Genomic Profiling of Circulating Tumor DNA Reveals Patterns of Response and Refractoriness in Aggressive B-Cell Lymphoma - a Nordic Lymphoma Group Correlative Study

Introduction Sequencing of circulating cell-free tumor DNA (ctDNA) has opened a diagnostic avenue for the patients with B-cell neoplasias, including diffuse large B-cell lymphoma (DLBCL). Treatment refractoriness and disease relapse after first-line therapy are associated with dismal survival. We sought to assess the clinical feasibility and prognostic value of ctDNA detection in prospectively collected samples from young high-risk patients treated uniformly in a Nordic phase II study. Materials and Methods The patients were treated in a phase II trial with dose-dense chemoimmunotherapy (biweekly R-CHOEP) and early systemic CNS prophylaxis with high-dose methotrexate (NLG-LBC-05; Leppä et al., 15-ICML; ClinicalTrials.gov NCT01325194). Longitudinal plasma samples from all trial centers were gathered and the plasma purified for cell-free DNA (cfDNA) in Helsinki, Finland (Figure 1A). We designed a 225 kb custom panel targeting most commonly mutated genomic drivers, regions of aberrant somatic hypermutation and immunoglobulin genes. Next-generation sequencing was performed on longitudinal cfDNA samples and primary tumor samples together with matched germline controls from the first 32 patients in the study. Sequencing was completed on Hiseq2500 platform and depth after duplicate removal with unique molecular identifiers was on average 1,926x (ctDNA), 3,073x (primary tumors) and 2,171x (germline controls). Multi-tumor variant calling was performed by Mutect2. Results cfDNA was successfully extracted from 96 patients (Figure 1B). Among the patients with completed sequencing and bioinformatics pipeline, we identified a median of 87 traceable somatic mutations in 97% of the patients. In plasma samples, ctDNA was detectable in 93% of the patients prior to treatment. Compellingly, we observed that the levels of total cfDNA and ctDNA were higher at baseline in the patients who relapsed. We evaluated the concordance between pretreatment ctDNA and primary tumor biopsy mutations in patients with available material. The percentage of shared somatic mutations ranged between 14 - 100%, suggesting substantial spatial heterogeneity in some cases. While the mutations in known lymphoma genes were mostly shared between the baseline ctDNA and the diagnostic tumor biopsy, some lymphomas displayed vast discordance mostly in the immunoglobulin loci, suggesting active somatic hypermutation processes upon clonal divergence in these lymphomas (Figure 1C). In all longitudinally analyzed plasma samples, the levels of ctDNA dropped after the first three treatment courses. At the end of therapy, the levels of ctDNA were undetectable in most of the patients with durable remissions (Figure 1D #1). However, in the patients with progressive disease, the ctDNA levels increased at the end of the therapy (Figure 1D #2). In the patients with late relapse (>12 months progression free survival), we observed the appearance of a subset of the mutations that were identified at diagnosis, suggesting clonal selection (Figure 1D #3). Conclusion Our findings elucidate the biology of ctDNA in B-cell lymphomas, and the ctDNA kinetics in homogeneously treated patients with primary high-risk DLBCL. Figure 1. A) Collection of cfDNA samples in the CHIC trial. B) Swimmers plot of the patients with extracted cfDNA in the liquid biopsy cohort. C) Concordance between primary tumor and ctDNA mutations at diagnosis. CHIC_100: high concordance. CHIC_88: low concordance. D) Kinetics of ctDNA in patients with different diseases courses. Figure 1 Disclosures Jørgensen: Roche: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees. Jerkeman:Janssen: Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Acerta: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Roche: Honoraria, Research Funding. Holte:Novartis: Honoraria, Other: Advisory board. Leppa:Celgene: Consultancy; Bayer: Research Funding; Roche: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Research Funding; Janssen: Consultancy, Research Funding.

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Potential Utility of Circulating Tumor DNA Monitoring in Primary Mediastinal B-Cell Lymphoma Treated with R-DA-EPOCH

Blood ◽

10.1182/blood-2021-152376 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 4491-4491

Author(s):

Ana Jimenez-Ubieto ◽

María Poza ◽

Alejandro Martín-Muñoz ◽

Sara Dorado ◽

Yanira Heredia ◽

...

Keyword(s):

