Obinutuzumab Research Articles

Human serum albumin-based drug-free macromolecular therapeutics induce apoptosis in chronic lymphocytic leukemia patient cells by crosslinking of CD20 and/or CD38 receptors.

This study explores the efficacy of human serum albumin (HSA)-based Drug-Free Macromolecular Therapeutics (DFMT) in treating Chronic Lymphocytic Leukemia (CLL), a prevalent adult leukemia subtype. DFMT, a novel strategy, employs biomimetic crosslinking of CD20 and CD38 receptors on malignant B cells without the need for low molecular weight drugs. Apoptosis is initiated via a two-step process: i) Recognition of a bispecific engager, Fab' fragment conjugated with morpholino oligonucleotide (Fab'-MORF1), by a cell surface antigen; followed by ii) crosslinking of the MORF1-decorated cells with a multivalent effector, HSA holding multiple copies of complementary MORF2, HSA-(MORF2)x. Herein we evaluated the efficacy of HSA-based DFMT in the treatment of 56 samples isolated from patients diagnosed with CLL. Fab' fragments from Obinutuzumab (OBN) and Isatuximab (ISA) were employed in the synthesis of anti-CD20 (Fab'OBN-MORF1) and anti-CD38 (Fab'ISA-MORF1) bispecific engagers. The efficacy of DFMT was significantly influenced by the expression levels of CD20 and CD38 receptors. Dual-targeting DFMT strategies (CD20 + CD38) were more effective than single-target approaches, particularly in samples with elevated receptor expression. Pretreatment of patient cells with gemcitabine or ricolinostat markedly increased cell surface CD20 and CD38 expression, respectively. Apoptosis was effectively initiated in 62.5% of CD20-targeted samples and in 42.9% of CD38-targeted samples. Our findings demonstrate DFMT's potential in personalized CLL therapy. Further research is needed to validate these outcomes in a larger number of patient samples and to explore DFMT's applicability to other malignancies.

Efficacy and Safety of Obinutuzumab in Relapsed or Refractory Hairy Cell Leukemia (R/R HCL): An Italian Multicenter Phase-2 Academic Trial (HCL-PG04)

INTRODUCTION About 50% of HCL patients (pts) relapse after chemotherapy with purine analogs (PA). After identifying the BRAF-V600E mutation as the genetic cause of HCL (Tiacci et al. NEJM 2011), we documented a high efficacy of the BRAF inhibitor vemurafenib in R/R pts (Tiacci, Park et al. NEJM 2015), especially when added to rituximab (Tiacci et al. NEJM 2021). HCL expresses bright CD20 and obinutuzumab (OBI) is a more effective anti-CD20 agent than rituximab (RTX) in other indolent B-cell neoplasms such as chronic lymphocytic leukemia and follicular lymphoma. RTX produces ~20% complete remissions (CR) in R/R HCL (Kreitman, ASH Educ Program 2012), while OBI activity in this setting is unknown. METHODS In the ongoing academic, phase-2, multi-center trial HCL-PG04, R/R HCL pts needing treatment due to cytopenia(s) received OBI 1000 mg intravenously on days 1-8-15 of cycle 1 and on day 1 of cycles 2-6 (1 cycle = 28 days). CR required resolution of cytopenias (platelets ≥ 100,000/mmc; neutrophils ≥ 1500/mmc; hemoglobin ≥ 11 g/dl), no palpable splenomegaly and no leukemic cells on morphologic analysis of the bone marrow biopsy, as assessed one month after the last OBI dose. Minimal residual disease (MRD) was analyzed by BRAF-V600E specific PCR in the bone marrow aspirate (sensitivity: 0.05% mutant alleles). RESULTS We enrolled 26 pts (M/F 24/2; median age 62 years, range 39-80) with a median of 2 prior therapies (range 1-7), including 7 refractory to PA (26%) and 2 to RTX (8%). Median values of disease burden parameters at baseline were: 70% BM HCL infiltration, 830 neutrophils/mmc, 62000 platelets/mmc, 14 g/dl hemoglobin, and 16 cm of longest spleen diameter (in 16/26 splenomegalic patients; 1 pts. had been splenectomized and 9 were not splenomegalic at baseline). Toxicity was as expected, largely of grade (G) 1-2, always reversible and mainly consisting in: infusion reactions (G1-2 92%; G3 4%, in a single pt allergic to previous RTX who discontinued OBI); asymptomatic increase of liver enzymes (G1-2 19%; G3 GGT 15%; G3 ALT 4%); transient worsening of baseline G1-G3 thrombocytopenia to G3 (23%) or G4 (35%), with only 1 minor bleeding (4%, G1 epistaxis); transient neutropenia (G2 4%; G3 15%; G4 15%); and rare infections (G1-2 herpes labialis 8%; G3 pneumonia 4%). CR was reached in 12/25 evaluable pts (48%), including 2 pts with incomplete platelet recovery (~70000-90000/mmc) and 2 pts with delayed resolution of palpable splenomegaly. Notably, CR was achieved in 5/7 pts refractory to PA and 1/2 pts refractory to RTX. Furthermore, CR was negative for MRD in 9/12 pts (75%, including 3 pts with delayed MRD clearance), something never observed with vemurafenib. However, the kinetics of cytopenia resolution was slower compared to our previous vemurafenib trial, in that in pts obtaining CR with OBI neutrophil recovered to ≥1500/mmc after a median of 7 weeks (vs 4 weeks with vemurafenib) and platelets recovered to ≥100000/mmc after a median of 8 weeks (vs 2 weeks with vemurafenib). Prior exposure to RTX (n=12 pts) did not compromise OBI efficacy (5 CR, all MRD-negative, in 11 evaluable pts). In pts achieving CR with OBI, progression-free and MRD-free survival were both 100% at 56 months (range 20-66) and 48 months (range 6.5-60) of median follow-up, respectively (Fig.1). The 13 non-CR pts (minor response 7; no response 3; progression 3) were effectively salvaged with another course of OBI combined with vemurafenib, which will be presented at the meeting. CONCLUSIONS OBI frequently produced deep and durable responses in R/R HCL, to an extent apparently greater than RTX, thus qualifying as an active and safe chemotherapy-free strategy in this setting.

