Rationale for optimal obinutuzumab/GA101 dosing regimen in B-cell non-Hodgkin lymphoma

Safety of Obinutuzumab in Children With Autoimmune Encephalitis and Early B-Cell Repopulation on Rituximab

BACKGROUND

Rituximab (RTX) resistance or early B-cells repopulation were observed in children but only few publications reported the use of Obinutuzumab and no recommendations were made concerning the dosage for children.

METHODS

This study was a single-center retrospective cohort study of all the children followed-up in the Pediatric Neurology Department of Necker-Enfants malades Hospital in Paris, France, and treated with obinutuzumab, between November 1, 2019, and November 1, 2021.

RESULTS

A total of eight children (three females, median age 4.5 years) were treated. Seven patients presented with autoimmune encephalitis and one with myeloradiculitis. The median delay of B-cell repopulation after a course of RTX was 87 days (range 41 to 160). A switch to obinutuzumab (anti-CD20) was performed for eight children. The median duration between the first RTX infusion and obinutuzumab administration was 6.6 months. The dosage regimen for obinutuzumab was one infusion of 1000 mg/1.73 m2, that is to say 580 mg/m2 (maximum 1000 mg/infusion), by extrapolation from the adult dosage. The median delay of B-cell repopulation after one course of obinutuzumab was 230 days (range 66 to 303 days) vs 87 days after one course of RTX (P < 0.01). None of the patients presented side effects with obinutuzumab treatment. All patients had a favorable evolution at the last-follow up. Median follow-up was 1.6 years.

CONCLUSIONS

This study reports the use of obinutuzumab in neurological inflammatory diseases in a pediatric population. Obinutuzumab seems to have a better biological efficacy than RTX with a longer time of B-cell repopulation.

Harnessing the Immune System: An Effective Way to Manage Diffuse Large B-Cell Lymphoma

Diffuse large B-cell lymphoma (DLBCL) is a heterogenous hematological disorder with malignant potential controlled by immunological characteristics of the tumor microenvironment. Rapid breakthrough in the molecular pathways has made immunological approaches the main anchor in the management of DLBCL, with or without chemotherapeutic agents. Rituximab was the first monoclonal antibody approved for the treatment of DLBCL. Following rituximab that transformed the therapeutic landscape, other novel immunological agents including chimeric antigen T-cell therapy have reshaped the management of relapsed/refractory DLBCL. However, resistance and refractory state remain a challenge in the management of DLBCL. For this literature review, we screened articles from Medline, Embase, Cochrane databases and the European/North American guidelines from March 2010 through October 2022 for DLBCL. Here we discuss immunological agents that will significantly affect future treatment of this aggressive type of lymphoma.

Rituximab versus obinutuzumab-based first-line chemoimmunotherapy for follicular lymphoma-a real-world multicenter retrospective cohort study

The GALLIUM study showed a progression-free survival advantage of 7% in favor of obinutuzumab vs. rituximab-based immunochemotherapies as first-line therapy in follicular lymphoma (FL) patients. Yet, the toxicity appears to be increased with obinutuzumab-based therapy. This is a multicenter retrospective-cohort study including adult FL patients comparing the toxicity of first-line rituximab vs. obinutuzumab-based chemo-immunotherapies (R and O groups, respectively). We compared the best standard-of-care therapy used per time period, before and after obinutuzumab approval. The primary outcome was any infection during induction and 6 months post-induction. Secondary outcomes included rates of febrile neutropenia, severe and fatal infections, other adverse events, and all-cause mortality. Outcomes were compared between groups. A total of 156 patients were included in the analysis, 78 patients per group. Most patients received bendamustine (59%) or CHOP (31.4%) as adjacent chemotherapy. Half of the patients received growth-factor prophylaxis. Overall, 69 patients (44.2%) experienced infections, and a total of 106 infectious episodes were recorded. Patients in the R and O groups had similar rates of any infection (44.8% and 43.5%, p = 1), severe infections (43.3% vs. 47.8%, p = 0.844), febrile neutropenia (15% vs. 19.6%, p = 0.606), and treatment discontinuation, as well as similar types of infections. No covariate was associated with infection in multivariable analysis. No statistically significant difference was evident in adverse events of grades 3-5 (76.9% vs. 82%, p = 0.427). To conclude, in this largest real-life study of first-line treated FL patients comparing R- to O-based therapy, we did not observe any difference in toxicity during the induction and 6 months post-induction period.

