Clinical improvement with a novel CD20 mAb, ofatumumab, in fludarabine-refractory chronic lymphocytic leukemia (CLL) also refractory to alemtuzumab or with bulky lymphadenopathy

7043 Background: Patients (pts) with CLL refractory tofludarabine and alemtuzumab (double-refractory, DR) or refractory to fludarabine with bulky (>5 cm) lymphadenopathy (bulky fludarabine-refractory, BFR) have a poor prognosis. Ofatumumab is a human mAb specific for a distinctive small-loop epitope of CD20 that appears more potent than rituximab in eliciting complement-dependent lysis of B cells in vitro. We report, for the first time, results from the planned interim analysis of the clinical benefit observed in pts with DR or BFR CLL treated with ofatumumab in an international pivotal clinical study. Methods: Pts with DR or BFR CLL received 8 weekly then 4 monthly ofatumumab infusions (Dose 1, 300 mg; Doses 2–12, 2,000 mg). Primary endpoint was overall response rate (ORR; 1996 NCI-WG criteria), as assessed by an Independent Review Committee, over 24 wks. Results: Of 138 treated pts (DR: N = 59; BFR: N = 79; median age 64 and 62 yrs, respectively), 63% had Rai stage III/IV disease at screening. Pts had a median of 5 prior therapies. ORR (99% CI) was 58% (40, 74%) in the DR and 47% (32, 62%) in the BFR groups, and median overall survival (95% CI) was 13.7 mo (9.4, NR) and 15.4 mo (10.2, 20.2), respectively. Resolution of disease symptoms (maintained for ≥2 mo) were observed in a large proportion of pts (Table), including in pts considered nonresponders by NCI-WG criteria. Improvements in hematologic values were also observed in some pts with abnormal baseline values, particularly for platelet counts. Pts with thrombocytopenia at baseline (n = 73) experienced sustained increases in median platelet counts from 65 × 109/L to over 100 × 109/L by Wk 8; a similar pattern of rapid improvement was observed in Hgb values. Conclusions: Ofatumumab as single-agent achieves high ORR, and improves disease symptoms and hematologic parameters in heavily pretreated pts with DR and BFR disease who lack standard treatment options. [Table: see text] [Table: see text]

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Relapsed Multiple Myeloma

Hematology ◽

10.1182/asheducation-2010.1.303 ◽

2010 ◽

Vol 2010 (1) ◽

pp. 303-309 ◽

Cited By ~ 29

Author(s):

Sagar Lonial

Keyword(s):

Multiple Myeloma ◽

Clinical Trials ◽

Phase 1 ◽

Treatment Options ◽

Single Agent ◽

Great Promise ◽

New Agents ◽

Ongoing Work ◽

The Many

Abstract Advances in treatment options for patients with multiple myeloma have made a significant impact on the overall survival of patients and have helped achieve levels of response and duration of remission previously not achievable with standard chemotherapy-based approaches. These improvements are due, in large part, to the development of the novel agents thalidomide, bortezomib, and lenalidomide, each of which has substantial single-agent activity. In addition, a large number of second-generation agents are also in clinical development, such that the repertoire of available treatment options continues to expand. To better interpret clinical trials performed in the relapsed setting, it is important that definitions of relapse categories are used to help better pinpoint the specific benefit for a given therapy, especially in the combination therapy setting as it aids in determining if ongoing work should be continued or abandoned for a given new agent. Insights from preclinical modeling and in vitro work have identified several new combinations, new targets and second- or third-generation versions of existing targets that hold great promise in the setting of relapsed myeloma. Combinations of thalidomide, bortezomib, and lenalidomide with conventional agents or among each other have resulted in enhanced response rates and efficacy. Clinical trials of agents such as carfilzomib, pomalidomide, vorinostat, panobinostat, and elotuzomab are just a few of the many exciting new compounds that are being tested in phase 1 and phase 2 clinical trials for relapsed patients. Further clinical and translational testing are critical to better understanding how best to combine these new agents, as well as identifying patient populations that may best benefit from treatment with these developing new agents.

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Combined Fludarabine, Cyclophosphamide, and Alemtuzumab (FCC), an Active Regimen for Treated Patients with Chronic Lymphocytic Leukemia (CLL).

Blood ◽

10.1182/blood.v110.11.3133.3133 ◽

2007 ◽

Vol 110 (11) ◽

pp. 3133-3133 ◽

Cited By ~ 3

Author(s):

Marco Montillo ◽

Sara Miqueleiz ◽

Alessandra Tedeschi ◽

Francesca Ricci ◽

Eleonora Vismara ◽

...

