Renal biopsy findings and followup of renal function in rheumatoid arthritis patients treated with cyclosporin A. An update from the International Kidney Biopsy Registry

OBJECTIVE

To review data from the International Kidney Biopsy Registry, which describes the occurrence of cyclosporin A (CSA)-induced nephropathy, and to discuss the potential risk factors for its development.

METHODS

The report examines data on a total of 60 first and 14 second renal biopsies performed in rheumatoid arthritis (RA) patients treated with CSA for up to 87 months.

RESULTS

Five of the 60 patients with RA included in the Biopsy Registry had findings consistent with CSA-induced nephropathy at first biopsy. One further patient had such findings at second biopsy. Of the 22 patients who started CSA at dosages < 4 mg/kg/day and subsequently received dosages no higher than 5 mg/kg/ day, none developed CSA-induced nephropathy. Continuous assessment of renal function did not show any evidence of deterioration over time in patients maintained on low-dose CSA.

CONCLUSION

The data indicate that in RA patients being treated according to current dosing recommendations, the risk of developing CSA-induced nephropathy is low.

Extracapillary glomerulonephritis in a patient with juvenile chronic arthritis

A patient with juvenile chronic arthritis (JCA) in remission developed the nephrotic syndrome 17 years after the onset of the disease. A renal biopsy showed diffuse extracapillary proliferative glomerulonephritis without immune complex deposits. The patient was treated with glucocortico-steroids and cyclophosphamide. Extracapillary glomerulonephritis without immune complex deposits appears to be a rare complication of JCA.

The effect of ranitidine on NSAID related dyspeptic symptoms with and without peptic ulcer disease of patients with rheumatoid arthritis and osteoarthritis

The efficacy of ranitidine in the treatment of NSAID-related dyspeptic symptoms with and without peptic ulcer disease (PUD) was investigated in 124 patients with rheumatoid arthritis (RA) and osteoarthritis (OA). The patients, who continued the use of NSAIDs were investigated by gastroduodenoscopy. Patients with PUD received open label ranitidine 150 mg b.i.d. and the patients without PUD were randomly allocated to receive ranitidine 150 mg b.i.d. or placebo for 4 weeks. PUD was found in 36 (26%) consecutive patients who presented with dyspeptic symptoms. Of these patients dyspeptic symptoms had disappeared in 8 (26%) of 31 evaluable patients and PUD was healed in 18 (56%) patients after 4 weeks of treatment. After 8 weeks of treatment PUD was healed in 27 (87%) patients. Of the remaining patients without PUD dyspeptic symptoms had disappeared in 24 (26%) of the ranitidine-treated patients which was significantly better (p < 0.02) than the 5 (6%) placebo-treated patients. The minor mucosal lesions found in this patient group improved to a similar extent in the ranitidine and placebo-treated patients although 1 placebo-treated patient deteriorated and 2 placebo-treated patients developed PUD during the 4 weeks of study. The results of this study show that oral ranitidine 150 mg b.i.d. is effective in the treatment of both dyspeptic symptoms and mucosal lesions in RA and OA patient who continue the use of NSAIDs.

Persistent CD3-crosslinking down-regulates interleukin-2 responsiveness in interleukin-2-competent cloned T cells: the possible involvement of protein kinase C

To investigate the regulation of interleukin-2 (IL-2) responsiveness of T cells, a human CD4+ T-cell clone with constitutive expression of IL-2 receptors was stimulated with recombinant IL-2 (rIL-2) in the presence or absence of immobilized anti-CD3 monoclonal antibodies (alpha CD3imm MoAb). Incubation of T cells with alpha CD3imm MoAb decreased IL-2-induced proliferation which could not be ascribed to the modulation of IL-2 receptor expression nor to cell death. Phorbol-myristate-acetate (PMA), an activator of protein kinase C (PKC), also induced down-regulation of IL-2 responsiveness. The alpha CD3sol MoAb, inducing Ca(2+)-mobilization without activating PKC, did not inhibit IL-2 responsiveness whereas cyclosporine A (CsA), a drug that inhibits the Ca(2+)-dependent activation pathway, did not prevent the induction of IL-2 hyporesponsiveness induced by alpha CD3imm MoAb. It is concluded that modulation of IL-2 responsiveness of T cells via the T-cell receptor/CD3 complex (TCR/CD3) may be mediated by a PKC-activating signal.