B Cell ◽

Somatic Mutations ◽

Cell Lymphoma ◽

B Cell Lymphoma ◽

Circulating Tumor Dna ◽

Plasma Samples ◽

Publicly Traded ◽

Advisory Committees ◽

Pet Ct ◽

Tumor Dna

Abstract Background: Primary mediastinal B-cell lymphoma (PMBCL) is a rare subtype of aggressive B-cell lymphoma. Most relapses occur within the first few months resulting in a dismal prognosis; therefore, it's important to identify primary chemorefractory patients at an early stage, to improve their prognosis. Our group have demonstrated that Circulating Tumor DNA (ctDNA) detected by deep sequencing (DeepSeq) constitute a new non-invasive marker for monitoring response in follicular lymphoma (Jimenez-Ubieto A. et al. ASH 2020). CtDNA monitoring in PMBCL might help to better assess therapeutic response, correct false positive PET/CT results due to residual uptake of the mediastinum and define patients who will benefit from radiation therapy (RT). Here we analyzed the potential value of ctDNA monitoring in 11 PMBCL treated with R-DA-EPOCH between 2018-2020 in the Hospital 12 de Octubre. Methods: Genomic DNA from paraffin embedded (FFPE) lymph node biopsies were obtained from 11 PMBCL cases at diagnosis. Samples were sequenced with a short length Ampliseq Custom Panel (Thermo-Fisher) designed to cover all coding regions of 56 lymphoma specific genes with an average depth of 700x. After annotation and filtering, 5-8 somatic mutations previously described in lymphoma were selected to be screened in plasma samples. The plasma derived cfDNA was obtained from 8-16mL of peripheral blood collected in EDTA tubes and processed in less than 4h by column purification (QIAamp Circulating Nucleic Acid Kit, Qiagen). A total of 31 different plasma time-points were sequenced in triplicates. On average 78ng (9-224 ng) of cfDNA was used for the DeepSeq of the specific mutations selected in each patient. An average coverage of 236.000x per triplicate was obtained for each mutation. The detection cut-off of 1E-4 was defined based on the LOD obtained in healthy controls donors. 18F-fluorodeoxyglucose (FDG) PET/CT scans were performed on a General Electric Discovery MI Scanner at basal, interim (after 4 cycles), end of induction (EOI) and after radiotherapy (RT). Results: The median age was 33 years and 63.6% were female. Most cases (81.8%) were diagnosed with stage I or II disease and 27.3% cases present with extranodal involvement. On interim PET, 4 patients reached Complete response (CR) and 7 Partial Response (PR, DS4). At EOI, the number of CR turned to 6/11 (55%). All patients in PR at EOI (n=5) and two patients in CR (DS3) with residual mass received RT consolidation (median dose 32Gy). After RT the rate of CR was 91% (10/11). One patient progressed to a classical Hodgkin lymphoma (cHL). None of the patients in CR have relapsed after a median follow-up of 22 months. One patient died due to a mediastinal synovial sarcoma. A total of 125 somatic mutations were detected in the 11 baseline samples with a median of 8 per patient (rank 5-35). The three most frequently mutated genes were SOCS1 (73%), B2M (55%) and TNFAIP3 (46%). Despite the reduced size of our cohort, the mutational frequencies were comparable to the described by Mottok A. et al (Blood 2018, Figure 1A). The DeepSeq of six diagnosis plasma samples showed a lower Variant Read Frequency (VRF) in cfDNA. On those paired samples, 25/28 mutations were detected in plasma, with a median VRF of 2% (0-53%) vs 24% (5.5%-87%) in Lymph nodes (Figure 1B). The rest of the plasma samples corresponded to 1st cycle (n=5), 4th cycle (n=6), EOI (n=7) and after RT (n=5). After 1 cycle of chemotherapy 3/4 patients who reached CR at EOI had already undetectable ctDNA (Figure 1C). One patient with positive ctDNA after 1 cycle needed RT to convert to CR. All the CR evaluations by PET-TC who had available ctDNA data, presented undetectable ctDNA (n=9). In the EOI analysis all+ patients except the one who progressed to cHL had undetectable ctDNA. In the PR interim evaluations 2/5 had undetectable ctDNA and converted to CR at EOI. Of the three patients with detectable ctDNA, one progressed to cHL (Figure 1D) and 2 needed RT to convert to CR. Conclusions: Our results demonstrate that disease monitoring using DeepSeq of plasma ctDNA is feasible in PMBCL. Regarding prediction of relapse, the positive predictive value of ctDNA was 100%. An early ctDNA analysis (even after only one R-DA-EPOCH cycle) was able to predict patients in need of RT. Despite the DeepSeq of ctDNA could be useful to disease monitoring to prevent relapse and toxicity reduction by selecting cases in need of RT, more patients are necessary to draw meaningful conclusions. Figure 1 Figure 1. Disclosures Martín-Muñoz: Altum sequencing: Current Employment. Dorado: Altum sequencing: Current Employment. Heredia: Altum sequencing: Current Employment, Current equity holder in publicly-traded company. Rufian: Altum sequencing: Current Employment. Canales: Incyte: Consultancy; iQone: Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; Karyopharm: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria; Sanofi: Consultancy; Eusa Pharma: Consultancy, Honoraria; Sandoz: Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Speakers Bureau; Gilead/Kite: Consultancy, Honoraria. Juarez: Altum sequencing: Current Employment. Sanchez: Altum sequencing: Current Employment. López-Muñoz: Amgen: Consultancy. Ayala: Incyte Corporation: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Astellas: Honoraria; Celgene: Honoraria. Martínez-López: Janssen, BMS, Novartis, Incyte, Roche, GSK, Pfizer: Consultancy; Roche, Novartis, Incyte, Astellas, BMS: Research Funding. Barrio: Altum sequencing: Current Employment, Current equity holder in publicly-traded company.

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Comprehensive Analyses of Genetic Features Identify Coordinate Signatures in Diffuse Large B-Cell Lymphoma

Blood ◽

10.1182/blood.v126.23.3922.3922 ◽

2015 ◽

Vol 126 (23) ◽

pp. 3922-3922

Author(s):

Bjoern Chapuy ◽

Andrew J Dunford ◽

Chip Stewart ◽

Atanas Kamburov ◽

Jaegil Kim ◽

...

Keyword(s):

B Cell ◽

Board Of Directors ◽

Research Funding ◽

Somatic Mutations ◽

Chromosomal Rearrangements ◽

Low Frequency ◽

B Cell Lymphoma ◽

Genetic Alterations ◽

B Cell Differentiation ◽

Advisory Committees

Abstract Diffuse large B-cell lymphoma (DLBCL) is a genetically heterogeneous disease characterized by multiple low-frequency alterations including somatic mutations, copy number alterations (CNAs) and chromosomal rearrangements. We sought to identify previously unrecognized low-frequency genetic events, integrate recurrent alterations into comprehensive signatures and associate these signatures with clinical parameters. For these reasons, our multi-institutional international group assembled a cohort of 304 primary DLBCLs from newly diagnosed patients, 87% of whom were uniformly treated with state-of-the-art therapy (rituximab-containing CHOP regimen) and had long term followup. Tumors were subjected to whole exome sequencing with an extended bait set that included custom probes designed to capture recurrent chromosomal rearrangements. In this cohort, 47% of samples had available transcriptional profiling and assignment to associated disease subtypes. Analytical pipelines developed at the Broad Institute were used to detect mutations (MuTect), CNAs (Recapseq+Allelic Capseq) and chromosomal rearrangements (dRanger+Breakpointer) and assess clonality (Absolute). To analyze formalin-fixed paraffin-embedded tumors without paired normals we developed a method which utilized 8334 unrelated normal samples to stringently filter recurrent germline events and artifacts. Significant mutational drivers were identified using the MutSig2CV algorithm and recurrent CNAs were assessed with GISTIC2.0. In addition, we utilized a recently developed algorithm, CLUMPS2, to prioritize somatic mutations which cluster in 3-dimensional protein structure. With this approach, we identified > 90 recurrently mutated genes, 34 focal amplifications and 41 focal deletions, 20 arm-level events and > 200 chromosomal rearrangements in the DLBCL series. Of note, 33% of the mutational drivers were also perturbed by chromosomal rearrangements or CNAs, underscoring the importance of a comprehensive genetic analysis. In the large DLBCL series, we identified several previously unrecognized but potentially targetable alterations including mutations in NOTCH2 (8%) and TET2 (5%). The majority of identified chromosomal rearrangements involved translocations of potent regulatory regions to intact gene coding sequences. The most frequently rearrangements involved Ig regulatory elements which were translocated to BCL2, MYC, BCL6 and several additional genes with known roles in germinal center B-cell biology. After identifying recurrent somatic mutations, CNAs and chromosomal rearrangements, we performed hierarchical clustering and identified subsets of DLBCLs with comprehensive signatures comprised of specific alterations. A large subset of tumors shared recurrent alterations previously associated with follicular lymphoma including mutations of chromatin modifiers such as CREBBP, MLL2, and EZH2 in association with alterations of TNFRSF14 and GNA13 and translocations of BCL2. This cluster was enriched in GCB-type DLBCLs and contained a subset with select genetic alterations associated with an unfavorable outcome. An additional cohort of tumors was characterized by alterations perturbing B-cell differentiation including recurrent BCL6 translocations or alterations of PRDM1. A subset of these DLBCLs had alterations of NOTCH2 and additional pathway components or mutations of MYD88 in association with TNFAIP3, CD70 and EBF1, a master regulator of B-cell differentiation. An additional group of DLBCLs exhibited frequent MYD88 mutations in association with alterations of CD79B, PIM1, TBL1XR1 and ETV6 and BCL2 copy gain; these tumors were highly enriched for ABC-type DLBCLs. This coordinate signature and additional alterations of p53 pathway components were associated with outcome. We explored bases for the identified genetic alterations in DLBCL by performing an in silico mutational signature analysis. The most frequent mutational signatures were those of spontaneous deamination (aging) and AID with rare cases of microsatellite instability. We also assessed the clonality of identified genetic features to define cancer cell fraction and establish the timing of specific genetic events. The comprehensive genetic signatures of clinically annotated DLBCLs provide new insights regarding approaches to targeted therapy. Disclosures Link: Kite Pharma: Research Funding; Genentech: Consultancy, Research Funding. Rodig:Perkin Elmer: Membership on an entity's Board of Directors or advisory committees; BMS: Research Funding. Pfreundschuh:Boehringer Ingelheim, Celegene, Roche, Spectrum: Other: Advisory board; Roche: Honoraria; Amgen, Roche, Spectrum: Research Funding. Shipp:Gilead: Consultancy; Sanofi: Research Funding; BMS: Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Somatic Mutations Associated with IgVH4-34 FR1 Region Unmutated QW and Avy Motifs in DLBCL Patients