Keyword(s):

Bone Marrow ◽

Residual Disease ◽

Single Agent ◽

Lymphocytic Leukemia ◽

Combination Regimen ◽

Synergistic Activity ◽

Color Flow ◽

Grade Iii

Abstract Fludarabine (F) in combination with cyclophosphamide (C) showed a relevant advantage over single-agent F in pts with relapsed CLL. Although minimal residual disease (MRD) remains detectable in many pts achieving CR, the combination of F and C seems to reduce MRD more efficiently. Still, pts in CR eventually relapse and require treatment, demonstrating the need for improved treatments able to further reduce or eliminate MRD and induce “better quality” and thus more durable responses. Alemtuzumab (CAM), anti-CD52 monoclonal antibody, acts synergistically with F in vitro and appears to have synergistic activity in vivo. Additionally, CAM is highly effective at clearing disease from bone marrow, the usual site of residual disease following purine analogue-based treatment. Therefore, we designed a phase II study to determine feasibility and efficacy, overall response rate (ORR)-duration of response-ability at clearing MRD, of a 4-weekly combination regimen consisting of F, C, and CAM (FCC). The study population is represented by pts with B-CLL with relapsed or refractory disease after at least one line of treatment. Subcutaneous route of administration of CAM has been adopted in this trial. MRD was measured by 4-color flow cytometry in the bone marrow. The FCC regimen consisted of F 40 mg/m2/d os (d 1–3), C 250 mg/m2/d os (d 1–3) and CAM 10 mg sc (d 1–3). This combination was repeated on d 29 for up to 6 cycles. The dose of CAM was increased after the first cohort of 10 treated pts from 10 mg to 20 mg sc. Currently, 25 pts have been enrolled in this trial. Median age was 57 years (range 42–79), 15/25 (60%) were male, 23/25 (92%) were in Binet stage B or C, median number of prior treatment regimens was 2 (range 1–4). In six (24%) pts 17p deletion was detected. IgVH unmutated was observed in 17 (68%) pts. At the moment of writing 19 pts are eligible for evaluation of toxicity and response. The ORR was 79%, with 7 (37%) pts achieving CR, 7 (37%) pts a PR, 1 (5%) pt a PRn. Three pts had SD, while 1 showed progression of the disease. MRD negativity was achieved in the bone marrow of 4/15 (27%) pts. Grade III-IV neutropenia episodes were observed in 43% of the administered courses while grade III-IV thrombocytopenia episodes were detected only in 8% of cycles. Four major infections were recorded: two sustained by Mycobacterium tuberculosis (1 cutis, 1 lung), one by Nocardia (lung) and one by E. coli (sepsis). The patient with pneumonia due to M. tuberculosis died because of respiratory failure. CMV reactivation occurred in 6 pts: no CMV disease was recorded. After a median follow up of 10 m (range 1–22) 73% of responding pts did not progressed. In conclusion, results from the interim analysis of this new, 4-weekly dosing FCC regimen suggest that combination therapy with F, C and CAM is feasible, safe, and effective in treating pts with relapsed and refractory CLL, even in those patients with inherent poor prognostic factors and who had received.

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Phase 2A Study of Copanlisib, a Novel PI3K Inhibitor, in Patients with Indolent Lymphoma

Blood ◽

10.1182/blood.v124.21.1701.1701 ◽

2014 ◽

Vol 124 (21) ◽

pp. 1701-1701 ◽

Cited By ~ 7

Author(s):

Martin Dreyling ◽

David Cunningham ◽

Krimo Bouabdallah ◽

Sarit Assouline ◽

Eric Van den Neste ◽

...

Keyword(s):

