Low-Dose Subcutaneous Anti-CD20 Treatment Depletes Disease Relevant B Cell Subsets and Attenuates Neuroinflammation

[Ofatumumab in the treatment of multiple sclerosis - A summary of preclinical and clinical data]

BACKGROUND

  B-cell targeted therapies are highly effective in multiple sclerosis (MS). Most of these therapies are administered intravenously at long intervals. Ofatumumab, an anti-CD20 antibody that is administered subcutaneously at low doses on a monthly basis due to its high affinity to the target structure, became available for the treatment of MS in 2021.

METHODS

  An overview of practice-relevant immunological and clinical data on ofatumumab is provided.

RESULTS

  The high affinity of ofatumumab to the target structure allows low dose and low volume administration, with the release and absorption profile after subcutaneous application allowing for high concentrations in the lymph nodes and gradual depletion of B-cells. Rapid onset of action is achieved as well as B-cell repletion within a few months in case of discontinuation of therapy. Long-term data show stable IgG levels over up to four years and high efficacy with respect to relapse rate, progression, and cognition. According to current study data, the effect compared to teriflunomide is greater the earlier therapy is initiated. Ofatumumab has a specific B-cell depletion pattern. CD20 expressing B-cell progenitor cells in the bone marrow are preserved and therefore also the inducibility and differentiation of plasma cells. The formation of a humoral immunological memory is therefore possible. Four-year study data showed no abnormalities in the rate of severe infections or malignancies.

CONCLUSIONS

  Ofatumumab is an innovative B-cell targeted therapy. It is highly effective with a good safety and tolerability profile, well controllable and maintains immunocompetence against pathogens.

[Optimal patient profile for ofatumumab treatment: analysis of Russian data from the Phase 3 study]

The article provides an analysis of the features of the action of ofatumumab in subgroups of patients with multiple sclerosis (MS) who participated in phase 3 ASCLEPIOS I and II studies both in the general subgroup of 1882 patients and among 352 patients from the Russian Federation who participated in these studies. The results of the influence of age, gender, body weight of patients, as well as the basic level of disability on the EDSS scale, the presence of active foci on MRI and previously received therapy with drugs that alter the course of MS (PITRS) are presented. In a total group of 1.882 patients, a more positive effect of ofatumumab compared with teriflunomide was noted on the average annual incidence of exacerbations in men, younger people and with a mild baseline disability level - with a baseline EDSS level less than or equal to 3. In a subgroup of 352 patients from Russia, the same trends were noted, but dependencies were also revealed from the number of previously taken PITRS: a more significant difference was noted in patients with the lowest number of PITRS in the anamnesis. This feature was also confirmed by analyzing the secondary endpoints of the study: the number of active foci on MRI and the confirmed progression of disability according to the EDSS scale. Analysis in clinical subgroups makes it possible to clarify the profile of patients in whom the greatest clinical effect can be expected when using this new drug for the treatment of MS.

The Development of Ofatumumab, a Fully Human Anti-CD20 Monoclonal Antibody for Practical Use in Relapsing Multiple Sclerosis Treatment