Blood ◽

10.1182/blood-2020-142486 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 20-21

Author(s):

Caitlin Coombes ◽

Keisuke Horikawa ◽

Sanjiv Jain ◽

Jun Hee Lim ◽

Sewa Rijal ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Board Of Directors ◽

Research Funding ◽

Somatic Mutations ◽

B Cell Lymphoma ◽

Clinical Samples ◽

Advisory Committees ◽

Ffpe Samples ◽

Self Antigens

There is increasing evidence for antigen-driven B-cell receptor (BCR) signalling in diffuse large B-cell lymphoma (DLBCL) and other lymphoid malignancies. This includes antigens from infections e.g.Helicobacter pyloriand Hepatitis C virus, but it is theorised that self-antigens may play a major role in some cases of lymphoid malignancy. IgVH4-34 demonstrates intrinsic autoreactivity to self-antigens on red cells, which appears to be largely mediated by two motifs within the first framework region (FR1); Q6W7 and A24V25Y26. These motifs work together to for a hydrophobic patch which determines red cell antigen binding and are frequently mutated away from self-reactivity in normal B cells. IgVH4-34 has been reported to be over-represented in DLBCL compared with expression in normal B cells. We therefore sought to identify IgVH4-34 DLBCL cases from a local cohort and to screen them for Q6W7 and A24V25Y26 motifs expecting them to be less frequently mutated in DLBCL compared with normal B cells.We also aimed to screen V4-34 cases for associated somatic mutations in other genes using high-throughput sequencing. DLBCL patient samples were obtained via the Haematology Research Tissue Bank (HRTB) in Canberra, Australia, and the Victoria Cancer BioBank. Forty-eight Formalin-Fixed, Paraffin-Embedded (FFPE) samples and 26 fresh frozen samples were screened. All samples were collected at the time of diagnosis. Patients were treated with standard chemoimmunotherapy approaches. IgVH 4-34 gene sequences were determined using an IgVH4 family-specific leader primer in combination with a JH consensus reverse primer. The IgVH region was then sequenced using Sanger sequencing. Sequences were analyzed using the IgBLAST database (National Centre for Biotechnology Information). DNA extracted from FFPE samples generally proved to have low concentration and fragmented DNA. Only 1 IgVH4-34 sequence was obtained from FFPE tissue. Five samples sequenced from fresh tissue were identified as using IgVH4-34. Using Hans criteria, it was possible to classify 3 of the 6 cases as germinal center (GC) and 1 as non-GC origin. Using fresh samples, we estimated the frequency of IgVH4-34 cases at 23%. Within FR1, Q6W7 was unmutated in all 6 samples. One sample had mutations in the A24V25Y26 motif resulting in a change to A24V25F26. The other 5 samples (83.3%) had unmutated AVY motifs. We extracted genomic DNA from and performed next generation sequencing on the 5 samples with unmutated Q6W7 and A24V25Y26 motifs using a customized capture library (SureSelectXT Target Enrichment System, Aqilent Technologies) covering genes involved in lymphomagenesis. The purified libraries were sequenced on the Illumina NextSeq500 platform at AGRF (Australian Genome Research Facility, Australia). Several genes (FCGR3A,NOTCH2andNOTCH2NLR) had mutations in all 5 samples.FCGR3Ais an IgG Fc receptor gene, and mutations inFCGR3Ahave previously been linked to systemic lupus erythematosus (SLE).NOTCH2pathway genes are frequently mutated in DLBCL.CREBBPwas mutated in four of the five samples. Mutations inCREBBPhave previously been linked with DLBCL development and regulation of immune responses. We identified high rates of IgVH4-34 (23%) in our cohort of fresh samples as previously reported. Further, we noted preservation of the Q6W7 and A24V25Y26 motifs in IgVH4-34-expressing DLBCL. This over-representation of unmutated FR1 motifs suggests that the ability to recognise self-antigens likely provides important ongoing BCR signalling that promotes survival in DLBCL. This study also highlights the difficulties in conducting DNA-based research on FFPE clinical samples which have not been collected for research purposes and the importance of tissue banking fresh samples. Studies are currently being conducted into the efficacy of BCR pathway inhibitors e.g. ibrutinib in the treatment of DLBCL and testing for unmutated IgVH4-34 FR1 motifs may present a method to predict patients who are more likely to respond. Mutations in genes such as FCGR3A,NOTCH2andCREBBPmay work in conjunction with the preserved QW and AVY motifs to promote lymphomagenesis in IgVH4-34-expressing B cells and may present targets for future research into treatment therapies. Figure Disclosures Talaulikar: Roche:Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding;Janssen:Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau;Amgen:Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding;Takeda:Research Funding.

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Impact of Interim FDG-PET (iPET) in the Outcomes of Patients with Aggressive B-Cell Lymphomas Receiving DA-EPOCH-R

Blood ◽

10.1182/blood-2019-122393 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 2898-2898

Author(s):

Vania Phuoc ◽

Leidy Isenalumhe ◽

Hayder Saeed ◽

Celeste Bello ◽

Bijal Shah ◽

...

Keyword(s):