The Non-Hodgkin Lymphoma Treatment and Side Effects: A Systematic Review and Meta-Analysis

OBJECTIVE

This paper aims to review studies regarding side effects found during Non-Hodgkin Lymphoma treatment, to suggest the drug class most associated with these effects, as well as the most prevalent side effect grade.

METHODS

This review is registered in PROSPERO (IDCRD42022295774) and followed the PICOS strategy and PRISMA guidelines. The search was carried out in the databases PubMed/MEDLINE, Scientific Electronic Library Online, and DOAJ. Medical Subject Headings Terms were used and quantitative studies with conclusive results regarding side effects during the non-Hodgkin lymphoma treatment were selected. Patent information was obtained from google patents.

RESULTS

Monoclonal antibodies were the main drug class associated with side effects during NHL therapy. The combination of Rituximab (Rituxan®; patent EP1616572B) and iInotuzumab (Besponsa®; patent EP1504035B3) was associated with a higher incidence of thrombocytopenia (p<0.05), while the combination of Rituximab and Venetoclax (Venclexta®; patent CN107089981A) was associated with a higher incidence of neutropenia (p<0.05) when compared to Bendamustine combinations (Treanda ™; patent US20130253025A1). Meta-analysis revealed a high prevalence of grade 3-4 neutropenia and thrombocytopenia in men. Finally, Americans and Canadians experienced a higher prevalence of these side effects, when compared to others nationalities (p<0.05).

CONCLUSION

Patents regarding the use of monoclonal antibodies in NHL treatment were published in the last year. Monoclonal antibodies associated with neutropenia (grade 3-4) and thrombocytopenia, especially in North American men treated for NHL, and with an average age of 62 years demonstrated importance in this study.

Obinutuzumab as consolidation after chemo-immunotherapy: Results of the UK National Cancer Research Institute phase II/III GALACTIC trial

The GA101 (obinutuzumab) monocLonal Antibody as Consolidation Therapy In chronic lymphocytic leukaemia (CLL) (GALACTIC) was a seamless phase II/III trial designed to test whether consolidation with obinutuzumab is safe and eradicates minimal residual disease (MRD) and, subsequently, whether this leads to prolonged progression-free survival (PFS) in patients with CLL who have recently responded to chemo-immunotherapy. Patients with a response 3-24 months after chemotherapy were assessed for MRD. MRD-positive patients were randomised to receive consolidation therapy with obinutuzumab or no consolidation. The trial closed after the phase II part due to slow recruitment. In all, 48 patients enrolled of whom 19 were MRD negative and were monitored. Of the 29 MRD-positive patients, 14 were randomised to receive consolidation and 15 to no consolidation. At 6 months after randomisation, 10 and 13 consolidated patients achieved MRD negativity by flow cytometry (sensitivity 10-4 ) in bone marrow and peripheral blood respectively. PFS was significantly better in consolidated patients compared to non-consolidated patients (p = 0.001). No difference was observed in PFS, overall survival or duration of MRD negativity when comparing the 10 MRD-negative patients after consolidation with the 19 MRD-negative patients in the monitoring group. Common adverse events in the consolidation arm were thrombocytopenia, infection, and cough. Only 1% of events were infusion-related reactions. This observation provides further evidence that consolidation to achieve MRD negativity improves outcomes in CLL and that obinutuzumab is well tolerated in patients with low levels of disease.

[Determining the dose to be injected in the first clinical trials with monoclonal antibodies: not so easy!]

Monoclonal antibodies are a therapeutic tool frequently used in oncology, as they allow the specific targeting of molecules expressed by cancer cells and, in most cases, induce minimal toxic effects on healthy tissues. Because monoclonal antibodies frequently lack significant toxicity and are not associated to a direct relationship between dose and effect, the methods of clinical development traditionally used for chemotherapy agents are scarcely useful for this class of drugs. In addition, no consensus exists on the definition of parameters different from toxicity that could assist the process of dose selection of monoclonal antibody in early clinical trials.

Clinical Pharmacokinetic and Pharmacodynamic Considerations in Treating Non-Hodgkin Lymphoma

Non-Hodgkin lymphoma (NHL) includes a variety of closely related malignancies that originate from lymphoid precursors. The majority of NHLs are of B-cell lineage, for which traditional therapy involves chemotherapy in combination with the anti-CD20 monoclonal antibody rituximab. Ongoing research into the pathogenesis of NHL subtypes has given rise to the use of novel agents that target specific molecular pathways. While the incidence of NHL extends over a range of ages from pediatric to elderly settings, the majority of diagnoses occur over age 60 years. Increasing the use of concomitant medication coupled with declining organ function among this group of patients creates pharmacokinetic (PK) challenges in administering a number of agents involved in the treatment of NHL. In addition, since many of the new agents are administered orally, there are a number of added PK factors that must be taken into consideration with their prescribing and administration. This article will review the available literature on the PK and pharmacodynamic properties of agents commonly used in the treatment of NHL, and intends to provide information that can assist with properly using these drugs in this setting.

