Phase I/II Study of Rituxan (R) in Combination with Doxil (D) in Patients (pts) with Relapsing or Refractory B-Cell Lymphoma: Clinical Efficacy without Cardiac Toxicity.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1369-1369
Author(s):  
Myron S. Czuczman ◽  
Marion Skipper ◽  
Alice Mohr ◽  
Zale P. Bernstein ◽  
Francisco J. Hernandez-Ilizaliturri ◽  
...  

Abstract In the past, the most common initial combination chemotherapy regimen used by most oncologists to treat B-cell lymphoma was the CHOP regimen. Although doxorubicin (DOX) is a major component of CHOP, it is associated with myelosuppression, alopecia, and potential cardiotoxicity. In vitro data has demonstrated synergistic activity between rituximab and certain drugs, including DOX. Because of D’s unique liposomal encapsulation, delivery, and toxicity profile, it may prove to be a more effective, less toxic anthracycline to combine with R. A formal Phase I/II trial to evaluate the safety and efficacy of R+D in pts with relapsing B-cell lymphoma was undertaken. R (375 mg/m2/dose) was given on day 1 and D (30 mg/m2/dose) on day 3 on q 21 day cycles for 6 cycles. Thirty-six of 42 pts have been enrolled to date. Four pts (n=3 with aggressive histologies) progressed while on treatment and did not complete the planned 6 cycles of therapy; 1 pt has not completed therapy, but is a PR mid-treatment. Demographics: 19M:17F; Median age = 63 (range 35–83); Follicular lymphoma (FL) grade 1 or 2 (n=14); FL, grade 3 (n=7); SLL (n=5); de novo DLBCL (n=3); Transformed NHL (n=6); Mantle cell lymphoma (n=1); Median number of prior treatments = 2 (range 1–8); prior anthracycline exposure (n=24; 67%). Overall, R + D was very well-tolerated. Reversible grade 3 (n=8) or grade 4 (n=4) neutropenia was seen and responded to growth factor support. Reversible grade 3 thrombocytopenia was seen in 2 pts. Of note, grade 3 palmar/plantar erythrodysesthesia occurred only in 3 pts whom were non-compliant with instructions given to avoid this side-effect associated with D therapy. Overall response rate (ITT) = 64% (42% CR, 22% PR); responses were equally distributed between both indolent and aggressive histologies. Median time-to-progression (TTP) = 12 months (range 1M to 57+M); mean TTP = 17 months. Median TTP in CRs = 14 months (range 4M to 57+M); Median TTP in PRs = 5 months (range 1M to 17M). Fifteen of 24 (63%) pts with prior anthracycline exposure demonstrated objective responses (9 CR; 6 PR). No clinical cardiac toxicity has been seen and comparison of pre-Rx to post-Rx LVEF remained >50% in all pts completing therapy. D + R immunochemotherapy is a unique, well-tolerated, non-cardiotoxic and effective salvage therapy for pts with either indolent or aggressive relapsed B-cell lymphoma. An update of the completed database will be presented at the annual ASH meeting.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1396-1396 ◽  
Author(s):  
Myron S. Czuczman ◽  
Marion Skipper ◽  
Alice Mohr ◽  
Zale P. Bernstein ◽  
Philip McCarthy ◽  
...  

