Nephrogenic systemic fibrosis: a gadolinium-associated fibrosing disorder in patients with renal dysfunction
Nephrogenic systemic fibrosis (NSF) is a debilitating fibrosing disorder that develops in patients with underlying kidney disease following exposure to gadolinium-containing contrast agents. NSF presents with cutaneous hyperpigmentation and induration and joint contractures, but fibrosis may also develop in other organs. NSF has been observed in up to 18% of patients receiving chronic haemodialysis and also may occur in individuals with stages 3 and 4 chronic kidney disease and, occasionally, in individuals who had experienced acute renal failure. Mortality is increased significantly among individuals with NSF. Although no medical treatment has been proved to be universally effective in patients with NSF, imatinib mesylate shows potential as a therapeutic agent and is currently being studied in these patients.
Rheumatic syndromes are cause for morbidity in patients with end-stage renal disease. Recent advances in understanding the role of tissue remodeling have provided insight into the pathogenic mechanisms responsible for some of these manifestations. Here, we survey recent and clinically relevant advances in translational research that impact our understanding of rheumatic syndromes seen in patients with significant renal disease. The management of acute and chronic crystalline arthropathies in chronic kidney disease and hemodialysis patients is discussed.
Wegener's granulomatosis (WG) is a complex autoimmune disorder that has been transformed from a uniformly lethal process to a chronic disease with a relapsing-remitting course. In the setting of frequent relapses, the need to manage cumulative disease damage and drug toxicities has spurred the identification and development of new potent and directed therapies. Biologic agents, which offer the potential for remission-induction and drug-sparing approaches to treat WG, have been studied in several small, open-label clinical series and one large, randomized, placebo-controlled clinical trial. This article discusses the results of these trials and the potential of these biologic agents to treat WG.
A significant body of experimental evidence has implicated the proinflammatory cytokine IL-1 in the pathogenesis of RA. For example, IL-1beta overexpression in rabbit knee joints causes arthritis with clinical and histological features characteristic of RA, whereas IL-1 deficiency is associated with reduced joint damage. In experimental models, IL-1 blockers, including IL-1 receptor antagonist (IL-1Ra), significantly reduce clinical and histological disease parameters. In RA patients, plasma and synovial fluid concentrations of IL-1 are elevated, and these correlate with various parameters of disease activity. The production of endogenous IL-1Ra, however, appears to be insufficient to balance these higher IL-1 levels. The efficacy of blocking IL-1 in patients with active RA has been established in controlled clinical trials of anakinra, a recombinant human IL-1Ra (r-metHuIL-1ra). When used alone or in combination with methotrexate, anakinra significantly reduces the clinical signs and symptoms of RA compared with placebo. Taken together, these results indicate that IL-1 plays an important role in the pathogenesis of RA.
Non-enzymatic glycation of proteins, such as collagen, results in the formation of advanced glycation endproducts (AGE). Advanced glycation endproducts result in pathologic stiffening of cartilage and extracellular matrix and accumulate with age. Pentosidine, an AGE, is present in serum, synovial fluid, and articular cartilage from patients with osteoarthritis (OA). However, AGE levels are not always increased, and may be decreased locally, in association with osteoarthritic pathology. The finding of pentosidine in articular cartilage of individuals with OA may not be specific for that disease, independent of chronologic age. Advanced glycation endproduct modification of normal articular cartilage increases its stiffness, increases chondrocyte-mediated proteoglycan degradation, reduces its susceptibility to matrix metalloproteinase-mediated degradation, and decreases proteoglycan synthesis by chondrocytes. These observations parallel findings in osteoarthritic cartilage, which suggests that AGE modification could contribute to the pathogenesis of OA. However, a causative link between AGEs and OA has not yet been established.