B Cell ◽

Board Of Directors ◽

Fdg Pet ◽

Research Funding ◽

Cell Lymphoma ◽

B Cell Lymphoma ◽

Advisory Committees ◽

End Of Treatment

Introduction: 2-[18F] fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) remains the standard of care for baseline and end of treatment scans for aggressive non-Hodgkin lymphomas (NHLs). However, the role of interim FDG-PET remains not as well defined across aggressive NHLs, especially in the era of high-intensity chemoimmunotherapy. Interim FDG-PET (iPET) can serve as an early prognostic tool, and prior studies evaluating the utility of iPET-guided treatment strategies primarily focused on diffuse large B-cell lymphomas (DLBCL) and frontline R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone). Classification criteria systems assessing response also differ between studies with no clear consensus between use of Deauville criteria (DC), International Harmonization Project (IHP), and the ΔSUVmax method. Methods: This study evaluates our institutional experience with iPET during treatment with DA-EPOCH ± R (dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin with or without Rituximab) in aggressive NHLs. We retrospectively evaluated 70 patients at Moffitt Cancer Center who started on DA-EPOCH ± R between 1/1/2014 to 12/31/2018 for aggressive NHLs. Response on interim and end-of-treatment (EOT) scans were graded per DC, IHP, and ΔSUVmax methods, and progression free survival (PFS) probability estimates were calculated with chi-square testing and Kaplan Meier method. PFS outcomes were compared between interim negative and positive scans based on each scoring method. Outcomes were also compared between groups based on interim versus EOT positive or negative scans. Results: We identified 70 patients with aggressive NHLs who received DA-EPOCH ± R at our institute. The most common diagnoses were DLBCL (61%) followed by Burkitt's lymphoma (10%), primary mediastinal B-cell lymphoma (9%), plasmablastic lymphoma (7%), gray zone lymphoma (6%), primary cutaneous large B-cell lymphoma (1%), primary effusion lymphoma (1%), and other high-grade NHL not otherwise specified (3%). Of the 43 patients with DLBCL, 21/43 (49%) had double hit lymphoma (DHL) while 7/43 (16%) had triple hit lymphoma (THL), and 3/43 (7%) had MYC-rearranged DLBCL while 2/43 (5%) had double expressor DLBCL. Thirty nine out of 70 (56%) were female, and median age at diagnosis was 58.39 years (range 22.99 - 86.86 years). Most patients had stage IV disease (49/70, 70%), and 43/70 (61%) had more than one extranodal site while 45/70 (64%) had IPI score ≥ 3. Forty-six out of 70 (66%) received central nervous system prophylaxis, most with intrathecal chemotherapy (44/70, 63%). Fifty-five out of 70 (79%) had iPET available while 6/70 (9%) had interim computerized tomography (CT) scans. Fifty-six out of 70 (80%) had EOT PET, and 4/70 (6%) had EOT CT scans. Sustained complete remission occurred in 46/70 (66%) after frontline DA-EPOCH ± R (CR1), and 12/70 (17%) were primary refractory while 5/70 (7%) had relapse after CR1. Four of 70 (6%) died before cycle 3, and 3/70 (4%) did not have long-term follow-up due to transition of care elsewhere. Median follow-up was 15.29 months (range 0.85 - 60.09 months). There was significantly better PFS observed if iPET showed DC 1-3 compared to DC 4-5 (Χ2=5.707, p=0.0169), and PFS was better if iPET was negative by IHP criteria (Χ2=4.254, p=0.0392) or ΔSUVmax method (Χ2=6.411, p=0.0113). Comparing iPET to EOT PET, there was significantly better PFS if iPET was negative with EOT PET negative (iPET-/EOT-) compared to iPET positive with EOT negative (iPET+/EOT-), and iPET+/EOT+ and iPET-/EOT+ had worse PFS after iPET-/EOT- and iPET+/EOT- respectively. This pattern in iPET/EOT PFS probability remained consistent when comparing DC (Χ2=30.041, p<0.0001), IHP (Χ2=49.078, p<0.0001), and ΔSUVmax method (Χ2=9.126, p=0.0104). These findings fit clinical expectations with positive EOT scans indicating primary refractory disease. There was no significant difference in PFS when comparing DLBCL versus non-DLBCL (Χ2=3.461, p=0.0628) or DHL/THL versus non-DHL/THL diagnoses (Χ2=2.850, p=0.0914). Conclusion: Our findings indicate a prognostic role of iPET during treatment with DA-EPOCH ± R for aggressive NHLs. Significant differences in PFS were seen when graded by DC, IHP, and ΔSUVmax methods used in prior studies and when comparing interim versus EOT response. Larger studies are needed to confirm these findings. Disclosures Bello: Celgene: Speakers Bureau. Shah:Novartis: Honoraria; AstraZeneca: Honoraria; Spectrum/Astrotech: Honoraria; Adaptive Biotechnologies: Honoraria; Pharmacyclics: Honoraria; Jazz Pharmaceuticals: Research Funding; Incyte: Research Funding; Kite/Gilead: Honoraria; Celgene/Juno: Honoraria. Sokol:EUSA: Consultancy. Chavez:Janssen Pharmaceuticals, Inc.: Speakers Bureau; Genentech: Speakers Bureau; Kite Pharmaceuticals, Inc.: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees.

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Waldenström's Macroglobulinemia (WM) Is Preceded By Clonal Lymphopoiesis Including MYD88 L265P in Progenitor B Cells

Blood ◽

10.1182/blood-2019-126889 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1527-1527

Author(s):

Sara Rodríguez ◽

Cirino Botta ◽

Jon Celay ◽

Ibai Goicoechea ◽

Maria J Garcia-Barchino ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Board Of Directors ◽

Research Funding ◽

Somatic Mutations ◽

Advisory Committees ◽

Normal Cells ◽

Cell Clones ◽

B Cell Precursors ◽

Myd88 L265p

Background: Although MYD88 L265P is highly frequent in WM, by itself is insufficient to explain disease progression since most cases with IgM MGUS also have mutated MYD88. In fact, the percentage of MYD88 L265P in CD19+ cells isolated from WM patients is typically <100%, which questions if this mutation initiates the formation of B-cell clones. Furthermore, a few WM patients have detectable MYD88 L265P in total bone marrow (BM) cells and not in CD19+ selected B cells, raising the possibility that other hematopoietic cells carry the MYD88 mutation. However, no one has investigated if the pathogenesis of WM is related to somatic mutations occurring at the hematopoietic stem cell level, similarly to what has been shown in CLL or hairy cell leukemia. Aim: Define the cellular origin of WM by comparing the genetic landscape of WM cells to that of CD34 progenitors, B cell precursors and residual normal B cells. Methods: We used multidimensional FACSorting to isolate a total of 43 cell subsets from BM aspirates of 8 WM patients: CD34+ progenitors, B cell precursors, residual normal B cells (if detectable), WM B cells, plasma cells (PCs) and T cells (germline control). Whole-exome sequencing (WES, mean depth 74x) was performed with the 10XGenomics Exome Solution for low DNA-input due to very low numbers of some cell types. We also performed single-cell RNA and B-cell receptor sequencing (scRNA/BCRseq) in total BM B cells and PCs (n=32,720) from 3 IgM MGUS and 2 WM patients. Accordingly, the clonotypic BCR detected in WM cells was unbiasedly investigated in all B cell maturation stages defined according to their molecular phenotype. In parallel, MYD88p.L252P (orthologous position of the human L265P mutation) transgenic mice were crossed with conditional Sca1Cre, Mb1Cre, and Cγ1Cre mice to selectively induce in vivo expression of MYD88 mutation in CD34 progenitors, B cell precursors and germinal center B cells, respectively. Upon immunization, mice from each cohort were necropsied at 5, 10 and 15 months of age and screened for the presence of hematological disease. Results: All 8 WM patients showed MYD88 L265P and 3 had mutated CXCR4. Notably, we found MYD88 L265P in B cell precursors from 1/8 cases and in residual normal B cells from 3/8 patients, which were confirmed by ASO-PCR. In addition, CXCR4 was simultaneously mutated in B cell precursors and WM B cells from one patient. Overall, CD34+ progenitors, B-cell precursors and residual normal B cells shared a median of 1 (range, 0-4; mean VAF, 0.16), 2 (range, 1-5; mean VAF, 0.14), and 4 (range, 1-13; mean VAF, 0.26) non-synonymous mutations with WM B cells. Some mutations were found all the way from CD34+ progenitors to WM B cells and PCs. Interestingly, concordance between the mutational landscape of WM B cells and PCs was <100% (median of 85%, range: 25%-100%), suggesting that not all WB B cells differentiate into PCs. A median of 7 (range, 2-19; mean VAF, 0.39) mutations were unique to WM B cells. Accordingly, many clonal mutations in WM B cells were undetectable in normal cells. Thus, the few somatic mutations observed in patients' lymphopoiesis could not result from contamination during FACSorting since in such cases, all clonal mutations would be detectable in normal cells. Of note, while somatic mutations were systematically detected in normal cells from all patients, no copy number alterations (CNA) present in WM cells were detectable in normal cells. scRNA/BCRseq unveiled that clonotypic cells were confined mostly within mature B cell and PC clusters in IgM MGUS, whereas a fraction of clonotypic cells from WM patients showed a transcriptional profile overlapping with that of B cell precursors. In mice, induced expression of mutated MYD88 led to a moderate increase in the number of B220+CD138+ plasmablasts and B220-CD138+ PCs in lymphoid tissues and BM, but no signs of clonality or hematological disease. Interestingly, such increment was more evident in mice with activation of mutated MYD88 in CD34+ progenitors and B-cell precursors vs mice with MYD88 L252P induced in germinal center B cells. Conclusions: We show for the first time that WM patients have somatic mutations, including MYD88 L265P and in CXCR4, at the B cell progenitor level. Taken together, this study suggests that in some patients, WM could develop from B cell clones carrying MYD88 L265P rather than it being the initiating event, and that other mutations or CNA are required for the expansion of B cells and PCs with the WM phenotype. Disclosures Roccaro: Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Transcan2-ERANET: Research Funding; AstraZeneca: Research Funding; European Hematology Association: Research Funding; Transcan2-ERANET: Research Funding; Associazione Italiana per al Ricerca sul Cancro (AIRC): Research Funding; Associazione Italiana per al Ricerca sul Cancro (AIRC): Research Funding; European Hematology Association: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees. San-Miguel:Amgen, Bristol-Myers Squibb, Celgene, Janssen, MSD, Novartis, Roche, Sanofi, and Takeda: Consultancy, Honoraria. Paiva:Amgen, Bristol-Myers Squibb, Celgene, Janssen, Merck, Novartis, Roche, and Sanofi; unrestricted grants from Celgene, EngMab, Sanofi, and Takeda; and consultancy for Celgene, Janssen, and Sanofi: Consultancy, Honoraria, Research Funding, Speakers Bureau.

