Abatacept in the treatment of lupus

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

BACKGROUND AND OBJECTIVES

SM03 is a novel recombinant, human/mouse chimeric immunoglobulin G1 monoclonal antibody directed against the CD22 antigen on human B lymphocytes. This was the first study to investigate the pharmacokinetics, pharmacodynamics, immunogenicity, safety and clinical activity of SM03 in patients with systemic lupus erythematosus (SLE).

METHODS

This study was an open, multiple-centre, parallel-group, multiple-ascending-dose, phase I study in 29 SLE patients. Pharmacokinetic assessment was conducted in 22 of these patients. Eligible patients received multiple intravenous infusions of SM03 for 4 weeks (240 mg/m², 600 or 900 mg, once weekly) and were monitored over an 84-day observation period for pharmacokinetics, pharmacodynamics, immunogenicity, safety and clinical response.

RESULTS

After multiple-dose SM03, the maximal serum concentration of SM03 was reached within 3-7 h. The mean elimination half-life was 15 days. The average accumulation ratios of the area under the time-concentration curve and the maximum concentration after the fourth administration of SM03 were 2.0 and 1.5. CD19⁺ B-lymphocyte counts were decreased. Infections were the most common adverse events. No drug-related serious adverse events were reported. The therapeutic benefit of SM03 was observed mainly in patients with moderate-to-severe disease activity.

CONCLUSION

Pharmacokinetic exposure increased in a lower-than-dose-proportional manner up to 900 mg. SM03 was well tolerated at doses ranging from 240 mg/m² to 900 mg, with no new safety signals identified. SM03 has potential efficacy in Chinese patients with SLE.

The safety of pharmacological treatment options for lupus nephritis

INTRODUCTION

The management of lupus nephritis (LN) has changed significantly over the last 10 years due to emerging evidence from large randomised clinical trials that produced good quality data and guided the formulation of two key concepts: the induction of remission and the maintenance phase of immunosuppressive therapy.

AREAS COVERED

Optimizing cyclophosphamide and glucocorticoid regimens and the introduction of mycophenolate mofetil for proliferative and membranous LN has been pivotal. Nevertheless, concerns remain about treatment toxicity especially long term glucocorticoid use and exposure to cumulative cyclophosphamide doses. Here we discuss the conventional and newer pharmacological options for managing LN focusing on drug safety and toxicity issues.

EXPERT OPINION

The need for effective and less toxic treatments led to the development of the role of targeted biologic therapies in LN. However, evidence from the initial randomized controlled trials has been disappointing, although this reflects inadequate trial design rather than true lack of efficacy.

Abatacept for the treatment of systemic lupus erythematosus

INTRODUCTION

Due to improvements in our understanding of the pathogenesis of systemic lupus erythematosus (SLE), several target drugs have been and are being developed. One of the possible targets in SLE is co-stimulation between antigen-presenting cells and T cells. Abatacept is a co-stimulation moderator approved for the treatment of several autoimmune diseases. There is an unmet need for drugs with a better efficacy and safety profile when treating patients with SLE.

AREAS COVERED

In this review, the authors discuss the mechanism of action of abatacept including its role in the immune system and glomeruli, and relevant information about its clinical efficacy and safety. Possible explanations for the failure of previous randomized clinical trials are also discussed.

EXPERT OPINION

Abatacept has demonstrated efficacy in other autoimmune diseases, but in SLE, randomized clinical trials have failed to achieve their primary outcome. Despite these disappointing results and based on its mechanism of action, abatacept seems to have a role in lupus nephritis and arthritis. This should be corroborated with new trials which hopefully will overcome the design pitfalls of the ones conducted to date.

Steroidal scaffolds as FXR and GPBAR1 ligands: from chemistry to therapeutical application

Bile acids (BAs) are experiencing a new life. Next to their ancestral roles in lipid digestion and solubilization, BAs are today recognized signaling molecules involved in many physiological functions. These signaling pathways involve the activation of metabolic nuclear receptors, mainly the BA sensor FXR, and the dedicated membrane G protein-coupled receptor, GPBAR1 (TGR5). As a consequence, the discovery of GPBAR1/FXR selective or dual modulators represents an important answer to the urgent demand of new pharmacological opportunity for several human diseases including dyslipidemia, cholestasis, nonalcoholic steatohepatitis, Type 2 diabetes and inflammation. Targeted oriented discovery of natural compounds and medicinal chemistry manipulation have allowed the development of promising drug candidates.