Osteoarticular disorders significantly limit the quality of long-term survival with chronic renal failure. beta 2M amyloidosis is a complication of chronic renal failure that has been recognized mostly in patients receiving long-term haemodialysis. Patients with beta 2M amyloidosis typically present with the triad of shoulder periarthritis, carpal tunnel syndrome, and flexor tenosynovitis of the hands. Other musculoskeletal manifestations of beta 2M amyloidosis include destructive spondyloarthropathy, cervico-occipital pseudotumours, bone cysts, and pathological fractures. At present, only renal transplantation may slow or halt the progession of beta 2M amyloidosis. Crystal-induced arthropathy, most commonly caused by basic calcium phosphate crystals, is an important cause of acute joint inflammation in the patient with renal failure. The incidence of bone and joint infection is increased in patients undergoing dialysis. Haemodialysis and peritoneal dialysis are also associated with an erosive or destructive arthropathy of finger joints, which is not explained by local amyloid deposition.
Nephrogenic systemic fibrosis (NSF) occurs in patients with advanced chronic kidney disease (CKD) or acute renal failure, most commonly following exposure to gadolinium-based contrast agents (GBCAs). NSF can be debilitating and associated with increased mortality. The putative association of NSF with GBCAs prompted the development of guidelines to limit the use of these contrast agents in at-risk patients. Indeed, the incidence of NSF has decreased dramatically following application of these guidelines, which appears to be the only effective means of decreasing NSF incidence. Thus, increasing clinician awareness of these updated guidelines is important. The present review introduces and compares updated guidelines for GBCA use and discusses the latest advances in the understanding of the pathogenic mechanisms and treatment of NSF. All rights reserved.
INTRODUCTION: Rituximab is a monoclonal antibody targeting CD20, used to treat B cell malignancies and B cell-mediated autoimmune diseases. Rituximab has the largest market of any monoclonal antibody therapeutic. Its patent will expire within the next few years and several manufacturers have already produced or are developing rituximab biosimilars that aim to match the innovator rituximab as closely as possible.
AREAS COVERED: In this review, we discuss key factors that determine the efficacy of rituximab therapy, potential technical challenges in the manufacture and evaluation of biosimilars, regulatory considerations regarding the review and approval of biosimilars, and the current status of biosimilar rituximab development by various manufacturers. Due to the nature of the topic, literature searches included conference abstracts, regulatory and industry websites as well as peer reviewed literature.
EXPERT OPINION: Cost is a key limitation of current biologics usage and there is a political impetus to the licensing of biosimilars. Concerns regarding potential dissimilarities of biosimilars are legitimate, but surmountable with techniques for in vitro, in vivo and clinical testing and more clearly defined regulatory requirements. These should provide reassurance to prescribers. However, the cost of manufacturing and licensing a biosimilar remains high and the reduction in cost may be more limited than for a non-biologic small molecule drug and its generic version. This cost reduction will be critical to the impact and use of rituximab biosimilars.
Treatment for RA has changed profoundly over the past 25 years, evolving from a strategy of providing symptomatic relief, to implementation of therapeutic regimens that impact disease activity and ultimately have been shown to slow or arrest structural joint damage. Drug therapy for RA has evolved from salicylates, to NSAIDs, CSs, DMARDs, MTX, and finally to biologic response modifiers. MTX has become the initial drug of choice in most patients with RA, and some do well on MTX monotherapy without the addition of other agents. Combination regimens including MTX and other conventional DMARDs may be an effective early approach to treatment of RA. The biologic response modifiers (biologics) became available in the late 1990s, based on our understanding of the molecular mediators of synovial inflammation in RA. The first biologics inhibited TNF-alpha, a cytokine active in host defences against some infections and malignancies, but which also promotes inflammation and bone erosion. Inhibitors of TNF-alpha are mostly given with MTX, although some can be given as monotherapy. Studies consistently show that combination MTX + TNF-alpha inhibitor therapy leads to better outcomes than with either agent alone. Tight control strategies, employing objective measures, also lead to improved outcomes. When patients fail treatment with one or more TNF-alpha inhibitor + MTX, a number of other possible alternatives may be tried, including treatment with biologics having other mechanisms, such as antibodies to certain ILs, other cytokines and inflammatory mediators. Current therapy for RA is such that progression from symptom onset to significant disability is now no longer inevitable, and RA patients can anticipate comfortable and productive lives on medical therapy.