Obinutuzumab-Based Drug-Free Macromolecular Therapeutics Synergizes with Topoisomerase Inhibitors.

Drug-free macromolecular therapeutics (DFMT) utilizes modified monoclonal antibodies (or antibody fragments) to generate antigen-crosslinking-induced apoptosis in target cells. DFMT is a two-component system containing a morpholino oligonucleotide (MORF1) modified antibody (Ab-MORF1) and human serum albumin conjugated with multiple copies of complementary morpholino oligonucleotide (MORF2), (HSA-(MORF2)x ). The two components recognize each other via the Watson-Crick base pairing complementation of their respective MORFs. One HSA-(MORF2)x molecule can hybridize with multiple Ab-MORF1 molecules on the cell surface, thus serving as the therapeutic crosslink-inducing mechanism of action. Herein, various anti-neoplastic agents in combination with the anti-CD20 Obinutuzumab (OBN)-based DFMT system are examined. Three different classes of chemotherapies are examined: DNA alkylating agents; proliferation pathway inhibitors; and DNA replication inhibitors. Chou-Talalay combination index mathematics is utilized to determine which drugs engaged synergistically with OBN-based DFMT. It is determined that OBN-based DFMT synergizes with topoisomerase inhibitors and DNA nucleotide analogs but is antagonistic with proliferation pathway inhibitors. Cell mechanism experiments are performed to analyze points of synergism or antagonism by investigating Ca2+ influx, mitochondrial health, lysosomal stability, and cell cycle arrest. Finally, the synergistic drug combinatorial effects of OBN-based DFMT with etoposide in vivo are demonstrated using a human xenograft non-Hodgkin's lymphoma mouse model.

Efficacy and safety of immunosuppressive agents for adults with lupus nephritis: a systematic review and network meta-analysis.

Various immunosuppressive regimens have been developed for the treatment of lupus nephritis (LN). This study aimed to compare the efficacy and safety of immunosuppressive regimens in adults with LN. We systematically searched the PubMed, Embase, and Cochrane Central Register of Controlled Trials databases, including conference proceedings, trial registries, and reference lists, from inception until July 10, 2022. The effects of treatment were compared and ranked using the surface under the cumulative ranking curve (SUCRA). The primary endpoint was total remission. The secondary endpoints were complete remission, systemic lupus erythematosus disease activity index (SLEDAI), relapse, all-cause mortality, end-stage renal disease (ESRD), infection, herpes zoster, ovarian failure, myelosuppression, and cancer. Sixty-two trials reported in 172 studies involving 6,936 patients were included in the network meta-analysis. The combination of tacrolimus (TAC), mycophenolate mofetil (MMF), and glucocorticoid (GC) provided the best result for the total remission rate (SUCRA, 86.63%) and SLEDAI (SUCRA, 91.00%), while the combination of voclosporin (VCS) , MMF and GC gave the best improvement in the complete remission rate (SUCRA, 90.71%). The combination of cyclophosphamide (CYC), MMF and GC was associated with the lowest risk of relapse (SUCRA, 85.57%) and cancer (SUCRA, 85.14%), while the combination of obinutuzumab (OTB), MMF and GC was associated with the lowest risk of all-cause mortality (SUCRA, 84.07%). Rituximab (RTX) plus MMF plus GC was associated with the lowest risk of ESRD (SUCRA, 83.11%), while the risk of infection was lowest in patients treated with azathioprine (AZA) plus CYC plus GC (SUCRA, 68.59%). TAC plus GC was associated with the lowest risk of herpes zoster (SUCRA, 87.67%) and ovarian failure (SUCRA, 73.60%). Cyclosporine (CsA) plus GC was associated with the lowest risk of myelosuppression (SUCRA, 79.50%), while AZA plus GC was associated with the highest risk of myelosuppression (SUCRA, 16.25%). This study showed that a combination of TAC, MMF and GC was the best regimen for improving the total remission rate. The optimal regimen for specific outcomes should be highlighted for high-risk patients.