Pharmacokinetics, exposure, efficacy and safety of obinutuzumab in rituximab-refractory follicular lymphoma patients in the GADOLIN phase III study

Aims

Rituximab is standard care in a number of lymphoma subtypes, including follicular lymphoma (FL), although many patients are resistant to rituximab, or develop resistance with repeated treatment, and a high proportion relapse. Obinutuzumab is a novel anti‐CD20 monoclonal antibody with improved efficacy over rituximab. It is approved for previously untreated chronic lymphocytic leukaemia (CLL), and for use with bendamustine in patients with rituximab‐relapsed/refractory FL.

Methods

Using a previously described population pharmacokinetic (PK) model of obinutuzumab in patients with non‐Hodgkin lymphoma and CLL, we conducted an exposure‐response analysis using data from 6 clinical trials in patients with CD20+ B‐cell malignancies (CLL11, GADOLIN, GATHER, GAUDI, GAUGUIN and GAUSS) to describe the PK properties of obinutuzumab, identify covariates influencing exposure, and explore how exposure affects safety, efficacy and pharmacodynamics.

Results

A 2‐compartment model with linear and time‐dependent clearance described obinutuzumab PK. Disease type and subtype, body weight, baseline tumour size, and sex had the largest effects on PK. Obinutuzumab exposure was not associated with occurrence or severity of adverse events, but higher exposure appeared to be associated with greater efficacy, particularly longer progression‐free survival. However, in multivariate Cox regression analysis, progression‐free survival benefit in the obinutuzumab plus bendamustine arm was independent of exposure.

Conclusion

The updated population PK model reported here accurately describes the PK of obinutuzumab patients with non‐Hodgkin lymphoma and CLL. The selected obinutuzumab dosing regimen offers clinical benefit in a majority of rituximab‐refractory FL patients treated with bendamustine, irrespective of variability in exposure, whilst minimising adverse events.

Role of obinutuzumab exposure on clinical outcome of follicular lymphoma treated with first-line immunochemotherapy

AIMS

Obinutuzumab (G) is a humanized type II, Fc-glycoengineered anti-CD20 monoclonal antibody used in various indications, including patients with previously untreated front-line follicular lymphoma. We investigated sources of variability in G exposure and association of progression-free survival (PFS) with average concentration over induction (C_meanIND ) in front-line follicular lymphoma patients treated with G plus chemotherapy (bendamustine, CHOP, or CVP) in the GALLIUM trial.

METHODS

Individual exposures (C_meanIND ) were obtained from a previously established population pharmacokinetic model updated with GALLIUM data. Multivariate Cox proportional hazard models and univariate Kaplan-Meier plots investigated relationships of PFS with exposure and other potential prognostic factors.

RESULTS

Overall, G exposure was lower in high body-weight patients and in males, and slightly lower in patients with high baseline tumour burden. Analysis of clinical outcomes showed that variability in G exposure did not impact PFS in G-bendamustine-treated patients; PFS was inferior in males and patients with FCGR2a/2b T232 T low-affinity receptor variant, and superior in patients with FCGR2a/2b I232T variant. In G-CHOP/CVP arms, PFS improved with increasing C_meanIND (hazard ratio = 1.74 and 0.394 at 5^th and 95^th percentile compared to median C_meanIND ) and was inferior in patients with high baseline tumour size and B symptoms.

CONCLUSIONS

It remains unclear whether for G-CHOP/CVP patients lower G exposure is a consequence of adverse disease biology and/or resistance to chemotherapy backbone (higher clearance in nonresponder patients, as demonstrated for rituximab) rather than being the cause of poorer clinical outcome. A study with >1 dose level of G could help resolve this uncertainty.

