scholarly journals BTKCys481Ser Mutation Drives Ibrutinib Resistance through ERK1/2 Hyperactivation, and Can Confer a Protective Effect on Bystander Waldenstrom's Macroglobulinemia and ABC DLBCL Cells through Paracrine Mediated Pro-Survival Signaling

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. 803-803
Author(s):  
Jiaji Chen ◽  
Xia Liu ◽  
Manit Munshi ◽  
Lian Xu ◽  
Nickolas Tsakmaklis ◽  
...  
Keyword(s):  
Protective Effect ◽  
Disease Progression ◽  
Tumor Cells ◽  
Research Funding ◽  
Waldenström’S Macroglobulinemia ◽  
Survival Signaling ◽  
Waldenstrom's Macroglobulinemia ◽  
Waldenstrom’S Macroglobulinemia ◽  
Ibrutinib Resistance ◽  
Waldenström's Macroglobulinemia

Abstract Activating mutations in MYD88 promote NF-kB survival signaling in WM and ABC DLBCL cells through BTK and HCK, both targets of ibrutinib (Yang et al, Blood 2013; 2016). These findings likely explain the high rates of response observed in MYD88 mutated WM and ABC DLBCL patients (Treon et al, NEJM 2015; Wilson et al, Nature Med 2015). Resistance to ibrutinib is increasingly being recognized with prolonged therapy in patients with various B-cell malignancies. Mutations at the BTKCys481 site are observed in half of WM patients with disease progression following initial response (Xu et al, Blood 2017), and are also associated with clinical resistance in patients with CLL and MCL. However, in many WM and CLL cases, BTKCys481 mutations are subclonal and their relevance to clinical disease progression remains unclear. Moreover, the signaling mechanisms that promote ibrutinib resistance remain to be clarified. We therefore performed lentiviral transduction studies in MYD88 mutated WM (BCWM.1, MWCL-1) and ABC DLBCL (TMD-8, HBL-1) cells with vector alone, wild-type BTK (BTKWT), and the BTK variant most frequently observed in ibrutinib resistant WM and CLL cases (BTKCys481Ser). BTKCys481Ser but not BTKWT or vector only transduced WM and ABC DLBCL cells uniformly demonstrated persistent BTK and PLCγ2 activation in the presence of ibrutinib (100, 500 nM), along with a 1-3 log fold increase in EC50 to ibrutinib. Western blot analysis showed persistent BTK signaling in BTKCys481Ser expressing cells that was accompanied by ERK1/2 hyperactivation. Use of highly selective and potent ERK1/2 inhibitors (ulixertinib, GDC-0994) induced apoptosis of BTKCys481Ser expressing WM and ABC DLBCL cells, and showed synergistic tumor cell killing with ibrutinib by CellTiter-Glo® Luminescent Cell Viability Assays using Calcasyn, as well as enhanced apoptosis by Annexin V staining. Using a multiplex cytokine assay and confirmed by TaqMan® quantitative RT-PCR assay for cytokine mRNA levels, we identified that ERK1/2 activation in ibrutinib treated BTKCys481Ser WM and ABC DLBCL cells was accompanied by persistent release of pro-inflammatory and growth enhancing cytokines including CXCL13, IL-2R, IL-6, IL-10, IL-12p40, and TNF-a that was blocked by ulixertinib. In contrast, ibrutinib blocked their release in BTKWT WM and ABC DLBCL cells. We next sought to clarify if cytokine release by ibrutinib treated BTKCys481Ser WM and ABC DLBCL could impact survival of bystander tumor cells. We performed experiments using a Transwell system in which BTKCys481Ser or BTKWT transduced WM or ABC DLBCL cells were co-cultured with their native counterpart cells in the presence or absence of ibrutinib (Figures 1A, B). These studies showed that native WM or ABC DLBCL cells were rescued in the presence of ibrutinib when co-cultured with their BTKCys481Ser but not BTKWT transduced counterparts. Finally, use of IL-6 and IL-10 blocking antibodies abolished the protective effect on native tumor cells conferred by co-culture with BTKCys481Ser expressing cells in the presence of ibrutinib (Figures 1C, D). Our findings show that BTKCys481Ser mutation drives ibrutinib resistance through hyperactivation of ERK1/2, and that paracrine mediated ERK1/2 dependent pro-survival signaling by BTKCys481Ser expressing cells can confer a protective effect on bystander Waldenstrom's Macroglobulinemia and ABC DLBCL cells in the presence of ibrutinib. Figure 1 Figure 1. Disclosures Castillo: Janssen: Consultancy, Research Funding; Abbvie: Research Funding; Pharmacyclics: Consultancy, Research Funding; Millennium: Research Funding. Treon: Pharmacyclics: Consultancy, Research Funding.