Direct Cell Death Induced by CD20 Monoclonal Antibodies on B Cell Lymphoma Cells Revealed by New Protocols of Analysis

CD20 monoclonal antibodies (mAbs) eliminate B cells in several clinical contexts. At least two of these Abs, obinutuzumab (OBI) and rituximab (RTX), induce quick elimination of targets and put cancer patients at risk of tumor lysis syndrome (TLS) within 12-24 h of the first dose. The mechanisms of killing can require the recruiting of effector mechanisms from the patient's immune system, but they can induce direct killing as well. This can be more rapid than recruiting cellular effectors and/or complement. We showed here that OBI and RTX induce quick (<1 h) and high (up to 60% for OBI) killing of two different B cell lines. This was unveiled by using two different techniques that circumvent cell centrifugation steps: a Muse® Cell Analyzer-based approach and a direct examination of the cells' physical properties by using forward scatter (FS) area and side scatter (SS) area by flow cytometry. These results excluded the presence of aggregates and were also confirmed by developing a normalized survival ratio based on the co-incubation of RTX- and OBI-sensitive cells with MOLM-13, an insensitive cell line. Finally, this normalized survival ratio protocol confirmed the RTX- and OBI-direct killing on primary tumor B cells from B cell chronic lymphocytic leukemia (B-CLL) and Non-Hodgkin's lymphoma (NHL) patients. Moreover, we unveiled that direct killing is higher than previously expected and absent in patients' samples at relapse. We also observed that these mAbs, prior to increasing intracellular calcium levels, decrease calcium entry, although manipulating calcium levels did not affect their cytotoxicity. Altogether, our results show that direct killing is a major mechanism to induce cell death by RTX and OBI mAbs.

Impact of Treatment with Anti-CD20 Monoclonal Antibody on the Production of Neutralizing Antibody Against Anti-SARS-CoV-2 Vaccination in Mature B-Cell Neoplasms.

Anti-CD20 monoclonal antibodies (MoAbs), rituximab (RIT), and obinutuzumab (OBZ) are the central components of immunochemotherapy for B-cell lymphoma (BCL). However, these agents potentially cause B-cell depletion, resulting in the impairment of antibody (Ab) production. During the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, the optimal prediction of Ab response against anti-SARS-CoV-2 vaccination is critically important in patients with BCL treated by B-cell depletion therapeutics to prevent coronavirus disease 2019 (COVID-19). We investigated the effect of using RIT and/or OBZ on the Ab response in 131 patients with various types of BCL who received the second SARS-CoV-2 mRNA vaccine either after, during, or before immunochemotherapy containing B-cell-depleting moiety between June and November 2021 at seven institutes belonging to the Kyoto Clinical Hematology Study Group. The SARS-Cov-2 neutralizing Ab (nAb) was measured from 14 to 207 days after the second vaccination dose using the iFlash3000 automatic analyzer and the iFlash-2019-nCoV Nab kit. Among 86 patients who received the vaccine within 12 months after B-cell depletion therapy, 8 (9.3%) were seropositive. In 30 patients who received the vaccine after 12 months from B-cell depletion therapy, 22 (73%) were seropositive. In 15 patients who were subjected to B-cell depletion therapy after vaccination, 2 (13%) were seropositive. The multivariate analysis indicated that an interval of 12 months between B-cell depletion therapy and the subsequent vaccination was significantly associated with effective Ab production. Receiver operating characteristic curve analysis identified the optimal threshold period after anti-CD20 MoAb treatment, which determines the seropositivity against SARS-CoV-2, to be 342 days. The use of anti-CD20 MoAb within 12 months before vaccination is a critical risk for poor Ab response against anti-SARS-CoV-2 vaccination in patients with BCL.

Four-year follow-up from a phase 2 study of obinutuzumab, ibrutinib, and venetoclax in CLL.

7540 Background: Targeted agent combinations for chronic lymphocytic leukemia (CLL) have resulted in safe regimens with improved progression-free survival (PFS) compared to chemoimmunotherapy. The optimal regimen and long-term outcomes remain unknown. We conducted a phase 2 study of obinutuzumab (OBIN), ibrutinib (IBR), and venetoclax (VEN) in relapsed/refractory (RR) and treatment-naïve (TN) CLL patients (pts) and report extended follow up on two previously reported cohorts (RR, TN 1) and a new cohort of identically treated TN pts (TN 2). Methods: Pts with TN or RR (≥1 prior treatment) CLL requiring treatment were eligible. Treatment was given for 14 28-day cycles (C). OBIN was started C1, IBR C2, and VEN C3 with standard dose escalation. Response was assessed 2 months (mos) after C14 (EOT) by iwCLL 2008 criteria. Minimal residual disease (MRD) was measured by 10-color flow cytometry with a cutoff of &lt; 1x10-4. The primary endpoint was complete remission (CR) with undetectable MRD (uMRD) in blood and bone marrow at EOT. A sample size of 25 pts per cohort achieves 90% power to test the null hypothesis of 10% against 30% with 1-sided α of 10%. The Kaplan-Meier method was used to estimate PFS and overall survival (OS). Results: 75 pts were treated in 3 cohorts (Table). Data are as of 1/3/2022. In the TN 2 cohort, the overall response rate (ORR) at EOT was 96% (95% CI: 80-100) and CR with uMRD was 20% (95% CI: 7-41). The ORR for TN 1 and TN 2 combined was 90% (95% CI: 78-97) and CR with uMRD was 24% (95% CI: 13-38). Median follow up was 56 (0-65), 57 (7-63), and 30 (24-35) mos, respectively, for RR, TN 1, and TN 2. There were 3 deaths (RR = 1, TN 1 = 1, TN 2 = 1) and 6 disease progressions (RR = 4, TN 1 = 2, TN 2 = 0). Estimated 48-month PFS for TN 1 and RR cohorts were both 96% (95% CI: 72-99) and OS was 85% (95% CI: 60-95) and 100%, respectively. The estimated 24-month PFS and OS for TN 2 were both 96% (95% CI: 75-99). The most frequent adverse events were neutropenia (95%, 73% grade ≥3), leukopenia (95%, 45% grade ≥3), lymphopenia (93%, 40% grade ≥3), and thrombocytopenia (91%, 28% grade ≥3). The only grade ≥3 non-hematologic toxicity occurring at ≥20% was hypertension (85%, 39% grade ≥3). Atrial fibrillation occurred in 11% of pts. Conclusions: At extended follow-up, remissions remain durable after fixed duration OBIN, IBR, and VEN. The efficacy and acceptable safety justify further study and are being compared to IBR and OBIN in 2 phase 3 US cooperative group trials. Clinical trial information: NCT02427451. [Table: see text]