Management of patients with follicular lymphoma treated first line with obinutuzumab

Recently, obinutuzumab was included in the Australian Pharmaceutical Benefits Scheme for use in first line, advanced or bulky stage 2, follicular lymphoma, providing more immunochemotherapy treatment options available than ever before. Rituximab with chemotherapy has been the standard of care since reimbursement in the late 1990s; however, obinutuzumab-based regimens have shown superior progression-free survival in comparison to rituximab-based options, albeit at an increased risk of grade ≥3 adverse events. As median overall survival approaches 20 years or more, the long-term effects and sequencing of any strategy should be considered. Here we discuss the considerations for selection of front-line therapy, based on evidence and local Australian clinician experience, in the management of first line follicular lymphoma.

Improving CD20 antibody therapy: obinutuzumab in lymphoproliferative disorders

Soon after the anti-CD20 monoclonal antibody rituximab began to change the management of indolent and aggressive B cell lymphomas, development of alternative antibodies - including chemoimmunoconjugates - was undertaken. Among humanized and fully human CD20 antibodies, obinutuzumab has emerged as one antibody that seems to have lived up to the promise of improved efficacy based on in vitro and preclinical experiments. The data available, thus, far establish obinutuzumab's preferred role as the anti-CD20 antibody of choice in chronic lymphocytic leukemia and untreated follicular lymphoma, as well as an important addition to the treatment of rituximab-refractory indolent lymphomas. Additional trials in aggressive lymphoma are required to define the place of this new antibody in the management of patients with curable lymphoma subtypes. There are greater toxicities associated with this treatment, including increased infusion-related reactions and cytopenias, but these are manageable with standard supportive care measures.

Anti-CD20 monoclonal antibodies: reviewing a revolution

Since the inception of rituximab in the 1990s, anti-CD20 monoclonal antibodies have revolutionised the treatment of B cell hematological malignancies and have become a cornerstone of modern gold-standard practice. Additionally, the potent efficacy of these agents in depleting the B cell compartment has been used in the management of a broad array of autoimmune diseases. Multiple iterations of these agents have been investigated and are routinely used in clinical practice. In this review, we will discuss the physiology of CD20 and its attractiveness as a therapeutic target, as well as the pharmacology, pre-clinical and clinical data for the major anti-CD20 monoclonal antibodies: rituximab, obinutuzumab and ofatumumab.

Safety, tolerability and pharmacokinetics of shorter duration of infusion of obinutuzumab in Japanese patients with B-cell non-Hodgkin lymphoma: final results of the phase II GATS study

Background

Shorter duration of infusion of monoclonal antibody treatments may reduce treatment burden and improve healthcare resource utilization.

Methods

This phase II study recruited Japanese patients with previously untreated CD20+ B-cell non-Hodgkin lymphoma. Patients received intravenous obinutuzumab 1000 mg by regular infusion on Days 1, 8 and 15 of Cycle 1, followed by 90-min shorter duration of infusion in up to seven subsequent cycles, provided they received ≥3 regular infusions without any grade ≥3 infusion-related reactions and had a lymphocyte count <5.0 × 109 cells/l. Standard cyclophosphamide, doxorubicin, vincristine and prednisolone chemotherapy was given in Cycles 1-6. The primary endpoints were as follows: incidence of grade ≥3 infusion-related reactions in Cycle 2 in patients who started shorter duration of infusion in Cycle 2, serum obinutuzumab concentrations and pharmacokinetic parameters and the time course of cytokine release. Adverse events and serious adverse events were monitored.

Results

Of 35 patients treated, 28 completed eight cycles; 31 started shorter duration of infusion in Cycle 2 and two patients in subsequent cycles. Two patients discontinued before starting shorter duration of infusion. No grade ≥3 infusion-related reactions occurred in Cycle 2. Twenty-one infusion-related reactions (all grades 1-2) were reported in 17/35 (49%) patients overall, mostly in Cycle 1 (18/21 infusion-related reactions [86%]). Grade ≥3 AEs occurring in ≥10% of patients included neutropenia/neutrophil count decreased (66%) and leukopenia/white blood cell count decreased (23%). Steady-state pharmacokinetics of obinutuzumab were attained in Cycle 2 and were not affected by shorter duration of infusion. No relevant cytokine elevations were reported with shorter duration of infusion.

Conclusions

Regular infusion and shorter duration of infusion of obinutuzumab have comparable tolerability and pharmacokinetics in Japanese patients.

Review of targeted therapy in chronic lymphocytic leukemia: what a radiologist needs to know about CT interpretation

The last 5 years have been marked by profound innovation in the targeted treatment of chronic lymphocytic leukemia (CLL) and indolent lymphomas. Using CLL as a case study, we present a timeline and overview of the current treatment landscape for the radiologist, including an overview of clinical and radiological features of CLL, discussion of the targeted agents themselves, and the role of imaging in response and toxicity assessment. The goal is to familiarize the radiologist with multiple Food and Drug Administration (FDA)-approved targeted agents used in this setting and associated adverse events which are commonly observed in this patient population.

