Qualitative and quantitative comparison of allergen component-specific to birch and grass analyzed by ImmunoCAP assay and Euroline immunoblot test.

Summary: Background.In the diagnostic work up of allergy, determining allergen component-specific immunoglobulin E (IgE) is important for diagnosis, prognosis and choice of treatment. The purpose of this study was to evaluate the performance of the immunoblotting assay (Euroline) in detection of IgE antibodies against timothy grass and birch pollen allergen components compared to fluorescent enzyme assay (ImmunoCAP, Phadia 250). Methods. A total of 128 serum samples from patients allergic to timothy grass and birch pollen were analysed. The levels of IgE antibodies to timothy grass and birch pollen were measured using Euroline DPA-Dx pollen 1 and ImmunoCAP assay. The two methods were then compared on binary (positive vs negative), semi-quantitative (IgE classes) and quantitative (concentration) levels. The two methods were also compared to results from skin prick testing. Results. The Euroline method showed a positive percentage agreement of 93% and negative percentage agreement of 94% with an overall accuracy of 94% when compared to ImmunoCAP. Kappa analysis showed moderate strength of agreement between the methods in determining IgE classes for 7/11 components tested. All components showed a positive correlation when analysed using Spearman's rank correlation. Conclusions. Overall, we found that there is good correlation between the Euroline and ImmunoCAP methods in measuring IgE sensitization.

Pre-treatment allergen-specific IgE analysis and outcomes of allergen immunotherapy.

Summary: Background. Patients show varied results to allergen immunotherapy (AIT. The reason for this variability is unclear. Objective. To describe the relationship between AIT efficacy and demographic characteristics, as well as pre-treatment plasma levels of specific IgE-antibodies to grass and birch pollen. Methods. A retrospective study was performed based on medical records of 128 patients who received AIT. The patients completed a questionnaire and pre-AIT plasma levels of allergen-specific IgE to grass and birch pollen were measured using EUROLINE DPA-Dx pollen 1 method. Results. Seventy percent of patients classified their allergic symptoms as less severe after AIT. Twenty-seven percent had received AIT targeting only grass pollen, 19% targeting only birch pollen, and 55% targeting both grass and birch. A total of 35 different IgE profiles were found across our study population. On comparison of the demographic characteristics and concentration of allergen-specific IgE-antibodies, no statistically significant differences could be found.Conclusions. The majority of patients rated their allergic symptoms as less severe after AIT. No clear relationship could be demonstrated between pre-treatment allergen-specific IgE concentration, or demographic characteristics, and effect of AIT. There may be other factors underlying the different responses to AIT.

Pharmacokinetic and pharmacogenomic modelling of the CYP3A activity marker 4ß-hydroxycholesterol during efavirenz treatment and efavirenz/rifampicin co-treatment.

OBJECTIVES: To assess the effect of the major efavirenz metabolizing enzyme (CYP2B6) genotype and the effects of rifampicin co-treatment on induction of CYP3A by efavirenz. PATIENTS AND METHODS: Two study arms (arm 1, n = 41 and arm 2, n = 21) were recruited into this study. In arm 1, cholesterol and 4ß-hydroxycholesterol were measured in HIV treatment-naive patients at baseline and then at 4 and 16 weeks after initiation of efavirenz-based antiretroviral therapy. In arm 2, cholesterol and 4ß-hydroxycholesterol were measured among patients taking efavirenz during rifampicin-based tuberculosis (TB) treatment (efavirenz/rifampicin) just before completion of TB treatment and then serially following completion of TB treatment (efavirenz alone). Non-linear mixed-effect modelling was performed. RESULTS: A one-compartment, enzyme turnover model described 4ß-hydroxycholesterol kinetics adequately. Efavirenz treatment in arm 1 resulted in 1.74 (relative standard error = 15%), 3.3 (relative standard error = 33.1%) and 4.0 (relative standard error = 37.1%) average fold induction of CYP3A for extensive (CYP2B6*1/*1), intermediate (CYP2B6*1/*6) and slow (CYP2B6*6/*6) efavirenz metabolizers, respectively. The rate constant of 4ß-hydroxycholesterol formation [mean (95% CI)] just before completion of TB treatment [efavirenz/rifampicin co-treatment, 7.40 × 10(-7) h(-1) (5.5 × 10(-7)-1.0 × 10(-6))] was significantly higher than that calculated 8 weeks after completion [efavirenz alone, 4.50 × 10(-7) h(-1) (4.40 × 10(-7)-4.52 × 10(-7))]. The CYP3A induction dropped to 62% of its maximum by week 8 of completion. CONCLUSIONS: Our results indicate that efavirenz induction of CYP3A is influenced by CYP2B6 genetic polymorphisms and that efavirenz/rifampicin co-treatment results in higher induction than efavirenz alone.