High-dose ranitidine for the prevention of recurrent peptic ulcer disease in rheumatoid arthritis patients taking NSAIDs

BACKGROUND

Continuous therapy with low-dose ranitidine (150 mg b.d.) is known to be effective for the prevention of recurrent nonsteroidal anti-inflammatory drug (NSAID)-associated duodenal ulcer but not for gastric ulcer.

AIM

To investigate, in a double-blind placebo-controlled study, the preventive effect of a high dose of ranitidine (300 mg b.d.) on the recurrence of both duodenal ulcers and gastric ulcers in rheumatoid arthritis patients with a continuous need for NSAIDs.

METHODS

Rheumatoid arthritis patients with a history of peptic ulcer disease were randomized to receive either ranitidine 300 mg b.d. or placebo for 12 months. Endoscopy was performed at study entry and after 6 and 12 months. End-point was the recurrence of gastric or duodenal ulcers.

RESULTS

The study was stopped after a blinded interim analysis; at that time 10 of the 15 included patients in each treatment group were evaluable. Recurrent duodenal ulcers had occurred in four patients treated with placebo and none of the patients treated with ranitidine (Fisher's exact one-tailed P = 0.04; 95% CI, - 0.70 to -0.10). Recurrent gastric ulcers had occurred in six patients in the placebo group and three patients in the ranitidine group (Fisher's exact one-tailed P = 0.18; 95% CI, -0.72 to 0.12). Two patients in the placebo group had developed both duodenal ulcers and gastric ulcers. No adverse events were observed.

CONCLUSIONS

High dose ranitidine is effective for the prevention of recurrent duodenal ulcer but not for recurrent gastric ulcer in rheumatoid arthritis patients taking NSAIDs.

Differential therapy in early and late stages of rheumatoid arthritis

Early and late stages of rheumatoid arthritis differ with respect to the severity of inflammation and the progression rate of irreversible joint destruction. There are no solid data showing that disease mechanisms underlying destructive arthritis differ between the various stages of the disease. Long-term observational studies have shown that rheumatoid arthritis is a severe progressive disease in many patients, highlighting the need for new therapeutic strategies. At present many centers are exploring whether early and aggressive treatment can improve long-term morbidity and mortality.

The tetracycline derivative minocycline differentially affects cytokine production by monocytes and T lymphocytes

Minocycline is a tetracycline derivative that has beneficial effects in noninfectious forms of arthritis and dermatitis. To investigate whether this effect may be attributed to interference with cytokine production, we studied the effect of minocycline on cytokine production by T cells and monocytes. Minocycline exerted an inhibitory effect on tumor necrosis factor alpha (TNF-alpha) and gamma interferon production by stimulated T cells, whereas the production of interleukin 6 (IL-6) remained unaffected. The effect of minocycline on TNF-alpha mRNA synthesis by T cells was shown to be stimulus specific. T cells stimulated by a Ca2+-independent mode exhibited a decrease in TNF-alpha mRNA in the presence of minocycline, whereas the TNF-alpha mRNA level remained unaffected by minocycline when cells were stimulated in a Ca2+-dependent manner. In contrast to the effect on T cells, addition of minocycline to lipopolysaccharide-stimulated monocytes led to a dose-dependent increase in TNF-alpha and IL-6 production which was paralleled by an enhancement of TNF-alpha mRNA synthesis. These results indicate that minocycline exerts differential effects on the regulation of cytokine production by T cells and monocytes that are partly reflected at the mRNA level. Given the pleiotropic effects of minocycline, it is suggested that the immunostimulatory effect on monocytes might counteract its beneficial properties in the treatment of several forms of chronic inflammation.

Inflammatory and immunological parameters of disease activity in rheumatoid arthritis patients treated with minocycline

The objective of this study was to analyze the anti-inflammatory effect of minocycline in rheumatoid arthritis. Serum samples of 65 RA patients who completed a 26-week randomized double-blind trial of minocycline (100 mg twice a day) versus placebo were studied. In this trial some clinical parameters and in particular the acute phase response decreased significantly in the minocycline-treated group. Serum levels of albumin and interleukin-6 (IL-6) were compared with CRP levels in order to study the acute phase response. Furthermore, rheumatoid factor (RF) and total immunoglobulin isotypes as well as serum levels of soluble interleukin-2 receptor (sIL2-2R) were determined in order to study immunological parameters of the disease. Immunoglobulins and cytokines were measured by ELISA. Serum levels of albumin remained stable, whereas serum CRP levels decreased both in the minocycline- and in the placebo-treated group. Serum levels of IL-6 decreased in the minocycline-treated group only and this decrease was positively correlated with the decrease in CRP levels. Minocycline significantly decreased serum IgM-RF, IgA-RF, total IgM and total IgA levels. In addition the ratio of IgM-RF/total IgM decreased in the minocycline-treated group. No such changes were observed in the placebo-treated group. The anti-inflammatory effect of minocycline in RA patients may be due to the reduction in the synthesis of IL-6 and rheumatoid factor.

