Efficacy Of Obinutuzumab Research Articles

Single-nucleotide Fcγ receptor polymorphisms do not impact obinutuzumab/rituximab outcome in patients with lymphoma

AbstractSingle-nucleotide polymorphisms (SNPs) have been shown to influence Fcγ receptor (FcγR) affinity and activity, but their effect on treatment response is unclear. We assessed their importance in the efficacy of obinutuzumab or rituximab combined with chemotherapy in untreated advanced follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL) in the GALLIUM (www.clinicaltrials.gov #NCT01332968) and GOYA (#NCT01287741) trials, respectively. Genomic DNA was extracted from patients enrolled in GALLIUM (n = 1202) and GOYA (n = 1418). Key germline SNPs, FCGR2A R131H (rs1801274), FCGR3A F158V (rs396991), and FCGR2B I232T (rs1050501), were genotyped and assessed for their impact on investigator-assessed progression-free survival (PFS). In both cohorts there was no prognostic effect of FCGR2A or FCGR3A. In FL, FCGR2B was associated with favorable PFS in univariate and multivariate analyses comparing I232T with I232I, with a more modest association for rituximab-treated (univariate: hazard ratio [HR], 0.78; 95% confidence interval [CI], 0.54-1.14; P = .21) vs obinutuzumab-treated patients (HR, 0.56; 95% CI, 0.34-0.91; P = .02). Comparing T232T with I232I, an association was found for obinutuzumab (univariate: HR, 2.76; 95% CI, 1.02-7.5; P = .0459). Neither observation retained significance after multiple-test adjustment. FCGR2B was associated with poorer PFS in multivariate analyses comparing T232T with I232I in rituximab- but not obinutuzumab-treated patients with DLBCL (HR, 4.40; 95% CI, 1.71-11.32; P = .002; multiple-test–adjusted P = .03); however, this genotype was rare (n = 13). This study shows that FcγR genotype is not associated with response to rituximab/obinutuzumab plus chemotherapy in treatment-naive patients with advanced FL or DLBCL.

Safety and efficacy of obinutuzumab alone or with chemotherapy in previously untreated or relapsed/refractory chronic lymphocytic leukaemia patients: Final analysis of the Phase IIIb GREEN study

The manageable toxicity profile of obinutuzumab (GA101; G) alone or with chemotherapy in first-line (1L; fit and non-fit) and relapsed/refractory (R/R) patients with chronic lymphocytic leukaemia (CLL) was established in the primary analysis of the Phase IIIb GREEN trial (Clinicaltrials.gov: NCT01905943). The final analysis (cut-off, 31 January 2019) is reported here. Patients received G (1000mg) alone (G-mono; fit and non-fit patients) or with chemotherapy [fludarabine and cyclophosphamide (FC; fit patients); chlorambucil (non-fit patients); bendamustine (any patient)]. Study endpoints were safety (primary) and efficacy (secondary). Subgroup analyses were performed on prognostic biomarkers in 1L CLL. Overall, 630 patients received 1L and 341 received R/R CLL treatment. At the final analysis, no new safety signals were observed [Grade≥3 adverse events (AEs): 1L 82·7%, R/R 84·5%; serious AEs: 1L 58·1%, R/R 62·5%]. Neutropenia (1L 50·5%, R/R 53·4%) and thrombocytopenia (1L 14·6%, R/R 19·1%) were the most common Grade 3-5 AEs. G-mono-, G-bendamustine and G-FC-treated patients with unmutated immunoglobulin heavy chain trended towards shorter progression-free survival. Achievement of minimal residual disease negativity was greatest in 1L patients treated with G-FC. In this final analysis of the GREEN trial, the safety profile of G was consistent with current risk management strategies. Biomarker analyses supported efficacy in the specific subgroups.

The role of obinutuzumab in the management of follicular lymphoma.