Abstract In the past, the most common initial combination chemotherapy regimen used by most oncologists to treat B-cell lymphoma was the CHOP regimen. Although doxorubicin (DOX) is a major component of CHOP, it is associated with myelosuppression, alopecia, and potential cardiotoxicity. In vitro data has demonstrated synergistic activity between rituximab and certain drugs, including DOX. Because of D’s unique liposomal encapsulation, delivery, and toxicity profile, it may prove to be a more effective, less toxic anthracycline to combine with R. A formal Phase I/II trial to evaluate the safety and efficacy of R+D in pts with relapsing B-cell lymphoma was undertaken. R (375 mg/m2/dose) was given on day 1 and D (30 mg/m2/dose) on day 3 on q 21 day cycles for 6 cycles. Thirteen pts have completed therapy to date: 9F, 4M; Follicular lymphoma, grade 1 (n=6), grade 2 (n=1), grade 3 (n=3), DLBCL (n=3); med age = 63 (38–78); median number of prior Rx’s = 3 (range 1–8); prior anthracycline exposure (n=8). Overall, the combination of R + D was well-tolerated. Transient grade 3 cytopenias were noted in 3 pts with limited bone marrow reserve and grade 3 palmar/plantar erythrodysesthesia seen in 2 pts. All 13 pts completed the planned 6 courses of Rx. Objective responses were seen in 85% (11 of 13 pts), including 54% CR, 31% PR. Median time-to-progression has not been reached at 7+ months (range 4.5+ to 19+ months). No cardiac toxicity was seen and comparison of pre-Rx to post-Rx LVEF remained unchanged in 9, increased in 2, and decreased in 2 (yet still remaining > 50%). D + R immunochemotherapy is a well-tolerated, unique, non-cardiotoxic, and apparently effective salvage therapy for relapsed B-cell lymphoma. The study will continue until accrual of 42 pts has been reached.


Blood ◽  
2019 ◽  
Vol 133 (1) ◽  
pp. 70-80 ◽  
Author(s):  
Kamil Bojarczuk ◽  
Kirsty Wienand ◽  
Jeremy A. Ryan ◽  
Linfeng Chen ◽  
Mariana Villalobos-Ortiz ◽  
...  

Abstract Inhibition of the B-cell receptor (BCR) signaling pathway is a promising treatment strategy in multiple B-cell malignancies. However, the role of BCR blockade in diffuse large B-cell lymphoma (DLBCL) remains undefined. We recently characterized primary DLBCL subsets with distinct genetic bases for perturbed BCR/phosphoinositide 3-kinase (PI3K) signaling and dysregulated B-cell lymphoma 2 (BCL-2) expression. Herein, we explore the activity of PI3K inhibitors and BCL-2 blockade in a panel of functionally and genetically characterized DLBCL cell line models. A PI3K inhibitor with predominant α/δ activity, copanlisib, exhibited the highest cytotoxicity in all BCR-dependent DLBCLs. The proapoptotic effect of copanlisib was associated with DLBCL subtype-specific dysregulated expression of BCL-2 family members including harakiri (HRK) and its antiapoptotic partner BCL extra large (BCL-xL), BCL2 related protein A1, myeloid cell leukemia 1 (MCL-1), and BCL2 interacting mediator of cell death. Using functional BH3 profiling, we found that the cytotoxic activity of copanlisib was primarily mediated through BCL-xL and MCL-1–dependent mechanisms that might complement BCL-2 blockade. For these reasons, we evaluated single-agent activity of venetoclax in the DLBCLs and identified a subset with limited sensitivity to BCL-2 blockade despite having genetic bases of BCL-2 dysregulation. As these were largely BCR-dependent DLBCLs, we hypothesized that combined inhibition of PI3Kα/δ and BCL-2 would perturb BCR-dependent and BCL-2–mediated survival pathways. Indeed, we observed synergistic activity of copanlisib/venetoclax in BCR-dependent DLBCLs with genetic bases for BCL-2 dysregulation in vitro and confirmed these findings in a xenograft model. These results provide preclinical evidence for the rational combination of PI3Kα/δ and BCL-2 blockade in genetically defined DLBCLs.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4441-4441
Author(s):  
Makoto Kodaira ◽  
Masahiro Yokoyama ◽  
Hiroaki Asai ◽  
Shuhei Yamada ◽  
Kyoko Ueda ◽  
...  