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Analysis of IgVH, BCL-6, PIM, RHO/TTF and PAX5 Mutational Status in Splenic and Nodal Marginal Zone B Cell Lymphoma Suggests a Particular B Cell Origin.

Blood ◽

10.1182/blood.v106.11.162.162 ◽

2005 ◽

Vol 106 (11) ◽

pp. 162-162 ◽

Cited By ~ 3

Author(s):

Alexandra Traverse-Glehen ◽

Aurelie Verney ◽

Lucille Baseggio ◽

Pascale Felman ◽

Evelyne Callet-Bauchu ◽

...

Keyword(s):

B Cells ◽

B Cell ◽

Germinal Center ◽

Somatic Mutations ◽

Marginal Zone ◽

Somatic Hypermutation ◽

B Cell Lymphoma ◽

Marginal Zone B Cells ◽

Mutational Status ◽

Frequent Absence

Abstract Background and Objectives Splenic and nodal marginal zone B cell lymphoma (SMZL and NMZL) have been recently identified as distinct clinicopathological entities in the WHO classification. These lymphomas entities may have a common origin in the marginal B-cell compartment of the lymphoid organs. However the precise cell of origin of marginal zone B cells, its status in the B cell differentiation pathway and the mechanisms involved in lymphomagenesis remain unclear. The most widely held view is that marginal zone B cells are mostly memory B cells. But the origin of these cells, especially the transit through germinal center pathway, remains contradictory. Somatically mutated variable-region of immunoglobulin genes and bcl-6 gene represent at this time faithful markers for exposure to the germinal center. In addition, aberrant somatic hypermutations have been suggested to contribute to the development of B-cell lymphomas, occurring in the 5′ sequence of several proto-oncogenes. Interestingly those mutation do not occur in normal germinal center B cells. Design and Methods: IgVH, BCL-6, PIM1, Rho/TTF and PAX 5 genes, highly mutated in DLBCL and other indolent lymphoma such as B-CLL, were analysed for the presence of somatic mutations from 50 marginal zone lymphoma tissue and blood samples (21 NMZL and 29 SMZL including 10 cases with numerous villous lymphoma cells in peripheral blood). According to the morphological and immunophenotypical analysis, the fraction of malignant cells in the specimen was 70% or more in all cases. Mutational analysis was restricted to the regions previously shown to contain more than 95% of mutations in DLBCL. PCR products were directly sequenced on both sides and perfomed in duplicate in two independent reactions. Results: Out of 18 NMZL cases analysed for IgVH mutational status (3 cases not analysed for IgVH) 15 cases were mutated and 21 out of 28 in SMZL cases. Mutation of BCL-6 was detected in only 1 NMZL patients (1/21) and 1 SMZL patients (1/29). For RhoH/TTF, PIM1, PAX5 the mutation average was also low with only 1 case mutated per group and per gene, with a different case mutated in each for each gene. Conclusion In summary, we demonstrate the low frequency of aberrant somatic mutations in SMZL and NMZL, suggesting that this process is probably not a major contributor to lymphomageneis. However the frequent absence of mutation in BCL6 suggest a particular differentiation pathway, as suggested before in normal marginal zone B cells, possibly without transit through the germinal center. Interestingly the relatively high frequency of VH mutated cases compared with the frequent absence of mutation of BCL6, considered as a specific germinal center tag, could suggest somatic hypermutation outside the germinal center. In addition the absence of hypermutation could be linked with the absence of recurrent translocation in SMZL and NMZL, the translocation process haveing been associated with somatic hypermutation dysfunction.

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Phase II Study Of Anti-CD19 Antibody Drug Conjugate (SAR3419) In Combination With Rituximab: Clinical Activity and Safety In Patients With Relapsed/Refractory Diffuse Large B-Cell Lymphoma (NCT01470456)

Blood ◽

10.1182/blood.v122.21.4395.4395 ◽

2013 ◽

Vol 122 (21) ◽

pp. 4395-4395 ◽

Cited By ~ 8

Author(s):

Bertrand Coiffier ◽

Catherine Thieblemont ◽

Sophie de Guibert ◽

Jehan Dupuis ◽

Vincent Ribrag ◽

...