The importance of B cells in multiple sclerosis (MS) has been demonstrated through the advent of B-cell-depleting anti-CD20 antibody therapies. Ofatumumab is the first fully human anti-CD20 monoclonal antibody (mAb) developed and tested for subcutaneous (SC) self-administration at monthly doses of 20 mg, and has been approved in the US, UK, EU, and other regions and countries worldwide for the treatment of relapsing MS. The development goal of ofatumumab was to obtain a highly efficacious anti-CD20 therapy, with a safety and tolerability profile that allows for self-administration by MS patients at home and a positive benefit-risk balance for use in the broad relapsing MS population. This development goal was enabled by the unique binding site, higher affinity to B cells, and higher potency of ofatumumab compared to previous anti-CD20 mAbs; these properties of ofatumumab facilitate rapid B-cell depletion and maintenance with a low dose at a low injection volume (20 mg/0.4 ml). The high potency in turn enables the selective targeting of B cells that reside in the lymphatic system via subcutaneous (SC) administration. Through a comprehensive dose-finding program in two phase 2 studies (one intravenous and one SC) and model simulations, it was found that safety and tolerability can be further improved, and the risk of systemic injection-related reactions (IRRs) minimized, by avoiding doses ≥ 30 mg, and by reaching initial and rapid B-cell depletion via stepwise weekly administration of ofatumumab at Weeks 0, 1, and 2 (instead of a single high dose). Once near-complete B-cell depletion is reached, it can be maintained by monthly doses of 20 mg/0.4 ml. Indeed, in phase 3 trials (ASCLEPIOS I/II), rapid and sustained near-complete B-cell depletion (largely independent of body weight, race and other factors) was observed with this dosing regimen, which resulted in superior efficacy of ofatumumab versus teriflunomide on relapse rates, disability worsening, neuronal injury (serum neurofilament light chain), and imaging outcomes. Likely due to its fully human nature, ofatumumab has a low immunogenic risk profile-only 2 of 914 patients receiving ofatumumab in ASCLEPIOS I/II developed anti-drug antibodies-and this may also underlie the infrequent IRRs (20% with ofatumumab vs. 15% with the placebo injection in the teriflunomide arm) that were mostly (99.8%) mild to moderate in severity. The overall rates of infections and serious infections in patients treated with ofatumumab were similar to those in patients treated with teriflunomide (51.6% vs. 52.7% and 2.5% vs. 1.8%, respectively). The benefit-risk profile of ofatumumab was favorable compared to teriflunomide in the broad RMS population, and also in the predefined subgroups of both recently diagnosed and/or treatment-naïve patients, as well as previously disease-modifying therapy-treated patients. Interim data from the ongoing extension study (ALITHIOS) have shown that long-term treatment with ofatumumab up to 4 years is well-tolerated in RMS patients, with no new safety risks identified. In parallel to the phase 3 trials in which SC administration was carried out with a pre-filled syringe, an autoinjector pen for more convenient self-administration of the ofatumumab 20 mg dose was developed and is available for use in clinical practice.

Remibrutinib (LOU064) inhibits neuroinflammation driven by B cells and myeloid cells in preclinical models of multiple sclerosis

BACKGROUND

Bruton's tyrosine kinase (BTK) is a key signaling node in B cell receptor (BCR) and Fc receptor (FcR) signaling. BTK inhibitors (BTKi) are an emerging oral treatment option for patients suffering from multiple sclerosis (MS). Remibrutinib (LOU064) is a potent, highly selective covalent BTKi with a promising preclinical and clinical profile for MS and other autoimmune or autoallergic indications.

METHODS

The efficacy and mechanism of action of remibrutinib was assessed in two different experimental autoimmune encephalomyelitis (EAE) mouse models for MS. The impact of remibrutinib on B cell-driven EAE pathology was determined after immunization with human myelin oligodendrocyte glycoprotein (HuMOG). The efficacy on myeloid cell and microglia driven neuroinflammation was determined in the RatMOG EAE. In addition, we assessed the relationship of efficacy to BTK occupancy in tissue, ex vivo T cell response, as well as single cell RNA-sequencing (scRNA-seq) in brain and spinal cord tissue.

RESULTS

Remibrutinib inhibited B cell-dependent HuMOG EAE in dose-dependent manner and strongly reduced neurological symptoms. At the efficacious oral dose of 30 mg/kg, remibrutinib showed strong BTK occupancy in the peripheral immune organs and in the brain of EAE mice. Ex vivo MOG-specific T cell recall response was reduced, but not polyclonal T cell response, indicating absence of non-specific T cell inhibition. Remibrutinib also inhibited RatMOG EAE, suggesting that myeloid cell and microglia inhibition contribute to its efficacy in EAE. Remibrutinib did not reduce B cells, total Ig levels nor MOG-specific antibody response. In brain and spinal cord tissue a clear anti-inflammatory effect in microglia was detected by scRNA-seq. Finally, remibrutinib showed potent inhibition of in vitro immune complex-driven inflammatory response in human microglia.

CONCLUSION

Remibrutinib inhibited EAE models by a two-pronged mechanism based on inhibition of pathogenic B cell autoreactivity, as well as direct anti-inflammatory effects in microglia. Remibrutinib showed efficacy in both models in absence of direct B cell depletion, broad T cell inhibition or reduction of total Ig levels. These findings support the view that remibrutinib may represent a novel treatment option for patients with MS.