Exploratory Study ◽

Research Funding ◽

Single Agent ◽

Objective Response ◽

Median Number ◽

Lymphocytic Leukemia ◽

Pi3k Inhibitor ◽

Aggressive Lymphoma ◽

Heavily Pretreated ◽

Grade 3

Abstract Background: Copanlisib is a novel pan-Class I phosphatidylinositol-3-kinase (PI3K) inhibitor with potent preclinical inhibitory activity against both PI3K-d and PI3K-α isoforms. Preliminary results from a phase II study of copanlisib in patients with relapsed/refractory non-Hodgkin lymphoma (NHL) or chronic lymphocytic leukemia (CLL) have been reported (Dreyling et al., ASH 2013), with an expansion cohort for patients with aggressive lymphoma still ongoing. We report here the final results of this exploratory study for patients with indolent NHL or CLL treated with copanlisib. Methods: Patients with histologically confirmed indolent NHL or CLL and relapsed or refractory to ≥2 prior lines of treatment were eligible. Copanlisib was administered at a dose of 0.8 mg/kg as a 1 hour intravenous infusion on days 1, 8 and 15 of a 28-day cycle until disease progression or unacceptable toxicity. The primary endpoint was objective response rate (ORR) as assessed per independent radiologic review according to the response criteria for lymphoma (Cheson et al., JCO 17:1244,1999) or the guidelines for diagnosis and treatment of CLL (Hallek et al., Blood 111:5446-56, 2008). Secondary endpoints included progression-free survival (PFS) and duration of response (DOR), safety and tolerability. Results: A total of 33 patients were treated in the indolent group, including: follicular NHL (FL) = 16, CLL = 13, marginal zone lymphoma (MZL) = 3, and small lymphocytic lymphoma (SLL) = 1. Median age was 68 years (range 46-89), M/F= 15/18. The median number of previous lines of treatment was 4. Thirty patients (91%) were previously exposed to rituximab. The median number of cycles received was 5.7 (mean 7.2); the median dose and median cumulative dosage of copanlisib administered were 52 mg (87% of planned dose) and 687 mg, respectively. Five patients were dose reduced to 0.6 mg/kg and 1 to 0.4 mg/kg. The ORR as determined by independent radiologic review in 32 evaluable patients was 47%, with 1 CR, 1 uCR, and 13 PRs. By histology, there were 1 CR, 1 uCR and 5 PRs for patients with FL (ORR 47%), and 2/3 PRs for patients with MZL and 1/1 PR for the patient with SLL, for an overall ORR for patients with indolent NHL (excluding CLL) of 53%. The ORR for patients with CLL was 38% (all PRs). Overall, the median DOR was 287 days (95% CI: 56; not yet reached); median PFS was 240 days (95% CI: 173; 419). The most common adverse events (AEs) of all grades were hyperglycemia (70%), hypertension (70%), fatigue (64%), diarrhea (36%), neutropenia (36%) and anemia (33%). Grade 3-4 AEs occurring in >10% of patients included: hypertension (49% grade 3), neutropenia (30%), hyperglycemia (30% grade 3), and anemia (15%). Dose reductions, interruptions, or permanent discontinuations due to AEs were reported in 4 (12%), 21 64%), and 11 (33%) patients, respectively. There was one drug-related grade-5 event; meningitis in a heavily-pretreated CLL patient with longstanding disease-related immunodeficiency, occurring shortly after first administration of copanlisib. Conclusions: Copanlisib is active as a single-agent in heavily pretreated, advanced refractory/relapsed FL, MZL, SLL, and CLL. Copanlisib exhibited an acceptable toxicity profile, consistent with previous reports. Based on the results of this exploratory study, a phase 2B study of copanlisib in relapsed or refractory indolent NHL (after prior treatment with an alkylating agent and rituximab) has been initiated and is ongoing. Disclosures Dreyling: Bayer HealthCare: Scientific advisory board/consultant Other. Cunningham:Roche: Research Funding; Amgen: Research Funding; Celgene: Research Funding; Sanofi: Research Funding; Merck Serono: Research Funding; Novartis: Research Funding; Astra Zeneca: Research Funding. Giurescu:Bayer Pharma AG: Employment. Mappa:Bayer S.p.A.: Employment. Grunert:Bayer Pharma AG: Employment. Childs:Bayer HealthCare Pharmaceuticals: Employment.

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A Tetravalent Biparatopic Antibody Causes Strong HER2 Internalization and Inhibits Cellular Proliferation

Life ◽

10.3390/life11111157 ◽

2021 ◽

Vol 11 (11) ◽

pp. 1157

Author(s):

Filippo Benedetti ◽

Katharina Stadlbauer ◽

Gerhard Stadlmayr ◽

Florian Rüker ◽

Gordana Wozniak-Knopp

Keyword(s):