Keyword(s):

B Cell ◽

Board Of Directors ◽

Research Funding ◽

Cell Lymphoma ◽

B Cell Lymphoma ◽

Clinical Activity ◽

Advisory Committees ◽

Large B Cell Lymphoma ◽

Duration Of Response ◽

Grade 3

Abstract Background SAR3419 is a humanized anti-CD19 antibody conjugated to maytansin DM4, a potent cytotoxic agent. SAR3419 targets CD19, an antigen expressed in the majority of B cell non-Hodgkin lymphomas (NHL). The recommended dose for single agent SAR3419 was previously determined to be 55 mg/m2 administered IV every week for 4 weeks, then bi-weekly. In phase I, clinical activity was shown mainly in patients with follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL). (Trial funded by Sanofi). Methods Patients (pts) with a CD20+ and CD19+ DLBCL relapsing or refractory (R/R) after at least 1 standard treatment including rituximab and not candidate for or who already underwent transplantation, were eligible. Refractory disease was defined as unresponsive to or progressing within 6 months of regimen completion. Fresh (or recent formalin-fixed, paraffin-embedded) biopsy was required before SAR3419 start. Pts received 375 mg/m2 of rituximab (R) IV and 55 mg/m² of SAR3419 on day 1, 8, 15, 22 (35-day cycle 1), followed by bi-weekly R and SAR3419 at the same doses for 2 additional 28-day cycles, provided there was no disease progression or other study discontinuation criteria met. The primary objective was the overall response rate (ORR) following Cheson 2007 criteria, with the first tumor assessment being done 42 days after the last study treatment administration. Secondary objectives were: safety, pharmacokinetics (PK), duration of response (DOR), progression free survival (PFS), overall survival (OS) and correlation of the antitumor and biological activity of the combination with tumor biomarker status. Results Fifty-three pts were enrolled, 52 treated. Median age was 66.5 years (range 38-85), 50% were male; 23%, 33% and 40% of patients had received 1, 2 or ≥3 prior chemo/immunotherapy regimens for DLBCL, respectively. Of the enrolled patients, 3.8% had received no prior regimen for DLBCL and therefore were excluded from primary analysis for efficacy. Seventy-three percent had stage III/IV disease, 59% had elevated lactate dehydrogenase (LDH), and 63% had bulky disease. Sixty percent were refractory to first regimen (primary refractory), 16% were refractory to last regimen and 24% were relapsed pts. The ORR in the per-protocol population (n=45) was 31.1% (80% confidence interval (CI): 22.0% to 41.6%). Among the 14 responders, 5 had progressed at the time of analysis, with duration of response beyond 6 months for 3 of them. The ORR was 58.3% (80% CI: 36.2% to 78.1%) for patients with relapsed DLBCL (n=12), 42.9% (80% CI: 17.0% to 72.1%) for pts refractory to last regimen (n=7) and 15.4% (80% CI: 6.9% to 28.4%) for primary refractory pts (n=26). Overall survival and PFS data are not yet mature. Biomarkers and PK data will be presented at the meeting. The most common (≥10%) all grades non-hematologic treatment-emergent adverse events (TEAEs) were asthenia (25.0%), nausea (21.2%), cough (19.2%), diarrhea (17.3%), weight decrease (17.3%), vomiting (15.4%), dyspnea (15.4%), abdominal pain (13.5%), back pain (13.5%), pyrexia (13.5%) and constipation (11.5%). Related grade 3-4 TEAEs were: 1 syncope, 1 bronchospasm, 2 neutropenia and 1 anemia. No TEAEs led to treatment discontinuation, no grade 3-4 peripheral neuropathy or grade 3-4 ocular events were observed. Two pts experienced grade 2 keratitis, both rapidly recovered with local treatment. Hematological toxicity was moderate, with grade 3-4 neutropenia and thrombocytopenia in 15.7% and 9.8% pts, respectively. No complications related to neutropenia were reported. Grade 3 transaminase increase was observed in 1 patient. Conclusions The combination of SAR3419 plus R showed moderate ORR in R/R DLBCL; however the study population was of poor prognosis (60% refractory to first line therapy). In the relapsed DLBCL patients a higher ORR was observed. SAR3419 plus R presented with a favorable safety profile. Further investigations on biomarker expression are ongoing to identify a sub-group of pts who could have better benefited from this combination. Disclosures: Coiffier: Sanofi: Membership on an entity’s Board of Directors or advisory committees. Off Label Use: Phase II of SAR3419. Ribrag:Johnson & Johnson: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Sanofi: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Bayer: Research Funding; Takeda: Membership on an entity’s Board of Directors or advisory committees; Servier: Membership on an entity’s Board of Directors or advisory committees, Research Funding. Cartron:LFB: Honoraria; GSK: Honoraria; Roche: Consultancy, Honoraria, Speakers Bureau. Casasnovas:Roche: Consultancy, Honoraria, Research Funding. Hatteville:Sanofi: Employment. Zilocchi:Sanofi: Employment. Oprea:Sanofi: Employment. Tilly:Amgen: Research Funding; Janssen: Honoraria; Pfizer: Honoraria; Takeda: Membership on an entity’s Board of Directors or advisory committees; Roche: Honoraria; Celgene: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding.

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Poor Outcomes Among Patients Failing Dose-Adjusted EPOCH in Aggressive Lymphoma: A Collaborative, Retrospective Study

Blood ◽

10.1182/blood.v126.23.1518.1518 ◽

2015 ◽

Vol 126 (23) ◽

pp. 1518-1518 ◽

Cited By ~ 1

Author(s):

Jackie Vandermeer ◽

Allison M Winter ◽

Ajay K. Gopal ◽

Ryan D. Cassaday ◽

Brian T. Hill ◽

...

Keyword(s):