Venetoclax, Obinutuzumab and Atezolizumab (PD-L1 Checkpoint Inhibitor) for Treatment for Patients with Richter Transformation

Venetoclax, Obinutuzumab and Atezolizumab (PD-L1 Checkpoint Inhibitor) for Treatment for Patients with Richter Transformation

Venetoclax, Obinutuzumab and Atezolizumab (PD-L1 Checkpoint Inhibitor) for First-Line Treatment for Patients with Chronic Lymphocytic Leukemia (CLL)

Venetoclax, Obinutuzumab and Atezolizumab (PD-L1 Checkpoint Inhibitor) for First-Line Treatment for Patients with Chronic Lymphocytic Leukemia (CLL)

Initial Results of the Phase 2 Treatment Naive Cohort in a Phase 1b/2 Study of Obinutuzumab, Ibrutinib, and Venetoclax in Chronic Lymphocytic Leukemia

BACKGROUNDVenetoclax (VEN), a once daily oral inhibitor of BCL2, achieves high response rates and acceptable toxicity in patients with relapsed or refractory (R/R) and treatment naïve (TN) CLL both as a single agent and in combination with anti-CD20 monoclonal antibodies such as obinutuzumab (OBIN), where minimal residual disease (MRD) negative responses have been observed in the majority of patients. Pre-clinical data suggest that concurrent treatment with the Bruton tyrosine kinase inhibitor ibrutinib (IBR) may further potentiate sensitivity to VEN. Given high individual response rates, largely non-overlapping toxicity, and distinct mechanisms of action, we initiated a phase 1b/2 study of combination OBIN, IBR, and VEN in CLL. A phase 1b study in R/R CLL patients established VEN 400mg daily as a safe dose for use in this combination. We report the initial results from the phase 2 cohort of TN patients.METHODSPatients with TN, symptomatic CLL meeting IWCLL 2008 guideline indications for therapy were eligible. Eligible patients had an ECOG PS ≤1 and preserved end-organ function, including creatinine clearance ≥50 mL/min/m2. Patients with chronic viral hepatitis infection, uncontrolled autoimmune cytopenia, and/or clinically apparent Richter's Transformation were excluded. Treatment was given at the doses and schedule established in the preceding phase 1b study (Jones ASH 2016). Treatment was planned for 14 cycles (C) of 28 days each with OBIN, IBR, and VEN started sequentially over the first 3 cycles. OBIN was started C1 (C1 D1: 100mg, C1 D2: 900mg, C1 D8,D15: 1,000mg, C2-8 D1: 1,000mg), IBR in C2 (C2-14 D1-28: 420mg), and VEN in C3 with dose escalation according to its US label (C3 20mg->50mg->100mg->200mg, C4-14 D1-28: 400mg). Risk for tumor lysis syndrome (TLS) with VEN was assessed according to US prescribing information. Adverse events (AEs) were assessed and graded using the NCI CTCAE v4.03 except hematologic AEs which were graded according to the IWCLL 2008 guidelines. Response was determined according to IWCLL 2008 criteria after cycles 8 and 14 with assessment for MRD in the bone marrow and peripheral blood by standard 4-color flow cytometry.RESULTSEnrollment was completed in November 2016 with 25 TN patients. The median age at enrollment was 59 (range 24-77) and 15 (60%) patients were men. Baseline risk characteristics included unmutated IGHV in 17 (71%) patients, complex karyotype in 6 (24%), FISH positive for del(17p) in 3 (12%), del(11q) in 5 (20%), del(13q) in 7 (28%), and tri(12) in 4 (16%). TLS risk was high for 7 (28%) and medium for 18 (72%) patients. In general, AEs were consistent with reports from the phase 1b study in R/R patients and the known safety profile of the individual agents. The most commonly experienced grade 1/2 treatment-related AEs were infusion reactions (76%), nausea (60%), and dyspepsia (52%). The most common grade 3/4 treatment-related AEs were neutropenia (44%), leukopenia (36%), thrombocytopenia (36%), lymphopenia (32%), and hypertension (20%). Hematologic toxicities were the most frequent high grade treatment-related AEs. There were no cases of neutropenic fever or TLS. Treatment-related AEs are in Table 1. To date 23 patients have reached the first (post-C8) response assessment with 1 patient leaving the study prior to C8 and 1 not yet reaching this time point. Of these 23 patients all had an objective response. The rate of complete remission (CR), including with incomplete marrow recovery (CRi), was 50% (12/24). MRD-negative status by flow cytometry in both blood and bone marrow was achieved in 14 (58%) patients; 3 CR, 5 CRi, 6 partial remission (PR). Responses at this early time point are summarized in Table 2. Twenty-two patients remain on study with 1 patient discontinuing treatment after C7 at the discretion of the treating physician, 1 patient after C10 electively, and 1 patient after C10 for the serious AEs of grade 3 colitis as well as grade 4 neutropenia which were both possibly related to study treatment.CONCLUSIONSOBIN, IBR, and VEN can be given safely without TLS and appears highly effective as initial therapy for CLL after response assessment at this initial (C8) time point. Objective responses, including MRD-negative complete responses, have been achieved in all patients to date and results for the primary endpoint of MRD (-) CR after C14 are expected in May 2018. Updated toxicity and response data will be presented for the 22 of 25 patients who remain on study. [Display omitted] DisclosuresMaddocks:Novartis: Research Funding; BMS: Research Funding; Pharmacylics: Research Funding; Merck: Research Funding.