Assessment of the treating physicians' first-hand experience with handling and satisfaction of ofatumumab therapy: findings from the PERITIA survey conducted in Europe

BACKGROUND

Real-world evidence on experience and satisfaction of ofatumumab as a treatment option for relapsing multiple sclerosis (RMS) is limited.

OBJECTIVE

To present cumulative responses from a questionnaire related to first-hand experience of treating physicians on handling and convenience of ofatumumab therapy along with concerns related to COVID-19.

METHODS

PERITIA was a multicentre survey conducted to collect responses from the ASCLEPIOS I/II trial investigators from Europe via an online questionnaire.

RESULTS

Forty-six physicians (Germany, n = 14; Spain, n = 12; Portugal, n = 10; Italy, n = 10) completed the survey. Overall, 43% of the physicians considered the benefit-risk ratio of ofatumumab as very good. Over 93% were in favour of ofatumumab self-administration at home and the majority (83%) believed it to be completely true that self-administration of ofatumumab eases the burden for patients in terms of time. All investigators would like to potentially use anti-CD20 therapy as a long-term strategy. Even during the COVID-19 pandemic, physicians were in favour of a self-administration of MS therapy at home over other anti-CD20 therapy infusions.

CONCLUSION

European neurologists who were part of this survey considered the benefit-risk-ratio of ofatumumab as favourable and the monthly self-administered subcutaneous injections offering convenience for patients in the clinical practice.

Intra-articular Injection of a B Cell Depletion Antibody Enhances Local Exposure to the Joint-Draining Lymph Node in Mice with Collagen-Induced Arthritis

Changes to the number, type, and function of immune cells within the joint-draining lymphatics is a major contributor to the progression of inflammatory arthritis. In particular, there is a significant expansion in pathogenic B cells in the joint-draining lymph node (jdLN). These B cells appear to clog the lymphatic sinuses in the lymph node, inhibit lymph flow, and therefore, reduce the clearance of inflammatory fluid and cells from the joint. Taken together, there is potential to treat inflammatory arthritis more effectively, as well as reduce off-target side effects, with localized delivery of B-cell depleting therapies to the jdLNs. We recently reported that joint-draining lymphatic exposure of biologic disease-modifying anti-rheumatic drugs (DMARDs), including the B cell depletion antibody rituximab, is increased in healthy rats following intra-articular (IA) compared to subcutaneous (SC) or intravenous (IV) administration. This suggests that IA administration of B cell depleting antibodies may increase delivery to target cells in the jdLN and increase the effectiveness of B cell depletion compared to standard SC or IV administration. However, whether enhanced local delivery of DMARDs to the jdLN is also achieved after IA injection in the setting of inflammatory arthritis, where there is inflammation in the joint and jdLN B cell expansion is unknown. We, therefore, assessed the lymph node distribution, absorption and plasma pharmacokinetics, and B cell depletion at different sites after IA, SC, or IV administration of a fluorescently labeled mouse anti-CD20 B cell depleting antibody (Cy5-αCD20) in healthy mice compared to mice with collagen-induced arthritis (CIA). The absorption and plasma pharmacokinetics of Cy5-αCD20 appeared unaltered in mice with CIA whereas distribution of Cy5-αCD20 to the jdLNs was generally increased in mice with CIA, regardless of the route of administration. However, IA administration led to greater and more specific exposure to the jdLNs. Consistent with increased Cy5-αCD20 in the jdLNs of CIA compared to healthy mice, there was a greater reduction in jdLN weight and a trend toward greater jdLN B cell depletion at 24 h compared to 4 h after IA compared to SC and IV administration. Taken together, this data supports the potential to improve local efficacy of B cell depletion therapies through a jdLN-directed approach which will enable a reduction in dose and systemic toxicities.

[History and prospects of multiple sclerosis treatment]

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system of unknown etiology. Based on a hypothesis that MS is caused by certain viral infections, the efficacy of interferon β was examined in patients and it became the first disease-modifying drug (DMD) approximately 30 years ago. Through the series of research utilizing experimental autoimmune encephalomyelitis, many other DMDs were later developed. With emerging insights on limitation of the animal model, newer treatment strategies are being developed based on pathological findings from MS patients. In the current article, the history of MS treatment and its future prospects will be reviewed and discussed.