Sildenafil citrate suppresses disease progression in patients with Waldenstrom’s macroglobulinemia

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 7556-7556 ◽  
Author(s):  
C. J. Patterson ◽  
J. Soumerai ◽  
Z. Hunter ◽  
X. Leleu ◽  
I. Ghobrial ◽  
...  
Keyword(s):  
Disease Progression ◽  
Maximum Tolerated Dose ◽  
Preliminary Evidence ◽  
Response To Therapy ◽  
Sildenafil Citrate ◽  
Waldenström’S Macroglobulinemia ◽  
Minor Response ◽  
Waldenstrom's Macroglobulinemia ◽  
Waldenstrom’S Macroglobulinemia ◽  
Waldenström's Macroglobulinemia

7556 Background: Responses to sildenafil citrate (Viagra), a phosphodiesterase-5 inhibitor used to treat erectile dysfunction, have been observed in patients with Waldenstrom’s Macroglobulinemia (WM). Moreover, sildenafil citrate induces apoptosis of WM lymphoplasmacytic cells (Clin Lymphoma 5:205, 2004). We therefore conducted a prospective phase II study of sildenafil citrate in patients with slowly progressing WM who did not meet consensus eligibility for active therapy (Semin Oncol 2003; 30:116). Intended therapy was as follows: Week 1 25 mg po qD Week 2 50 mg po qD Week 3 75 mg po qD Week 4, then Months 2–24 100mg po qD or Maximum Tolerated Dose Methods: Thirty patients were enrolled, 18 of whom were previously untreated. All patients demonstrated progressing disease prior to enrollment. Median age was 66 (range 43–85 yrs), baseline BM involvement was 30% (range 5–90%), serum IgM was 3,640 (range 790–6,720 mg/dL), hematocrit was 37.1% (range 32.7–58.5%), and B2M was 2.3 (range 1.5–8.9 mg/dL). Patients were evaluable for response after 3 months of therapy. Results: At a median of 3 months, serum IgM levels declined in 19/30 (63%) patients from a median of 3,640 (range 790–6,720 mg/dL) to 2,965 (range 1,170–6,110 mg/dL). 5/30 patients (17%) demonstrated at least a minor response (≥25% IgM decrease). Two patients were taken off study for non-response to therapy. Toxicities were mild and included headaches, sinus congestion, facial flushing, dyspepsia, and generally resolved on their own with prolonged sildenafil citrate usage. Only two patients required dose modification to 25 mg and 75 mg po qD, respectively. Corollary studies to determine putative mechanisms of action for sildenafil citrate in WM were also performed and will be updated at the meeting. Conclusions: This prospective clinical trial provides preliminary evidence for activity of sildenafil citrate in patients with advancing WM. With minimal toxicity, sildenafil citrate appears to have suppressed disease progression in more than half of patients and has resulted in objective responses, thus warranting further investigation in WM and possibly other B-cell disorders. No significant financial relationships to disclose.

Molecular Basis of Ibrutinib Resistance in Waldenstrom's Macroglobulinemia

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 756-756 ◽  
Author(s):  
Lian Xu ◽  
Nicholas Tsakmaklis ◽  
Guang Yang ◽  
Jiaji G Chen ◽  
Xia Liu ◽  
...  
Keyword(s):  
Missense Mutation ◽  
Deep Sequencing ◽  
Molecular Basis ◽  
Research Funding ◽  
Waldenström’S Macroglobulinemia ◽  
Targeted Deep Sequencing ◽  
Pcr Assays ◽  
Waldenstrom's Macroglobulinemia ◽  
Ibrutinib Resistance ◽  
Waldenström's Macroglobulinemia