Chloroquine combined with cyclosporine in rheumatoid arthritis: more than the addition of 2 drugs alone

Combination therapy in rheumatoid arthritis (RA) with 2 or more disease modifying antirheumatic drugs (DMARD) is theoretically attractive if the drugs exert additional or even synergistic effects and have different toxicity patterns to avoid cumulative toxicity. The combination of cyclosporin A (CsA) with chloroquine has shown in in vitro studies a synergistic ability to inhibit the proliferation of peripheral blood mononuclear cells and clonal T cells and the production of interferon gamma by clonal T cells. This synergy is probably based on different mechanisms of action of the 2 drugs: CsA primarily inhibits the production of interleukin 2 (IL-2) (and other cytokines) at the level of transcription, whereas chloroquine primarily inhibits the responsiveness of T cells to IL-2 stimulation. To evaluate whether these in vitro data can be extrapolated in vivo, a large 2 phase trial has been initiated in the Netherlands in which the combination of CsA with chloroquine is evaluated in patients with RA.

Increased bone mass with pamidronate treatment in rheumatoid arthritis. Results of a three-year randomized, double-blind trial

OBJECTIVES

Osteoporosis is a frequent complication of rheumatoid arthritis (RA). We therefore investigated the effect of oral pamidronate therapy as a specific bone-sparing agent in RA.

METHODS

The study design was a 3-year randomized, double-blind trial of 300 mg oral pamidronate/day compared with placebo in 105 RA patients. Bone mineral density (BMD) measured at 12-month intervals was the primary efficacy parameter.

RESULTS

In 3 years, lumbar spine and forearm BMD increased significantly in the pamidronate-treated group (by 8.4 +/- 6.9% [mean =/- SEMI] [P < 0.00011 and 5.2 =/- 6.5% [P < 0.005], respectively), compared with nonsignificant changes in the placebo-treated patients (increase of 0.6 =/- 5.2% and decrease of 1.2 =/- 5.8%, respectively). Femoral neck BMD increased in the pamidronate-treated group (by 2.6 =/- 8.6%) and decreased significantly in the placebo-treated group (by 4.0=/- 1.3% [P < 0.005]). The changes in BMD with time at all 3 measurement sites were significantly different between the treatment groups (P < 0.0001). Changes in radiographic signs of joint damage and in disease activity were similar in the 2 groups.

CONCLUSION

The present study provides the first evidence that long-term treatment with an orally administered bisphosphonate overcomes bone loss and increases bone mass when compared with placebo. This finding may have significance with regard to the treatment of patients with RA.

Randomised placebo-controlled study of stopping second-line drugs in rheumatoid arthritis

BACKGROUND

A favourable benefit/risk ratio for treatment of rheumatoid arthritis (RA) with second-line drugs has been established only in short-term studies. The present investigation addresses the question of whether RA patients with a good response to long-term treatment with second-line drugs benefit from continuation of such treatment.

METHODS

A 52-week randomised double-blind placebo-controlled multicentre study was conducted to assess the effect of stopping second-line therapy in 285 RA patients with a good long-term therapeutic response. The patients either continued the second-line drug (n = 142) or received a placebo (n = 143). The endpoint was a flare, defined as recurrence of synovitis.

FINDINGS

At entry into the study median duration of second-line drug therapy was 5 years (range 2-33). At 52 weeks the cumulative incidence of a flare was 38% for the placebo group and 22% for the continued therapy group (p = 0.002). The risk of a flare was 2.0 times higher for patients receiving placebo than for those continuing the second-line drug (95% CI 1.27 to 3.17). The same trend was found for each second-line drug separately, with the exception of d-penicillamine. Side-effects that necessitated dose reduction or discontinuation occurred in 2 patients in each group.

INTERPRETATION

Second-line drugs continue to be effective in RA patients who have responded well to initial treatment.