Abstract <Background> Patients with relapsed and refractory diffuse large B-cell lymphoma are usually treated with platinum-based salvage chemotherapy. We retrospectively analyzed the efficacy of adding rituximab with ICE as a salvage treatment for relapsed and refractory diffuse large B-cell lymphoma. <Method>From November 2003 to December 2006, patients with relapsed or refractory de novo diffuse large B-cell lymphoma represented CD20 positivty who received R-ICE (rituximab375mg/m2, Ifosfamide 1200mg/m2, calboplatin 400mg/m2 and etopside100mg/m2 ), were analyzed retrospectively. <Result>23 patients (19 relapse and 4 reflactory) (M:F=14:9) (median age 69, 28–77) were included. At starting treatment, twelve patients received rituximab and 11 patients were rituximab naive. In all 23 patients, responses were 11 Complete remission (CR), and 6 partial response (PR), resulting in overall response (ORR) was 74.9%. With median follow up of 10.5 months, estimated 1yr-progression free survival (PFS) was 49% and 1yr-overall survival (OS) was 70%.In patients received rituximab, ORR was 66.7% and 5 patiets achieved CR (41.7%).In the without rituximab, ORR was 90.9% and 7 patiets achieved CR (63.6%). No statistical differences were observed in response even with retuximab pretreatment. Estimated 1yr-PFS was 23% and 70% (p=0.0752) and 1yr-OS was 59% and83% (P=0.0049),respectively. NCI-CTC grade 3/4 neutropenia and thrombocytopenia were reported 100% and 91%, For non-hematological adverse event, there were grade 3 liver dysfunction (2/23) and grade 3 arrythmia (1/23). No toxic death was reported in this study. <Conclusion> R-ICE showed promising efficacy with tolelable toxicity. Available date suggested adding rituximab to ICE is more effective for patients not received rituximab in the pretreament.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3707-3707
Author(s):  
Beth Christian ◽  
Lapo Alinari ◽  
Jeffrey A. Jones ◽  
Don M Benson ◽  
Joseph M. Flynn ◽  
...  

Abstract Abstract 3707 Background: Preclinical studies conducted at our institution (Alinari et al. Blood. 2011;117:4530–41) demonstrated superior efficacy of milatuzumab (Immunomedics, Inc.), a humanized anti-CD74 antibody, in combination with rituximab in vitro and in an in vivo preclinical model of mantle cell lymphoma (MCL), compared to either agent alone. Veltuzumab (Immunomedics, Inc.), a humanized anti-CD20 antibody, has been reported to have several advantages over rituximab including slower off-rates, shorter infusion times, higher potency, and improved therapeutic responses in animal models. As a result of the anti-tumor activity observed in vitro with combined veltuzumab and milatuzumab, we initiated a phase I/II trial in pts with relapsed or refractory B-cell NHL after at least 1 prior therapy to determine the safety, tolerability, and overall response rate with this combination. Methods: Pts received veltuzumab 200 at mg/m2 weekly combined with escalating doses of milatuzumab at 8, 16, and 20 mg/kg twice per wk of wks 1–4, 12, 20, 28, and 36. All pts received premedication with acetaminophen, diphenhydramine, hydrocortisone 50 mg, and famotidine prior to veltuzumab and milatuzumb doses. Dose limiting toxicity (DLT) was defined during weeks 1–4. Although not defined as DLT, 3 of the first 6 pts enrolled at dose levels 1–2, had significant grade 3 infusion reactions with milatuzumab. The study was amended to separate veltuzumab and milatuzumab dosing days and add 20 mg dexamethasone immediately prior to and 10 mg post-milatuzumab. Enrollment resumed with 3 additional pts at dose levels 1 and 2 in order to determine if tolerability was improved. Results: The phase I study has completed enrollment with 18 pts (follicular NHL grade 1–2 n=5; grade 3 n=5; transformed follicular n=1; diffuse large B-cell lymphoma (DLBCL) n=4; marginal zone lymphoma (MZL) n=1; MCL n=1; and lymphoplasmacytic lymphoma n=1) that have completed at least 4 weeks of combination therapy. Median age was 65 years (range 44–81), and pts received a median of 3 prior therapies (range 1 – 9), including 3 pts who had undergone prior autologous stem cell transplant. Ten of 18 (56%) pts were refractory to rituximab defined as having less than a partial response to the last rituximab-containing regimen. No DLTs were observed, and no pts experienced grade 3 infusion reactions after the protocol was modified. Other grade 3–4 toxicities at least possibly related to protocol therapy consisted of lymphopenia (n=8, 44%), fatigue (n=2, 11%), neutropenia (n=1, 6%), hyperglycemia (n=1, 6%), and anemia (n=1, 6%). Grade 1–2 infections (n=5, 27%) included thrush, sinusitis, and pneumonia with no pts requiring dose delays or hospitalization. Other frequently observed grade 1–2 toxicities were transient hyperglycemia (n=12, 66%), thrombocytopenia (n=11, 61%), reversible infusion reactions (n=9, 50%), fatigue (n=8, 44%), leukopenia (n=8, 44%), and anemia (n=7, 39%). Human anti-veltuzumab and anti-milatuzumab antibodies, collected pretreatment and day 1 of weeks 4, 12, and 36, have not been detected in any pt. Pharmacokinetic data available from 16 pts through week 10 indicated mean plasma veltuzumab and milatuzumab concentrations immediately post-infusion were 108 ± 7 and 296 ± 22 μg/mL, and mean trough levels were 47 ± 7 and 3 ± 0.3 μg/mL, respectively. All 18 pts were assessable for response at wk 5 with 5 pts currently remaining on active therapy and 4 pts completing treatment through wk 36. To date, complete response was observed in 1 pt with grade 1–2 follicular NHL (3 prior therapies) who was rituximab-refractory and ultimately underwent allogeneic transplant. Partial responses were observed in 3 pts; 2 with grade 3 follicular NHL refractory to rituximab (3 prior therapies including autologous transplant and 5 prior therapies, respectively) and 1 with MZL (1 prior therapy). All responding pts achieved response following induction therapy. Stable disease was observed in 10 pts; of these pts, 6 pts had SD of a median duration of 6 months (range 2.5–10 months) and 4 remain on active therapy. Conclusions: Combination therapy with veltuzumab and milatuzumab was well-tolerated in a population of heavily pre-treated pts with relapsed or refractory NHL. 14/18 pts had evidence of antitumor activity with 22% having an objective overall response, including rituximab-refractory pts. Disclosures: Christian: Immunomedics, Inc.: Research Funding. Off Label Use: Veltuzumab and milatuzumab in non-Hodgkin's lymphoma is off-label drug use. Wegener:Immunomedics, Inc.: Employment, Management and Stock / Stock-options. Goldenberg:Immunomedics, Inc.: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees.