Biologicals for the treatment of systemic lupus erythematosus: current status and emerging therapies

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease resulting from the dysregulation of various immunological pathways. There has been major progress in recent years in the understanding of the pathogenesis of SLE, which has led to an emergence of a new class of drugs designed to target specific components of the disease process.Evidence from a number of open-label, uncontrolled studies has supported the use of rituximab (an anti-CD20 monoclonal antibody) in SLE for more than one decade. However, these promising results are in clear contrast with the poor results of the completed Efficacy and Safety of Rituximab in Patients with Severe SLE (EXPLORER) and Efficacy and Safety of Rituximab in Subjects with class III or IV Lupus Nephritis (LUNAR) randomized controlled trials. In contrast to EXPLORER and LUNAR results, controlled trials for belimumab (a fully humanized monoclonal antibody against B lymphocyte stimulator) showed positive results and subsequently, belimumab was the first drug approved for the treatment of SLE patients. This has paved the way for the development of further biological agents, potentially revolutionizing the treatment of SLE. In this study, the potential benefits of novel biological agents are explored, obstacles to the development of a treatment target in SLE are identified, and possible strategies to achieve this goal are discussed.

Recurrent Focal Segmental Glomerulosclerosis and Abatacept: Case Report

Focal segmental glomerulosclerosis is a common cause of end-stage renal disease in children. Focal segmental glomerulosclerosis recurrence in renal transplants is a challenging disease, and can cause graft dysfunction and loss. Different therapies exist with varying responses, from complete remission to resistance to all modes of treatment. Abatacept was recently introduced as a treatment for primary focal segmental glomerulosclerosis in native kidneys and in recurrent disease after transplant. We present a pediatric case with immunosuppression-resistant primary NPHS2-negative focal segmental glomerulosclerosis recur-rence after renal transplant. The standard therapy for recurrent focal segmental glomerulosclerosis (rituximab, plasmapheresis, high-dose cyclosporine, and corticosteroids) was tried but failed to induce remission. Abatacept (10 mg/kg) was given at 0, 2, and 4 weeks (total, 3 doses) with no good response. We conclude that abatacept may work in patients with B7-1-positive focal segmental glomerulosclerosis recurrence and its efficacy is uncertain in disease with B7-1-negative or unknown staining status.

Novel approaches to the development of targeted therapeutic agents for systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic multisystem disease in which various cell types and immunological pathways are dysregulated. Current therapies for SLE are based mainly on the use of non-specific immunosuppressive drugs that cause serious side effects. There is, therefore, an unmet need for novel therapeutic means with improved efficacy and lower toxicity. Based on recent better understanding of the pathogenesis of SLE, targeted biological therapies are under different stages of development. The latter include B-cell targeted treatments, agents directed against the B lymphocyte stimulator (BLyS), inhibitors of T cell activation as well as cytokine blocking means. Out of the latter, Belimumab was the first drug approved by the FDA for the treatment of SLE patients. In addition to the non-antigen specific agents that may affect the normal immune system as well, SLE-specific therapeutic means are under development. These are synthetic peptides (e.g. pConsensus, nucleosomal peptides, P140 and hCDR1) that are sequences of conserved regions of molecules involved in the pathogenesis of lupus. The peptides are tolerogenic T-cell epitopes that immunomodulate only cell types and pathways that play a role in the pathogenesis of SLE without interfering with normal immune functions. Two of the peptides (P140 and hCDR1) were tested in clinical trials and were reported to be safe and well tolerated. Thus, synthetic peptides are attractive potential means for the specific treatment of lupus patients. In this review we discuss the various biological treatments that have been developed for lupus with a special focus on the tolerogenic peptides.

Abatacept in B7-1-positive proteinuric kidney disease

Abatacept (cytotoxic T-lymphocyte-associated antigen 4-immunoglobulin fusion protein [CTLA-4-Ig]) is a costimulatory inhibitor that targets B7-1 (CD80). The present report describes five patients who had focal segmental glomerulosclerosis (FSGS) (four with recurrent FSGS after transplantation and one with primary FSGS) and proteinuria with B7-1 immunostaining of podocytes in kidney-biopsy specimens. Abatacept induced partial or complete remissions of proteinuria in these patients, suggesting that B7-1 may be a useful biomarker for the treatment of some glomerulopathies. Our data indicate that abatacept may stabilize β1-integrin activation in podocytes and reduce proteinuria in patients with B7-1-positive glomerular disease.