Atezolizumab + obinutuzumab + venetoclax in patients with relapsed or refractory indolent non-Hodgkin’s lymphoma (R/R iNHL): Primary analysis of a phase 2 trial from LYSA.

7544 Background: R/R iNHL treatment remains challenging. Atezolizumab (ATE) and obinutuzumab (OBI) are monoclonal antibodies acting respectively to inhibit T-lymphocyte exhaustion or by inducing lymphoma cells cytotoxicity, whereas venetoclax (VEN) is a small molecule inhibiting BCL-2. Combining tumor-targeted therapies with agents that enhance anti-tumor immunity represents an attractive treatment paradigm. This LYSA sponsored multicenter phase 2 trial (NCT03276468) evaluated ATE, OBI and VEN combination in R/R B-cell lymphomas. Herein, we present primary efficacy and safety data from the iNHL cohort including Follicular Lymphoma (FL) and Marginal Zone Lymphomas (MZL). Methods: Patients ≥18 years with biopsy-confirmed R/R FL and MZL who failed at least one line of therapy were eligible. OBI was given IV at 1 g on day (D) 1, 8 and 15 of cycle (C) 1 and on D1 from C2 to C8 every 3 weeks. ATE was given IV, 1.2 g every 3 weeks, started at D2 of C1, then administered at D2 of each cycle for 24 cycles. VEN was given orally at 800 mg/D at full dose, starting on D8C1 for 24 cycles. The primary endpoint was the Overall Response Rate (ORR) evaluated by Lugano criteria at the end of induction (EOI) after 8 cycles of ATE, OBI and VEN (M6) or at premature treatment discontinuation. Results: At the time of the primary analysis (08 Jan 2021), 78 patients were enrolled. FL cohort (n = 58): the median follow-up was 14.5 months. Main baseline characteristics were: Ann Arbor Stage III/IV, 85.7%; FLIPI HR, 47.3%; &gt; 2 prior lines of therapy, 32.1%; and exposed to ASCT, 30.4%. The ORR on PET scan at EOI was measured at 53.6% [41.8%-65.1%], including 30.4% of CMR. 37 patients (63%) received the full induction treatment. MZL cohort (n = 20; 13 nMZL, 5 eMZL, 2 sMZL): the median follow-up was 11.9 months. Main baseline characteristics were: Ann Arbor Stage IV, 100%; bone marrow infiltration, 38.9%; ≥ 2 extra-nodal sites, 50%; and &gt; 2 prior lines of therapy, 22.2%. The ORR on CT scan at EOI was measured at 66.76% [44.6%-84.4%], including 16.7% of CR and 50.0% PR. 11 patients (55%) received the full induction treatment. At time of the present analysis, responses in the 2 cohorts seem durable with only 21,4% of responders who have reported relapse/progression. Out of the 78 pts, a total of 55 (70.5%) pts experienced grade 3–4 adverse event (AE) and 1 patient experienced an AE that led to discontinuation of any drug. Main AE of grade 3 or more were hematologic cytopenias, with only one febrile neutropenia (1.3%). Three pts experienced immune-related AE (1 grade 2 myositis and 2 grade 3 colitis), no tumor lysis syndrome was observed. Conclusions: ATE, OBI and VEN triplet appears to be well tolerated, with no unexpected toxicity brought by the combination. The ORR at EOI seems to be comparable to other innovative regiments in this setting, with durable responses to date. Clinical trial information: NCT03276468.

Obinutuzumab in Kidney Transplantation: Effect on B-cell Counts and Crossmatch Tests.