Abstract Ibrutinib is a small molecule that is approved by the U.S. FDA for the treatment of chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL), and Waldenström's Macroglobulinemia (WM). In WM, mutated MYD88 supports the growth and survival of malignant lymphoplasmacytic cells (LPC) through BTK, while CXCR4WHIM mutations promote ibrutinib resistance (Yang et al, Blood 2013; Cao et al, Leukemia 2013). Ibrutinib irreversibly binds to Cys481 on BTK, and blocks its kinase activity. Despite high response rates and durable remissions in WM (Treon et al, NEJM 2015; Dimopoulos et al, ASH 2015), disease progression can occur in WM patients on active ibrutinib therapy. To investigate the molecular basis of ibrutinib resistance in WM, we first focused on BTK mutations at Cys481 that have been associated with ibrutinib resistance in CLL and MCL using Sanger sequencing and nested AS-PCR. To capture the known variants at BTK Cys481, three AS-PCR assays for Cys481SerG>C, Cys481SerT>A, and Cys481ArgT>C were developed with a sensitivity of detecting 0.1% of mutant alleles. Using these assays, we evaluated 8 WM patients who progressed on ibrutinib. Among these 8 patients, 5 had BTK Cys481 mutations: 3 were positive for Cys481SerG>C, and2 were positive for all the three (Cys481SerG>C, Cys481SerT>A, and Cys481ArgT>C) mutations. Cloning/sequencing analysis confirmed co-occurrence of multiple Cys481 mutations within individual WM patients and the presence of mutations at different alleles. Furthermore, targeted deep sequencing (>300X coverage) confirmed all BTK Cys481 mutations, and identified an additional mutation at Cys481 (Cys481TyrG>A) in both patients who were positive for Cys481SerG>C, Cys481SerT>A and Cys481ArgT>C. The estimated allele frequencies by targeted deep sequencing for individual BTK mutations ranged from 1-34%. In contrast, no BTK Cys481 mutations were identified in 100 ibrutinib naive WM patients using the nested AS-PCR assays. Among the 8 WM patients included in this study, all had activating MYD88 mutations, and 4 had CXCR4WHIM mutations. All 4 patients with CXCR4WHIM mutations had BTK Cys481 mutations. We next utilized targeted deep sequencing to expand the mutation analysis to the entire coding regions of the BTK, as well as select genes relevant to BCR and MYD88 signaling. A missense mutation in CARD11 (L878F) was identified in one patient who lacked any BTK Cys481 mutations, while a missense mutation in PLCG2 (Y495H) was found in another patient with a Cys481SerG>C mutation. The findings provide the first reported insights into the molecular mechanisms associated with ibrutinib resistance in WM, and highlight the emergence of multiple BTK mutated clones within individual patients who progress on ibrutinib. Disclosures Castillo: Biogen: Consultancy; Abbvie: Research Funding; Pharmacyclics: Honoraria; Millennium: Research Funding; Otsuka: Consultancy; Janssen: Honoraria. Palomba:Pharmacyclics: Consultancy. Furman:Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria, Speakers Bureau. Treon:Janssen: Consultancy; Pharmacyclics: Consultancy, Research Funding.

Phase II Trial of Weekly Bortezomib in Combination with Rituximab in Relapsed or Relapsed/Refractory Waldenstrom's Macroglobulinemia.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2727-2727
Author(s):  
Irene M. Ghobrial ◽  
Fangxin Hong ◽  
Swaminathan Padmanabhan ◽  
Ashraf Z. Badros ◽  
Meghan Rourke ◽  
...  
Keyword(s):  
Board Of Directors ◽  
Research Funding ◽  
Significant Activity ◽  
Waldenström’S Macroglobulinemia ◽  
Advisory Committees ◽  
Minor Response ◽  
Waldenstrom's Macroglobulinemia ◽  
Waldenstrom’S Macroglobulinemia ◽  
Grade 3 ◽  
Waldenström's Macroglobulinemia

