downstream, the pathway triggers autocrine IL-6 and IL-10 signaling, which phosphorylates JAK1 and then STAT3; STAT3 enhances expression of NF-κB, PI3K-AKT-mTORC1, and cell cycle checkpoint genes while suppressing interferon signaling components such as IRF7, IRF9, STAT1, and STAT2. Notably, selective IRAK1 and IRAK4 inhibitors killed ABC-DLBCL cells but promoted survival in GCB-DLBCL and myeloma lines, underscoring the context dependence of pathway targeting.

These insights are already shaping therapy. Although no drug directly approved against MyD88 exists for WM, the current frontline agent is the BTK inhibitor ibrutinib, and patients with MyD88 mutations respond exceptionally well: nearly all, 97.2 percent, achieve a major response, a phenomenon the authors attribute to MyD88’s involvement in B-cell receptor signaling. Combining BTK and IRAK inhibition is a plausible future strategy, and the review suggests that MyD88 itself remains a significant therapeutic target under active investigation.

In solid tumors, the story stretches back to Rudolf Virchow’s nineteenth-century observation linking inflammation to tumor growth. Chronic inflammation promotes cancer by augmenting DNA damage, driving tissue remodeling, secreting growth factors, and enhancing angiogenesis, and MyD88 sits at the center of these processes through its role in inflammation and the tumor microenvironment. In colitis-associated colorectal cancer, work in APC(Min/+) mice showed that MyD88 phosphorylates c-Myc via the ERK pathway, preventing its ubiquitination and proteasomal degradation; mice lacking MyD88 developed fewer and smaller tumors. MyD88-deficient myofibroblasts rendered mice resistant to AOM/DSS-induced tumorigenesis, partly by preventing macrophage M2 polarization through STAT3 and PPARγ signaling, and MyD88 inhibitors have been shown to curb both local and systemic inflammation while suppressing ERK signaling in intestinal epithelial cells.

The liver offers a parallel narrative. Human hepatocellular carcinoma tissues express higher levels of MyD88 than normal liver, and the adaptor activates PI3K-Akt signaling and accelerates epithelial-mesenchymal transition, promoting proliferation and metastasis. Knocking down the chemokine receptor CXCR3 reduces MyD88 expression, inhibiting cell proliferation and migration and slowing progression from fibrosis to cancer, while silencing MyD88 with siRNA impedes tumor cell growth. MyD88 also promotes non-alcoholic fatty liver-related hepatocarcinogenesis by fostering M2 macrophage polarization. In gastric cancer, the TLR2/MyD88 axis drives tumor cell stemness within the inflammatory microenvironment created by Helicobacter pylori infection, with TLR2 simultaneously inducing cytokines such as TNF-α and GM-CSF while suppressing the chemokines CXCL1 and CXCL8. In skin carcinogenesis, MyD88-dependent NF-κB activation is required for the pro-inflammatory response of oncogenic RAS in keratinocytes, and TLR4, activated by high mobility group box-1 protein, accelerates melanoma progression. In pancreatic cancer, TLR7/MyD88 signaling activates STAT3, NF-κB, and MAPK to promote tumor initiation, and MyD88 blockade dramatically ameliorated cachexia-associated anorexia, fatigue, and muscle wasting in models of pancreatic ductal adenocarcinoma.

Yet the review’s most provocative theme is that MyD88 is a double-edged sword. In some settings, its absence worsens disease. In DSS-induced colitis, MyD88 in macrophages maintains intestinal homeostasis; its deficiency upregulates S100A8, activating the NLRP3 inflammasome and pyroptosis in epithelial cells via a RAGE-dependent pathway. MyD88 knockout mice are more susceptible to AOM/DSS-induced colitis-associated cancer, partly because IL-18 receptor signaling, which regulates dendritic cells and IL-22-binding protein secretion by Th17 and Th22 cells, depends on MyD88 to drive epithelial repair. In the authors’ own experiments, systemic MyD88 inhibition accelerated the growth of established H22 liver tumors, and H22 cells implanted in MyD88 knockout mice grew faster than in wild-type animals, indicating that MyD88-mediated anti-tumor inflammation is essential once cancer has taken hold. Similar protective roles for TLR4 have been reported in DMBA-induced skin and breast cancer models.