The outcomes for follicular lymphoma (FL) have improved significantly in recent years. This has been driven by an improved understanding of the pathobiology of FL and the development of therapeutic anti-CD20 antibodies. Combining rituximab with chemotherapy, coupled with its use as maintenance therapy, has contributed to significant improvements in disease control and progression-free survival. However, FL remains incurable and almost all patients invariably relapse. Therefore, there remains a need to develop novel therapeutic options and optimize existing regimens. Obinutuzumab (a first-in-class, glycoengineered, humanized type 2 anti-CD20 antibody) has been evaluated in a number of clinical trials. In this review, we will summarize the evaluable results of clinical trials investigating the efficacy of obinutuzumab in the treatment of FL.

Obinutuzumab plus fludarabine and cyclophosphamide in previously untreated, fit patients with chronic lymphocytic leukemia: a subgroup analysis of the GREEN study

GREEN (NCT01905943) is a nonrandomized, open-label, single-arm, phase 3b study investigating the safety and efficacy of obinutuzumab alone or in combination with chemotherapy in chronic lymphocytic leukemia (CLL). We report the preplanned subgroup analysis of 140 previously untreated, fit CLL patients who received obinutuzumab plus fludarabine and cyclophosphamide (G-FC). The primary endpoint was safety and tolerability. Efficacy was the secondary endpoint. Obinutuzumab 1000 mg was administered intravenously on Day (D)1 (dose split D1‒2), D8 and D15 of Cycle (C)1, and D1 of C2–6 (28-day cycles). Standard intravenous/oral doses of fludarabine and cyclophosphamide were administered on D1–3 of C1–6. Overall, 87.1% of patients experienced grade ≥ 3 adverse events (AEs), including neutropenia (67.1%) and thrombocytopenia (17.1%). Serious AEs were experienced by 42.1% of patients. Rates of grade ≥ 3 infusion-related reactions and infections were 19.3% and 15.7%, respectively. Overall response rate was observed in 90.0%, with 46.4% of patients achieving complete response (CR; including CR with incomplete marrow recovery). Minimal residual disease negativity rates were 64.3% in peripheral blood and 35.7% in bone marrow (intent-to-treat analysis). After a median observation time of 25.6 months, 2 year progression-free survival was 91%. Frontline G-FC represents a promising treatment option for fit patients with CLL.

Obinutuzumab plus CHOP is effective and has a tolerable safety profile in previously untreated, advanced diffuse large B-cell lymphoma: the phase II GATHER study

This study investigated the safety and efficacy of obinutuzumab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (G-CHOP) in patients with advanced diffuse large B-cell lymphoma (DLBCL) and explored the impact of cell-of-origin (COO) on patient outcomes. Patients (N = 100) received obinutuzumab (1000 mg on the days 1, 8, and 15 of cycle 1, and day 1 of cycles 2–8) plus CHOP (cycles 1–6). For patients without grade ≥3 infusion-related reactions (IRRs) to standard-rate obinutuzumab infusion, a shorter duration of infusion (SDI) was evaluated. Overall and complete response rates, as determined according to the Cheson et al. criteria by investigators/independent radiological facility, were 82.0/75.0% and 55.0/58.0%, respectively. SDI of 120 minutes and 90 minutes were well tolerated with no grade ≥3 IRRs. Among all patients, IRRs typically occurred during cycle 1, day 1. G-CHOP is active and has an acceptable safety profile in the first-line treatment of patients with advanced DLBCL.Clinical Trials: NCT01414855DLBCL

Safety and efficacy of obinutuzumab with CHOP or bendamustine in previously untreated follicular lymphoma.