Abstract Abstract 2727 Poster Board II-703 INTRODUCTION: This study aimed to determine activity and safety of weekly bortezomib and rituximab in patients with relapsed/refractory Waldenstrom's Macroglobulinemia (WM). METHODS: Patients who had at least one previous therapy were eligible. All patients received bortezomib IV weekly at 1.6 mg/m2 on days 1, 8, 15, q 28 days x 6 cycles, and rituximab 375 mg/m2 weekly on cycles 1 and 4. Primary endpoint was the percent of patients with at least a minor response. RESULTS: Thirty-seven patients were treated. Majority of patients (78%) completed treatment per protocol. At least minimal response (MR) or better was observed in 81% (95% CI: [65,92]) with 2 patients (5%) in complete remission (CR)/near CR, 17 (46%) in partial response (PR), and 11(30%) in MR. The median time to progression was 16.4 months (95% CI, 11.4–21.1). Death occurred in 1 patient due to viral pneumonia. The most common grade 3 and 4 therapy related adverse events included reversible neutropenia in 16%, anemia in 11%, and thrombocytopenia in 14%. Grade-3 peripheral neuropathy occurred in only 2 patients (5%). The median event-free survival (EFS) is 12 months (95% CI, 11–20) with estimated 12 month and 18 month EFS of 49% (95% CI: [31, 67%]) and 38% (95% CI: [20, 56%]). The median overall survival has not been reached. CONCLUSIONS: The combination of weekly bortezomib and rituximab showed significant activity and minimal neurological toxicity in patients with relapsed WM. Disclosures: Ghobrial: Millennium: Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau. Anderson:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Millennium: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Richardson:Millennium Pharmaceuticals, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Johnson and Johnson: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Keryx: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Treon:Millennium: Honoraria, Research Funding, Speakers Bureau; Celgene: Honoraria, Research Funding, Speakers Bureau; Genentech: Honoraria, Research Funding, Speakers Bureau. Matous:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Cephalon: Membership on an entity's Board of Directors or advisory committees.

scholarly journals Global Waldenström's Macroglobulinemia Patient-Derived Data Registry, Whimsical, Highlights Real-World Treatment Outcomes and COVID-19 Data

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1343-1343
Author(s):  
Ibrahim Tohidi-Esfahani ◽  
Andrew Warden ◽  
Elena Malunis ◽  
Peter Liburdi deNardis ◽  
Michelle Postek ◽  
...  
Keyword(s):  
Real World ◽  
Research Funding ◽  
Waldenström’S Macroglobulinemia ◽  
First Line ◽  
Advisory Committees ◽  
Eortc Qlq C30 ◽  
Waldenstrom's Macroglobulinemia ◽  
Waldenstrom’S Macroglobulinemia ◽  
Eortc Qlq ◽  
Waldenström's Macroglobulinemia