The authors conclude that timing, location, duration, dosage, and formulation of any MyD88 intervention may determine whether the outcome is protective or harmful, since inhibiting the adaptor can simultaneously weaken immune surveillance against tumor cells and relieve inflammation-driven tumorigenesis. Drug development faces further hurdles: many candidate MyD88 inhibitors suffer from low bioavailability, short half-lives, and poor pharmacokinetics, and clinical trials remain scarce, with most evidence drawn from animal studies. Encouragingly, the inhibitor TJ-M2010-6 produced no significant weight loss or increased infection rates in mice. As the first example of a malignancy driven by a single dominant mutation, Waldenström’s macroglobulinemia demonstrates how targeting the MyD88 axis, directly or through partners such as BTK, can yield striking clinical benefit. The review argues that integrating MyD88-targeted therapy with immunotherapeutic approaches could reshape cancer treatment, provided researchers can resolve the biphasic biology of this indispensable, and occasionally dangerous, immune adaptor.

Subject of Research: The role of the MyD88 adaptor protein in tumor initiation and progression

Article Title: MyD88's function in the emergence and growth of tumors

Article References: Liu, J., Zhu, S., Huang, Q., Yao, Y., Li, W., & Zhang, S. (2024). MyD88's function in the emergence and growth of tumors. Clinical Cancer Bulletin, 3(1), Article 19. https://doi.org/10.1007/s44272-024-00023-x

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DOI: 10.1007/s44272-024-00023-x

Keywords: MyD88, Toll-like receptors, NF-κB, Waldenström's macroglobulinemia, MYD88 L265P, colorectal cancer, hepatocellular carcinoma, inflammation, tumor microenvironment, BTK inhibitor, IRAK4, cancer immunotherapy

Regulators have moved quickly. After a positive opinion from the European Medicines Agency’s Committee for Medicinal Products for Human Use in June 2026, the European Commission approved pirtobrutinib in August 2026 for adults with CLL across all lines of therapy, and an equivalent decision from the US Food and Drug Administration is anticipated in the second half of 2026. An accompanying editorial by Davids argued that the two trials open the door for noncovalent BTK inhibition as initial therapy. On the surface, the case seems overwhelming: a drug that works at least as well as the incumbent, with dramatically better cardiovascular tolerability, seems destined to become the new default first choice.

But a correspondence published in Annals of Hematology by Boyi Chen and Shenxian Qian throws a careful, technically grounded brake on that enthusiasm. The authors highlight what they call a sequencing asymmetry, a structural imbalance in the evidence that neither of the new trials was designed to address. The order in which the two BTK inhibitor classes are given, they argue, matters enormously, and only one of the two possible orders is currently supported by randomized evidence. That order is the covalent-first sequence, and the argument for preserving it rests on the molecular biology of drug resistance as much as on clinical trial data.

The covalent BTK inhibitors, including ibrutinib, acalabrutinib and zanubrutinib, bind permanently to a cysteine residue at position 481 of the BTK kinase. Resistance to these drugs most often emerges through the C481S mutation, which replaces that cysteine with serine and blocks covalent attachment while leaving the binding pocket otherwise intact. Crucially, pirtobrutinib does not depend on covalent chemistry, so it retains activity against C481-mutant BTK. In the phase 1/2 BRUIN study, pirtobrutinib achieved a 73.3 percent response rate and a median progression-free survival of 19.6 months in patients whose disease had progressed on a covalent inhibitor, regardless of C481 status. In the phase III BRUIN CLL-321 trial, it outperformed idelalisib plus rituximab or bendamustine plus rituximab in this setting, with a hazard ratio of 0.54 and a median progression-free survival of 14.0 versus 8.7 months. A patient who begins treatment with a covalent inhibitor therefore keeps a rational, evidence-backed exit ramp if resistance develops.

The reverse sequence has no comparable data, and the resistance mechanisms give concrete reason for concern. Work by Wang and colleagues showed that acquired resistance to pirtobrutinib does not arise through C481 but through a distinct set of kinase-domain mutations: V416L, A428D, M437R, T474I and L528W. Of these, A428D and L528W conferred in vitro cross-resistance to ibrutinib and prevented multiple covalent BTK inhibitors from inhibiting the mutant enzyme. In other words, a patient who progresses on first-line pirtobrutinib may harbor leukemic clones that have compromised not just one drug but much of the covalent class, the very class that currently anchors relapse management. Notably, no patient in the Wang series acquired a new C481 mutation on pirtobrutinib, indicating that the two drug classes select largely distinct mutations, and that the mutations selected by the noncovalent agent can reduce sensitivity to covalent drugs. As Mato and colleagues observed in the original BRUIN publication, no information is currently available on the efficacy of covalent BTK inhibitors in patients who receive pirtobrutinib first and in whom resistance develops.