B Cell ◽

Board Of Directors ◽

Salvage Therapy ◽

Research Funding ◽

Cell Lymphoma ◽

B Cell Lymphoma ◽

First Line ◽

Advisory Committees ◽

First Line Therapy

Abstract Introduction Among patients with aggressive B-NHL who fail RCHOP, about half respond to standard salvage regimens and may proceed to curative-intent, transplant-based therapy. However, whether pts failing more intensive regimens such as dose-adjusted, infusional EPOCH benefit from standard salvage regimens is unclear. We hypothesized that such patients comprise a higher-risk cohort, facing inferior response rates and outcomes using standard salvage regimens. We undertook a collaborative study to assess response rates and survival among pts failing EPOCH for aggressive B-NHL, to inform patient management and design of clinical trials in this setting. Methods Pharmacy records and institutional databases were queried, identifying pts receiving EPOCH over the last 10 years at the University of Washington/SCCA and the Cleveland Clinic Foundation, for combined analysis. Under IRB approval, patient characteristics, histology, outcome with EPOCH, time to EPOCH failure, response to salvage, and overall survival were analyzed. Diffuse large B cell lymphoma (DLBCL), primary mediastinal B-cell lymphoma, B-cell-lymphoma unclassifiable, HIV-associated B cell lymphoma, and transformed B cell non-Hodgkin lymphoma were included. Pts receiving <2 cycles EPOCH, or who had inadequate follow-up (<3 months), were excluded. Failure of EPOCH was defined as failure to respond or progression during therapy, need for initiation of salvage therapy, or death during therapy of any cause. Adverse events or treatment change due to toxicity were not included in the definition of failure. JMP 11 was used to generate kaplan-meier survival estimates. Results 124 pts with aggressive B-NHL receiving EPOCH were identified. 54 had not relapsed, and among 70 remaining da-EPOCH failures, 37 met the above inclusion criteria. Median age was 55. 27% were female, and 23 received EPOCH as first-line therapy. All but 3 received rituximab with EPOCH. Histologies were primarily DLBCL in 22/37 (60%) and BCL-U in 12/37 (32%) carrying a MYC translocation; most of these harbored additional translocations in BCL2 and/or BCL6 (10/12). However, data regarding MYC rearrangement was not available for all pts. 2 had HIV-associated B-NHL and 3 had PMBCL. With 18 months follow up, the median time to EPOCH failure was 5 months. Only 3 EPOCH failures occurred late (>12 months). Median OS from the date of EPOCH failure was 10 months (Figure 1). Those receiving EPOCH as first-line therapy (23) had a median OS of 14 months from EPOCH failure, as opposed to 4 months for those receiving EPOCH as salvage therapy (log-rank p=.01). Salvage chemotherapy regimens after EPOCH were diverse, and generally ineffective; 6/28 (21%) regimens produced a response (Table 1). Among patients failing EPOCH within a year, platinum-containing salvage (RICE/RDHAP) was effective in only 2/13 patients (15%). 9 patients did not receive any salvage, most of whom died or proceeded to palliative measures and/or hospice care. Conclusions A relatively low overall response rate (21%) was observed in this retrospective analysis of patients failing EPOCH. Analogous to early RCHOP failure in the CORAL study, those failing EPOCH within a year may face inferior outcomes with platinum-based salvage therapy. While combined from two institutions, our data represent a modest sample size and require confirmation. If verified, examination of mechanisms of resistance to EPOCH, and selecting EPOCH failures for clinical trials of novel targeted therapies and transplant-based approaches, may prove critical. Table 1. Salvage Therapy for REPOCH failures Regimen: response/total number treated Notes Response to any salvage: 6/28 (21%) Some patients received more than 1 chemo salvage; responses were tabulated per regimen. RICE: 4/12 2/3 alive post transplant(1 auto 1 allo; 1 declined transplant and survived; 1 died) RDHAP: 1/6 Gemcitabine-based: 0/5 HyperCVAD (Part A and/or B): 1/5 Survivor had CNS only relapse, received regimen B and transplant 9- received no systemic treatmen; most died or proceeded to palliative measures and/or hospice Figure 1. Figure 1. Disclosures Gopal: Gilead: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Spectrum: Consultancy, Research Funding; Emergent/Abbott: Research Funding; Sanofi-Aventis: Honoraria; Seattle Genetics: Consultancy, Honoraria; BioMarin: Research Funding; Piramal: Research Funding; Janssen: Consultancy; Millenium: Honoraria, Research Funding; BMS: Research Funding; Merck: Research Funding. Hill:Seattle Genetics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Till:Roche/Genentech: Research Funding; Pfizer: Research Funding.

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Phase I/Ib Study of the Novel Immunotoxin MT-3724 in Relapsed/Refractory Non-Hodgkin's B-Cell Lymphoma (NHL)

Blood ◽

10.1182/blood.v126.23.5112.5112 ◽

2015 ◽

Vol 126 (23) ◽

pp. 5112-5112

Author(s):

Paul A Hamlin ◽

Catherine S. Diefenbach ◽

David J. Valacer ◽

Jack Higgins ◽

Michelle A. Fanale

Keyword(s):

B Cells ◽

Phase I ◽

B Cell ◽

Board Of Directors ◽

Research Funding ◽

B Cell Lymphoma ◽

Advisory Committees ◽

Dose Cohort ◽

Mixed Response

Abstract Background CD20 is selectively expressed on the surface of early pre-B-cells, remains throughout B-cell development, and is then lost from plasma cells. Because CD20 is present on the majority of B-cell lymphomas, anti-CD20 monoclonal antibody (MAb) therapy is widely employed in the treatment of NHL. However a majority of NHL patients eventually become refractory to CD20 MAb(s). Resistance mechanisms may include increased MAb catabolism, initial or post treatment selection of low CD20 expressing tumor cells, trogocytosis of surface CD20, failure of MAb effector mechanisms and/or impaired patient immune cell function. MT-3724 is a recombinant fusion protein consisting of a CD20 binding variable fragment (scFv) fused to the enzymatically active Shiga-like toxin-I A1 subunit (SLT-I A1). SLT-I A1 is an N-glycosidase that catalytically inactivates 60S ribosomal subunits causing inhibition of protein synthesis. Upon its scFv binding to cell surface CD20 in vitro, SLT-I A1 forces MT-3724 internalization which then routes in a predictable fashion to the cytosol and irreversibly inactivates the cell ribosomes triggering cell death. MT-3724 has been shown to specifically bind and kill CD20+ malignant human B-cells in vitro and non-human primate (NHP) B-cells in vivo. MT-3724 was tested for safety in healthy NHPs: 6 intravenous (IV) doses of MT-3724 were given over 12 days at doses of 50, 150, and 450 mcg/kg. There were no deaths or effects on serum chemistries in the NHP studies. The major observed toxicity (inappetence) resolved within 48 hours of last dose. There was a significant, dose-dependent NHP B-cell depletion by Day 3 at all doses. Given the preclinical activity and mechanism of action, a Phase I/Ib study of MT-3724 was initiated in NHL. Methods MT-3724 is being tested for safety and tolerability in a first-in-human, open label, ascending dose study (3 + 3 design) in sequential cohorts of 5, 10, 20 and 50 mcg/kg/dose. Eligible subjects who previously responded to a CD20 MAb containing therapy followed by relapse/recurrence of NHL receive 6 doses by 2 hour IV infusions over the first 12 days of a 28 day cycle (first cycle). With continued safety, tolerability and lack of tumor progression, subjects may receive up to 4 additional 6-dose cycles (21 days) with tumor assessments after cycles 2, 4 and 5. Dose escalation is based on < 33% dose limiting toxicities (DLTs) observed during the first 28 day cycle. Results Three NHL subjects (2 transformed DLBCL, 1 FL) have completed at least one cycle in the 5 mcg/kg/dose cohort with no protocol DLTs or infusion related reactions and are evaluable for safety. Non-DLTs included grade (Gr) 2-3 transient hyperglycemic episodes related to pre-infusion corticosteroid therapy (n=1); transient Gr 4 neutropenia, possibly related to MT-3724 during cycle 1, week 4 (n=1); Gr 4 hypercalcemia and acute kidney injury with Gr 3 hypophosphatemia during cycle 1, week 4 due to leukemic disease progression (n=1). Subject 1 completed 5 cycles of therapy, with a partial response achieved post cycle 2 sustained through cycle 5; Subject 3 had a mixed response (both subjects had transformed DLBCL). Three subjects have now initiated treatment in the 10 mcg/kg/dose cohort with updated data to be presented at the meeting. Conclusions MT-3724 at 5 mcg/kg/dose has been safely administered for up to 5 cycles in this first-in-human study in relapsed/refractory NHL subjects. Treatment with the 10 mcg/kg cohort has commenced with continuing dose ascension planned. There is early evidence of clinical activity. Disclosures Diefenbach: Gilead: Equity Ownership, Research Funding, Speakers Bureau; Jannsen Oncology: Consultancy; Idera: Consultancy; Immunogen: Consultancy; Incyte: Research Funding; Genentech: Research Funding; Celgene: Consultancy; Molecular Templates: Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding. Valacer:Molecular Templates: Employment. Higgins:Molecular Templates: Employment. Fanale:Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Honoraria, Research Funding; Infinity: Membership on an entity's Board of Directors or advisory committees; Spectrum: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Honoraria, Research Funding; Genentech: Research Funding; Medimmune: Research Funding; Novartis: Research Funding; Bayer: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Molecular Templates: Research Funding; ADC Therapeutics: Research Funding; Onyx: Research Funding; Gilead: Research Funding.