The GAUDI study assessed safety and preliminary efficacy of induction therapy with obinutuzumab plus chemotherapy, followed by maintenance therapy with obinutuzumab alone, in previously untreated patients with follicular lymphoma. Assignment to chemotherapy was decided on a per-center basis before the patients’ enrollment. Patients (n=81) received four to six cycles of obinutuzumab plus bendamustine every 4 weeks or six to eight cycles of obinutuzumab plus CHOP every 3 weeks. Patients with an end-of-treatment response were eligible for obinutuzumab maintenance therapy every 3 months for 2 years or until disease progression. Induction treatment was completed by 90% of patients in the obinutuzumab plus bendamustine group and 95% in the obinutuzumab plus CHOP group, while maintenance was completed by 81% and 72% of patients, respectively. All patients experienced at least one adverse event during induction, most commonly infusion-related reactions (58%), the majority of which were grade 1/2. The most common hematologic adverse event was grade 3/4 neutropenia (36% during induction and 7% during maintenance). One treatment-related death occurred during the maintenance phase. At the end of induction, 94% of patients had achieved an overall response, with complete response based on computed tomography in 36%. The progression-free survival rate at 36 months was 90% in the obinutuzumab plus bendamustine group and 84% in the obinutuzumab plus CHOP group. These results demonstrate that induction therapy with obinutuzumab plus bendamustine or obinutuzumab plus CHOP, followed by obinutuzumab maintenance, is associated with tolerable safety and promising efficacy. This study is registered at ClinicalTrials.gov as NCT00825149.

A TLR7 agonist enhances the antitumor efficacy of obinutuzumab in murine lymphoma models via NK cells and CD4 T cells

Anti-CD20 monoclonal antibodies (mAb) such as rituximab have been proven to be highly effective at improving outcome in B-cell malignancies. However, many patients ultimately relapse and become refractory to treatment. The glycoengineered anti-CD20 mAb obinutuzumab was developed to induce enhanced antibody-dependent cellular cytotoxicity, antibody-dependent phagocytosis and direct cell death and was shown to lead to improved outcomes in a randomized study in B-CLL. We hypothesized that immune stimulation through Toll-like receptor 7 (TLR7) agonism in combination with obinutuzumab would further enhance lymphoma clearance and the generation of long-term antitumor immune responses. Here we demonstrate, in syngeneic human CD20 (hCD20)-expressing models of lymphoma, that systemic administration of a TLR7 agonist (R848) increases responses when administered in combination with obinutuzumab and protects against disease recurrence. Depletion studies demonstrate that primary antitumor activity is dependent on both NK cells and CD4+ T cells but not on CD8+ T cells. However, both CD4+ and CD8+ T cells appear necessary for the generation of protective immunological memory. Importantly, increased tumor-free survival post obinutuzumab and R848 combination therapy was seen in hCD20 transgenic mice, which express hCD20 on normal B cells. These findings provide a rationale for clinical testing of obinutuzumab in combination with systemically administered TLR7 agonists to further improve outcome.

Abstract 2460: Dissecting the in vitro and in vivo mechanism of action of obinutuzumab (GA101) in preclinical models using an immune effector-dead version of obinutuzumab