Davids offers a reasonable counterargument: many older patients with comorbidities may need only one or two lines of therapy over their remaining lifetime, making downstream resistance a less salient concern. For that subgroup, Chen and Qian concur that first-line pirtobrutinib is defensible, since a single effective line may be the realistic horizon. But CLL is not uniformly a disease of the very old. Younger patients, and those with unmutated IGHV genes or TP53 aberrations, can expect disease courses lasting ten to twenty years and multiple lines of treatment. Patients with del(17p) were even excluded from the CLL-313 trial. For these individuals, sequencing is not a footnote but the central strategic question, and spending the noncovalent agent first may forfeit options decades before they are needed.

Nor does toxicity, the argument that once favored abandoning covalent inhibitors altogether, justify skipping the class today. The cardiovascular case against ibrutinib has been substantially overtaken by the second-generation covalent agents. Zanubrutinib more than halved the rate of atrial fibrillation compared with ibrutinib in the ALPINE trial, 5.2 percent versus 13.3 percent, while improving progression-free survival, and acalabrutinib reduced atrial fibrillation in the ELEVATE-RR trial, 9.4 percent versus 16.0 percent, with non-inferior efficacy. The covalent-first strategy also preserves later options: beyond pirtobrutinib monotherapy after covalent inhibitor failure, the triplet of pirtobrutinib with venetoclax and rituximab has outperformed venetoclax plus rituximab in previously treated disease in BRUIN CLL-322, with a hazard ratio of 0.547. Frontline pirtobrutinib, by contrast, forgoes at present the only BTK-inhibitor class with phase III-validated salvage value.

The authors are careful to qualify their own argument. The cross-resistance evidence is preclinical, resting on in vitro potency and binding studies, and every patient in the Wang series who developed a non-C481 mutation had prior exposure to ibrutinib, so whether frontline pirtobrutinib selects the same mutational spectrum is unknown. Cross-resistance is also not strictly one-directional, since mutations such as L528W have been reported, less frequently, after covalent inhibitor therapy as well. These uncertainties, the authors stress, argue for caution and surveillance rather than regulatory delay. They also caution against treating BTK degraders, an emerging class of drugs that eliminate BTK rather than merely blocking it, as a ready safety net. Degraders such as NX-2127 can degrade kinase-impaired mutants including L528W, and early-phase studies of BGB-16673 and bexobrutideg report rapid, durable responses, but the evidence remains at the abstract level, pivotal trials are still accruing patients, and A428D can itself confer resistance to degrader therapy.

From this analysis flow four concrete recommendations. First, frontline trials of noncovalent BTK inhibitors should mandate BTK and PLCG2 mutation testing at progression, so the field learns which mutations first-line pirtobrutinib actually selects in previously untreated patients. Second, real-world registries should systematically track responses to covalent agents after pirtobrutinib failure, which the authors identify as the single most urgent evidence gap. Third, routine practice should incorporate BTK and PLCG2 testing whenever a patient progresses on any BTK inhibitor, since the mutational profile at relapse directly informs what can work next. Fourth, forthcoming guideline updates should explicitly address sequencing, and post-pirtobrutinib outcomes should be collected systematically while reverse-sequence data remain absent.

The BRUIN program has undeniably given CLL a highly effective drug, and its first-line efficacy is not in doubt. What remains unknown is what early use may cost at relapse. Until prospective sequencing data emerge, the authors conclude, the uncertainty argues for an individualized, sequencing-aware choice rather than a wholesale shift of the treatment default, particularly for the younger patients whose long disease courses give the order of therapy its greatest weight.

Subject of Research: Treatment sequencing and resistance mechanisms for first-line pirtobrutinib in chronic lymphocytic leukemia

Article Title: Sequencing asymmetry: the case for caution before first-line pirtobrutinib in chronic lymphocytic leukemia

Article References: Chen, B., & Qian, S. (2026). Sequencing asymmetry: the case for caution before first-line pirtobrutinib in chronic lymphocytic leukemia. Annals of Hematology, 105(9), Article 404. https://doi.org/10.1007/s00277-026-07264-x

Image Credits: AI Generated

DOI: 10.1007/s00277-026-07264-x

Keywords: chronic lymphocytic leukemia, pirtobrutinib, BTK inhibitor, drug resistance, treatment sequencing, BTK C481S, kinase-domain mutations, BRUIN trials, cross-resistance, BTK degraders, hematology, clinical trials