Cell Line ◽

Cellular Proliferation ◽

Treatment Options ◽

Single Agent ◽

Her2 Positive ◽

Proliferative Effect ◽

Efficient Reduction ◽

Anti Cancer ◽

Suitable Target

The overexpression of tyrosine kinase HER2 in numerous cancers, connected with fierce signaling and uncontrolled proliferation, makes it a suitable target for immunotherapy. The acquisition of resistance to currently used compounds and the multiplicity of signaling pathways involved prompted research into the discovery of novel binders as well as treatment options with multiple targeting and multispecific agents. Here we constructed an anti-HER2 tetravalent and biparatopic symmetrical IgG-like molecule by combining the Fab of pertuzumab with a HER2-specific Fcab (Fc fragment with antigen binding), which recognizes an epitope overlapping with trastuzumab. In the strongly HER2-positive cell line SK-BR-3, the molecule induced a rapid and efficient reduction in surface HER2 levels. A potent anti-proliferative effect, specific for the HER2-positive cell line, was observed in vitro, following the induction of apoptosis, and this could not be achieved with treatment with the mixture of pertuzumab and the parental Fcab. The inhibitory cytotoxic effect of our antibody as a single agent makes it a promising contribution to the armory of anti-cancer molecules directed against HER2-addicted cells.

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Randomized comparison of ibrutinib versus ofatumumab in relapsed or refractory (R/R) chronic lymphocytic leukemia/small lymphocytic lymphoma: Results from the phase III RESONATE trial.

Journal of Clinical Oncology ◽

10.1200/jco.2014.32.18_suppl.lba7008 ◽

2014 ◽

Vol 32 (18_suppl) ◽

pp. LBA7008-LBA7008 ◽

Cited By ~ 3

Author(s):

John C. Byrd ◽

Jennifer R. Brown ◽

Susan Mary O'Brien ◽

Jacqueline Claudia Barrientos ◽

Neil E. Kay ◽

...

Keyword(s):

Treatment Options ◽

Randomized Study ◽

Data Monitoring Committee ◽

Progression Free Survival ◽

Lymphocytic Leukemia ◽

Phase Iii ◽

Drug Discontinuation ◽

Purine Analog ◽

Independent Review ◽

Secondary Endpoints

LBA7008 Background: Treatment options for CLL/ SLL patients (pts) who fail chemoimmunotherapy are limited. We report interim results from a phase III randomized study of ibrutinib (ibr), a first in class covalent BTK inhibitor, vs ofatumumab (ofa) in R/R CLL/SLL. The Data Monitoring Committee recommended this analysis be considered final, based on meeting the primary and a key secondary endpoint. Methods: R/R CLL/SLL pts who failed ≥1 therapy received 420 mg oral ibr daily until progression or IV ofa 300/2000mg for 12 doses. Primary endpoint was progression-free survival (PFS) assessed by an independent review committee (IRC). Secondary endpoints included overall survival (OS), IRC assessed overall response rate (ORR) and safety. Results: Of 391 pts enrolled (median age 67 years; 40% ≥70 years; 57% Rai stage III/IV disease; 30% del 17p), 195 were randomized to ibr and 196 to ofa. Ibr pts had median 3 prior therapies vs 2 for ofa. Median follow-up was 9.4 months (m). Ibr significantly lengthened PFS (median not reached vs 8.1 m; HR 0.215, CI 0.146–0.317, p<0.0001; 78.5% risk reduction), and significantly improved OS (median not reached; HR 0.434, CI 0.238–0.789, p=0.0049) compared with ofa. ORR was 42.6 vs 4.1% (p<0.0001) and ORR+PR with lymphocytosis was 62.6 vs 4.1% for ibr vs ofa. Similar effects were seen in del17p and purine analog refractory subsets. In each arm 2 pts had confirmed Richter’s transformation. Most frequent adverse events (AE) for ibr vs ofa were diarrhea (47.7 vs 17.8%) fatigue (27.7 vs 29.8%), and nausea (26.2 vs 18.3%). Atrial fibrillation was more frequent with ibr (5.1 vs 0.5%). Major hemorrhages were reported in 1.0 vs 1.6% for ibr vs ofa. Drug discontinuation due to AE was 4.1 vs 3.6% for ibr vs ofa. 86% of ibr pts were continuing treatment. 57 pts randomized to ofa with confirmed PD had initiated ibr at cross-over. Conclusions: Compared with ofa, ibr significantly improved PFS, OS and ORR in pts with R/R CLL/SLL. The safety profile was comparable with that previously reported (Byrd NEJM 2013). These results support ibr as a beneficial therapy for R/R CLL patients irrespective of del 17p or purine analog refractory disease. Clinical trial information: NCT01578707.

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DREAMM-2: Single-agent belantamab mafodotin (GSK2857916) in patients with relapsed/refractory multiple myeloma (RRMM) and high-risk (HR) cytogenetics.