The cervical spine in rheumatoid arthritis: relationship between neurologic signs and morphology of MR imaging and radiographs

OBJECTIVE

Comparison of clinically observed neurologic long tract signs in a heterogeneous group of patients with rheumatoid arthritis (RA), with morphologic abnormalities of the cervical spine as depicted on radiographs and magnetic resonance (MR) images.

DESIGN

The patients were prospectively assigned to one of three classes on the basis of their neurologic status. Lateral cervical spine radiographs and sagittal T1-weighted and gradient echo images were performed. The qualitative MR features evaluated were erosion of the dens and atlas, brain stem compression, subarachnoid space encroachment, pannus around the dens, appearance of the fat body caudal to the clivus, and the signal intensity of the pannus. The quantitative imaging parameters were the cervicomedullary angle and the distance of the dens to the line of McRae.

PATIENTS

Sixty-three consecutive patients with RA and subjective symptoms, especially neck or occipital pain, and/or clinical objective signs consistent with a compromised cervical cord were included in this study.

RESULTS AND CONCLUSIONS

Damage documented with radiographs and MR imaging in patients with RA is often severe, even in those without neurologic signs (class 1). None of the abnormalities confined to the atlantoaxial level correlated significantly with neurologic classification. Subarachnoid space encroachment anywhere in the entire cervical spine did correlate significantly with neurologic classification.

Low dose cyclosporine in early rheumatoid arthritis: effective and safe after two years of therapy when compared with chloroquine

Forty-four patients with early RA who had participated in a six months double-blind trial, comparing cyclosporine A (CsA) (n = 22) with chloroquine (Chl) (n = 22), were followed for a further 18 months irrespective of their treatment status. At two years follow up, the mean CsA dose was 2.7 +/- 1.1 mg/kg/day (n = 15) and the dose of Chl (n = 11) was 100 mg/day in every patient. Maximal difference in efficacy (represented by the percentage of patients who fulfilled the Paulus 50% response) was reached at one year (CsA group: 68% and Chl group: 36%; p = 0.07). At two years, the differences in efficacy and toxicity between the two groups had diminished. The conclusions of this follow-up study are: 1. maximal efficacy of low dose CsA in early RA patients is reached after one year of therapy. 2. CsA can maintain clinical efficacy and safety comparable to Chl for a period of at least two years.

Longterm low dose cyclosporine in patients with rheumatoid arthritis: renal function loss without structural nephropathy

OBJECTIVE

To investigate whether administration of low dose cyclosporine for 2 years induces structural changes in the kidneys of patients with rheumatoid arthritis (RA).

METHODS

Renal biopsies were performed in 11 patients with RA who had been treated with cyclosporine [mean dose 3.3 mg/kg/day; mean maximum dose 4.4 (3.5-5.1) mg/kg/day; mean cumulative dose 2.8 (1.6-3.9) g/kg] [mean (range)] for a mean period of 26 (15-30) months. The renal biopsy specimens and specimens of autopsy material of 22 control patients with RA matched for age, disease duration, sex, and previous use of gold and/or D-penicillamine were scored by 2 renal pathologists according to a semiquantitative scoring system (absence of lesions to severe lesions).

RESULTS

In the patients taking cyclosporine, creatinine clearance decreased from 111 ml/min before cyclosporine to 82 ml/min (-26%) after 24 months. Seven percent of the glomeruli in the renal biopsy specimens compared to 13% of glomeruli in the autopsy specimens showed obsolescence. Minimal arteriolopathy (one hyaline deposition in one arteriole) was detected in 3 biopsy specimens and in one autopsy specimen. Moderate and severe lesions were not seen. Tubular atrophy was common but mild in both the biopsy specimens (10/11 patients) and the autopsy specimens (16/22 patients). Five of 11 renal biopsy specimens and 13 of 22 autopsy specimens showed minimal to slight interstitial fibrosis. All biopsy specimens were classified as Group I (minimal lesions) according to the advisory board of nephropathologists.

CONCLUSION

Longterm continuous treatment of RA with low dose cyclosporine does not result in more structural nephropathy than the disease process itself, in spite of substantial and persistent deterioration of the renal function.