Waldenström macroglobulinemia is a rare and indolent B-cell lymphoma characterized by the accumulation of malignant lymphoplasmacytic cells in the bone marrow and, crucially, by the overproduction of monoclonal immunoglobulin M, an antibody protein that thickens the blood and can cause hyperviscosity, neuropathy, and organ damage. Because the disease is uncommon, most treatment evidence comes from small trials and single-arm studies, leaving clinicians with genuine uncertainty when patients relapse after frontline therapy. This rarity is precisely why the French group’s multicenter approach matters: by pooling patients from 17 centers, the investigators assembled one of the larger cohorts ever reported for this specific treatment strategy.

The drug at the center of the study, venetoclax, belongs to a class of agents known as BH3 mimetics. These small molecules bind to BCL-2, an anti-apoptotic protein that many B-cell cancers exploit to evade programmed cell death. By occupying the BCL-2 binding groove, venetoclax releases the cellular brakes on apoptosis, allowing malignant lymphocytes to self-destruct. The drug has already transformed the treatment landscape for chronic lymphocytic leukemia, and earlier monotherapy studies suggested promising activity in relapsed or refractory Waldenström macroglobulinemia, a population with significant unmet medical need. What remained unclear was whether venetoclax should be given alone or in combination with other agents in this disease.

The WAVE investigators turned to real-world clinical practice to answer that question. The 46 patients included in the analysis had received a median of three prior lines of treatment before starting venetoclax, and 89 percent had already been exposed to a Bruton tyrosine kinase inhibitor, the class of drugs that has become a cornerstone of Waldenström macroglobulinemia therapy. This detail is important: these were heavily pretreated patients whose disease had already evaded the most effective modern targeted therapies, meaning that any meaningful response signal carries real clinical weight. Among the cohort, 25 patients, or 54 percent, received venetoclax combined with an anti-CD20 antibody, typically rituximab or a related monoclonal antibody that targets the CD20 surface protein found on B cells and recruits the immune system to destroy antibody-coated tumor cells.

The headline finding concerns response depth. At the time of best response, patients treated with the combination achieved a deep response rate, defined as very good partial response plus uncertain complete response, of 56 percent, compared with just 24 percent among those treated with venetoclax monotherapy, a difference that reached statistical significance with a p value of 0.03. In lymphoma care, depth of response is not an academic nicety. Deeper remissions, particularly those in which the monoclonal IgM protein falls to very low or undetectable levels, are consistently associated with longer periods of disease control before relapse. For a disease in which the abnormal protein itself drives many of the symptoms, pushing IgM down as far as possible translates directly into clinical benefit.

Perhaps more striking was the result of the multivariate analysis. When the investigators adjusted for other clinical variables, anti-CD20 combination therapy emerged as the only factor independently associated with achieving a deep response, with a hazard ratio of 4.07 and a p value of 0.03. In other words, the antibody combination quadrupled the odds of a deep remission regardless of other patient characteristics. This kind of signal, emerging from a retrospective dataset where treatment assignment was not randomized, cannot prove causation on its own, but it provides a strong rationale for the prospective trials that the authors say are needed to confirm the strategy.

The progression-free survival data reinforced the same direction of benefit, though with more statistical uncertainty. At two years, 78 percent of patients treated with venetoclax plus anti-CD20 had not experienced disease progression or death, compared with 54 percent of those on monotherapy. The confidence intervals were wide, spanning 54 to 90 percent for the combination arm and 27 to 74 percent for monotherapy, and the difference did not reach statistical significance with a p value of 0.25. That lack of formal significance is unsurprising given the modest sample size, but the magnitude of the gap, nearly 25 percentage points at two years, is the kind of signal that clinicians and trial designers take seriously.

Safety, as always in combination therapy, is the counterweight to efficacy, and here the picture was more nuanced. Grade 3 or higher adverse events occurred in 17 patients, or 68 percent, of those receiving the combination, versus 7 patients, or 33 percent, of those on venetoclax alone, a difference that was statistically significant with a p value of 0.02. Three cases of febrile aplasia, episodes of fever accompanied by severe suppression of blood cell production, were reported, though these did not differ significantly between the two groups. The increased toxicity of the combination is consistent with what is known about adding antibody therapy to targeted agents: the pairing amplifies immune-mediated tumor killing but also increases the burden on the bone marrow and the immune system. For a largely elderly patient population, this trade-off between deeper remissions and higher rates of serious side effects will need careful weighing in future prospective studies.