Advances in our understanding of the pathogenesis of RA over the past two decades, particularly the identification of cytokines that promote synovial inflammation (e.g. TNF-alpha, IL-1 and IL-6), have led to treatment courses that affect the disease process itself, beyond alleviation of symptoms. In turn, emphasis has shifted to intervention early enough in the disease course to prevent the joint destruction that follows inflammation. Accordingly, in 2010 the ACR and the European League Against Rheumatism (EULAR) put forward revised classification criteria emphasizing RA characteristics that emerge early in the disease course, including ACPAs, a biomarker that predicts aggressive disease. These were in contrast with the 1987 ARA criteria, which distinguished established RA patients from those with other forms of arthritis, and identified patients with later disease. The categories of the 2010 ACR/EULAR criteria are grouped into four classifications, with point scores for each: joint symptoms; serology (including RF and/or ACPA); symptom duration, whether < 6 weeks or > 6 weeks; and acute-phase reactants (CRP and/or ESR). The criteria were developed in a three-phase process, beginning with an analysis of patient cohorts to determine what disease characteristics had persuaded clinicians to initiate MTX therapy, followed by consensus-based decisions and the creation of a scoring system that would predict which patients would go on to develop persistent and/or erosive disease.
Health Canada/BIOTECanada Summit on regulatory and clinical topics related to subsequent entry biologics (biosimilars), Ottawa, Canada, 14 May 2012
In May 2012, Health Canada and other participants held a National Summit on Subsequent Entry Biologics (SEBs). Health Canada released a guidance document in March 2010 describing policy positions and data requirements for approval of SEBs. While Health Canada and health agencies in other regulatory jurisdictions are aligned on many scientific principles related to biosimilar drugs, Health Canada's specific requirements may not be widely understood by many Canadian stakeholders. The Summit provided an opportunity for education and dialog among physicians who prescribe biologics, provincial payers, and industry on the following topics: preclinical and clinical comparability studies; manufacturing and other product differences; extrapolation of indications; substitution and interchangeability of SEBs with reference biologic drugs in clinical practice; payers' current perspective; pharmacovigilance and naming. It is anticipated that the consensus reached at this meeting will further educate Canadian healthcare professionals, provincial payers, and insurers about the appropriate use of SEBs, and may be of general interest to others internationally. rights reserved.
Patents for many key biological agents will soon expire. Third-party companies are, therefore, in the process of developing their own versions, termed biosimilar agents, of these innovator products. However, manufacture of biosimilar agents is complicated by the requirement for their production in biological systems, small variations in which can influence the structure, activity and metabolism of the biosimilar product. The development of biosimilar therapies for the treatment of patients with rheumatic diseases could potentially result in substantial cost savings for patients and health care providers, and consequently, increased availability of effective therapies. However, legislation that regulates the manufacture, registration and approval of biosimilar therapies varies considerably between different countries. In addition, major safety and efficacy concerns must be addressed before a rheumatologist can routinely substitute an innovator pharmaceutical with a biosimilar product.
Biosimilars are protein products that are sufficiently similar to a biopharmaceutical already approved by a regulatory agency. Several biotechnology companies and generic drug manufacturers in Asia and Europe are developing biosimilars of tumor necrosis factor inhibitors and rituximab. A biosimilar etanercept is already being marketed in Colombia and China. In the US, several natural source products and recombinant proteins have been approved as generic drugs under Section 505(b)(2) of the Food, Drug, and Cosmetic Act. However, because the complexity of large biopharmaceuticals makes it difficult to demonstrate that a biosimilar is structurally identical to an already approved biopharmaceutical, this Act does not apply to biosimilars of large biopharmaceuticals. Section 7002 of the Patient Protection and Affordable Care Act of 2010, which is referred to as the Biologics Price Competition and Innovation Act of 2009, amends Section 351 of the Public Health Service Act to create an abbreviated pathway that permits a biosimilar to be evaluated by comparing it with only a single reference biological product. This paper reviews the processes for approval of biosimilars in the US and the European Union and highlights recent changes in federal regulations governing the approval of biosimilars in the US.