2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 7544-7544 ◽  
Author(s):  
Connie Lee Batlevi ◽  
Paul A. Hamlin ◽  
Matthew J. Matasar ◽  
Steven M. Horwitz ◽  
John F. Gerecitano ◽  
...  

7544 Background: In vitro studies of BTK and PI3K inhibitors demonstrate synergy in non-Hodgkin lymphoma (NHL). We embarked on a phase I/Ib investigator-initiated clinical trial evaluating the combination of ibrutinib (BTK inhibitor) and buparlisib (pan-PI3K inhibitor) in relapsed/refractory (R/R) NHL. The completed dose escalation is reported. Methods: Patients (pts) were eligible if they had R/R DLBCL, MCL, or FL with ECOG≤2 and adequate organ function. Ibrutinib and buparlisib were given daily by mouth on a 28-day cycle. Dose reductions were permitted after cycle 1. Tumor response was based on Lugano Classification however CR required both PET resolution and ≥ PR by CT. Results: As of Dec 16, 2016, 13 pts were enrolled and evaluated for toxicity (DLBCL 5, FL 2, MCL 6). Dose levels and DLT per table. Six pts discontinued treatment for disease progression (DLBCL 4, FL 2). Hematologic AE ≥ grade 3 are anemia (2), leukocytosis (2), and leukopenia (4). Relevant non-hematologic AEs of any grade ≥ 20% across all pts were fatigue (77%), diarrhea (62%), anorexia (54%), rash (46%), hyperbilirubinemia (46%), gastric reflux (46%), CMV reactivation (31%), mood change (31%), and hypertension (23%). Most common related grade 3/4 toxicity is rash (N = 3). No grade 5 toxicities noted. Serious adverse events (SAE) include: grade 2 pleural effusion and grade 2 nausea (N = 1), grade 1 fever with hospitalization (N = 1), grade 2 confusion and grade 4 hyponatremia (N = 1) were unrelated to therapy. Responses noted in 13 pts: MCL (N = 6: CR 4, PR 2), FL (N = 2: SD 2), DLBCL (N = 5: SD 1). One CR was a MCL pt with CR after 2 cycles on combination therapy and continues in remission on ibrutinib alone because of buparlisib toxicity. Conclusions: Combination of ibrutinib and buparlisib while generally well tolerated has predicted toxicities of both BTK and PI3K inhibitors. The recommended phase 2 dose is ibrutinib 560 mg and buparlisib 100 mg though dose reductions for tolerability may be needed for long term oral therapies. Promising efficacy is observed in MCL. Clinical trial information: NCT02756247. [Table: see text]