The WAVE study also illustrates a broader shift in how rare-cancer evidence is generated. Randomized trials in diseases with incidence rates as low as Waldenström macroglobulinemia’s can take years to accrue even modest numbers of patients, and many relapsed patients cannot wait. Retrospective multicenter cohorts like this one, harmonized across 17 institutions and analyzed with multivariate statistics, offer a pragmatic middle path: they capture the messy reality of clinical practice, including heterogeneous prior treatments and variable dosing schedules, and they generate hypothesis-driving signals that can justify the prospective studies that ultimately change guidelines. The French FILO network has been particularly productive in this regard, leveraging the centralized structure of French hematology care to assemble cohorts that individual centers never could.

For patients and their physicians, the practical message is cautiously encouraging. Venetoclax, with or without an anti-CD20 antibody, is an oral, targeted, chemotherapy-free approach for a disease that has historically been treated with rituximab-based chemoimmunotherapy, proteasome inhibitors, or BTK inhibitors. The WAVE data suggest that in the relapsed or refractory setting, particularly after BTK inhibitor exposure, the combination strategy offers the best chance of a deep and durable response, at the cost of more frequent severe side effects. The authors themselves frame the findings as warranting further evaluation in prospective studies, and that is the appropriate note of restraint. Until randomized data arrive, the study gives hematologists a real-world benchmark and gives patients with few remaining options a reason for measured optimism that the next generation of trials will refine exactly who benefits most from this two-pronged attack on their cancer.

Subject of Research: Venetoclax with or without anti-CD20 antibody therapy for relapsed or refractory Waldenström macroglobulinemia

Article Title: Relapsed/refractory WAldenström macroglobulinemia patients treated by VEnetoclax with or without anti-CD20 antibody: WAVE a retrospective study of the French CLL/WM group (FILO)

Article References: Vonfeld, M., Systchenko, T., Debureaux, P.-E., Dupuis, J., Roos-Weil, D., Ysebaert, L., Dilhuydy, M.-S., Malphettes, M., Croizier, C., Aurran, T., Inchiappa, L., Willems, L., Hivert, B., Lévy, V., Bussot, L., Bouclet, F., Laribi, K., Clavert, A., Durand, A., & Tomowiak, C. (2026). Relapsed/refractory WAldenström macroglobulinemia patients treated by VEnetoclax with or without anti-CD20 antibody: WAVE a retrospective study of the French CLL/WM group (FILO). Annals of Hematology. https://doi.org/10.1007/s00277-026-07293-6

Image Credits: AI Generated

DOI: 10.1007/s00277-026-07293-6

Keywords: Waldenström macroglobulinemia, venetoclax, anti-CD20 antibody, BTK inhibitor, relapsed refractory lymphoma, BCL-2, targeted therapy, retrospective study, hematology, monoclonal antibody, progression-free survival, FILO

Zanubrutinib belongs to a class of targeted drugs known as Bruton’s tyrosine kinase inhibitors, or BTK inhibitors, which block a signaling protein that B cells, the immune cells that turn malignant in chronic lymphocytic leukemia, rely on for survival and proliferation. First-generation inhibitors such as ibrutinib transformed outcomes for this patient population but carried a burden of off-target effects, because they also inhibited related kinases including those involved in cardiac rhythm, platelet aggregation, and other signaling pathways. Zanubrutinib was engineered for greater selectivity, binding BTK more completely while sparing neighboring targets, and the new cohort study set out to test whether that improved pharmacological profile translates into better tolerability and sustained disease control outside the carefully curated environment of a clinical trial.

The researchers interrogated treatment patterns across the full cohort with unusual granularity. Therapy was discontinued in 76 patients, or 18.5 percent of the total, but the reasons tell an encouraging story. Disease progression accounted for only 32 discontinuations, or 7.8 percent of all patients, meaning the vast majority of patients who stopped the drug did so for reasons unrelated to treatment failure. Patient preference led 25 patients, or 6.1 percent, to discontinue, adverse events prompted 15 patients, or 3.7 percent, to stop, and four patients, or 1.0 percent, died of unknown causes. In an era when treatment duration on continuous oral therapy is a key measure of a drug’s real-world value, these numbers suggest that zanubrutinib keeps patients on treatment and keeps their disease in check for extended periods.