Abstract Introduction: WhiMSICAL (Waldenström's Macroglobulinemia Study Involving CArt-wheeL) is the first global Waldenström's Macroglobulinemia (WM) registry capturing patient-derived data to complement scarce clinical trials data in this rare cancer (Tohidi-Esfahani et al, Am J Hematol 2021). The registry was interrogated to identify real-world first line treatment outcomes, quality of life (QoL) and coronavirus disease 2019 (COVID-19) data. Methods: The registry captures data through www.cart-wheel.org, an online rare cancer database, utilizing a tailored questionnaire developed by clinician and patient investigators. WM patients complete consent online, then enter symptom, pathology, treatment, QoL (EORTC QLQ-C30) and COVID-19 data, and can return to update their data on an ongoing basis. Recruitment is driven by social media messaging by the International Waldenström's Macroglobulinemia Foundation investigators. Time to next treatment (TTNT) was assessed from start of first therapy to start of second therapy. Patients without a documented second therapy were censored at the time of last edit to their account. COVID-19 questions included testing, disease severity, vaccination and impact on WM management. Results: As of July 2021, 558 patients from 20 countries have participated in the registry, predominantly from USA (50%), Australia (22%) and the UK (9%). Median age at diagnosis was 61 years (range 24-83) with male predominance (61%). 371 patients documented first-line therapies, with a total of 54 unique therapeutic combinations listed. The seven most common therapies were: bendamustine rituximab (BR, n=94), rituximab monotherapy (Rit., n=52), dexamethasone rituximab cyclophosphamide (DRC, n=33), ibrutinib (n=25), bortezomib dexamethasone rituximab (n=15), rituximab cyclophosphamide vincristine prednisolone (n=14) and chlorambucil (n=10). Comparison of TTNT was limited to the four most common first-line therapies: BR, Rit., DRC, with zanubrutinib (n=5) and ibrutinib plus rituximab (n=2) adding to the first line Bruton tyrosine Kinase inhibitor (BTKi) cohort (n=32). Median ages for the BR, BTKi, DRC and Rit. cohorts were 65, 66, 61 & 65 years, respectively. More patients in the BR cohort listed comorbidities (37%), with BTKi-treated patients reporting the least (19%). Pre-treatment disease burden (median IgM and hemoglobin) trended to being higher in the BR and DRC cohorts (figure 1B-D, IgM p=0.24, Hb p=0.27). At median follow up ranging from 31 to 39 months, BR had superior TTNT to DRC (median: not reached and 104 months, p=0.007, figure 1C) and Rit. (median 26 months, p < 0.0001, figure 1D), and trended to superiority compared to BTKi (median not reached, p=0.08, figure 1B). Median TTNT for the entire cohort (n=371) was 108 months (median follow up 55 months, figure 1A). Assessment of QoL was conducted in all patients (any line of treatment) and compared between patients currently on BTKi therapy (n=64) and patients not exposed to BTKi and treated within the last 12 months (n=84). The expanded BTKi cohort reported better QoL, with mean EORTC QLQ-C30 global scale of 82 ± 14.4 compared to the BTKi-naïve cohort mean 73.4 ± 20.9, p=0.005. This was despite more prior lines of treatment (median 2 [IQR 1-4] compared to 1 [IQR 1-1]; p<0.0001). 324 (58%) patients responded to the COVID-19 questions. 144/324 (44%) had undergone testing for COVID-19, with 11 (8%) returning a positive result; none after vaccination. Median length of symptoms was seven days (range 2-30), with two hospitalized, one requiring intensive care. Both hospitalized patients were on second line ibrutinib. Of 211 responses regarding vaccination status, 15 (7%) were not vaccinated, eight due to availability, five due to personal choice and two due to clinician advice. Regarding impact of the pandemic on their WM management, 5% had treatment schedule disruption and 53% reported reduced face-to-face consultations. Conclusion: The WhiMSICAL registry provides a scientifically robust and ethically approved portal for the patients' voice. The data highlight the real-world efficacy of combination chemoimmunotherapy, particularly first-line BR, and suggest a better QoL with BTKi than other therapies. As this global data platform grows, the breadth of data allows for new insights into WM with patient reported outcomes advancing knowledge and facilitating treatment decisions for clinicians and patients. Figure 1 Figure 1. Disclosures D'Sa: Sanofi: Honoraria; BeiGene: Honoraria, Research Funding; Janssen Cilag: Honoraria, Research Funding. Kersten: Roche: Consultancy, Honoraria, Other: Travel support, Research Funding; Miltenyi Biotec: Consultancy, Honoraria, Other: Travel support; Novartis: Consultancy, Honoraria, Other: Travel support; BMS/Celgene: Consultancy, Honoraria; Takeda: Research Funding; Kite, a Gilead Company: Consultancy, Honoraria, Other: Travel support, Research Funding; Celgene: Research Funding. Thomas: Acerta Pharma: Research Funding; Ascentage Pharma: Research Funding; BeiGene: Membership on an entity's Board of Directors or advisory committees; BMS: Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees; X4 Pharma: Research Funding; Genentech: Research Funding. Palomba: Ceramedix: Honoraria; Rheos: Honoraria; Nektar: Honoraria; Priothera: Honoraria; Lygenesis: Honoraria; WindMIL: Honoraria; Wolters Kluwer: Patents & Royalties; Juno: Patents & Royalties; BeiGene: Consultancy; Kite: Consultancy; Magenta: Honoraria; Seres: Honoraria, Other: Stock, Patents & Royalties, Research Funding; PCYC: Consultancy; Notch: Honoraria, Other: Stock; Novartis: Consultancy; Pluto: Honoraria. Olszewski: Acrotech Pharma: Research Funding; Celldex Therapeutics: Research Funding; TG Therapeutics: Research Funding; PrecisionBio: Research Funding; Genentech, Inc.: Research Funding; Genmab: Research Funding. Trotman: PCYC: Research Funding; roche: Research Funding; BMS: Research Funding; TAKEDA: Research Funding; JANSSEN: Research Funding; beigene: Research Funding.