Tenidap, but not nonsteroidal anti-inflammatory drugs, inhibits T-cell proliferation and cytokine induction

T-lymphocytes are involved in the inflammatory response that occurs in affected joints of patients with rheumatoid arthritis (RA). Some second-line disease modifying anti-rheumatic drugs used in the treatment of patients with RA are known to block T-cell activation. The present study assessed whether tenidap, an investigational anti-rheumatic drug, affects in vitro T-cell responses such as proliferation and cytokine production. It was found that tenidap, in contrast to several nonsteroidal anti-inflammatory drugs, inhibits anti-CD3 or IL-2 driven proliferative responses of cloned human T-cells. Furthermore, tenidap was found to inhibit IFN-gamma production as well as the induction of mRNA encoding IFN-gamma or TNF-alpha. The results indicate that tenidap may exert at least part of its anti-inflammatory activity via inhibition of T-cell function and cytokine production.

The influence of tetracyclines on T cell activation

Minocycline has been shown to have an anti-inflammatory effect in patients with rheumatoid arthritis (RA). Since there is evidence that RA is a T cell-mediated disease, we investigated the effect of minocycline on human T cell clones derived from the synovium of an RA patient. The T cells, when activated via the T cell receptor (TCR)/CD3 complex, were suppressed functionally by minocycline, resulting in a dose-dependent inhibition of T cell proliferation and reduction in production of IL-2, interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha). Besides an inhibition of IL-2 production, minocycline exerted its effect on T cell proliferation by induction of a decreased IL-2 responsiveness. We showed that the chelating capacity of minocycline plays a crucial role in the inhibitory effect on T cell function, since the inhibitory effect on T cell proliferation could be annulled by addition of exogenous Ca2+. However, minocycline did not markedly influence the typical TCR/CD3-induced intracellular Ca2+ mobilization. Taken together, the results clearly indicate that minocycline has immunomodulating effects on human T cells.

Folate supplementation and methotrexate

This review concentrates on the influence of folate supplementation on the toxicity and efficacy of methotrexate (MTX) in rheumatoid arthritis patients. The design, type of folate supplementation and timing of supplementation vary considerably between the six published controlled studies. Folate supplementation seems to have no effect on the efficacy of MTX but may influence toxicity in a favourable way. Further studies are needed to assess the type of supplementation (folic acid, folinic acid), the predisposing factors for toxicity and cost effectiveness.

Antimicrobial therapy for rheumatoid arthritis

New interest in the use of antibiotics in the treatment of arthritis was stimulated by two factors: (1) observations that, in some forms of chronic arthritis, microbial antigens persist in the synovial membrane, and (2) the increasing knowledge of the anti-inflammatory and immunosuppressive effects of antibiotics. Recently, several published controlled studies reported a beneficial effect of tetracyclines on RA and reactive arthritis. Whether the anti-arthritic activity of the tetracyclines investigated is mediated by the antimicrobial, anti-inflammatory or immunomodulatory properties remains to be determined. It may be concluded from these studies that tetracyclines have a beneficial effect on RA, especially when laboratory parameters are considered. The effect on the clinical parameters is not unequivocal. The adverse effects seem to be mild but the long-term efficacy and safety of tetracyclines as disease-modifying antirheumatic drugs remain to be demonstrated.

Polymyalgia rheumatica and temporal arteritis: a retrospective study of 111 patients

There is no unanimity as to whether polymyalgia rheumatica (PMR) and temporal arteritis (TA) are two distinct diseases or different features of one disease. The objective of this study was to assess the value of histological findings of temporal artery biopsy and the efficacy and complications of drug therapy as well as the frequency of malignancies. It was carried out as a retrospective follow-up study. One hundred eleven patients (89 PMR, 14 TA and 8 PMR+TA) were studied. In 56 patients with PMR a temporal artery biopsy was performed; in none of these biopsies was active arteritis found. Of the 19 patients with TA or PMR+TA, where a temporal artery biopsy was performed, arteritis was found in 15 patients. Reactivation occurred in 27 patients: 4 patients using NSAIDs and 23 patients using corticosteroids. Side effect of the medication included vertebral compression in 10 patients, most of whom were using corticosteroids. Malignancies were diagnosed in 12 of the 111 patients. Most malignancies were diagnosed long before or after the diagnosis of PMR. In case of a PMR diagnosed by the clinician a biopsy of the temporal artery has no value, while the yield of this diagnostic procedure is high in TA. Reactivation was seen quite often and warrants a prolonged period of medical treatment.