Diabetes mellitus and insulin resistance in patients with rheumatoid arthritis: risk reduction in a chronic inflammatory disease
OBJECTIVE: To perform a systematic literature review of the potential association among molecular markers of inflammation, alterations in body composition, and insulin resistance (IR), a precursor to type 2 diabetes mellitus (DM), in rheumatoid arthritis (RA) patients. To determine the impact of tumor necrosis factor alpha (TNFalpha) as a pivotal proinflammatory cytokine in the pathophysiology of type 2 DM and RA, and the effect of antirheumatic drugs on glycemic control.
METHODS: We performed a search of PubMed to identify articles on IR and body habitus in patients with RA.
RESULTS: Patients with RA had characteristics placing them at high risk for IR and type 2 DM. The incidence and prevalence of type 2 DM in RA was not clearly increased compared with the general population; however, studies suggested that patients with RA are likely to have IR and have increased risk of cardiovascular disease (CVD). The prevalence of type 2 DM and IR could be estimated from reports of risk factors for CVD in RA patients. The TNFalpha antagonists provided rapid and effective control of RA-related inflammation. Evidence indicated that extended use of TNFalpha antagonists in RA may provide the additional benefit of improving insulin sensitivity. These treatment-related changes may contribute to an overall reduction in the risk of type 2 DM and CVD in RA patients.
CONCLUSION: Controlling inflammation may improve insulin sensitivity and subsequently reduce the risk of developing type 2 DM in RA patients. This may also reduce the risk of CVD in this high-risk group. Future studies are required to elucidate the relationships between inflammation, body composition, IR, TNFalpha antagonist use, and the risk of developing type 2 DM in RA patients.
Golimumab: A novel human anti-TNF-alpha monoclonal antibody for the treatment of rheumatoid arthritis, ankylosing spondylitis, and psoriatic arthritis
INTRODUCTION: The introduction of tumor necrosis factor-alpha (TNF-alpha) inhibitors represented a significant advance in the management of rheumatoid arthritis (RA) and other chronic inflammatory diseases. Although three TNF-alpha inhibitors have been approved for the treatment of RA by the US Food and Drug Administration (FDA) and the European Medicinal Products Evaluation Agency (EMEA), not all patients achieve a satisfactory clinical improvement with these therapeutic agents. The mode of administration of these medications is inconvenient for some patients. AIMS: Golimumab is a novel anti-TNF-alpha monoclonal antibody that is in clinical development for the treatment of RA, psoriatic arthritis (PsA), and ankylosing spondylitis (AS), either as a first-line biologic therapy or an alternative after other TNF-alpha inhibitors have been discontinued. This review summarizes the development of, and clinical evidence achieved with, golimumab.
EVIDENCE REVIEW: Golimumab has demonstrated significant efficacy in randomized, double-blind, placebo-controlled trials when administered subcutaneously once every four weeks. It has been generally well tolerated in clinical trials and demonstrates a safety profile comparable with currently available TNF-alpha inhibitors.
OUTCOMES SUMMARY: Golimumab has been confirmed to be an effective treatment for patients with RA, PsA, and AS in phase III clinical trials as evaluated by traditional measures of disease activity, such as signs and symptoms, as well as measures of physical function, patient reported outcomes, and health economic measures. The efficacy and safety profile of golimumab in RA, PsA, and AS appears to be similar to other anti-TNF agents. However, golimumab has the potential advantage of once monthly subcutaneous administration and the possibility of both subcutaneous and intravenous administration.