Abstract Introduction: Obinutuzumab (GA101) is a glycoengineered type II CD20 antibody mediating superior direct cell death induction, ADCC and ADCP compared to rituximab while CDC is strongly reduced. Obinutuzumab is approved for 1st line treatment of CLL in combination with chlorambucil in the US and Europe. The contribution of these mechanisms of action (MOA) to the efficacy of obinutuzumab in patients is unclear. In order to further dissect the MOA GA101 and rituximab and variants with abolished FcγR and C1q binding were assessed in vitro and in vivo. Methods: Glycoengineered GA101, non-glycoengineered wild type (wt) GA101, effector-dead GA101 and rituximab with P329G LALA mutations in the Fc were generated and characterized i) for binding to FcγRs and CD20 positive cells by FACS, ii) for cell death induction by AnnexinV/PI staining, iii) in ADCC, ADCP and CDC assays, and iv) for depletion of CD19 positive B cells in whole blood from healthy volunteers. Anti-tumoral efficacy was assessed using established 300 mm2 s.c. SU-DHL4 xenograft tumors in Scid beige mice (30 mg/kg, q7d x 4, ip). Results: Variants of GA101 and rituximab retain CD20 binding and cell death inducing properties of the respective parental antibody. The introduction of P329G LALA in the Fc part abolishes binding to Fcγ receptors and C1q, so that they do not mediate ADCC, ADCP or CDC any longer, while direct cell death induction is not affected as compared to GA101 and rituximab, respectively. In whole blood assays GA101 showed the best B cell depletion in terms of potency and absolute B cell depletion followed by wtGA101 and rituximab. Notably, GA101 P329G LALA retained significant B cell depletion, while rituximab P329G LALA did not mediate B cell depletion. Thus, in whole blood B cell depletion, ADCC/ADCP plays an important role, but direct cell death induction is equally important for the MOA of GA101, whereas it does not contribute to B cell depletion of rituximab. In the SU-DHL4 xenograft model GA101 (TGI > 100%, non-parametric TCR (npTCR) 0 with 95% CI 0-0) and wtGA101 (TGI > 100%, npTCR 0, 95% CI 0-0.006) showed equivalent efficacy with complete tumor remission in 9/10 mice for GA101 and 8/10 mice for wtGA101. GA101 P329G LALA showed anti-tumoral efficacy (TGI 62%, npTCR 0.43, 95% CI 0.30-0.60) comparable to rituximab (TGI 71%, npTCR 0.37, 95% CI 0.29-0.50), while rituximab P329G LALA showed only residual anti-tumoral activity (TGI 26%, npTCR 0.73, 95% CI 0.44-0.92). Summary: These data indicate that in whole blood B cell depletion and xenograft models, direct cell death and ADCC/ADCP through the glycoengineered Fc part are required for anti-tumoral efficacy of obinutuzumab. Most notably, the effector dead version of obinutuzumab that completely lacks ADCC, ADCP and CDC activity, but has retained direct cell death induction, is as efficacious as rituximab in vivo supporting the role of direct effects for the efficacy of obinutuzumab. Citation Format: Sylvia Herter, Frank Herting, Gunter Muth, Erwin van Puijenbroek, Claudia Ferrara, Sabine Lang, Marina Bacac, Ekkehard Moessner, Pablo Umana, Christian Klein. Dissecting the in vitro and in vivo mechanism of action of obinutuzumab (GA101) in preclinical models using an immune effector-dead version of obinutuzumab. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2460. doi:10.1158/1538-7445.AM2015-2460

Obinutuzumab (GA101) Is Less Prone to Antagonism of Immune Effector Function By Ibrutinib Than Rituximab in Vitro and in Vivo