A Novel Functional Role for Soluble CD27 in the Pathogenesis of Waldenstrom’s Macroglobulinemia.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4701-4701 ◽  
Author(s):  
Allen W. Ho ◽  
Xavier Leleu ◽  
Evdoxia Hatjiharissi ◽  
Olivier Tournilhac ◽  
Lian Xu ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Tumor Cells ◽  
Functional Role ◽  
Flow Cytometric Analysis ◽  
Waldenström’S Macroglobulinemia ◽  
Flow Cytometric ◽  
Waldenstrom's Macroglobulinemia ◽  
Waldenstrom’S Macroglobulinemia ◽  
Waldenström's Macroglobulinemia

Abstract The tumor necrosis factor (TNF) receptor family member, CD27, is a transmembrane co-stimulatory molecule present on primed T and B lymphocytes that also secrete a soluble form (sCD27). Recent evidence has suggested that interactions between CD27 and its TNF-like ligand, CD70, play a critical role in regulating B-cell activation and survival, though the detailed mechanism(s) by which this occurs remain unclear. Waldenstrom’s Macroglobulinemia (WM) represents a lymphoplasmacytic lymphoma characterized by a monoclonal IgM gammopathy and possesses a mast cell component that may contribute to its pathogenesis (Blood 104; 646a). Using ELISA assays, we observed that WM patients displayed significantly higher levels of sCD27 in their sera (median 7.45, range 0–19.42 U/ml) versus healthy donors (median 0, range 0–2.78 U/ml; p=2.5 x 10−7). CD27 was expressed in 7/7 patients using RT-PCR analysis, but was expressed on the cell surface of tumor cells in 5/12 patients using flow cytometric analysis. Conversely, CD70 expression was widely expressed on both tumor cells (6/6 patients) and mast cells (10/11 patients) using flow cytometric analysis. In order to define the functional role of sCD27 in WM, we cultured BCWM.1 (CD27−CD70+) WM cells, and LAD1 (CD27−CD70+) mast cells with sCD27 (0.1–50 ug/mL), and observed no effect on proliferation or induction of apoptosis. Culture of LAD1 cells with sCD27 did, however, result in marked upregulation of the TNF family ligands CD40L (CD154) and a proliferation induction ligand (APRIL), which previous work in our laboratory had implicated as mast cell proliferation and survival factors in WM. Taken together, these studies suggest a novel functional role for sCD27, and imply a pivotal role in the pathogenesis of WM.

IgM-Expressing Waldenstrom’s Macroglobulinemia Tumor Cells Reveal a Potential for Isotype Switch.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 994-994
Author(s):  
Surinder S. Sahota ◽  
Gavin Babbage ◽  
Mark Townsend ◽  
Ian C. Mockridge ◽  
Niklas Zojer ◽  
...  
Keyword(s):  
B Cell ◽  
Tumor Cells ◽  
Cytidine Deaminase ◽  
Expression Profiles ◽  
Phenotypic Change ◽  
Waldenström’S Macroglobulinemia ◽  
Waldenstrom's Macroglobulinemia ◽  
Waldenstrom’S Macroglobulinemia ◽  
Tumor Clone ◽  
Waldenström's Macroglobulinemia

Abstract In Waldenstrom’s macroglobulinemia (WM), which locates primarily in the bone marrow (BM), VH gene analysis had previously suggested origins from a post-follicular B-cell arresting prior to isotype switch. Using more sensitive assays, facilitated by amplified cDNA from BM cells, nested PCR unexpectedly revealed tumor-derived isotype-switch transcripts in 7/7 cases. In 5/7 cases, both Cγ and Cα variant transcripts were identified, and Cγ or Cα only in 2/7. Detection of activation induced cytidine deaminase (AID) and germline and circle transcripts confirmed switching activity. Selected gene expression profiles established the memory B-cell marker CD27 as highly expressed in all cases. These findings were evaluated further in additional WM cases where availability of tumor material allowed detailed analysis. In 2/2 cases, phenotype suggested a variable CD27 expression within the tumor clone. In these, tumor IgM transcripts were readily detected in both the CD19+CD27+ and CD19+CD27− fractions, and in 1 of the 2 cases, post-switched tumor-derived Cα transcripts were also identified in each fraction. In this WM case, the frequency of tumor-derived transcripts was then assessed at the single cell level. Switch transcripts were identified in 3/96 cells with no co-expression of the IgM isotype. Similarly, AID transcripts were observed in some cells, not always correlating with switch events or with ongoing somatic mutation, which was apparent in VDJ-Cμ sequences. These findings reveal a dynamic intratumoral diversification, with AID activated and ongoing mutational and switch activity occurring post-transformation in a proportion of the tumor clone. Heterogeneity in CD27 expression is also evident within tumor cells, revealing phenotypic change. Interestingly, these data indicate that although WM tumor cells have arrested at the IgM stage and do not express isotype switched Ig, they retain the capacity to initiate events critical for isotype switch.