Resistance to the action of rituximab (RTX) has been documented in several diseases. More recently, obinutuzumab (OBZ) has shown promise where RTX has failed in oncology and lupus nephritis. Unlike RTX, OBZ is a weak activator of complement, which may avoid the false-positive complement-dependent cytotoxicity (CDC) crossmatch tests after RTX infusions. The aim of this study was to explore the effect of OBZ on B-cell depletion in kidney-transplant candidates and its impact on crossmatch test results. We included 12 patients, who were either highly sensitized kidney-transplant candidates or kidney-transplant recipients presenting with antibody-mediated rejection. Six received OBZ, and 6 received RTX. CD-19 counts, flow cytometry, and CDC crossmatch tests were run immediately before and at 2 wk after drug infusion. OBZ reduced CD-19 counts: median reduction was 98%. B-cell CDC crossmatch test results became positive following RTX infusion but were not affected by OBZ infusion. OBZ effectively depleted B-cell counts in sensitized kidney-transplant candidates and, unlike RTX, had no effect on CDC crossmatch results.

Obinutuzumab for Desensitization: An Unexpected Benefit?

Obinutuzumab for Desensitization: An Unexpected Benefit?

Immune checkpoint markers and anti-CD20-mediated NK cell activation.

Anti-CD20 mAb is an effective therapy for most B-cell malignancies. Checkpoint blockade has been used to enhance T-cell-mediated antitumor response. Little is known about the biologic significance of immune checkpoints expressed by NK cells in anti-CD20-based therapy. To investigate the role of checkpoints in anti-CD20-mediated NK cell biology, Raji B-cell lymphoma cells, and PBMCs from normal donors were cocultured with rituximab (RTX), obinutuzumab (OBZ), or trastuzumab as a control mAb for between 20h and 9 d. RTX and OBZ induced a dose-dependent NK cell up-regulation of T-cell immunoreceptor with Ig and ITIM domain (TIGIT) and T-cell immunoglobulin mucin-3 (TIM3), but not PD1, CTLA4, or LAG3. Resting CD56dim NK had higher TIGIT and TIM3 expression than resting CD56bright NK although TIGIT and TIM3 were up-regulated on both subsets. NK cells with the CD16 158VV single nucleotide polymorphism had greater TIM3 up-regulation than did NK from VF or FF donors. TIGIT+ and TIM3+ NK cells degranulated, produced cytokines, and expressed activation markers to a greater degree than did TIGIT- or TIM3- NK cells. Blockade of TIGIT, TIM3, or both had little impact on RTX-induced NK cell proliferation, degranulation, cytokine production, or activation. Taken together, TIGIT and TIM3 can serve as markers for anti-CD20-mediated NK cell activation, but may not serve well as targets for enhancing the anti-tumor activity of such therapy.

Obinutuzumab-Retreatment in Combination with Bendamustine Is Effective for Obinutuzumab Resistant Models in Vitro and In Vivo

