Slow drugs: slow progress? Use of slow acting antirheumatic drugs (SAARDs) in rheumatoid arthritis

Side effects of methotrexate therapy for rheumatoid arthritis: A systematic review

Methotrexate (MTX) is used as an anchor disease-modifying anti-rheumatic drugs (DMARDs) in treating rheumatoid arthritis (RA) because of its potent efficacy and tolerability. MTX benefits a large number of RA patients but partially suffered from side effects. A variety of side effects can be associated with MTX when treating RA patients, from mild to severe or discontinuation of the treatment. In this report, we reviewed the possible side effects that MTX might cause from the most common gastrointestinal toxicity effects to less frequent malignant diseases. In order to achieve regimen with less side effects, the administration of MTX with appropriate dose and a careful pretreatment inspection is necessary. Further investigations are required when combining MTX with other drugs so as to enhance the efficacy and reduce side effects at the same time. The management of MTX treatment is also discussed to provide strategies for occurred side effects. Thus, this review will provide scholars with a comprehensive understanding the side effects of MTX administration by RA patients.

To stop the erosion of hope: the DMARD category and the place of semantics in modern rheumatology

The category of disease-modifying anti-rheumatic drugs (DMARDs) emerged in the 1970s to describe drugs capable of altering the long-term destructive course of arthritis. It became a core concept in rheumatology’s reorientation towards pharmaceuticals in the late twentieth century. By examining the earliest use of the term “disease-modifying” in scientific publications, this paper identifies the drugs that the category described when it first emerged. Leaning on systematic reviews of each of these drugs towards the end of their career in rheumatology, it then establishes that posterity would not recognize any of these early DMARDs as capable of altering the long-term course of the disease. The notion of disease-modifying drugs was thus originally used to categorize drugs that were not disease-modifying. Instead of interpreting this inconsistency as an anomaly, the paper argues that the DMARD category may have gained currency because it allowed a number of actors to respond pragmatically to an ongoing crisis in the pharmacological approach to treating arthritis. The term offered to conjure prospects of disease-modifying effects regardless of drugsʼ actual capacities, and thus to semantically solve the tensions between needs and means that characterized rheumatology at the time. While shedding light on a pivotal moment in the history of rheumatology, the paper also models an approach to understanding drug categories as meaning-making mechanisms by which people can mediate the sometimes uneasy connections that exist between medical practice and science.

A history of the term "DMARD"

The article outlines a history of the concept of “disease-modifying antirheumatic drugs” or DMARDs—from the emergence in the 1970s of the idea of drugs with decisive long-term effects on bone erosion in rheumatoid arthritis (RA), through the consolidation and popularisation in the term DMARD in 1980s and 1990s. It then examines the usage of the terms “remission-inducing drugs” (RIDs) and “slow-acting anti-rheumatic drugs” (SAARDs), which for some years offered competition to the term DMARDs, thus underscoring the contingency of the establishment of DMARD as a word. Finally, it juxtaposes the apparently spontaneous emergence of the three terms DMARD, SAARD and RID, and the disappearance of the latter two, with a failed attempt in the early 1990s to replace these terms with the new term “disease-controlling antirheumatic treatment” (DC-ART). The analysis highlights the paradoxical qualities of the DMARD concept as robust albeit tension ridden, while playing down the role of identified individuals and overarching explanations of purpose.

Anti-TNF agents for rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory, autoimmune disease with a prevalence of approximately 1% and an annual incidence of 0.04%. Up to 50% of patients with RA are unable to work 10 years after diagnosis. The disease is associated with significant morbidity and mortality with associated medical costs to the UK of between £240 m and £600 m per year.

Non steroidal anti-inflammatory drugs (NSAIDs) have little effect on the underlying course of RA, but they have some anti-inflammatory and analgesic properties. Disease modifying antirheumatic drugs (DMARDs) have been shown to slow progression of RA and are currently recommended early in the course of treatment of RA which is when disease progression is most rapid.

Etanercept and infliximab belong to a new group of parentally administered antitumour necrosis factor (TNF) drugs.

Etanercept is licensed in the UK for the treatment of active rheumatoid arthritis in patients who have not responded to other DMARDs and in children with polyarticular-course juvenile arthritis who have not responded to or are intolerant of methotrexate. In adults it produces significant improvements in all measures of rheumatic disease activity compared to placebo. In patients whose disease remains active despite methotrexate treatment, further improvement in control is obtained with the addition of etanercept without an increase in toxicity. In one small trial, etanercept was found to be more effective than placebo in a selected group of children.

Infliximab is a monoclonal antibody which is currently licensed in the UK for Crohn's disease and, in combination with methotrexate for the treatment of rheumatoid arthritis in patients with active disease when the response to disease-modifying drugs, including methotrexate, has been inadequate. In clinical trials infliximab produced significant improvements in all measures of rheumatic disease activity compared with placebo. Infliximab in combination with methotrexate was shown to be superior to methotrexate or infliximab alone.