Abstract Introduction: Kohrt et al., Blood, 2014 demonstrated that ibrutinib antagonizes ADCC function of rituximab in vitro in ADCC assays and in vivo in the DHL-4 xenograft model through inhibition of FcgammaR signaling in immune effector cells, possibly mediated by inhibition of ITK. Obinutuzumab (GA101) is a glycoengineered type II CD20 antibody that mediates higher direct cell death induction than rituximab, and by being glycoengineered mediates enhanced induction of ADCC and ADCP. Here we aimed to investigate the impact of ibrutinib on the immune effector function of obinutuzumab as compared to rituximab. Experimental methods: The impact of ibrutinib (dose range 30, 100, 300 ng/ml to cover Cmax and Ctrough in patients) on NK cell mediated ADCC induction by obinutuzumab and rituximab was investigated using SU-DHL4 and Z138 cells as targets in LDH and chromium release assays or measuring CD16 downmodulation and the degranulation marker CD107a. IFNg release as a surrogate for NK cell activation was investigated using DHL-4 target cells or an autologous in vitro system using leukemic cells derived from CLL/NHL patients. Depletion of CD19 positive B-cells was determined in whole blood from healthy volunteers in flow cytometry-based whole blood assay. In vivo the combination of obinutuzumab or rituximab (10 mg/kg once weekly for 3 weeks) with ibrutinib (25mg/kg BID days 14-28) was investigated in the DHL-4 xenograft model. Results: In ADCC assays, ibrutinib (dose range 30, 100, 300 ng/ml) resulted in a reduction of the ADCC potency of obinutuzumab and rituximab. However, at saturating antibody concentrations of 10 ug/ml, ADCC mediated by obinutuzumab was retained while ADCC mediated by rituximab was strongly reduced as measured by chromium release (Figure 1A). Interestingly, in the whole blood B cell depletion assay only little impact of ibrutinib on obinutuzumab-mediated B cell depletion in terms of EC50 and maximal killing was observed at clinically meaningful concentrations of ibrutinib (30, 100, 300 ng/ml), while the activity of rituximab could be completely abolished with 300 ng/ml ibrutinib (Figure 1B). Notably, control experiments using an effector dead version of obinutuzmab that cannot any longer mediate ADCC or ADCP demonstrate that the retained B cell depletion by obinutuzumab in presence of ibrutinib is not due to direct cell death induction, but also due to immune effector cell mediated function (ADCC and ADCP). In the DHL-4 xenograft model where ibrutinib as a single agent has no anti-tumoral efficacy, the combination resulted in a reduced anti-tumoral efficacy of rituximab, whereas efficacy of obinutuzumab was not affected (Figure 1C). Conclusions: Surprisingly, we found that the inhibitory effect of ibrutinib on the immune effector mediated activity of obinutuzumab is not observed when compared to rituximab. Most notably, ADCC at saturating antibody doses, whole blood B cell depletion and in vivo efficacy of obinutuzumab were retained in presence of clinically relevant concentrations of ibrutinib covering Cmax and Ctrough levels, whereas the activity of rituximab was almost completely abolished under these conditions. We hypothesize that the differential behavior of obinutuzumab and rituximab may be related to the enhanced FcgRIII affinity and stronger FcgRIII signaling activation mediated by obinutuzumab as a consequence of glycoengineering that may subsequently overwrite inhibitory effects of ibrutinib. While the clinical relevance of the observed preclinical antagonism for the combination of rituximab with ibrutinib still needs further clinical investigation, these preclinical data strongly support the clinical investigation of ibrutinib in combination with the glycoengineered Type II CD20 antibody obinutuzumab for the treatment of chronic lymphocytic leukemia and other B-cell malignancies. Figure 1 Figure 1. Disclosures Herter: Roche: Employment. Bacac:Roche: Employment. Umana:Roche: Employment. Klein:Roche: Employment, Equity Ownership, Patents & Royalties.

Preliminary Safety Results from the Phase IIIb GREEN Study of Obinutuzumab (GA101) Alone or in Combination with Chemotherapy for Previously Untreated or Relapsed/Refractory Chronic Lymphocytic Leukemia (CLL)