2008 ◽  
Vol 3 (1) ◽  
pp. 316-322 ◽  
Author(s):  
Toru Takahashi ◽  
Tadashi Koike ◽  
Shigeo Hashimoto ◽  
Tomofumi Miura ◽  
Junichiro Nakamura ◽  
...  

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 711-711
Author(s):  
Anagh Anant Sahasrabuddhe ◽  
Xiaofei Chen ◽  
Kaiyu Ma ◽  
Rui Wu ◽  
Richa Kapoor ◽  
...  

Abstract Introduction: Diffuse large B cell lymphoma (DLBCL) is the most common form of malignant lymphoma and may arise de novo, or through transformation from a pre-existing low-grade B cell lymphoma such as follicular lymphoma (FL). However, the post-translational mechanisms and deregulated pathways underlying the pathogenesis of disease evolution are not fully understood. Methods: We employed integrated functional and structural genomics and mass spectrometry (MS)-driven proteomics which implicated a possible novel tumor suppressor role for a conserved E3 ubiquitin ligase FBXO45 in DLBCL pathogenesis. We generated conditional knockout mice targeting loss of Fbxo45 in germinal center (GC) B-cells using the Cg1-Cre-loxP system and an assortment of CRISPR-mediated knockouts of FBXO45 in B cell lymphoma cells (FL518, BJAB, U2932). We engineered B cell lines (BJAB, U2932) to inducibly express FLAG-tagged FBXO45 to identify candidate substrates of FBXO45 using liquid chromatography-tandem MS. In vitro biochemical and in vivo studies using a variety of genetically-modified lines in xenograft studies in immunodeficient mice were performed to validate observations from proteogenomic studies. Whole genome sequencing (WGS) and genomic copy number studies were interrogated to investigate structural alterations targeting FBXO45 in primary human lymphoma samples. Results: Conditional targeting of Fbxo45 in GCB-cells in transgenic mice resulted in abnormal germinal center formation with increased number and size of germinal centers. Strikingly, targeted deletion of Fbxo45 in GCB-cells resulted in spontaneous B cell lymphomas with (22/22);100%) penetrance and none of the wild-type (WT) littermates (0/20; 0%) developed lymphoma at 24 months. Macroscopic examination revealed large tumor masses, splenomegaly, and lymphadenopathy at different anatomic locations including ileocecal junction, mesenteric, retroperitoneal and cervical lymph nodes and thymus. Next generation sequencing of immunoglobulin heavy chain genes revealed monoclonal or oligoclonal B cell populations. Using proteomic analysis of affinity-purified FBXO45-immunocomplexes and differential whole proteome analysis from GCB-cells of Fbxo45 wt/wt vs Fbxo45 fl/fl mice, we discovered that FBXO45 targets the RHO guanine exchange factor GEF-H1 for ubiquitin-mediated proteasomal degradation. FBXO45 exclusively interacts with GEF H1 among 8 F-box proteins investigated and silencing of FBXO45 using three independent shRNA and CRISPR-Cas9-mediated knockouts in B-cell lymphoma cell lines promotes RHOA and MAPK activation, B cell growth and enhances proliferation. GEF-H1 is stabilized by FBXO45 depletion and GEF-H1 ubiquitination by FBXO45 requires phosphorylation of GEF-H1. Importantly, FBXO45 depletion and expression of a GEF-H1 mutant that is unable to bind FBXO45 results in GEF-H1 stabilization, promotes hyperactivated RHO and MAPK signaling and B-cell oncogenicity in vitro and in vivo. Notably, this phenotype is reverted by co-silencing of GEF-H1. Inducible ectopic expression of FBXO45 triggers accelerated turnover of GEF H1 and decreased RHOA signaling. Genomic analyses revealed recurrent loss targeting FBXO45 in transformed DLBCL (25%), de novo DLBCL (6.6%) and FL (2.3%). In keeping with our observation of prolonged hyperactivation of pERK1/2 consequent to FBXO45 ablation, in vitro and in vivo studies using B-cell lymphoma cell lines and xenografts demonstrated increased sensitivity to pharmacologic blockade with the MAP2K1/2 (ERK1/2) inhibitor Trametinib. Conclusions: Our findings define a novel FBXO45-GEF-H1-MAPK signalling axis, which plays an important role in DLBCL pathogenesis. Our studies carry implications for potential exploitation of this pathway for targeted therapies. Disclosures Siebert: AstraZeneca: Speakers Bureau. Lim: EUSA Pharma: Honoraria.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2761-2761
Author(s):  
Juan J Gu ◽  
Qunling Zhang ◽  
Cory Mavis ◽  
Myron S. Czuczman ◽  
Francisco J. Hernandez-Ilizaliturri