Journal of Clinical Oncology ◽

10.1200/jco.2020.38.15_suppl.8541 ◽

2020 ◽

Vol 38 (15_suppl) ◽

pp. 8541-8541 ◽

Cited By ~ 2

Author(s):

Adam D. Cohen ◽

Suzanne Trudel ◽

Sagar Lonial ◽

Edward N. Libby ◽

Hans Chulhee Lee ◽

...

Keyword(s):

Partial Response ◽

Safety Profile ◽

Single Agent ◽

Median Number ◽

Blurred Vision ◽

Duration Of Response ◽

Heavily Pretreated ◽

Independent Review ◽

Clinical Responses ◽

Number Of Cycles

8541 Background: Patients with RRMM and HR cytogenetics have a poor prognosis and need effective therapies. In DREAMM-2 (NCT03525678), single-agent belantamab mafodotin (an immunoconjugate targeting B-cell maturation antigen) demonstrated clinically meaningful activity and a manageable safety profile in patients with heavily pretreated RRMM ( Lancet Oncol.2020). We present outcomes in patients with HR-cytogenetics (9-month follow-up). Methods: Patients with RRMM received single-agent belantamab mafodotin (2.5 or 3.4 mg/kg). For this post hoc analysis, HR-cytogenetics included t(4;14), t(14;16), 17p13del, or 1q21+ (tested locally). Results: The median number of cycles was 3 (2.5: range: 1–15) and 4 (3.4: range: 1–14). Overall response rate (ORR; ≥partial response [PR] per independent review committee) was 27% in the 2.5 mg/kg group (22% with ≥very good partial response [VGPR]) and 40% in the 3.4 mg/kg group (27% with ≥VGPR). The median duration of response (DoR) was not reached in the 2.5 mg/kg group and was 6.2 months in the 3.4 mg/kg group. The most common adverse events ( > 30% in either group) were consistent with the overall population ( Lancet Oncol.2020): keratopathy (2.5: 59%;3.4: 79%), thrombocytopenia (2.5: 44%; 3.4: 65%), nausea (2.5: 27%; 3.4: 33%), anemia (2.5: 24%; 3.4: 42%), and blurred vision (2.5: 20%; 3.4: 42%). Conclusions: Patients with HR-cytogenetics maintain deep and durable clinical responses with single-agent belantamab mafodotin, comparable to that reported in the overall population. The safety profile remained consistent with previous reports. Funding: GlaxoSmithKline (205678). Drug linker technology licensed from Seattle Genetics; monoclonal antibody produced using POTELLIGENT Technology licensed from BioWa. Clinical trial information: NCT03525678 . [Table: see text]

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IL-21 Promotes Apoptosis through Induction of the BH3 Only Protein Bim and Enhacnes Direct and Innate Immune-Promoted Death of Chronic Lymphocytic Leukemia Cells.

Blood ◽

10.1182/blood.v110.11.3118.3118 ◽

2007 ◽

Vol 110 (11) ◽

pp. 3118-3118

Author(s):

Julie M. Roda ◽

Aruna Gowda ◽

Rehan Hussain ◽

Asha Ramanunni ◽

Amy Lehman ◽

...

Keyword(s):