Management of patients with previously untreated chronic lymphocytic leukaemia with obinutuzumab and chlorambucil

Patients with chronic lymphocytic leukaemia (CLL) are generally older, with many considered 'unfit' for fludarabine-cyclophosphamide-rituximab therapy. In these patients, the combination of obinutuzumab-chlorambucil may be an appropriate therapeutic choice. Obinutuzumab-chlorambucil has been demonstrated to improve overall survival rates compared to chlorambucil alone and to improve progression-free survival and overall response rates compared to rituximab-chlorambucil. This combination can lead to certain toxicities that need to be addressed through appropriate patient selection, pre-medication and management. In this paper, we discuss evidence-based and author-recommended practical management of first-line CLL patients receiving obinutuzumab-chlorambucil.

Strategies for clinical development of monoclonal antibodies beyond first-in-human trials: tested doses and rationale for dose selection

BACKGROUND

Our previous survey on first-in-human trials (FIHT) of monoclonal antibodies (mAbs) showed that, due to their limited toxicity, the recommended phase II dose (RP2D) was only tentatively defined.

METHODS

We identified, by MEDLINE search, articles on single-agent trials of mAbs with an FIHT included in our previous survey. For each mAb, we examined tested dose(s) and dose selection rationale in non-FIHTs (NFIHTs). We also assessed the correlation between doses tested in the registration trials (RTs) of all FDA-approved mAbs and the corresponding FIHT results.

RESULTS

In the 37 dose-escalation NFIHTs, the RP2D indication was still poorly defined. In phase II-III NFIHTs (n=103 on 37 mAbs), the FIHT RP2D was the only dose tested for five mAbs. For 16 mAbs, only doses different from the FIHT RP2D or the maximum administered dose (MAD) were tested and the dose selection rationale infrequently indicated. In the 60 RTs on 27 FDA-approved mAbs with available FIHT, the FIHT RP2D was tested only for two mAbs, and RT doses were much lower than the FIHT MAD.

CONCLUSIONS

The rationale beyond dose selection in phase II and III trials of mAbs is often unclear in published articles and not based on FIHT data.

Dual-Color Bioluminescent Sensor Proteins for Therapeutic Drug Monitoring of Antitumor Antibodies

Monitoring the levels of therapeutic antibodies in individual patients would allow patient-specific dose optimization, with the potential for major therapeutic and financial benefits. Our group recently developed a new platform of bioluminescent sensor proteins (LUMABS; LUMinescent AntiBody Sensor) that allow antibody detection directly in blood plasma. In this study, we targeted four clinically important therapeutic antibodies, the Her2-receptor targeting trastuzumab, the anti-CD20 antibodies rituximab and obinutuzumab, and the EGFR-blocking cetuximab. A strong correlation was found between the affinity of the antibody binding peptide and sensor performance. LUMABS sensors with physiologically relevant affinities and decent sensor responses were obtained for trastuzumab and cetuximab using mimotope and meditope peptides, respectively, with affinities in the 10^-7 M range. The lower affinity of the CD20-derived cyclic peptide employed in the anti-CD20 LUMABS sensor ( K_d = 10^-5 M), translated in a LUMABS sensor with a strongly attenuated sensor response. The trastuzumab and cetuximab sensors were further characterized with respect to binding kinetics and their performance in undiluted blood plasma. For both antibodies, LUMABS-based detection directly in plasma compared well to the analytical performance of commercial ELISA kits. Besides identifying important design parameters for the development of new LUMABS sensors, this work demonstrates the potential of the LUMABS platform for point-of-care detection of therapeutic antibodies.