Pharmacogenetic and pharmacokinetic aspects of CYP3A induction by efavirenz in HIV patients.

We investigated the effects of pharmacogenetic variations and efavirenz pharmacokinetics on inter-individual differences in the extent of CYP3A induction by efavirenz using 4ß-hydroxycholesterol/cholesterol (4ß-OHC/Chol) as a marker for CYP3A induction. Plasma 4ß-hydroxycholesterol and cholesterol concentrations were determined at baseline, and at the 4th, 16th and 48th week of efavirenz-based highly active antiretroviral therapy in antiretroviral therapy-naive HIV patients (n=77). Efavirenz plasma concentrations were quantified at weeks 4 and 16. CYP2B6, CYP3A5, ABCB1, UGT2B7 genotyping were done. Compared with baseline, the median plasma 4ß-OHC/Chol ratio increased at the 4th (257%), 16th (291%) and 48th (165%) week (P<0.0001). CYP2B6*6 genotype significantly influenced 4ß-OHC/Chol ratio at weeks 16 (P=0.02) and 48 (P=0.04) being highest in CYP2B6*6/*6>*1/*6>*1/*1. There were positive correlations between plasma efavirenz and 4ß-OHC/Chol ratios (week 4: P=0.02, week 16: P=0.001). CYP3A enzyme induction by efavirenz is pronounced in CYP2B6 slow metabolizers who have high efavirenz plasma exposure.

UGT1A4*3 encodes significantly increased glucuronidation of olanzapine in patients on maintenance treatment and in recombinant systems.

Olanzapine, a world leader in antipsychotic drugs, is used in the treatment of schizophrenia and bipolar disorder. There is considerable interpatient variability in its hepatic clearance. Polymorphic glucuronidation of olanzapine by uridine diphosphate glucuronosyltransferase 1A4 (UGT1A4) was investigated retrospectively in patient samples taken for routine therapeutic drug monitoring (TDM) and in recombinant metabolic systems in vitro. Multivariate analyses revealed that patients who were heterozygous as well as those who were homozygous for the UGT1A4*3 allelic variant had significantly higher concentrations of the major metabolite olanzapine 10-N-glucuronide in serum (+38% (P = 0.011) and +246% (P < 0.001), respectively). This finding was in line with the significant increases in glucuronidation activity of olanzapine observed with recombinant UGT1A4.3 (Val-48) as compared with UGT1A4.1 (Leu-48) (1.3-fold difference, P < 0.001). By contrast, serum concentrations of the parent drug were not significantly influenced by UGT1A4 genotype. Our findings therefore indicate that UGT1A4-mediated metabolism is not a major contributor to interpatient variability in olanzapine levels. However, with respect to other drugs for which UGT1A4 has a dominant role in clearance, increased glucuronidation encoded by UGT1A4*3 might impact the risk for subtherapeutic drug exposure.

A 5-year prospective population-based study of juvenile chronic arthritis: onset, disease process, and outcome.

OBJECTIVES: To investigate, in a population-based cohort of patients with juvenile chronic arthritis (JCA), onset characteristics, progression, outcome, and prognostic factors longitudinally for 5 years. METHODS: This cohort consisted of 132 incidence cases identified between 1984 and 1986 in southwestern Sweden followed for 5 years with annual reports of subgroup, joint assessment, disease activity, eye examinations, laboratory measurements, and medication. At the 5-year follow-up, the Childhood Health Assessment Questionnaire (Child-HAQ) was evaluated. European League Against Rheumatism (EULAR) criteria for diagnosis and disease activity were used. RESULTS: During the 5 years only four patients were lost to follow-up, 34% changed subgroup and 8% developed uveitis. At the 5-year follow-up the disease was active in 12% of the patients, stable in 28%, inactive in 25%, and in remission in 34%. Among those examined, 24% had radiological changes, of whom half had advanced changes. The Child-HAQ median score at the 5-year follow-up was 0.13 (range 0.0-1.9). The number of involved joints at inclusion correlated positively with active disease at the 5-year follow-up. Age at disease onset, the number of involved joints, and the number of joints with arthritis correlated positively with continuous disease and Child-HAQ score. CONCLUSION. Our study shows a diverse disease course during the first 5 years of JCA where one-third changed subgroup and two-thirds did not reach remission. Age of disease onset, the number of involved joints, and the number of joints with arthritis at inclusion were associated with poor outcome at the 5-year follow-up.

The dopaminergic stabilizer pridopidine is to a major extent N-depropylated by CYP2D6 in humans.