Perhaps the most clinically consequential finding concerns dose reductions, a topic that has generated anxiety among both oncologists and patients. Forty-six patients, or 11.2 percent of the cohort, required at least one dose reduction, most commonly because of adverse events, which affected 17 patients, or 4.1 percent, or because of patient preference, cited by 26 patients, or 6.3 percent. The critical question has always been whether lowering the dose compromises efficacy. The answer from this cohort appears to be no. Among the 46 patients who reduced their dose, the researchers observed no cases of disease progression or death after the reduction occurred, over a median follow-up of 10.9 months from the first dose modification. While the follow-up window is relatively short and the subgroup modest in size, the signal is reassuring for the many patients who need to taper their dose to manage side effects.

The study also shed light on a growing phenomenon in leukemia care: switching between BTK inhibitors. Fifty-four patients in the cohort moved to zanubrutinib from another BTK inhibitor without any evidence of disease progression, meaning they switched for tolerability or convenience rather than treatment failure. Thirty-two of these patients made the move because of adverse events on their previous drug, 19 because of patient preference, and four for unknown reasons, with some reasons overlapping. The median duration of zanubrutinib treatment after the switch was 10.1 months among patients who switched due to side effects and 16.5 months among those who switched by preference. Most notably, progression-free survival had not been reached in either group at the time of analysis, indicating that patients who transition from an older BTK inhibitor to zanubrutinib for non-progressive reasons can continue to achieve durable disease control on the newer agent.

From a technical standpoint, the study’s design merits attention. The investigators conducted a retrospective, multicenter cohort analysis drawing on data from hospitals across China, including Peking University People’s Hospital, the First Affiliated Hospital of Nanjing Medical University, Nanfang Hospital, West China Hospital, and several others, with Peking University People’s Hospital serving as the central ethics committee. The primary endpoint was progression-free survival, the standard measure of how long patients live without their disease worsening, analyzed with confidence intervals to quantify uncertainty. The three-year PFS estimate of 91.6 percent for treatment-naive patients carried a 95 percent confidence interval of 83.8 to 95.8 percent, while the 83.2 percent estimate for later-line patients spanned 74.6 to 89.1 percent. These intervals, while wide in places due to the evolving follow-up time, place real-world outcomes squarely in the territory previously reported in registration trials, a consistency that strengthens confidence in the drug’s effectiveness.

The distinction between initial and later-line therapy matters enormously in chronic lymphocytic leukemia, an indolent malignancy that predominantly affects older adults and often follows a relapsing course over many years. Patients receiving zanubrutinib as initial therapy had not been exposed to prior BTK inhibition and typically had fewer accumulated resistance mechanisms. Those receiving it later had often been through chemoimmunotherapy or earlier targeted agents. The roughly eight-percentage-point gap in three-year progression-free survival between the two groups is consistent with the expected biology, yet the fact that later-line patients still achieved better than 83 percent freedom from progression at three years underscores how much the BTK inhibitor class has reshaped the prognosis of relapsed and refractory disease, which was historically one of the most difficult scenarios to manage.

Why does real-world evidence of this kind matter so much? Registration trials enroll selected patients, often excluding those with significant comorbidities, competing medications, or atypical disease features, and they monitor adherence intensively. Routine practice is different. Patients forget doses, stop drugs because they feel well, reduce doses on their own initiative, and switch therapies based on quality-of-life considerations that never appear in a case report form. By documenting that only 3.7 percent of patients discontinued zanubrutinib because of adverse events, and that dose reductions did not precipitate disease progression, this nationwide cohort provides the kind of pragmatic evidence that health systems, guideline committees, and prescribing physicians need when weighing treatment options for a disease that may require years of continuous oral therapy.

The findings also carry implications for how clinicians counsel patients about side effect management. Patient preference was the single most common reason for both dose reduction and discontinuation in this cohort, a reminder that shared decision-making is not a formality but a genuine determinant of treatment trajectories. Some patients in the study chose to reduce or stop their medication despite adequate tolerability, and the data suggest that, at least within the observed follow-up, such choices did not immediately translate into disease progression. That said, the authors and the broader hematology community would caution that longer observation is needed before dose attenuation can be considered fully equivalent to continuous full-dose therapy, particularly given the indolent nature of the disease and the possibility of late relapse.