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Nanatinostat (Nstat) and Valganciclovir (VGCV) in Relapsed/Refractory (R/R) Epstein-Barr Virus-Positive (EBV +) Lymphomas: Final Results from the Phase 1b/2 VT3996-201 Study

Blood ◽

10.1182/blood-2021-152603 ◽

2021 ◽

Vol 138 (Supplement 1) ◽

pp. 623-623

Author(s):

Bradley M. Haverkos ◽

Onder Alpdogan ◽

Robert Baiocchi ◽

Jonathan E Brammer ◽

Tatyana A. Feldman ◽

...

Keyword(s):

T Cell ◽

B Cell ◽

Board Of Directors ◽

Research Funding ◽

Cell Lymphoma ◽

B Cell Lymphoma ◽

T Cell Lymphoma ◽

Phase 2 ◽

Advisory Committees ◽

Phase 1B

Abstract Introduction: EBV can be associated with several types of lymphomas, with reported frequencies of up to 8-10% in diffuse large B cell lymphoma (DLBCL), 30-100% in peripheral T cell lymphoma (PTCL) subtypes, 80% in post-transplant lymphoproliferative disease (PTLD), and 15-30% in classical Hodgkin lymphoma (HL), with adverse impact on outcomes. Nanatinostat (Nstat) is a Class-I selective oral HDAC inhibitor that induces the expression of the lytic BGLF4 EBV protein kinase in EBV + tumor cells, activating ganciclovir (GCV) via phosphorylation. This results in GCV-induced inhibition of viral and cellular DNA synthesis and apoptosis. Herein we report the final results from this exploratory study for patients with R/R EBV + lymphomas (NCT03397706). Methods: Patients aged ≥18 with histologically confirmed EBV + lymphomas (defined as any degree of EBER-ISH positivity), R/R to ≥1 prior systemic therapies with an absolute neutrophil count ≥1.0×10 9/L, platelet count ≥50×10 9/L, and no curative treatment options per investigator were enrolled into 5 dose escalation cohorts to determine the recommended phase 2 doses (RP2D) of Nstat + VGCV for phase 2 expansion. Phase 2 patients received the RP2D (Nstat 20 mg daily, 4 days per week + VGCV 900 mg orally daily) in 28-day cycles until disease progression or withdrawal. Primary endpoints were safety/RP2D (phase 1b) and overall response rate (ORR) (phase 2); secondary endpoints were pharmacokinetics, duration of response (DoR), time to response, progression free survival and overall survival. Responses were assessed using Lugano 2014 response criteria beginning at week 8. Results: As of 18 June 2021, 55 patients were enrolled (phase 1b: 25; phase 2: 30). Lymphoma subtypes were DLBCL (n=7), extranodal NK/T-cell (ENKTL) (n=9), PTCL, not otherwise specified (PTCL-NOS) (n=5), angioimmunoblastic T cell lymphoma (n=6), cutaneous T cell (n=1), HL (n=11), other B cell (n=3), and immunodeficiency-associated lymphoproliferative disorders (IA-LPD) (n=13), including PTLD (n=4), HIV-associated (n=5), and other [n=4: systemic lupus erythematosus (SLE) (n=2), common variable/primary immunodeficiency (n=2)]. Median age was 60 years (range 19-84), M/F 35/20, median number of prior therapies was 2 (range 1-11), 76% had ≥2 prior therapies, 78% were refractory to their most recent prior therapy, and 84% had exhausted standard therapies. EBER positivity ranged from <1 to 90% in 42 tumor biopsies with central lab review. The most common treatment-emergent adverse events (TEAEs) of all grades were nausea (38%), neutropenia (34%), thrombocytopenia (34%), and constipation (31%). Grade 3/4 TEAEs in >10% of patients included neutropenia (27%), thrombocytopenia (20%), anemia (20%), and lymphopenia (14%). Dose reductions and interruptions due to treatment-related AEs were reported in 14 (25%) and 16 (29%) patients, respectively. Only 1 patient had to discontinue therapy. There were no cases of CMV reactivation. For 43 evaluable patients (EBER-ISH + with ≥ 1 post-treatment response assessment) across all histologies, the investigator-assessed ORR and complete response (CR) rates were 40% (17/43) and 19% (8/43) respectively. Patients with T/NK-NHL (n=15; all refractory to their last therapy) had an ORR of 60% (n=9) with 27% (n=4) CRs. Two patients (ENKTL and PTCL-NOS) in PR and CR respectively were withdrawn at 6.7 and 6.6 months (m) respectively for autologous stem cell transplantation. For DLBCL (n=6), ORR/CR was 67%/33% (both CRs were in patients refractory to first-line R-CHOP). For IA-LPD (n=13), ORR/CR was 30%/20% (PTLD: 1 CR, other: 1 CR, 1 PR). For HL (n=10), there was 1 PR (4 SD). The median DoR for all responders was 10.4 m, with a median follow-up from response of 5.7 m (range 1.9-34.1 m). For the 17 responders, 8 lasted ≥ 6 months. Conclusions: The combination of Nstat and VGCV was well-tolerated with a manageable toxicity profile and shows promising efficacy in patients with R/R EBV + lymphomas, particularly in refractory T/NK-NHL, a heterogeneous group of aggressive lymphomas with dismal outcomes, with multiple durable responses. Further evaluation of this novel combination therapy for the treatment of recurrent EBV + lymphomas is ongoing in the phase 2 VT3996-202 trial. Disclosures Haverkos: Viracta Therapeutics, Inc.: Honoraria, Research Funding. Baiocchi: Prelude Therapeutics: Consultancy; viracta: Consultancy, Current holder of stock options in a privately-held company; Codiak Biosciences: Research Funding; Atara Biotherapeutics: Consultancy. Brammer: Seattle Genetics: Speakers Bureau; Celgene: Research Funding; Kymera Therapeutics: Consultancy. Feldman: Alexion, AstraZeneca Rare Disease: Honoraria, Other: Study investigator. Brem: Karyopharm: Membership on an entity's Board of Directors or advisory committees; SeaGen: Speakers Bureau; BeiGene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bayer: Membership on an entity's Board of Directors or advisory committees; KiTE Pharma: Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Consultancy; ADC Therapeutics: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics/Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Morphosys/Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Scheinberg: Roche: Consultancy; Abbvie: Consultancy; BioCryst Pharmaceuticals: Consultancy; Alexion pharmaceuticals: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau. Joffe: AstraZeneca: Consultancy; Epizyme: Consultancy. Katkov: Viracta Therapeutics, Inc.: Current Employment. McRae: Viracta Therapeutics, Inc.: Current Employment. Royston: Viracta Therapeutics, Inc.: Current Employment. Rojkjaer: Viracta Therapeutics, Inc.: Current Employment. Porcu: Viracta: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Innate Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BeiGene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Research Funding; Daiichi: Honoraria, Research Funding; Kiowa: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Spectrum: Consultancy; DrenBio: Consultancy.

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