Obinutuzumab: A Review in Rituximab-Refractory or -Relapsed Follicular Lymphoma

Obinutuzumab (Gazyva^®, Gazyvaro^®) is a recombinant, monoclonal, humanized and glycoengineered, type II, anti-CD20, IgG1 antibody. It has recently been granted an additional indication for the treatment of patients with follicular lymphoma who relapsed after, or are refractory to, a rituximab-containing regimen. In the primary analysis of the large, phase III GADOLIN study, induction therapy with obinutuzumab plus bendamustine followed by obinutuzumab maintenance prolonged progression-free survival (PFS) to a statistically significant extent relative to induction with bendamustine monotherapy in patients with indolent non-Hodgkin's lymphoma (iNHL). The improvement in PFS was largely driven by the subgroup of patients with follicular lymphoma, who also had prolonged overall survival (OS) in a planned updated analysis. Obinutuzumab had a generally manageable tolerability profile in these patients; mild to moderate infusion-related reactions (IRRs) were the most common treatment-emergent adverse events (AEs) and neutropenia the most common grade 3 or 4 treatment-related AEs. Although additional studies and longer-term data are needed to further assess treatment benefits with obinutuzumab, current evidence indicates that obinutuzumab is a useful treatment option for patients with rituximab-refractory or -relapsed follicular lymphoma.

Impact of obinutuzumab alone and in combination for follicular lymphoma

Although rituximab-based chemoimmunotherapy prolongs the survival of patients with follicular lymphoma (FL), this disease is considered incurable in most patients. Thus, new therapies are needed not only for those in the relapsed/refractory setting, but also for initial treatment. Obinutuzumab (G, GA101) is a third-generation, fully humanized type II glycoengineered, anti-CD20 monoclonal antibody that results in increased direct cell death and antibody-dependent, cell-mediated cytotoxicity/phagocytosis compared to rituximab. Obinutuzumab has significant antitumor activity when used alone or in combinations in untreated or relapsed refractory FL patients. Studies have demonstrated its ability to prolong progression-free survival and, in some cases, overall survival, and to eliminate minimal residual disease. Several ongoing trials are investigating combinations with chemotherapy, immunomodulators, targeted drugs, and immunotherapy agents. G is generally well tolerated, with associated adverse effects including infusion-related reactions, neutropenia, thrombocytopenia, and reactivation of hepatitis B virus. Future studies with this antibody should focus on identifying predictive markers and developing chemotherapy-free combinations that will improve the outcome of patients with FL.

Obinutuzumab for the First-Line Treatment of Follicular Lymphoma

BACKGROUND

Rituximab-based immunochemotherapy has improved outcomes in patients with follicular lymphoma. Obinutuzumab is a glycoengineered type II anti-CD20 monoclonal antibody. We compared rituximab-based chemotherapy with obinutuzumab-based chemotherapy in patients with previously untreated advanced-stage follicular lymphoma.

METHODS

We randomly assigned patients to undergo induction treatment with obinutuzumab-based chemotherapy or rituximab-based chemotherapy. Patients with a response received maintenance treatment for up to 2 years with the same antibody that they had received in induction. The primary end point was investigator-assessed progression-free survival.

RESULTS

A total of 1202 patients with follicular lymphoma underwent randomization (601 patients in each group). After a median follow-up of 34.5 months (range, 0 to 54.5), a planned interim analysis showed that obinutuzumab-based chemotherapy resulted in a significantly lower risk of progression, relapse, or death than rituximab-based chemotherapy (estimated 3-year rate of progression-free survival, 80.0% vs. 73.3%; hazard ratio for progression, relapse, or death, 0.66; 95% confidence interval [CI], 0.51 to 0.85; P=0.001). Similar results were seen with regard to independently reviewed progression-free survival and other time-to-event end points. Response rates were similar in the two groups (88.5% in the obinutuzumab group and 86.9% in the rituximab group). Adverse events of grade 3 to 5 were more frequent in the obinutuzumab group than in the rituximab group (74.6% vs. 67.8%), as were serious adverse events (46.1% vs. 39.9%). The rates of adverse events resulting in death were similar in the two groups (4.0% in the obinutuzumab group and 3.4% in the rituximab group). The most common adverse events were infusion-related events that were considered by the investigators to be largely due to obinutuzumab in 353 of 595 patients (59.3%; 95% CI, 55.3 to 63.2) and to rituximab in 292 of 597 patients (48.9%; 95% CI, 44.9 to 52.9; P<0.001). Nausea and neutropenia were common. A total of 35 patients (5.8%) in the obinutuzumab group and 46 (7.7%) in the rituximab group died.

CONCLUSIONS

Obinutuzumab-based immunochemotherapy and maintenance therapy resulted in longer progression-free survival than rituximab-based therapy. High-grade adverse events were more common with obinutuzumab-based chemotherapy. (Funded by F. Hoffmann-La Roche; GALLIUM ClinicalTrials.gov number, NCT01332968 .).

Direct targeting of cancer cells with antibodies: What can we learn from the successes and failure of unconjugated antibodies for lymphoid neoplasias?