Taken together, the study offers a comprehensive portrait of zanubrutinib as it is actually used: a drug with high selectivity for its target, low rates of discontinuation for toxicity, reassuring outcomes after dose modification, and strong progression-free survival in both first-line and later-line settings. As BTK inhibitors continue to evolve and as fixed-duration combinations challenge the paradigm of continuous therapy, cohorts like this one, registered as NCT06489184 on ClinicalTrials.gov, will remain essential for understanding how these powerful targeted agents perform in the hands of real patients and real physicians, far from the protocolized confines of the clinical trial.

Subject of Research: Real-world effectiveness, dose modification and discontinuation patterns of the BTK inhibitor zanubrutinib in chronic lymphocytic leukemia/small lymphocytic lymphoma

Article Title: Dose modifications, discontinuation patterns and PFS of zanubrutinib in 410 CLL/SLL patients – a nationwide real-world cohort

Article References: Yang, S., Zhu, H., Hu, L., Feng, R., Guo, X., Niu, T., Shen, K., Li, Z., Dong, Y., Wang, B., Su, L., Wang, L., Wang, L., Sun, W., Fang, F., Zhao, Y., Huang, X., & Li, J. (2026). Dose modifications, discontinuation patterns and PFS of zanubrutinib in 410 CLL/SLL patients – a nationwide real-world cohort. BMC Cancer. https://doi.org/10.1186/s12885-026-17043-6

Image Credits: AI Generated

DOI: 10.1186/s12885-026-17043-6

Keywords: zanubrutinib, chronic lymphocytic leukemia, small lymphocytic lymphoma, BTK inhibitor, progression-free survival, dose reduction, real-world evidence, drug discontinuation, adverse events, hematology, targeted therapy, BMC Cancer

CD19 has become the single most important target in B-cell malignancy therapy. Chimeric antigen receptor T-cell therapies, bispecific antibodies, and antibody-drug conjugates overwhelmingly depend on the dense, consistent expression of CD19 on the surface of malignant B lymphocytes. Yet relapse after CD19-directed immunotherapy is common, and one of the best-documented mechanisms of that relapse is the loss or masking of surface CD19. Tumor cells that downregulate the antigen effectively become invisible to the therapy, resuming their growth once the immune pressure has been evaded. Understanding what controls CD19 abundance at the cell surface, and how clinical drugs might stabilize it, is therefore a question of substantial therapeutic consequence. The new work addresses that question directly, and its answer involves an unlikely player.

Matriptase, encoded by the ST14 gene, is a type II transmembrane serine protease with a well-established role in epithelial biology. It is best known for initiating proteolytic cascades that regulate barrier function, filaggrin processing, and growth factor signaling in skin and other epithelial tissues. Its dysregulation has been implicated in epithelial cancers, where excessive matriptase activity can promote invasion and metastasis. Its role in lymphoid malignancies, by contrast, has been far less explored. The new study now places matriptase at the center of a drug-responsive circuit in malignant B cells, where it appears to act on the fate of CD19 itself, preserving the antigen in its extracellular, antibody-accessible form rather than allowing it to be shed, internalized, or otherwise lost from the cell surface.

The central observation is a causal chain. When malignant B cells are exposed to ibrutinib, the drug does more than inhibit BTK signaling; it triggers an increase in matriptase activity or abundance. That protease, in turn, acts to maintain extracellular CD19. In practical terms, cells treated with the drug retain the surface target that CAR-T cells and CD19-directed antibodies recognize, whereas cells in which the matriptase arm of this circuit is disrupted lose that protection and become prone to antigen escape. The authors frame this as a mechanism by which ibrutinib limits antigen escape in B-cell malignancy, a framing that carries immediate translational weight because ibrutinib is already approved and widely used in chronic lymphocytic leukemia, mantle cell lymphoma, and other B-cell disorders.

The clinical logic of the finding is compelling. Ibrutinib and CD19-directed immunotherapies are frequently considered in overlapping patient populations, and sequencing decisions between BTK inhibition and cellular immunotherapy are often made empirically. If ibrutinib treatment stabilizes surface CD19, then a period of BTK inhibition before leukapheresis or CAR-T infusion could, in principle, improve the quality of the target presented to the engineered cells, reducing the likelihood that the manufactured product encounters antigen-low tumor cells. Conversely, the study raises a caution: interventions or tumor adaptations that suppress matriptase might undermine CD19 display and thereby predispose patients to escape from CD19-directed therapies, even when the malignant cells remain otherwise sensitive to cytotoxic pressure.