Abstract Background: The poor clinical outcomes of patients with aggressive B-cell lymphoma in the post-rituximab era, stress the need to identify and/or optimize novel targeted agents. Several retrospective and prospective clinical studies had demonstrated that C-myc expression correlates with a poor clinical outcome in patients with newly diagnosed or relapsed/refractory diffuse large B-cell lymphoma (DLBCL). To this end, we evaluated the therapeutic effects of targeting C-myc using JQ1, a novel bromodomain inhibitor in rituximab-sensitive or -resistant models. Methods: A panel of rituximab-sensitive (RSCL) or rituximab-resistant (RSCL) cell lines was exposed to JQ1 (0-100 µM) for 24-72 hrs. Changes in cell viability and cell cycle distribution were evaluated using the Presto Blue assay and flow cytometry respectively. IC50 values were calculated using the GraphPad Prism6 software. Subsequently lymphoma cells were exposed to JQ1 or vehicle and various chemotherapy agents such as doxorubicin (0.5, 1, 2µM), dexamethasone (1µM), Ibrutinib (1µM), bortezomib (10-20nM) or carfilzomib (10nM) for 48 hours. Coefficient of synergy was calculated using the CalcuSyn software. Results: In vitro exposure of RRCL and to a lesser degree RSCL to JQ1 resulted in a dose- and time-dependent cell death. Strong synergistic activity was observed when JQ1 was combined with doxorubicin, dexamethasone bortezomib or carfilzomib in vitro. Cell cycle analysis demonstrated that in vitro of RSCL or RRCL to JQ1 resulted in G1 cell cycle arrest. Conclusions: In summary, our data suggests that targeting C-myc expression using JQ1 results in anti-tumor activity against RSCL and RRCL. In addition, JQ1 exhibited synergistic activity when combined with chemotherapy agents (doxorubicin or dexamethasone) or targeted agents (bortezomib or carfilzomib). On going studies are aimed to study the mechanisms by which c-myc inhibition results in cell death in RSCL and RRCL. JQ1 is a distinct targeted agent undergoing clinical evaluation in patients with relapsed/refractory lymphomas. Molecular studies dissecting the cellular pathways affected by JQ1 are important in order to further advance the clinical development of c-myc inhibitors in lymphoid malignancies. (Research, in part, supported by a NIH grant R01 CA136907-01A1 awarded to Roswell Park Cancer Institute and The Eugene and Connie Corasanti Lymphoma Research Fund) Disclosures Czuczman: Boehringer-Ingelheim: Other: Advisory Board; Immunogen: Other: Advisory board; MorphoSys: Consultancy; Celgene: Employment.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 5379-5379
Author(s):  
Sumera Khan ◽  
Kyle Runckel ◽  
Cory Mavis ◽  
Matthew J. Barth ◽  
Francisco J. Hernandez-Ilizaliturri