scholarly journals Bendamustine and Rituximab Combination Is Safe and Effective As Salvage Regimen in Waldenstrom's Macroglobulinemia

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3072-3072
Author(s):  
Alessandra Tedeschi ◽  
Giulia Benevolo ◽  
Gloria Casaluci Margiotta ◽  
Simone Ferrero ◽  
Paola Picardi ◽  
...  
Keyword(s):  
Disease Progression ◽  
Refractory Disease ◽  
Waldenström’S Macroglobulinemia ◽  
Purine Analogues ◽  
Salvage Regimen ◽  
Waldenstrom's Macroglobulinemia ◽  
Waldenstrom’S Macroglobulinemia ◽  
Waldenström's Macroglobulinemia

Abstract Introduction: Accordingto National Comprehensive Cancer Network (NCCN) and ESMO guidelines on Waldenstrom’s Macroglobulinemia (WM) bendamustine may be considered as a therapeutic option in first line treatment or in relapsed refractory disease. Even though there are only two clinical trials including a limited number of patients addressing the role of bendamustine and rituximab (BR) treatment in WM. Patients and Methods: To define the efficacy and tolerability of BR combination as salvage regimen in WM patients, we retrospectively analyzed the outcome of symptomatic refractory relapsed patients treated with BR in 14 Italian centres. All patients receiving at least one day of treatment were included in the study. Treatment consisted of: R 375 mg/sqm iv day 1 and B iv days 1, 2. Therapy was administered every 4 weeks up to 6 courses. Results: Seventy-one patients are included in the study. As regards B dosage; 45 patients (63%) received the highest dose of 90 mg/sqm while 22 (31%) were treated with 70 mg/sqm. The 4 patients (6%) with a cumulative illness rating scale ≥ 6, received the lowest dose of 50 mg/sqm. At treatment, median age was 72 years (49-88), sex ratio M/F 46/25. Mediannumber of prior regimens was 2 (range 1-6). Twenty-four patients (34%) presented with refractory disease. The majority (90%) of patients had been previously treated with alkylating agents, 30% had also received purine analogues based treatments. Previous R was administered in the 77% of cases. The main reason (62%) for starting treatment was anemia followed by adenopathy and/or splenomegaly (35%). Median IgM level at treatment was 3815 mg/dL.Overall 361 courses of BR treatment were administered, median number 6 (range 1-6) with 47 (66%) of patients completing the 6 planned courses. Toxicity was discontinuation cause in 10 patients (14%): 4 infection, 1 fatal, 6 myelosuppression. In the remaining 14 treatment was discontinued for clinical clinical decision after disease reassessment. No difference in terms of treatment discontinuation was observed according to B dosage and age. Overall response rate (ORR) was 80.3% including: 7% complete remissions (CR), 15.5 % very good partial remissions (VGPR), 52.2% partial remissions (PR) and 5.6% of minor responses. A stable disease was observed in 16.9% of patients. One (1.4%) disease progression and one death were recorded. A progressive decrease of IgM level was observed during follow-up leading to an amelioration of response in 4 cases leading to a final ORR of 84.5%. None of the clinical and biological characteristics considered (age, sex, disease status, previous lines of treatment, previous fludarabine, bulky disease, Hb and IgM level, beta 2 microglobulin, B dosage) had an impact on ORR achievement. A better quality of response (CR plus VGPR) was observed in patients with an IgM level < 3000 mg/dL and in those treated with the higher dosage of B (90 mg/sqm). After a median follow-up of 19 months (3-54) 11 of the 57 responding patients met the criteria for disease progression. No difference was observed when patients were stratified according to the quality of response. B dosage did not impact disease progression. Considering that most of the patients received prophylactic growth factors, grade 3-4 neutropenia developed in only 13% of courses, 36% of patients. Dose modification or delayed treatment administration was necessary in 4 and 10% of courses respectively. During treatment we recorded 14 episodes of FUO and 5 major infections, leading death in one case. After a median follow up of 19 months none of the patients developed secondary myelodisplastic syndrome, acute leukemia or diffuse large B-cell lymphoma. In 3 cases a solid cancer was observed. Conclusion: BR combination showed to be as effective as more intensive salvage regimens in pretreated WM patients. Treatment showed to be well tolerated even in elderly patients with limited episodes of myelosuppression and infections when compared to purine analogues including regimens. Disclosures No relevant conflicts of interest to declare.

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