Pharmacokinetics, Pharmacodynamics and Preliminary Observations for Clinical Activity and Safety of Multiple Doses of Human Mouse Chimeric Anti-CD22 Monoclonal Antibody (SM03) in Chinese Patients with Systemic Lupus Erythematosus

SM03, an Anti-CD22 Antibody, Converts Cis-to-Trans Ligand Binding of CD22 against α2,6-Linked Sialic Acid Glycans and Immunomodulates Systemic Autoimmune Diseases

SM03, an anti-CD22 recombinant IgG1 mAb, is currently in a phase III clinical trial for the treatment of rheumatoid arthritis (NCT04312815). SM03 showed good safety and efficacy in phase I systemic lupus erythematosus and phase II moderate to severe rheumatoid arthritis clinical trials. We propose the success of SM03 as a therapeutic to systemic autoimmune diseases is through the utilization of a novel mechanism of action unique to SM03. CD22, an inhibitory coreceptor of the BCR, is a potential immunotherapeutic target against autoimmune diseases. SM03 could disturb the CD22 homomultimeric configuration through disrupting cis binding to α2,6-linked sialic acids, induce rapid internalization of CD22 from the cell surface of human B cells, and facilitate trans binding between CD22 to human autologous cells. This in turn increased the activity of the downstream immunomodulatory molecule Src homology region 2 domain-containing phosphatase 1 (SHP-1) and decreased BCR-induced NF-κB activation in human B cells and B cell proliferation. This mechanism of action gives rationale to support the significant amelioration of disease and good safety profile in clinical trials, as by enabling the "self" recognition mechanism of CD22 via trans binding to α2,6 sialic acid ligands on autologous cells, SM03 specifically restores immune tolerance of B cells to host tissues without affecting the normal B cell immune response to pathogens.

SM03, an anti-human CD22 monoclonal antibody, for active rheumatoid arthritis: a phase II randomized, double-blind, placebo-controlled study

OBJECTIVE

SM03, a novel chimeric monoclonal antibody specific to B cell-restricted antigen CD22, has been developed to treat rheumatoid arthritis (RA) and other B cell-related diseases. This 24-week Phase II randomized, double-blind, multi-dose, placebo-controlled study aimed to evaluate the efficacy and safety of SM03 in moderately-to-severely active RA patients in China.

METHODS

One hundred fifty-six patients on background methotrexate were randomized in a 1:1:1 ratio to receive a cumulative dose of 3600 mg (high dose, 600 mg * 6 infusions at weeks 0, 2, 4, 12, 14, and 16) or 2400 mg SM03 (low dose, 600 mg * 4 infusions at weeks 0, 2, 12, and 14), or the placebo. The primary outcome was the 24-week American College of Rheumatology 20% improvement criteria (ACR20) response rate. Safety was also assessed.

RESULTS

The 24-week ACR20 response rate was significantly higher with high (65.3%, p= 0.002) and low-dose SM03 (56.9%, p= 0.024) than placebo (34.0%), but comparable between the high and low dose group. The rate of adverse events was not statistically different among the high dose group (35.3%), the low dose group (51.9%) and the placebo group (34.6%). Thirteen (12.6%) patients receiving SM03 reported treatment-emergent infections, including 3.9% patients in the high-dose group. No patients reported severe treatment-emergent infections or malignancies.

CONCLUSIONS

In active RA Chinese patients receiving background methotrexate, SM03 at a cumulative dose of both 2400 mg and 3600 mg is efficacious and well-tolerated throughout the 24 weeks of treatment. Moreover, SM03 has demonstrated a good safety profile.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov, https://clinicaltrials.gov, NCT04192617.