Background: The novel, glycoengineered type II anti-CD20 monoclonal antibody, obinutuzumab (GA101) has demonstrated superior efficacy to chlorambucil (Clb) monotherapy and to Clb in combination with rituximab (R-Clb) with an acceptable safety profile in CLL. However, an increased rate of infusion-related reactions (IRRs) has been observed with the obinutuzumab(G)-Clb combination compared with R-Clb during the first cycle of treatment. The GREEN study (NCT01905943) is an ongoing phase IIIb, multicenter, open-label trial investigating the safety and efficacy of obinutuzumab alone or in combination with chemotherapy in patients with previously untreated or relapsed/refractory CLL. We report safety data from cohort 1, which aimed to reduce IRRs on the first day of obinutuzumab administration in previously untreated patients using a lower dose and slower infusion rate than in previous studies.Methods: Subjects aged ≥18 years withdocumented CLL, an Eastern Cooperative Oncology Group (ECOG) performance status of 0–2 and adequate hematologic function are enrolled. Treatment includes obinutuzumab (1000mg) administered intravenously on days (D) 1 (25mg) and 2 (975mg), D8, and D15 of cycle (C) 1, and on D1 of C2–6, alone (any patient: n=18) or in combination with 28-day cycles of chemotherapy: fludarabine plus cyclophosphamide (FC; n=46) for fit patients (cumulative illness rating scale [CIRS] ≤6 and creatinine clearance [CrCl] ≥70mL/min), Clb (n=8) for unfit patients (CIRS >6 and/or CrCl <70mL/min) or bendamustine (B; n=86) for fit/unfit patients. The primary outcome is safety, including the frequency, type and severity of adverse events (AEs). The present analysis focuses on IRRs, defined as treatment-related AEs occurring during or within 24 hours of infusion. Results were assessed to determine if a low obinutuzumab dose (25mg) and slow infusion rate (12.5mg/hour) on D1 (the current recommended C1D1 regimen is 100mg at 25mg/hour) could reduce IRRs. Analysis was based on a data cut-off of 28 April 2014, planned for when the first 150 previously untreated patients had completed cohort 1.Results: Of 158 subjects eligible for the IRR analysis (Table), median age was 65.0 (34.0–83.0) years and the majority were males (65.2%) with Binet stage B (52.5%) or C (31.0%) CLL. Median observation time was 2.09 (0.2–6.0) months and median exposure time was 1.0 (0.0–4.8) month. IRRs occurring in ≥10% of patients were chills (14.6%) and pyrexia (15.2%). Serious IRRs in ≥1% of patients were tumor lysis syndrome (TLS; 3.8%) and pyrexia (1.3%). Grade ≥3 IRRs experienced by ≥1% of patients were TLS (5.7%), hypertension (1.3%) and hypotension (1.3%). IRRs were most frequent in C1D1 (Fig).In the overall safety population (n=172; previously untreated patients) the most frequently reported serious AEs of special interest included IRR (8.1%) and neutropenia (11.0%). AEs of particular interest, thrombocytopenia, cardiac, and hemorrhagic events, were experienced by 16.3%, 3.5% and 3.5% of patients, respectively. [Display omitted] Conclusions: Preliminary safety data from the GREEN study, assessing the use of obinutuzumab alone or in combination with chemotherapy (B, FC or Clb) in subjects with untreated CLL, are in line with the known safety profile of obinutuzumab in similar populations. Although there is limited exposure time available for subjects in GREEN, IRRs seemed to be more manageable and a lower proportion of subjects with IRRs grade ≥3 was observed compared with previous studies. No new safety signals were reported. However, since the number of discontinuations during C1 was comparable with previous obinutuzumab studies, the decision was taken to further improve IRR rates by assessing additional dexamethasone premedication in cohort 2. Final safety data from the study will be presented at a later timepoint. [Display omitted] DisclosuresBosch:Roche: Consultancy, Research Funding, Speakers Bureau. Off Label Use: GAZYVA (obinutuzumab) is a CD20-directed cytolytic antibody and is indicated, in combination with chlorambucil, for the treatment of patients with previously untreated chronic lymphocytic leukemia (CLL). This abstract reports on obinutuzumab alone or in combination with chemotherapy for previously untreated or relapsed/refractory CLL.. Lasserre:F. Hoffmann–La Roche: Employment. Truppel-Hartmann:F. Hoffmann–La Roche: Employment. Leblond:Roche: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau. Foà:Roche-Genentech: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau. Stilgenbauer:Roche: Consultancy, Honoraria, Research Funding.

Obinutuzumab (GA101) in relapsed/refractory chronic lymphocytic leukemia: final data from the phase 1/2 GAUGUIN study

AbstractGAUGUIN evaluated the safety and efficacy of obinutuzumab (GA101) monotherapy in patients with relapsed/refractory chronic lymphocytic leukemia (CLL). In phase 1 (dose escalation), 13 patients received obinutuzumab 400 to 1200 mg (days 1 and 8 of cycle 1; day 1 of cycles 2-8). In phase 2, 20 patients received a fixed dose of 1000 mg (days 1, 8, and 15 of cycle 1; day 1 of cycles 2-8). Infusion-related reactions occurred in nearly all patients, but few were grade 3/4. Grade 3/4 neutropenia occurred in 7 patients in phase 1 (but was not dose-related) and in 4 patients in phase 2. Overall end-of-treatment response (all partial responses) was 62% (phase 1) and 15% (phase 2); best overall response was 62% and 30%, respectively. Phase 2 median progression-free survival was 10.7 months and median duration of response was 8.9 months. In summary, obinutuzumab monotherapy is active in patients with heavily pretreated relapsed/refractory CLL. GAUGUIN was registered at www.clinicaltrials.gov as #NCT00517530.