There are currently no predictors of a good response to anti-TNF drugs and a percentage of patients fail to respond to treatment (25% to 38% of etanercept patients; 21% to 42% of infliximab patients). Infliximab monotherapy induces the production of anti-infliximab antibodies, which may reduce its effectiveness. Adding methotrexate to infliximab therapy may prevent this response.

Anti-TNF drugs may affect host defences against infection and malignancy; whether these agents affect the development and course of malignancies and chronic infections is unknown and safety and efficacy in patients with immunosuppression or chronic infections has not been investigated. With infliximab, upper respiratory tract infections, general infections and those requiring antimicrobial treatment were more common in patients than placebo. Likewise, upper respiratory tract infections were more common in patients treated with etanercept than with placebo. Injection site reactions occur with both infliximab (16%–20%) and etanercept (37%).

There are approximately 600 000 patients with RA in the UK, and of these between 2% and 3.5% may have severe disease which has failed to respond to conventional treatment and who might be eligible for anti-TNF therapy. If between 50% and 70% of patients treated with anti-TNF drugs respond and continue on long-term treatment then the recurrent annual cost to the NHS could be between £48 m and £129 m .

Clinical pharmacokinetics of low-dose pulse methotrexate in rheumatoid arthritis

Low-dose pulse methotrexate has emerged as one of the most frequently used slow-acting, symptom-modifying antirheumatic drugs in patients with rheumatoid arthritis (RA) because of its favourable risk-benefit profile. Methotrexate is a weak bicarboxylic acid structurally related to folic acid. The most widely used methods for the analysis of methotrexate are immunoassays, particularly fluorescence polarisation immunoassay. After oral administration, the drug is rapidly but incompletely absorbed. Since food does not significantly affect the bioavailability of oral methotrexate in adult patients, the drug may be taken regardless of meals. There is a marked interindividual variability in the extent of absorption of oral methotrexate. Conversely, the intraindividual variability is moderate even over a long time period. Intramuscular and subcutaneous injections of methotrexate result in comparable pharmacokinetics, suggesting that these routes of administration are interchangeable. A mean protein binding to serum albumin of 42 to 57% is usually reported. Again, the unbound fraction exhibits a large interindividual variability. The steady-state volume of distribution is approximately 1 L/kg. Methotrexate distributes to extravascular compartments, including synovial fluid, and to different tissues, especially kidney, liver and joint tissues. Finally, the drug is transported into cells, mainly by a carrier-mediated active transport process. Methotrexate is partly oxidised by hepatic aldehyde oxidase to 7-hydroxymethotrexate. This main, circulating metabolite is over 90% bound to serum albumin. Both methotrexate and 7-hydroxy-methotrexate may be converted to polyglutamyl derivatives which are selectively retained in cells. Methotrexate is mainly excreted by the kidney as intact drug regardless of the route of administration. The drug is filtered by the glomeruli, and then undergoes both secretion and reabsorption processes within the tubule. These processes are differentially saturable, resulting in possible nonlinear elimination pharmacokinetics. The usually reported mean values for the elimination half-life and the total body clearance of methotrexate are 5 to 8 hours and 4.8 to 7.8 L/h, respectively. A positive correlation between methotrexate clearance and creatinine clearance has been found by some authors. Finally, the pharmacokinetics of low-dose methotrexate appears to be highly variable and largely unpredictable even in patients with normal renal and hepatic function. Furthermore, studies in patients with juvenile rheumatoid arthritis provide evidence of age-dependent pharmacokinetics of the drug. These features must be considered when judging the individual clinical response to methotrexate therapy. Various drugs currently used in RA may interact with methotrexate. Aspirin might affect methotrexate disposition to a greater extent than other nonsteroidal anti-inflammatory drugs without causing greater toxicity. Corticosteroids do not interfere with the pharmacokinetics of methotrexate, whereas chloroquine may reduce the gastrointestinal absorption of the drug. Folates, especially folic acid, have been shown to reduce the adverse effects of methotrexate without compromising its efficacy in RA. Finally, both trimethoprim-sulfamethoxazole (cotrimoxazole) and probenecid lead to increased toxicity of methotrexate, and hence should be avoided in patients receiving these drugs. A relationship between oral dosage and efficacy has been found in the range 5 to 20mg methotrexate weekly. The plateau of efficacy is attained at approximately 10 mg/m2/week in most patients. No clear relationship between pharmacokinetic parameters and clinical response has been demonstrated. Overall, the dosage must be individualised because of interindividual variability in the dose-response curve. This variability is probably related, at least in part, to the wide interindividual variability in the disposition of the drug.