Abstract Background: The addition of Rituximab to front-line therapy has improved clinical outcomes in diffuse large B-cell lymphoma (DLBCL), but it has also altered the biology of relapsed/refractory disease. To better understand the mechanisms responsible for Rituximab associated chemotherapy cross-resistance our group developed and characterized several Rituximab resistance cell lines (RRCL). We previously demonstrated using SiRNA interference, that X-linked inhibitor of apoptosis (XIAP) is critical for chemotherapy sensitivity and survival in RRCL. MX69, a dual inhibitor of Mdm2 and XIAP that indirectly downregulates XIAP, is undergoing pre-clinical testing. MX69 affects XIAP levels by its effects on the ubiquitination and degradation of endogenous MDM-2, resulting in decrease XIAP translation and activation of caspase 3, 7 and 9 as well as PARP cleavage leading to apoptosis of cancer cells. In our current work, we pharmacologically inhibited XIAP in lymphoma pre-clinical models using MX69. Materials and Methods: A panel of Burkitt's Lymphoma (BL, including RRCL), germinal center B-cell (GCB)-DLBCL (including RRCL), activated B-cell (ABC)-DLBCL, Mantle cell Lymphoma (MCL) and Pre-B cell Leukemia cell lines were exposed to MX69 as a single agent (0-80uM) over 24, 48, 72 hrs and IC50 concentrations were calculated for each cell line. Changes in Mdm2, p53, XIAP and PARP expressions were determined following MX69 exposure (at IC50 doses) for 24 hrs. Induction of apoptosis was evaluated by Annexin V/propidium iodine staining. Subsequently, cell lines were exposed to MX69 (0-80 uM), in combination with Doxorubicin (0-1uM), Cytarabine(0-50uM), Vincristine (0-10nM), Etoposide(0-50uM), Carboplatin (0-20uM), Ixazomib (0-1.5uM), Ibrutinib (0-20uM) and Venetoclax (0-10uM) for 48 hours. Cell viability was determined by Cell Titerglo. Coefficient of synergy was calculated using CalcuSyn. Results: In vitro, MX69 single agent exposure induced cell death in a dose and time-dependent manner in all cell lines tested. Western blotting studies confirmed downregulation of Mdm2, XIAP and changes in P53 and PARP, following in vitro exposure to MX69. Induction of apoptosis was observed by flow cytometry in all cell lines tested. The combination of MX69 with Doxorubicin, Cytarabine, Vincristine, Ixazomib, Carboplatin, Etoposide, Ibrutinib, and Venetoclax resulted in significant synergistic activity. The strongest CI of synergy was observed when cell lines were exposed to MX69 and Venetoclax, Ixazomib, Etoposide or Ibrutinib. Conclusion: Our data suggests that in vitro exposure of a wide variety of B-cell lymphoma cell lines (including BL, DLBCL, MCL or RRCL) to MX69 resulted in anti-tumor activity. Perhaps related to its anti-tumor effects, MX69 inhibited XIAP levels. These findings are similar to prior SiRNA XIAP knockdown experiments. Strong synergistic activity was observed when XIAP was combined with various chemotherapy agents and small molecules inhibitors (such as Venetoclax, ixazomib or ibrutinib). Ex vivo experiments using primary tumor cells isolated from lymphoma patients and lymphoma mouse models are been planned. Targeting Mdm2 and XIAP can be an attractive therapeutic strategy in patients with Rituximab-sensitive or -resistant B-cell lymphoma. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4162-4162 ◽  
Author(s):  
Tony Reiman ◽  
Kerry J. Savage ◽  
Michael Crump ◽  
Matthew Cheung ◽  
David A. MacDonald ◽  
...  