Following approval in 1997 of the anti-CD20 antibody rituximab for the treatment of B-NHL and CLL, many other unconjugated IgG1 MAbs have been tested in pre-clinical and clinical trials for the treatment of lymphoid neoplasms. Relatively few have been approved however and these are directed against a limited number of target antigens (CD20, CD52, CCR4, CD38, CD319). We review here the known biological properties of these antibodies and discuss which factors may have led to their success or may, on the contrary, limit their clinical application. Common factors of the approved MAbs are that the target antigen is expressed at relatively high levels on the neoplastic targets and their mechanism of action is mostly immune-mediated. Indeed most of these MAbs induce ADCC and phagocytosis by macrophages, and many also activate complement, leading to target cell lysis. In contrast direct cell death induction is not a common feature but may enhance efficacy in some cases. Interestingly, a key factor for the success of several MAbs appears to be their capacity to skew immunity towards an anti-tumour mode, by inhibiting/depleting suppressor cells and/or activating immune cells within the microenvironment, independently of FcγRs. We also expose here some of the strategies employed by industry to expand the clinical use of these molecules beyond their original indication. Interestingly, due to the central role of lymphocytes in the control of the immune response, several of the antibodies are now successfully used to treat many different autoimmune diseases and have also been formally approved for some of these new indications. There is little doubt that this trend will continue and that the precise mechanisms of therapeutic MAbs will be further dissected and better understood in the context of both tumour immunology and autoimmunity.

Obinutuzumab: what is there to learn from clinical trials?

Obinutuzumab (OBZ) is a recombinant type II anti-CD20 and immunoglobulin G1 Fc-optimized monoclonal antibody (mAb), recently approved in chronic lymphocytic leukemia (CLL; B-cell CLL) and follicular lymphoma (FL). Rituximab (RTX) is frequently considered as its "ancestor" and OBZ clinical development was justified by the importance of FcγRIIIA-mediated mechanisms in RTX clinical activity. However, RTX differs from OBZ in 2 critical independent properties: being a type I anti-CD20 mAb and not being Fc-optimized. Moreover, the use of a different dosing regimen for RTX and OBZ further complicates any interpretation of clinical results. The results obtained for OBZ in CLL provide new arguments for FcγRIIIA-mediated mechanisms when the target antigen is expressed at a low density. Results of OBZ in FL confirm the interest for FcγRIIIA-mediated mechanisms, with some limitations, some of them being possibly due to lack of OBZ-induced complement activation. The situation in diffuse large B-cell lymphoma is deceiving, as the possible gains of activity of OBZ appear to be annihilated by the lack of complement activation. Although RTX was by chance an anti-CD20 mAb with equilibrated pharmacodynamic properties, the reinforcement of some of these properties, which has been done at the expense of complement activation, has conferred an advantage in some B-cell disorders while restricting OBZ indications. The OBZ story nicely demonstrates that the future of naked mAbs is to design agents with optimized and tailored properties, and that this must be done step by step, with a full clinical validation.

The clinical development of obinutuzumab for the treatment of follicular lymphoma

Impressive progress has been made in recent decades for advanced-stage follicular lymphoma with the availability of anti-CD20 monoclonal antibodies, initially rituximab and more recently obinutuzumab. Obinutuzumab is a unique, third-generation, fully humanized glycoengineered IgG1 type II anti-CD20 monoclonal antibody. It has been shown to have increased antitumor activity compared to rituximab in preclinical studies, including whole-blood B-cell depletion assays, xenograft models, and primate models. This has spurred on the development of obinutuzumab through Phase I/II trials as monotherapy and in combination with chemotherapeutic agents and other targeted therapies. Its efficacy compared to rituximab and in rituximab-refractory disease has led to its continued development and eventual approval for the treatment of follicular lymphoma. Here in this review, we highlight the design and development of obinutuzumab in the treatment of advanced stage grade 1-3A follicular lymphoma and its future directions.

Pharmacokinetics of obinutuzumab in Chinese patients with B-cell lymphomas

Aim

The Phase Ib GERSHWIN study (NCT01680991) assessed the pharmacokinetic (PK) profile of obinutuzumab following multiple intravenous (i.v.) doses to Chinese patients with B‐cell lymphomas, and compared findings with previous obinutuzumab PK studies in mainly Caucasian (non‐Chinese) patients.