Antigen escape is not a single mechanism but a family of them. Tumor cells can mutate the CD19 locus, introduce truncating mutations, alter exon splicing so that the epitope is lost while the protein remains, internalize the antigen faster than it is replaced, or shield it from antibody binding through changes in the membrane microenvironment. Each of these routes has been documented in patients relapsing after CD19 CAR-T therapy. What the new study contributes is the idea that the extracellular maintenance of CD19 is an actively regulated process, one that a protease can influence and that an approved drug can modulate. That reframing matters because it converts antigen loss from an apparently random escape event into a process with identifiable molecular control points that might be monitored and manipulated.

The mechanistic details also connect two previously separate strands of B-cell biology. BTK signaling sits at the heart of the B-cell receptor pathway, and its chronic engagement is a hallmark of many B-cell malignancies, particularly those dependent on active B-cell receptor signaling such as chronic lymphocytic leukemia and mantle cell lymphoma. Ibrutinib’s inhibition of BTK disrupts survival signals and drives malignant cells toward apoptosis. The new data suggest that this well-characterized pharmacologic action has a second, previously underappreciated consequence: a protease-mediated remodeling of the tumor cell surface that favors target retention. In effect, a drug designed to weaken the tumor may simultaneously make the tumor easier to see for the immune system, an unintended benefit that could be exploited deliberately.

For researchers in the immunotherapy field, the study suggests several lines of immediate follow-up. Measuring matriptase activity in patient samples before CD19-directed therapy could reveal whether protease status predicts who is at risk of antigen-negative relapse. Pharmacologic or genetic modulation of matriptase in preclinical models could test whether enhancing its activity further improves CD19 persistence under immune pressure. Combination trials pairing ibrutinib with CD19 CAR-T or bispecific antibodies are already underway for various indications, and the new mechanism provides a biological rationale for such combinations that goes beyond simple additive cytotoxicity. Biomarker strategies that track surface CD19 density longitudinally during BTK inhibition could also help clinicians time cellular therapy infusions for maximal target availability.

There are, of course, important caveats. Matriptase is a protease with pleiotropic effects, and its activity in epithelial cancers has often been associated with tumor progression, so any therapeutic strategy aimed at boosting its function in lymphoid malignancy would need to account for tissue-specific context and potential off-tumor consequences. The relationship between ibrutinib exposure, matriptase activation, and CD19 maintenance will also need to be validated across the full diversity of B-cell malignancies, since the biology of chronic lymphocytic leukemia, diffuse large B-cell lymphoma, and mantle cell lymphoma differ substantially in their dependence on BTK signaling and their patterns of antigen expression. Clinical outcomes, not only cell-culture measurements, will ultimately determine whether the mechanism translates into lower rates of antigen-escape relapse in treated patients.

Even with those qualifications, the study adds a genuinely new concept to the immunotherapy conversation: that the target itself can be pharmacologically defended. Much of the effort in overcoming antigen escape has focused on the therapeutic side, through multi-antigen CAR constructs targeting CD19 together with CD20 or CD22, or through sequential and dual-targeting strategies. The alternative approach suggested here is to act on the tumor cell so that it continues to display the antigen the therapy needs. If ibrutinib-triggered matriptase activity proves to be a reliable and safe lever for maintaining extracellular CD19, it would represent a rare example of an approved small-molecule drug being repurposed, at least conceptually, as a target-preservation agent for cellular immunotherapy. In a field where antigen loss remains one of the leading causes of treatment failure, that is an idea with the potential to reshape how BTK inhibitors and CD19-directed therapies are sequenced and combined in the clinic.

Subject of Research: Ibrutinib-triggered matriptase activity maintains extracellular CD19 and limits antigen escape in B-cell malignancy

Article Title: Ibrutinib-triggered matriptase maintains extracellular CD19 and limits antigen escape in B-cell malignancy

Article References: Lu, X.-J., Lai, H.-F., Hung, Y.-S., Wang, Y.-J., Wu, S.-C., Wang, J.-K., Wu, Y.-Y., & Chiu, Y.-L. (2026). Ibrutinib-triggered matriptase maintains extracellular CD19 and limits antigen escape in B-cell malignancy. Cell Death Discovery. https://doi.org/10.1038/s41420-026-03306-5

Image Credits: AI Generated

DOI: 10.1038/s41420-026-03306-5

Keywords: ibrutinib, matriptase, CD19, antigen escape, B-cell malignancy, BTK inhibitor, CAR-T therapy, immunotherapy, Cell Death Discovery, serine protease, chronic lymphocytic leukemia, target preservation