Abstract Background: The outcome of peripheral T-cell lymphomas (PTCLs) remains poor and improved therapies are needed. Retrospective data suggest that integration of anthracyclines in the primary therapy may not impact outcome, providing the rationale to explore alternative regimens. Histone deacetylase inhibitors appear to have a class effect in PTCLs andromidepsin monotherapy demonstrates activity in a proportion of patients with relapsed/refractory PTCLs and can induce durable remissions. Gemcitabine is reported to be a highly active agent in PTCL, and the GDP (gemcitabine, dexamethasone, cisplatin) regimen has become a standard chemotherapy backbone for relapsed aggressive lymphomas (Crump, JCO 2014). We investigated the feasibility, safety and efficacy of GDP combined with romidepsin in a phase I dose escalation trial. Patients with relapsed/refractory diffuse large B-cell lymphoma (DLBCL) were also included. Methods: Patients with relapsed/refractory PTCL or DLBCL, PS 0-2, with measurable disease and who had received one or two prior lines of systemic therapy, were treated with standard doses of GDP (gemcitabine, 1000 mg/m2 d1, d8; dexamethasone, 40 mg po d1-4; cisplatin, 75 mg/m2 d1) every 21 days, plus escalating doses of romidepsin (6, 8, 10 and 12 mg/m2) on days 1 and 8 to a maximum of 6 cycles in a standard 3+3 design. After the first 4 patients were enrolled, based on the observed pattern of thrombocytopenia, the treatment schedule was modified so that gemcitabine and romidepsin were given on days 1 and 15 and cycles extended to every 28 days. Dose-limiting toxicities (DLTs) were assessed during the first 2 cycles and defined as requiring platelet transfusion for bleeding, grade 3 hematological toxicity lasting >10 days, grade 4 hematological toxicity lasting >7 days, febrile neutropenia, or grade 3-4 non-hematological toxicity attributable to romidepsin. Responses were as per Cheson, JCO 2007 excluding PET scans. Results: 20 eligible patients (PTCL n=10; DLBCL n=10) were enrolled between 10/2013 and 01/2016 and treated with GDP plus romidepsin. The main PTCL subtype was PTCL, not otherwise specified (50%). Median age was 65 years (24-74); 9 were female; ECOG performance status was 0 (n=2), 1 (n=13), or 2 (n=5). Number of prior therapies was 1 (n=17) or 2 (n=3). 17 (85%) patients received >90% of the planned dose each cycle. The median number of cycles was 2 (range, 1-6); one patient is still on therapy. The reasons for treatment discontinuation were lymphoma progression (n=10), toxicity (n=2), proceeding to autologous stem cell transplant (ASCT, n=3), intercurrent illness (n=1), or completion of 6 cycles (n=3). On the 21-day schedule at 6 mg/m2 romidepsin, there were 3 DLTs among four patients (2 with grade 3-4 thrombocytopenia, 1 venous thromboembolic event). On the 28-day schedule, there were no DLTs observed in the three patients treated at each of the 6, 8 or 10 mg/m2 dose levels. At 12 mg/m2 there were 4 observed grade 3 DLTs among six evaluable patients (hypotension, acute kidney injury, anorexia, thrombocytopenia >10 days). Notable toxicities during any cycle were: febrile neutropenia (n=2); grade 3-4 thrombocytopenia (n=9); grade 3-4 neutropenia (n=4); and grade 3-4 anemia (n=4); grade 2 atrial fibrillation (n=2); grade 2 QTc prolongation (n=1); grade 1 sinus tachycardia (n=1); grade 2-3 infections (n=16); grade 1-3 cutaneous toxicity (n=9); grade 1-3 thromboembolic events (n=2); TIA (n=2) or stroke (n=1). One patient died after cycle 1 due to sepsis. 7 other patients have died of progressive lymphoma. The overall response rate was 9/20 (45%), all were partial remissions (PR), 3 had stable disease (SD), 4 had progressive disease (PD), and 4 were not objectively evaluable. Of the responders, 5 had PTCL and 4 had DLBCL. Four patients went on to ASCT. With a median follow-up of 5.8 months, the median duration of response was 2.8 months and median PFS is 2.2 months. For all patients, the 1 year PFS was 6% and 1 year OS was 43% Discussion: Full doses of GDP can be combined with a recommended phase II romidepsin dose of 10 mg/m2 given on a day 1, 15 every 28 days schedule. Thrombocytopenia prohibits this combination on a 21-day schedule. Toxicity is otherwise acceptable and as expected. Further study at the recommended dose and schedule would be required to properly define the activity of this regimen in PTCLs and DLBCL. Disclosures Reiman: Celgene: Honoraria, Research Funding. Buckstein:Novartis: Honoraria; Celgene: Honoraria, Research Funding. Kuruvilla:Merck & Co., Inc.: Consultancy, Honoraria. Villa:Lundbeck: Honoraria; Roche: Honoraria, Research Funding; Celgene: Honoraria. Hay:Amgen: Research Funding; Novartis: Research Funding; Janssen: Research Funding; Kite Pharmaceuticals: Research Funding.


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