Sulfasalazine. A review of its pharmacological properties and therapeutic efficacy in the treatment of rheumatoid arthritis

Sulfasalazine was first used for rheumatic polyarthritis in the 1940s and in the past 2 decades has become firmly established as a disease-modifying antirheumatic drug (DMARD). The drug is split by the action of bacterial azoreductases in the large intestine into sulfapyridine and mesalazine (mesalamine, 5-aminosalicylic acid), although whether the parent molecule or the sulfapyridine moiety, or both, is the active principle remains uncertain. Sulfasalazine is an effective treatment for rheumatoid arthritis (RA), producing improvements in disease parameters similar to those seen with penicillamine, hydroxychloroquine or oral or parenteral gold in comparative clinical trials. However, there are no direct comparisons of the drug with methotrexate. Most adverse events associated with sulfasalazine are minor and tend to occur within 3 months of starting therapy. A meta-analysis of studies investigating DMARD therapy, which included almost 5000 evaluable patients, concluded that sulfasalazine was close to methotrexate in terms of efficacy but was slightly less well tolerated. However, unlike sulfasalazine, many DMARDs may be unsuitable for women who are, or may become, pregnant because of their potential to cause teratogenic effects. Sulfasalazine may also offer a more rapid onset of action than other DMARDs and may slow down the radiological progression of RA. Combination therapy with other DMARDs, particularly methotrexate, appears more effective than single DMARD therapy. If the safety of these regimens is shown in large numbers of patients they are likely to become more widely used in the future. Sulfasalazine is a therapy of first choice in patients with RA and may be the DMARD of choice in women who are, or may become, pregnant.

A simple in vivo model of collagen degradation using collagen-gelled cotton buds: the effects of collagenase inhibitors and other agents

A simple in vivo model of collagen degradation has been developed, and the effects of various agents have been tested. Type I collagen was prepared from rat skin and acetylated with either [3H]- or [14C] acetic anhydride. The radiolabelled collagen was added to sterile cotton buds and incubated at 37 degrees C to allow the collagen to form native fibrils that were firmly adsorbed to the cotton matrix. After subcutaneous implantation of the collagen-gelled cotton buds into rats, the radiolabelled collagen was progressively removed over a period of weeks by an infiltrating granuloma. Of the agents that were administered directly into the cotton buds using subcutaneously implanted osmotic mini-pumps, only the synthetic collagenase inhibitors CI-A (containing a hydroxamate moiety as a zinc ligand) and CI-C (containing a thiol moiety as a zinc ligand) were able to prevent the removal of collagen: their efficacy correlated with the level of collagenase inhibitory activity assayed in the exudate fluid sequestered within the cotton bud granuloma. Of the agents that were administered systemically, including anti-inflammatory drugs and other compounds used as therapies for arthritis, only hydrocortisone was able to inhibit the removal of radiolabelled collagen. These results suggest that, in this model, interstitial collagenase, a member of the matrix metalloproteinase family, comprised the major degradative pathway for collagen. The collagen-gelled cotton bud model is a useful test system for delineating those processes that result in collagen catabolism. In addition, the model can be used for testing agents, including those of limited or unknown systemic bioavailability, in order to discover novel therapeutic agents for preventing collagen degradation in connective tissue diseases such as arthritis.

Medical management of rheumatoid arthritis

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Second line (disease modifying) treatment in rheumatoid arthritis: which drug for which patient?

OBJECTIVES

The objectives were to assess (a) the comparative merits of commonly used disease modifying drugs in the treatment of rheumatoid arthritis (RA) and (b) the influence of age, gender, and disease duration on the outcome of treatment.

METHODS

Collected analysis (meta-analysis) was performed on results obtained during the first year of treatment in 1140 patients with RA treated with gold, penicillamine, sulphasalazine, or auranofin from a single centre.

RESULTS

Gold, penicillamine, and sulphasalazine performed similarly, with about 60% of patients continuing to receive each of these drugs for at least one year. Neither gender nor age had an influence on the response to treatment, but patients with a longer disease duration showed a greater tendency to stop treatment. The median percentage improvement was 33% in visual analogue pain score and 50% in erythrocyte sedimentation rate.

CONCLUSIONS

Routine use of these drugs should at least equal these results. Any new drug should either be substantially less toxic or at least as efficacious.

Beneficial effects of SK&F 105685 in rat adjuvant arthritis: prophylactic and therapeutic effects on disease parameter progression

Prophylactic administration of SK&F 105685 (N, N-dimethyl-8,8,-dipropyl-2-azaspiro[4.5]decane-2-propanamine dihydrochloride) at 30 mg/kg/day inhibited hindpaw lesions in adjuvant arthritic (AA) rats following 16 (84% inhibition) and 24 (70% inhibition) days of treatment. In a therapeutic protocol, where dosing was initiated on day 10 after disease induction, SK&F 105685 (20 mg/kg/day) effectively halted disease progression, and the inflammatory lesion was suppressed by 70% following treatment for 20 days. Histological evaluation of the joint periarticular soft tissue, bone and articulation (joint space and joint surface) from therapeutically treated rats showed a clear beneficial effect. Most rats presented moderate lesions rather than the severe lesions seen in the AA animals. AA control rats and AA rats treated prophylactically or therapeutically with SK&F 105685 had significant and similar increases in their total white blood cell (WBC), neutrophil, monocyte and platelet counts. Although increases were seen in the absolute number of neutrophils and platelets, there were no differences in the levels of leukotriene B4 (LTB4) and hydroxyheptadecatrienoic acid (HHT), per cell when these cells were stimulated with the calcium ionophore A23187. These results, describing the beneficial effects of SK&F 105685 administered therapeutically to the AA rat, indicate that this compound possesses properties desirable of an anti-arthritic agent and may potentially modify the disease outcome.