Mechanistic insights into the role of B cells in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease epitomized by severe inflammation that induces tendon, cartilage, and bone damage over time. Although different types of cells undertake pathogenic functions in RA, the B cell's significant involvement has increasingly been known following the development of rheumatoid factor and it has been re-emphasized in recent years. Therefore, the rheumatoid factors and anti-cyclic citrullinated peptide antibodies are well-known indications of infection and clinical manifestations, and that they can precede the development of illness by several years. The emergence of rituximab a B cell reducing chimeric antidote in 1997 and 1998 transformed B-cell-targeted therapy for inflammatory disorder from a research hypothesis to a functional fact. Ever since, several autoantibody-related conditions were addressed, including the more intriguing indications of effectiveness seen in rheumatoid arthritis patients. Numerous types of B-cell-targeted compounds are currently being researched. From the beginning, one of the primary goals of B-cell therapy was to reinstate some kind of immune tolerance. While B cells have long been recognized as essential autoantibody producers, certain antibody-independent functions and usefulness as a key targeted therapy were not recognized until recently. The knowledge of B cells' diverse physical and pathogenic roles in autoimmune diseases is growing. As a result, the number of successful agents targeting the B cell complex is becoming more ubiquitous. Therefore, in this article, we explore fresh perspectives upon the roles of B cells in arthritis treatment, as well as new evidence regarding the effectiveness of B lymphocytes reduction and the therapeutic outcome of biological markers.

Immunotherapies application in active stage of systemic lupus erythematosus in pregnancy: A case report and review of literature

BACKGROUND

Pregnancy in the setting of systemic lupus erythematosus can worsen the condition from the stable to active stage, with quality of life and fertility desire being particular concerns. Pregnancy in the active stage of systemic lupus erythematosus (ASLE), although rare and complicated to manage, can be treated favorably with immunotherapies ifs used properly. Here we report such a success case.

CASE SUMMARY

A 31-year-old primigravida patient, diagnosed with SLE seven years ago, was induced ASLE after a cold at 21 + weeks. The patient’s vital signs on presentation were normal. Her laboratory exam was remarkable for significant proteinuria, liver and renal dysfunction, and low C3 and C4 levels. Infectious work-up was negative. The patient was diagnosed with ASLE. She was given immunosuppressive agents (methylprednisolone, gamma globulin and azathioprine etc.) and plasma adsorption therapy, monitoring blood pressure every 8 h, fetal heart rate twice a day, and liver and renal function at least twice a week. Successful maternal and fetal outcomes are presented here.

CONCLUSION

Child-bearing in ASLE has become more promising, even for this difficult case of ASLE with multiple organ damage. Thorough antepartum counseling, cautious maternal-fetal monitoring, and multi-organ function monitoring by multidisciplinary specialties are keys to favorable pregnancy outcomes.

The 2018 pipeline of targeted therapies under clinical development for Systemic Lupus Erythematosus: a systematic review of trials

Currently, Systemic Lupus Erythematosus (SLE) therapies range from antimalarials to glucocorticoids, in addition to immunosupressive agents or biologics such as rituximab or belimumab, when needed. Several unmet needs remain in the treatment SLE and more targeted drugs with improved safety profiles are expected. Based on recent advances in the understanding of the complex pathogenesis of SLE, several targeted treatments are currently assessed in clinical trials. In this study, we performed a systematic review of all targeted therapies under clinical development in SLE in 17 online registries of clinical trials. The search yielded a total of 1140 trials, from which we identified 74 targeted therapies for SLE. Those treatments target inflammatory cytokines, chemokines, or their receptors (n = 17), B cells or plasma cells (n = 17), intracellular signalling pathways (n = 10), T/B cells costimulation molecules (n = 8), interferons (n = 7), plasmacytoid dendritic cells (pDC) (n = 3), as well as various other targets (n = 12). Not all these candidate drugs will reach phase III, but the broad spectrum of drugs being investigated may satisfy the urgent need for improved lupus medications. The identification of biomarkers that would allow adequate prediction of response-to-therapy remains high, but when solved will allow a more rationale selection of the optimal pharmacological agent at the patient level.

Targeting B Cells and Plasma Cells in Autoimmune Diseases

Success with B cell depletion using rituximab has proven the concept that B lineage cells represent a valid target for the treatment of autoimmune diseases, and has promoted the development of other B cell targeting agents. Present data confirm that B cell depletion is beneficial in various autoimmune disorders and also show that it can worsen the disease course in some patients. These findings suggest that B lineage cells not only produce pathogenic autoantibodies, but also significantly contribute to the regulation of inflammation. In this review, we will discuss the multiple pro- and anti-inflammatory roles of B lineage cells play in autoimmune diseases, in the context of recent findings using B lineage targeting therapies.