Background: Follicular lymphoma (FL) commonly recurs and is difficult to cure. Obinutuzumab (OBI) is a humanized type II anti-CD20 antibody. It's mode of action is mainly characterized by the induction of direct cell death and it shows stronger antibody-dependent cellular cytotoxicity (ADCC) than rituximab. While OBI is indicated for previously untreated or relapsed/refractory (r/r) FL, there is no evidence on the efficacy of retreatment with OBI in r/r FL after prior OBI-containing therapy. To demonstrate the effectiveness of OBI-retreatment in a non-clinical study, we established in vitro and in vivo OBI resistant models, consisting of human non-Hodgkin lymphoma (NHL) cells resistant to OBI-induced ADCC and OBI-resistant tumors established from NHL cells under xenotransplantation conditions, and investigated the combination efficacy of OBI and bendamustine (Benda) in these OBI-resistant models. Methods: OBI-induced ADCC resistant clones were established from an RL cell line by inducing ADCC three times with CD16-transfected NK-92 cells. The in vivo resistant model was established from a SU-DHL-4 xenograft model through repeated treatment with OBI and re-inoculation of the regrown tumors. CD20 expression was assessed by flow cytometry or immunohistochemistry (IHC). ADCC activity was evaluated using calcein-AM with CD16-transfected NK-92 cells. To examine antitumor activity, OBI, human immunoglobulin G (HuIgG), Benda, or vehicle were intravenously administered on Day 1, 8 and 15 (OBI and HuIgG) or Day 1 and 2 (Benda and vehicle), and tumor volume was measured. Intratumorally infiltrated NK cells were assessed by IHC of CD335. Cell surface CD107a expression was assessed by flow cytometry. Results: OBI-induced ADCC resistant clones derived from RL (RL-OR-8 and RL-OR-22) showed a reduction in ADCC sensitivity compared with RL. These resistant clones exhibited CD20 expression similar to RL. Pretreatment of the effector NK cells with Benda enhanced ADCC induction of OBI in RL-OR-8 and RL-OR-22. Treatment with OBI (30 mg/kg) in combination with Benda (13.3 mg/kg) also significantly increased antitumor activity compared with each single agent alone on Day 18 (when tumor volume reached euthanasia criteria (*) in control and OBI monotherapy groups) in the RL-OR-22 xenograft model (Table 1). An in vivo OBI resistant model derived from SU-DHL-4 xenografts (SU-DHL-4-OR-18-8) was also established. While SU-DHL-4 xenografted tumors disappeared in 6/6 mice after the third OBI treatment (6 mg/kg), SU-DHL-4-OR-18-8 tumors did not regress in 6/6 mice. CD20 expression in SU-DHL-4-OR-18-8 tumors did not decrease compared with SU-DHL-4 tumors. The ratio of CD335-positive cells to tumor cells after 6 mg/kg of OBI treatment (Day 4) in SU-DHL-4-OR-18-8 was significantly decreased compared with the ratio in SU-DHL-4 (0.31 ± 0.12% vs 0.93 ± 0.23%). The combination efficacy of OBI and Benda was also assessed in an SU-DHL-4-OR-18-8 xenograft model. OBI (6 mg/kg) in combination with Benda (25 mg/kg) significantly increased the antitumor activity compared with each single agent alone on Day 22 (*in control group) and 29 (Table 1). Finally, the expression of CD107a, an NK cell-degranulation marker, was detected to examine the effect of Benda on NK activity in vitro. Pretreating effector NK cells with Benda upregulated CD107a expression on NK cell surfaces after OBI treatment in RL-OR-8 and RL-OR-22. Conclusions: The decreased CD335-positive cell ratio observed in the in vivo SU-DHL-4-OR-18-8 resistant model suggests that the mechanism of resistance to OBI also involves the attenuation of ADCC as in the in vitro OBI-induced ADCC resistant clones. The combination treatment of OBI and Benda was effective in both RL-OR-22 and SU-DHL-4-OR-18-8 xenograft models. It is possible that activation of NK cells by Benda might be involved in this combination mechanism. Although the mechanisms need to be examined in more detail, these results indicate the possible effectiveness of OBI-retreatment after prior OBI-containing therapy. Disclosures Yamashita-Kashima: Nippon Shinyaku Co., Ltd.: Research Funding; Chugai Pharmaceutical Co., Ltd.: Current Employment. Kawasaki:Chugai Pharmaceutical Co., Ltd.: Current Employment; Nippon Shinyaku Co., Ltd.: Research Funding. Yorozu:Chugai Pharmaceutical Co., Ltd.: Current Employment; Nippon Shinyaku Co., Ltd.: Research Funding. Yoshiura:Chugai Pharmaceutical Co., Ltd.: Current Employment; Nippon Shinyaku Co., Ltd.: Research Funding. Fujimura:Chugai Pharmaceutical Co., Ltd.: Current Employment; Nippon Shinyaku Co., Ltd.: Research Funding. Kurasawa:Chugai Pharmaceutical Co., Ltd.: Current Employment; Nippon Shinyaku Co., Ltd.: Research Funding. Harada:Chugai Pharmaceutical Co., Ltd.: Current Employment; Nippon Shinyaku Co., Ltd.: Research Funding. Yoshimura:Nippon Shinyaku Co., Ltd.: Research Funding; Chugai Pharmaceutical Co., Ltd.: Current Employment.

Ibrutinib and Obinutuzumab in CLL: MRD Responses Sustained for Several Years with Deepest MRD Depletion in Patients with >1 Year Prior Ibrutinib Exposure

Ibrutinib and Obinutuzumab in CLL: MRD Responses Sustained for Several Years with Deepest MRD Depletion in Patients with >1 Year Prior Ibrutinib Exposure

Three-Year Follow-up from a Phase 2 Study of Combination Obinutuzumab, Ibrutinib, and Venetoclax in Chronic Lymphocytic Leukemia

Three-Year Follow-up from a Phase 2 Study of Combination Obinutuzumab, Ibrutinib, and Venetoclax in Chronic Lymphocytic Leukemia

Impact of Treatment Sequencing on Outcomes and Costs in Relapsed Follicular or Other Low Grade B-Cell Non-Hodgkin Lymphoma - Results of an Evidence-Based Budget Impact Model