Chloroquine inhibits T cell proliferation by interfering with IL-2 production and responsiveness

Chloroquine (Chl) is an anti-rheumatic drug that is widely used in the treatment of rheumatoid arthritis (RA). It seems that T cells are important in the pathogenesis of RA, but it is not known whether Chl acts via inhibition of T cell function. We here present evidence that Chl, just like cyclosporine A (CsA), inhibits T cell proliferation as induced with immobilized alpha CD3 MoAb in a concentration-dependent manner, at least partly through interfering with the production of IL-2 protein and the induction of IL-2 mRNA. Furthermore, Chl impedes the responsiveness of T cell clones to IL-2 since (1) the inhibition of alpha CD3 MoAb-induced proliferation by Chl could not be reversed by rIL-2 and (2) Chl directly blocks IL-2-driven proliferation of cloned T cells. Chl appeared to interfere with the internalization (50% inhibition) and degradation (total blockade) of rIL-2. Finally, the combination of Chl and CsA synergistically inhibited T cell proliferation. We conclude that Chl may inhibit functional properties of human T cells, although the drug is 100- to 1000-fold less potent than CsA in inhibiting T cell proliferation and IL-2 production, respectively. It is speculated that the in vitro effects of Chl might be relevant in explaining the anti-rheumatic effect of this drug in patients with RA.

Discordance between objective and subjective assessment of functional ability of patients with rheumatoid arthritis

The objectives were to investigate whether there is a discordance between observed and reported functional ability in patients with rheumatoid arthritis (RA) as measured by the Health Assessment Questionnaire (HAQ) and, if so, which demographic, clinical and psychological factors contribute to that discordance. Fifty-one consecutive RA patients of the out-patient clinic were included. Self-reported functional ability was compared with the observed performance of tasks as described by the HAQ. The amount of discordance was computed by subtracting reported scores from observed scores. A positive sign stands for overestimation of functional ability by the patient. The average amount of discordance was low, 0.09 (S.D. 0.39), but showed a large range: -0.88 to 1.00. Multiple regression analysis showed that male patients overestimate their functional ability by 0.21 HAQ units compared with female patients. RA patients overestimate their functional ability with increasing disease duration and severity, while RA patients in the early stage of the disease tend to underestimate their functional ability.

Teenager with an irritable hip, anaemia and malaise

We have described a boy with a juvenile spondyloarthropathy who also showed inflammatory changes in the gut. Gastrointestinal symptoms initially indicated the presence of an inflammatory bowel disease, but this was excluded histopathologically.

A randomized, double-blind, placebo-controlled study of CD4 monoclonal antibody therapy in early rheumatoid arthritis

OBJECTIVE

To assess the efficacy of the CD4 monoclonal antibody (MAb) cM-T412 in the treatment of early rheumatoid arthritis (RA).

METHODS

Sixty patients were enrolled in a 6-week randomized, double-blind, placebo-controlled study investigating multiple dose regimens of cM-T412. Thirty patients subsequently were enrolled in a 9-month randomized, double-blind, placebo-controlled study investigating monthly single-dose administrations of cM-T412.

RESULTS

Analysis of clinical parameters revealed no changes in arthritis activity in the groups that received CD4 MAb or the placebo group, and no difference between the groups, in either in the first or the second part of the study. The number of circulating CD4+ cells decreased substantially in the patients treated with CD4 MAb.

CONCLUSION

CD4 MAb treatment of patients with early RA induced no therapeutic effect.

Minocycline in the treatment of rheumatoid arthritis: relationship of serum concentrations to efficacy

OBJECTIVE

To assess the relationships between serum concentrations of minocycline and clinical efficacy and toxicity during the treatment of patients with rheumatoid arthritis (RA) with minocycline.

METHODS

Forty patients with active RA were administered minocycline (maximal oral dose 100 mg twice a day) for 26 weeks. At 3 time points during the treatment, serum samples were collected for measurement of minocycline activity using a microbiological assay. An analysis of variance was performed to estimate an extrapolated concentration at time = 0 (C0) for each patient separately and this value of C0 was regarded to be proportional to the average serum concentration in each patient. The relation between C0 and clinical response and between C0 and the occurrence of adverse effects was evaluated.

RESULTS

Minocycline was detected in 96 serum samples from 37 patients. Eighty-two percent of the variance in serum concentrations was accounted for by a model incorporating patient, dose, and time effects. A weak correlation between C0 and clinical response, as expressed by a Ritchie articular index and number of swollen joints, was demonstrated. No correlation was seen between C0 and toxicity, including gastrointestinal or vestibular adverse effects.

CONCLUSION

Results suggest a relationship between the serum concentrations of minocycline and the clinical response, including Ritchie articular index and number of swollen joints, in the treatment of patients with RA. No relationship was seen between the serum concentrations of minocycline and its toxicity.