Distribution and efficacy of ofatumumab and ocrelizumab in humanized CD20 mice following subcutaneous or intravenous administration

Approval of B-cell-depleting therapies signifies an important advance in the treatment of multiple sclerosis (MS). However, it is unclear whether the administration route of anti-CD20 monoclonal antibodies (mAbs) alters tissue distribution patterns and subsequent downstream effects. This study aimed to investigate the distribution and efficacy of radiolabeled ofatumumab and ocrelizumab in humanized-CD20 (huCD20) transgenic mice following subcutaneous (SC) and intravenous (IV) administration. For distribution analysis, huCD20 and wildtype mice (n = 5 per group) were imaged by single-photon emission computed tomography (SPECT)/CT 72 h after SC/IV administration of ofatumumab or SC/IV administration of ocrelizumab, radiolabeled with Indium-111 (111In-ofatumumab or 111In-ocrelizumab; 5 µg, 5 MBq). For efficacy analysis, huCD20 mice with focal delayed-type hypersensitivity lesions and associated tertiary lymphoid structures (DTH-TLS) were administered SC/IV ofatumumab or SC/IV ocrelizumab (7.5 mg/kg, n = 10 per group) on Days 63, 70 and 75 post lesion induction. Treatment impact on the number of CD19+ cells in select tissues and the evolution of DTH-TLS lesions in the brain were assessed. Uptake of an 111In-labelled anti-CD19 antibody in cervical and axillary lymph nodes was also assessed before and 18 days after treatment initiation as a measure of B-cell depletion. SPECT/CT image quantification revealed similar tissue distribution, albeit with large differences in blood signal, of 111In-ofatumumab and 111In-ocrelizumab following SC and IV administration; however, an increase in both mAbs was observed in the axillary and inguinal lymph nodes following SC versus IV administration. In the DTH-TLS model of MS, both treatments significantly reduced the 111In-anti-CD19 signal and number of CD19+ cells in select tissues, where no differences between the route of administration or mAb were observed. Both treatments significantly decreased the extent of glial activation, as well as the number of B- and T-cells in the lesion following SC and IV administration, although this was mostly achieved to a greater extent with ofatumumab versus ocrelizumab. These findings suggest that there may be more direct access to the lymph nodes through the lymphatic system with SC versus IV administration. Furthermore, preliminary findings suggest that ofatumumab may be more effective than ocrelizumab at controlling MS-like pathology in the brain.

Animal Models of Multiple Sclerosis

Animal models with high translational validity are essential tools in understanding disease pathogenesis and in the development of therapeutic strategies. Multiple sclerosis (MS) is an autoimmune demyelinating disease of the central nervous system characterized by progressive neurological deficits and socioeconomic burden. Experimental autoimmune encephalomyelitis (EAE) is the most extensively utilized animal model of MS, with well-characterized rodent and non-human primate variants. The EAE model is typically induced by either active immunization with myelin-derived proteins or peptides in adjuvant or by passive transfer of activated myelin-specific CD4⁺ T lymphocytes. To date, the EAE model has been an essential tool in the development of at least seven U.S. Food and Drug Administration (FDA)-approved immunomodulatory drugs for the treatment of MS, including glatiramer acetate, fingolimod, and natalizumab. However, the translational validity of the EAE model is frequently compromised due to poor study design, inconsistent clinical scoring endpoints, and inappropriate statistical calculations. No single animal model accurately reflects the complexity of human MS pathogenesis. Beyond EAE, multiple additional animal models are described, including Theiler's murine encephalomyelitis virus and cuprizone-induced demyelination, which facilitate the study of pathogen-induced CNS autoimmunity and remyelination, respectively. This overview summarizes several of the most frequently used animal models of MS and highlights key factors that significantly influence the experimental outcome and affect translational validity. © 2021 Wiley Periodicals LLC.

Effect of Subcutaneous Anti-CD20 Antibody-Mediated B Cell Depletion on Susceptibility to Pneumocystis Infection in Mice

Anti-CD20 antibody therapy is used for both cancer and autoimmune disease but has been shown to be associated with Pneumocystis pneumonia in humans. This study shows that low-dose subcutaneous anti-CD20 can modulate B cell populations without grossly perturbing fungal immunity against Pneumocystis lung infection.