Clinical Trials ◽

B Cells ◽

Chronic Lymphocytic Leukemia ◽

Nk Cell ◽

Single Agent ◽

Innate Immune ◽

Lymphocytic Leukemia ◽

Clinical Activity ◽

Specific Lysis

Abstract Chemoimmunotherapy with fludarabine and the anti-CD20 monoclonal antibody rituximab has demonstrated promising clinical activity in chronic lymphocytic leukemia (CLL). We hypothesized that the gamma chain receptor cytokine IL-21, which is currently in clinical trials for lymphoma, might enhance the efficacy of this regimen by augmenting both immune-mediated clearance of CLL cells and a direct apoptotic mechanism involved in the homeostasis of normal B cells. CLL cells expressed variable levels of the IL-21 receptor alpha subunit (<10–80% positive cells, n = 16). IL-21 induced direct apoptosis in CLL cells from a subset of patients (40% ± 15.9 apoptotic cells; n = 9; p <0.0001), which directly correlated with increased expression of surface IL-21R (p = 0.001). The in vitro apoptosis occurred at physiologically attainable concentrations (25 ng/ml) and was time- and dose-dependent. As a single agent, IL-21 did not activate CLL cells, as evidenced by lack of surface expression of CD86, HLADR, CD95, or CD40. However, IL-21 induced phosphorylation of STAT-1Tyr-701 and STAT-3 Tyr-705 in CLL cells exhibiting > 20% apoptosis at 72 hours, whereas phosphorylation of these proteins was not seen in CLL cells failing to undergo apoptosis. Similar to normal murine B cells, IL-21-mediated death was associated with up-regulation of the pro-apoptotic BH3 only domain protein Bim, whereas Bim was not up-regulated in CLL cells insensitive to IL-21-induced apoptosis. Furthermore, silencing of Bim in primary CLL cells with siRNA antagonized IL-21-mediated death. Preliminary studies examining the mechanism of Bim up-regulation demonstrated that both total levels and phosphorylation of FOXO3AThr32 increases following IL-21 treatment. FOXO3a is involved in transcriptional regulation of Bim, and further mechanistic studies are ongoing and will be presented. Given the favorable modulation of Bim, we examined the ability of IL-21 to enhance apoptosis in response to rituximab, alemtuzumab, or fludarabine. Our studies confirm that CLL cells pre-treated with IL-21 are sensitized to rituximab and fludarabine, whereas IL-21 had no effect on fludarabine-mediated apoptosis of normal T cells. IL-21 also enhanced NK cell ADCC against rituximab-coated autologous CLL cells (42 ± 4.4% rituximab-specific lysis vs. 28 ± 3.1% at an E:T ratio of 25:1; p < 0.0001). These data provide evidence that IL-21 promotes direct apoptosis through induction of Bim and also enhances fludarabine- and rituximab-mediated apoptosis. Additionally, IL-21 enhances autologous innate immune activation of NK cells toward primary CLL cells coated with rituximab. Overall, these findings provide justification for combination studies of IL-21 with fludarabine and rituximab chemoimmunotherapy in CLL and point to Bim induction as a pharmacodynamic endpoint to predicting surrogate biologic activity of IL-21 in vivo as part of planned clinical trials with this agent.

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Clinical Experience of Bendamustine Treatment for Non-Hodgkin Lymphoma and Chronic Lymphocytic Leukemia: Spanish Registry.

Blood ◽

10.1182/blood.v114.22.3698.3698 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3698-3698

Author(s):

Blanca Sanchez-Gonzalez ◽

Francisco Javier Peñalver ◽

Helga Guillen ◽

Marta Calleja ◽

Raquel de Oña ◽

...

Keyword(s):

Retrospective Analysis ◽

Cell Lymphoma ◽

Single Agent ◽

B Cell Lymphoma ◽

Lymphocytic Leukemia ◽

Prior Treatment ◽

Compassionate Use ◽

Non Hodgkin Lymphoma ◽

Purine Analog ◽

Heavily Pretreated

Abstract Abstract 3698 Poster Board III-634 Introduction Bendamustine (B) is a purine analog/alkylator hybrid that has demonstrated clinical activity in relapsed indolent non-Hodgkin lymphoma (NHL), including those refractory to other alkylating or purine analog agents, chronic lymphocytic leukemia (CLL) and multiple myeloma patients. Bendamustine is currently licensed in Germany and Switzerland for use in NHL and CLL, and in evaluation process by European Medication Agency (EMA) in other countries. Aim Retrospective analysis of efficacy and toxicity of bendamustine as a single-agent or in combination for NHL and CLL treatment in the setting of compassionate use in Spain. Retrospective analysis of efficacy and toxicity of bendamustine as a single-agent or in combination for NHL and CLL treatment in the setting of compassionate use in Spain. Retrospective analysis of efficacy and toxicity of bendamustine as a single-agent or in combination for NHL and CLL treatment in the setting of compassionate use in Spain. Patients and methods Patients with relapsed or refractory NHL or CLL after at least 1 prior treatment regimen were eligible. Any bendamustine regimen was included. Results 91 patients(pts) from 18 institutions were included in the registry. The median age was 69 years (range: 36-88); male: 58%. Histology: 30 pts CLL; 16 pts aggressive NHL: pts (13 mantle cell lymphoma and 3 diffuse large B-cell lymphoma); 45 indolent NHL: (36 follicular lymphoma, 6 extranodal marginal zone B-cell lymphoma of MALT type and 3 lymphoplasmocytic lymphoma); ECOG/PS 0-1: 73%; Ann Arbor III-IV: 79% and IPI score >3: 48% in NHL, and Binnet B-C in CLL: 96%. Median time from diagnosis to Bendamustine treatment was 4,6 years (range 1-19,2) and median prior treatment regimens was 3 (range 1-11). 31 pts were refractory to prior treatment. The most frequent used regimen was Rituximab plus B (RB) independently of the histology (see table 1). Median number of Bendamustine cycles was 3 (range 1-7). 322 cycles of B were administered. 60% of de pts had adverse events grade 3-4, being hematologic toxicity the most frequent adverse event (54% neutropenia, 33% leucopenia, 29,7% thrombocytopenia, and 20% anemia). 15% cycles of B required pts admission in hospital. Sixty-nine pts were assessable for response at the time of analysis. Response rate are showed in table 1. 22 pts died (7 infection, 11 progression, 2 infection plus progression, 1 infection plus respiratory insufficiency and 1 isquemia). Table 1. Conclusions The most common regimen was Bendamustine at dose 90 mg/m2 associated with rituximab. Treatment with B produced a high response rate, independently of the histology in this population of heavily pretreated NHL and CLL pts, including refractory to prior therapies. Treatment with B produced durable objective responses with acceptable toxicity in this population of heavily pretreated NHL and CLL pts, including refractory to prior therapies. Updated data will be presented at the meeting. Disclosures: No relevant conflicts of interest to declare.