Introduction: The choice of initial therapy in follicular lymphoma can be a key determinant in future therapy, as irreversible toxicities with first line regimens can impact the patient's ability to tolerate future treatment. Minimizing drug exposure will result in less frequent occurrence of significant adverse events and associated treatment costs. In the era of COVID-19 pandemic, there is additional benefit to minimizing the number of patient visits and hospital admissions. Limited information exists related to the outcomes and associated costs of existing treatment sequences. Additionally, treatment administration at different types of clinical sites results in varied reimbursement models, making informed evaluation of clinical and financial evidence challenging. Methods: The current study applies a budget impact model methodology in order to describe the associated impact of treatment selection and sequencing on outcomes and costs in the treatment of relapsed or refractory low-grade follicular lymphoma in first line therapy followed by Consolidation and also in first line therapy to second line therapy. Key model inputs included: Number of treatment cycles, number of days a treatment was received, duration of response (DOR), rate of side effects and associated costs, and total treatment costs, including drugs, medical treatment, laboratory testing and adverse event costs. Treatment outcomes were based on the published literature that summarized the overall response rate, median DOR, and toxicity. Treatment regimen costs were evaluated based on payer pricing, Wholesale Acquisition Cost (WAC), Average Selling Price (ASP) and Average Wholesale Price (AWP) and modified to adjust for weight-based dosing and negotiate payer reimbursement rates. Associated medical costs for medical treatment and supportive care were estimated using current Medicare fee schedule rates. Included were seven options for first line therapy of follicular lymphoma from 2020 NCCN Guidelines - (Bendamustine + rituximab (BR); Bendamustine + Obinutuzumab (OB); CHOP rituximab (RCHOP); CHOP + Obinutuzumab (OCHOP); CVP+ rituximab (RCVP); CVP + Obinutuzumab (OCVP); Lenalidomide + rituximab (R2)), followed by three for Consolidation (Rituximab maintenance (RM); Obinutuzumab maintenance (O); Radioimmunotherapy (RIT with 90 Y-ibritumomab tiuxetan (Y90-IT, Zevalin)) and three Second Line therapy options (RIT; Lenalidomide only; Lenalidomide + Obinutuzumab (LO)). Results: The treatment sequence of first line BR followed by Consolidation with RIT Y90 (Zevalin) had the longest predicted DOR (2586 days). The associated treatment sequence costs were $212,485 for BR followed by Y90-IT, compared with $233, 388 for BR followed by rituximab maintenance, which had a predicted DOR of 2478 days. The predicted DOR for treatment sequences starting with OCHOP, OCVP and RCHOP and followed by RIT with Y90-IT was approximately 1000 days less than BR followed by Y90-IT for a cost difference of $4,421, $12,914 and $25,826, respectively. The treatment sequence of first line BR followed by Second Line RIT Y90-IT had the second longest predicted DOR of 2586 days at costs of $212,485, compared to 2778 days for BR followed by LO, at a total sequence costs of $796,695. Conclusion: The use of Y90-IT in Consolidation or Second Line treatment demonstrated desired patient outcomes at one of the lowest cost profiles. Additionally, Y90-IT administration can be completed in only two clinic visits, reducing patient travel and contact, improving safety in an era of COVID-19 precautionary measures and reducing cost. Figure 1. Duration of Response and Total Sequence Costs for Twelve First Line to Consolidation and First Line to Second Line Treatment Regimens. Disclosures McBride: Merck: Speakers Bureau; Coherus BioSciences: Consultancy, Speakers Bureau; Pfizer: Consultancy; Bristol-Myers Squibb: Consultancy; MorphoSys: Consultancy; Sandoz: Consultancy.

Obinutuzumab-Induced B Cell Depletion Reduces Spinal Cord Pathology in a CD20 Double Transgenic Mouse Model of Multiple Sclerosis.

B cell-depleting therapies have recently proven to be clinically highly successful in the treatment of multiple sclerosis (MS). This study aimed to determine the effects of the novel type II anti-human CD20 (huCD20) monoclonal antibody (mAb) obinutuzumab (OBZ) on spinal cord degeneration in a B cell-dependent mouse model of MS. Double transgenic huCD20xHIGR3 (CD20dbtg) mice, which express human CD20, were immunised with the myelin fusion protein MP4 to induce experimental autoimmune encephalomyelitis (EAE). Both light and electron microscopy were used to assess myelination and axonal pathology in mice treated with OBZ during chronic EAE. Furthermore, the effects of the already established murine anti-CD20 antibody 18B12 were assessed in C57BL/6 wild-type (wt) mice. In both models (18B12/wt and OBZ/CD20dbtg) anti-CD20 treatment significantly diminished the extent of spinal cord pathology. While 18B12 treatment mainly reduced the extent of axonal pathology, a significant decrease in demyelination and increase in remyelination were additionally observed in OBZ-treated mice. Hence, the data suggest that OBZ could have neuroprotective effects on the CNS, setting the drug apart from the currently available type I anti-CD20 antibodies.

Analytical comparability study of anti-CD20 monoclonal antibodies rituximab and obinutuzumab using a stability-indicating orthogonal testing protocol: Effect of structural optimization and glycoengineering

Glycoengineering and biosimilarity are the key factors for growing, promising and progressive approaches in monoclonal antibodies development. In this study, the physicochemical stability of anti-CD20 rituximab (RTX); originator and biosimilar was compared to its glycoengineered humanized version; obinutuzumab (OBZ). An orthogonal stability-indicating protocol using a set of validated bioanalytical techniques; size exclusion high performance liquid chromatography (SE-HPLC), reversed phase liquid chromatography (RP-HPLC), quantitative gel electrophoresis by TapeStation, receptor binding assay and dynamic light scattering (DLS) was used to investigate the effect of different stress factors on the pattern and kinetics of degradation. SE-HPLC results supported with spectral purity showed similar degradation extent with a different pattern of degradation between RTX and OBZ. A lower tendency to form degraded fragments and a relatively higher favorability for degradation through aggregate formation has been revealed in case of OBZ. Results were in agreement with those of DLS and receptor binding assay which showed specificity to the intact antibodies in the presence of their degradation products. Furthermore, results were additionally confirmed through denaturing quantitative gel electrophoresis which suggested reducible covalent bonds as the mechanism for aggregates formation. RP-HPLC results showed two oxidized forms via excessive oxidation of RTX and OBZ with nearly the same degradation percent. Comparability data of RTX and OBZ using the applied methodologies showed that although glycoengineering; carried out to enhance the therapeutic and biological activity of OBZ altered the pattern of degradation but did not significantly affect the overall stability. Results showed also consistent stability profile between the biosimilar and its originator RTX products.