Methods

GERSHWIN was an open‐label, single‐arm intervention study. Patients aged >18 years with CD20+ relapsed/refractory chronic lymphocytic leukaemia (CLL), diffuse large B‐cell lymphoma (DLBCL) or follicular lymphoma (FL) were enrolled from four centres in China. The treatment period was 24 weeks; patients received obinutuzumab 1000 mg i.v. on Days (D)1, 8 and 15 of Cycle (C)1 (CLL patients: first infusion split over 2 days) and on D1 of C2–8 (all cycles: 21 days). PK parameters were estimated using non‐compartmental analysis (NCA), and a population PK analysis was used to determine whether observed GERSHWIN PK data were in accordance with previous obinutuzumab PK studies in non‐Chinese patients.

Results

The PK analysis population included 48 patients: 28 patients completed all treatment cycles. NCA showed a similar PK profile in Chinese patients with FL, DLBCL and CLL. Steady‐state concentrations of obinutuzumab appeared to be reached at the start of C2 irrespective of histology. There was no apparent relationship between body weight and systemic exposure. Most PK profiles observed in GERSHWIN lay within the 90% prediction interval of simulated profiles.

Conclusions

Obinutuzumab exposure was comparable in CLL, DLBCL and FL patients. NCA and population PK analysis indicate that PK characteristics of Chinese patients with B‐cell lymphomas are similar to those in non‐Chinese patients.

A Review of Obinutuzumab (GA101), a Novel Type II Anti-CD20 Monoclonal Antibody, for the Treatment of Patients with B-Cell Malignancies

Obinutuzumab (GA101) is a novel, type II, glycoengineered, humanized anti-CD20 monoclonal antibody that has been developed to address the need for new therapeutics with improved efficacy in patients with lymphocytic leukemia and lymphoma of B-cell origin. Obinutuzumab has a distinct mode of action relative to type I anti-CD20 antibodies, such as rituximab, working primarily by inducing direct cell death and antibody-dependent cell-mediated cytotoxicity. Obinutuzumab is under investigation in a wide-ranging program of clinical trials in patients with B-cell malignancies. Efficacy as monotherapy has been reported in patients with relapsed/refractory indolent and aggressive non-Hodgkin lymphoma (NHL) and in chronic lymphocytic leukemia (CLL) of B-cell origin. Improved outcomes have also been noted when obinutuzumab is added to chemotherapy in patients with B-cell NHL, and superiority over rituximab has been reported with combination therapy in patients with CLL. Ongoing research is focusing on developing options for chemotherapy-free treatment and on new combinations of obinutuzumab with novel targeted agents.

Obinutuzumab in chronic lymphocytic leukemia: design, development and place in therapy

For decades, treatment of chronic lymphocytic leukemia (CLL) has been based on chemotherapy. This changed when the first CD20 antibody rituximab was introduced. Since 2008, the combination of chemotherapy and CD20 antibodies has become the standard of care for most patients, and a significant fraction of patients had very long-lasting remissions after chemoimmunotherapy. Despite the improvement of response rates and overall survival (OS) by the use of chemoimmunotherapy, most CLL patients will relapse eventually. One approach to achieve more durable responses was the development of obinutuzumab (GA101), a new type of CD20 antibody that has unique molecular and functional characteristics. Obinutuzumab is a type II fully humanized CD20 antibody that binds to a partly different epitope of the CD20 protein than rituximab and due to its glycoengineered design induces greater antibody-dependent cell-mediated cytotoxicity (ADCC). Initial preclinical observations of a more effective B-cell depletion have been successfully reproduced in clinical trials with CLL patients. This review summarizes results of preclinical as well as clinical studies with obinutuzumab and provides an outlook on its future role in the therapy of CLL.

Obinutuzumab for the treatment of indolent lymphoma

Obinutuzumab is a humanized, type II anti-CD20 monoclonal antibody designed for strong induction of direct cell death and antibody-dependent cell-mediated cytotoxicity. The Phase III GADOLIN trial tested the clinical efficacy of obinutuzumab plus bendamustine followed by obinutuzumab monotherapy in rituximab-refractory indolent non-Hodgkin lymphoma versus treatment with bendamustine alone. It demonstrated significantly longer progression-free survival for the obinutuzumab-containing regimen in this difficult to treat patient group. Based on the results of this trial, US FDA approval was most recently granted for obinutuzumab in the treatment of follicular lymphoma that has relapsed after or was refractory to a rituximab-containing regimen. This article summarizes the available data on chemistry, pharmacokinetics, clinical efficacy and safety of obinutuzumab in the treatment of indolent non-Hodgkin lymphoma.