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The Hsp90 Inhibitor SNX7081 Restores the Fludarabine Sensitivity of Chronic Lymphocytic Leukemia (CLL) Cells Harbouring Mutations of ATM or TP53

Blood ◽

10.1182/blood.v116.21.2473.2473 ◽

2010 ◽

Vol 116 (21) ◽

pp. 2473-2473

Author(s):

O. Giles Best ◽

Stephen P Mulligan

Keyword(s):

Chronic Lymphocytic Leukemia ◽

Cell Lines ◽

Caspase 3 ◽

Mononuclear Cells ◽

Single Agent ◽

Treatment Strategies ◽

Lymphocytic Leukemia ◽

Functional Assay ◽

Simultaneous Exposure

Abstract Abstract 2473 Introduction: Resistance to fludarabine-based treatment represents a challenge in the clinical management of Chronic Lymphocytic Leukemia (CLL). Despite the unprecedented response rates seen with the fludarabine (F), cyclophosphamide (C), Rituximab (R) regimen novel treatment strategies are required that do not rely on an intact p53 signaling pathway. We recently described the activity of a novel, synthetic inhibitor of the molecular chaperone, heat-shock protein 90 (Hsp90) named SNX7081 (Serenex, now Pfizer) against CLL cells in vitro (Best et al., 2010 BJH). Here we explored the effect of this inhibitor on the fludarabine sensitivity of 3 haematological cell lines and 12 patient samples with mutations of ATM or TP53. Methods: Mononuclear cells were isolated by density centrifugation from CLL patients following informed consent. The 13 patient samples selected for study were determined to have mutations of either ATM or TP53 using a functional assay described in detail elsewhere (Best et al., 2008). The Mec1 (CLL), Mec2 (CLL) and U266 (B-ALL) cell lines were maintained under standard conditions in RPMI-1640 with 2mM L-glut and 1% pen/strep. Sensitivity to fludarabine, with and without SNX7081, was assessed using the MTT (3–4, 5-dimethylthiazol-2,5-diphenyl tetrazolium bromide) assay. Synergy between the agents, activation of caspase-3 and the induction of double stranded DNA (dsDNA) breaks following treatment were all assessed by flow cytometry using the mitochondrial membrane potential dye DilC1 (5) and propidium iodide (PI) or appropriate antibodies. Results: The IC50 for fludarabine was significantly higher in the 3 cell lines and 13 patient samples with ATM/TP53 lesions than in 4 cell lines or 10 patient samples defined as ATM/TP53 wild-type. Simultaneous exposure to a combination of fludarabine and SNX7081 at a ratio based on the IC50 of the compounds as single agent significantly reduced the IC50 for fludarabine (P<0.01); in 11 patient samples the IC50 for fludarabine was reduced to within a clinically achievable range (<5μM). Synergy between fludarabine and SNX7081 was evident as an effect on the distribution of the cell lines in the cell cycle and as a marked effect on the proportion of apoptotic cells (DilC (1)5 negative/PI negative) in cultures of both the cell lines and patient samples. Furthermore, we show that the combination of the compounds has a greater than additive effect on the activation of caspase-3 and on the formation of dsDNA breaks, as evidenced by the phosphorylation of g-H2Ax. Conclusions: Our studies suggest that inhibition of Hsp90 may overcome fludarabine resistance conferred by mutations of ATM or TP53. The mechanism of the synergy between these compounds appears to be via augmentation of fludarabine-induced dsDNA breaks and is concomitant with an increase in caspase-3 signaling. The data suggest that this combination may represent a promising regimen in the treatment of fludarabine-refractory CLL. Disclosures: Mulligan: Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bayer Schering, now Genzyme: Honoraria.