Prior work has shown that parenterally administered anti-CD20 (5D2) inhibits CD4⁺ T cell priming in response to challenge with Pneumocystis murina and predisposes to pneumonia. In this study, we investigated the effect of subcutaneous anti-CD20 antibody and Pneumocystis infection. In mice with primary infection, anti-CD20 antibody treatment depleted both CD19⁺ and CD27⁺ CD19⁺ cells but not T cells in the lung at days 14 and 28 after Pneumocystis inoculation. Although anti-CD20 antibody treatment impaired fungal clearance at day 14 postinfection, fungal burden in the lungs was substantially reduced at day 28 in both depleted and control mice in the low-dose group. Subcutaneous anti-CD20 antibody treatment did not alter antigen-specific serum immunoglobulin levels in mice compared with control mice, and there were no significant differences in the numbers of lung gamma interferon-positive (IFN-γ⁺) CD4⁺, interleukin 4-positive (IL-4⁺) CD4⁺, IL-5⁺ CD4⁺, and IL-17A⁺ CD4⁺ cells between depleted and control mice after infection. In mice with secondary infection, the lung fungal burden was comparable between depleted and control mice 14 days after reinfection. Low-dose subcutaneous anti-CD20 antibody treatment may delay fungal clearance, but it did not impair the ability of the host to clear Pneumocystis infection, irrespective of primary or secondary infection.

IMPORTANCE Anti-CD20 antibody therapy is used for both cancer and autoimmune disease but has been shown to be associated with Pneumocystis pneumonia in humans. This study shows that low-dose subcutaneous anti-CD20 can modulate B cell populations without grossly perturbing fungal immunity against Pneumocystis lung infection.

Patients with systemic lupus erythematosus show increased proportions of CD19+CD20- B cells and secretion of related autoantibodies

BACKGROUND

At present, anti-CD20 monoclonal antibody treatments targeting systemic lupus erythematosus (SLE) are complex, variable, and often have disappointing outcomes. High levels of programmed cell death-1 (PD-1) and its ligands (PD-L1, PD-L2) or CD80/CD86 on B cell surfaces are markers of increased B cell activity. However, their expression levels on CD19⁺CD20^+/- B cells and their clinical significance for SLE dynamics have not been carefully investigated.

METHODS

Flow cytometry was used to detect the expression levels of PD-1, PD-L1, PD-L2, CD80, and CD86 on CD19⁺CD20^+/- B cells in peripheral blood from SLE patients and healthy controls (HCs). The amount of anti-dsDNA and immunoglobin G (IgG) secreted by CD19⁺CD20^+/- B cells was measured by enzyme-linked immunosorbent assay.

RESULTS

CD19⁺CD20^- B cell frequency was significantly higher in SLE patients than in HCs (P < 0.001), and was positively correlated with disease activity. In SLE patients, frequencies of PD-1, PD-L1, PD-L2, and CD86 on CD19⁺CD20^- B cells were significantly higher than CD19⁺CD20⁺ B cells (P ≤ 0.002) and were significantly correlated with individual laboratory and clinically based parameters (P < 0.05). In vitro tests, we found that the levels of anti-dsDNA and IgG secreted by CD19⁺CD20^- B cells from patients with SLE were significantly higher than the HC group (P < 0.05).

CONCLUSIONS

We found abnormal frequency of CD19⁺CD20^- B cells and increased expression of surface markers on these cells from SLE patients. And the CD19⁺CD20^- B cells had the ability to proliferate and secrete anti-dsDNA and IgG. Additionally, our results suggested that CD19⁺CD20^- B cells from SLE patients may be the activated B cells and caused poor efficacy of rituximab. Key Points • CD19⁺CD20^- B cell frequencies were significantly higher in SLE patients. • Frequencies of PD-1 and its ligands on CD19⁺CD20^- B cells increased significantly in SLE patients. • CD19⁺CD20^- B cells in SLE patients had the ability to secrete anti-dsDNA and IgG. • CD19⁺CD20^- B cells in SLE patients may be the activated B cells and caused poor efficacy of rituximab.