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Clinical and Biological Characteristics Associated with In Vitro Activity of Anti-CD20 Monoclonal Antibodies, Rituximab and GA101, Against Chronic Lymphocytic Leukemia Cells

Blood ◽

10.1182/blood.v116.21.2459.2459 ◽

2010 ◽

Vol 116 (21) ◽

pp. 2459-2459

Author(s):

Loic Ysebaert ◽

Emilie Laprévotte ◽

Christian Klein ◽

Guy Laurent ◽

Jean-Jacques Fournié ◽

...

Keyword(s):

Chronic Lymphocytic Leukemia ◽

B Cell ◽

Single Agent ◽

Biological Data ◽

Lymphocytic Leukemia ◽

Clinical Activity ◽

Antibody Treatment ◽

Cd20 Antibody ◽

The Impact

Abstract Abstract 2459 Introduction: The CD20 antibody rituximab (RTX) is an important therapeutic agent in the armamentarium against chronic lymphocytic leukemia (CLL) cells. Several mechanisms have been described that affect low single agent efficacy of CD20 antibodies in B-CLL and relapse after treatment. The novel CD20 antibody GA101 has been developed with the aim of further improving CLL therapy and is currently in phase II/III clinical trials. It is a type II, glyco-engineered CD20 antibody with enhanced ADCC through improved CD16A binding. Aim: To assess in vitro pre-clinical activity of RTX and GA101 against CLL cells in either freshly isolated PBMCs, or after 14 days of culture in vitro, to allow the outgrowth of Nurse-Like Cells (NLC) that may presumably alleviate mAb activity (a process called Environment Mediated-Drug Resistance, or EM-DR). Methods: In 34 CLL patients (all naive for treatment), PBMCs were isolated from blood samples by Ficoll gradient centrifugation. Antibody-mediated B cell depletions was determined by enumerating trypan blue negative, flow cytometrically CD19-positive B lymphocytes after antibody treatment. Three conditions were assessed, all with starting concentrations of 107cells/ml: (i) depletion in freshly isolated PBMCs after 7 days of culture in RPMI+10%FCS and 10μg/ml RTX or GA101 (DEP7), or, after 14 days culture of PBMCs in RPMI+10% FCS, PBMCs were collected and either (ii) washed and cultured in fresh RPMI+10%FCS and antibodies for 7 extra-days (DEP21/RPMI), or (iii) re-suspended in their own conditioned RPMI medium and cultured with NLC and antibodies for 7 extra-days (DEP21/NLC). The Mann-Whitney analysis was used to compare median depletion according to relevant clinical and biological data. Results: The median B-CLL depletion in freshly isolated PBMC were 56% for GA101 vs 5% for RTX (p=0.000031). As indicated in Table 1, no clinico-biological parameter was significantly associated with antibody response, though unmutated IgVH status seemed to impact on GA101 efficacy. We next sought to study the impact of EM-DR mechanisms afforded by CLL PBMCs+NLC co-cultures in vitro. While RTX activity was virtually abrogated under those conditions, B cell depletion induced by GA101 was significantly reduced to 27% if PBMCs were collected after 14 days of culture with NLC, and incubated with antibodies from days 14–21 either in fresh RPMI (DEP21/RPMI=27% vs 56% for DEP7 GA101, n=18, p=0.024), or to 14% in conditioned RPMI and NLC (DEP21/NLC=14% vs 56% for DEP7 GA101, n=12, p=0.008). This time, clinico-biological parameters linked with active CLL disease like bulky lymph nodes>5cm (p=0.049), presence of at least one NCIWG2008 criteria for initiation of treatment (p=0.01), and unmutated IgVH status (p=0.03) appeared significantly linked to reduced GA101 activity. Interestingly, karyotype abnormalities did not seem to negatively impact on GA101-triggered depletion. Conclusions: Our results suggest that in vitro EM-DR abrogates the small RTX activity as single agent against CLL cells, whereas GA101 still retains activity under those conditions. It remains to be studied whether this may impact the clinical activity of GA101 in subgroups of patients. Overall, GA101 appeared much more active than rituximab, and should be investigated in combination with strategies aiming at disrupting EM-DR mechanisms. Disclosures: Off Label Use: GA101 is not currently approved for CLL treatment. Klein: Roche: Employment, Equity Ownership, Patents & Royalties.

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