PURPOSE: The influence of the cytochrome P450 enzyme CYP2D6 in the metabolism of the novel dopaminergic stabilizer pridopidine was investigated in healthy Swedish Caucasians. METHODS: Six extensive metabolizers (EM) and six poor metabolizers (PM) of debrisoquine were given a single oral dose of pridopidine (EM, 50 mg; PM, 25 mg). RESULTS: The mean total plasma clearance of pridopidine was 541 and 138 mL/min in EM and PM, respectively (p = 0.003), and was slightly higher in PM than the mean renal plasma clearance (105 mL/min; p = 0.11). The mean plasma area under the time-concentration curve between time zero and 32 h (AUC(0-32 h)) of the N-depropyl metabolite ACR30 was higher in EM than in PM (1,377 vs. 61 nmol h/mL, respectively; p < 0.001). The urinary excretion of pridopidine + ACR30 was high in both EM (85 %) and PM (78 %). The dose-adjusted peak concentration (C(max)) was not statistically different in EM and PM; consequently, the oral absorption of pridopidine was close to complete. CONCLUSIONS: Following a single dose of pridopidine, the drug is N-depropylated by CYP2D6 in EM, while in PM the most important elimination pathway is renal glomerular filtration. Results of studies examining the effects of multiple repeat dosing suggest that the CYP2D6 enzyme is at least partly inactivated by pridopidine.

Effect of rifampicin and CYP2B6 genotype on long-term efavirenz autoinduction and plasma exposure in HIV patients with or without tuberculosis.

We performed a prospective comparative study to examine, from a pharmacogenetics perspective, the effect of rifampicin (RIF) on long-term efavirenz (EFV) autoinduction and kinetics. In a study population of patients with HIV receiving EFV with RIF (arm 2, n = 54) or without RIF (arm 1, n = 128 controls), intraindividual and interindividual plasma EFV and 8-hydroxyefavirenz levels were compared at weeks 4 and 16 of EFV therapy. In arm 2, RIF was initiated 4 weeks before starting EFV. In controls (arm 1), the plasma EFV was significantly lower whereas 8-hydroxyefavirenz was higher at week 16 as compared to week 4. By contrast, there were no significant differences in plasma EFV and 8-hydroxyefavirenz concentrations over time in arm 2. At week 4, the plasma EFV concentration was significantly lower in arm 2 as compared to arm 1, but no significant differences were observed by week 16. When stratified by CYP2B6 genotype, significant differences were observed only with respect to CYP2B6*1/*1 genotypes. Ours is the first report of the CYP2B6 genotype-dependent effect of RIF on long-term EFV autoinduction.

Clinically significant CYP2C inhibition by noscapine but not by glucosamine.

Noscapine and glucosamine reportedly interact with warfarin. We investigated the effects of these drugs on various cytochrome P450 (CYP) activity markers. Twelve healthy subjects were phenotyped at baseline and during separate treatments with noscapine and glucosamine. Whereas glucosamine had no significant effect on CYP activity, noscapine caused marked inhibition of CYP2C9 (4.9-fold increase in urinary losartan/E3174 ratio) and CYP2C19 (3.6-fold increase in the plasma omeprazole/5-hydroxyomeprazole ratio). Noscapine-dependent inhibition of CYP2C9 may explain the interaction with warfarin.

Voriconazole increases while itraconazole decreases plasma meloxicam concentrations.

This study investigated the effect of voriconazole, an inhibitor of cytochrome P450 2C9 (CYP2C9) and CYP3A4, and itraconazole, an inhibitor of CYP3A4, on the pharmacokinetics and pharmacodynamics of meloxicam. Twelve healthy volunteers in a crossover study ingested 15 mg of meloxicam without pretreatment (control), after voriconazole pretreatment, and after itraconazole pretreatment. The plasma concentrations of meloxicam, voriconazole, itraconazole, and thromboxane B(2) (TxB(2)) generation were monitored. Compared to the control phase, voriconazole increased the mean area under the plasma concentration-time curve from 0 to 72 h (AUC(0-72)) of meloxicam by 47% (P < 0.001) and prolonged its mean half-life (t(1/2)) by 51% (P < 0.01), without affecting its mean peak concentration (C(max)). In contrast, itraconazole decreased the mean AUC(0-72) and C(max) of meloxicam by 37% (P < 0.001) and by 64% (P < 0.001), respectively, and prolonged its t(1/2) and time to C(max). The plasma protein unbound fraction of meloxicam was unchanged by voriconazole and itraconazole. Lowered plasma meloxicam concentrations during the itraconazole phase were associated with decreased pharmacodymic effects of meloxicam, as observed by weaker inhibition of TxB(2) synthesis compared to the control and voriconazole phases. Voriconazole increases plasma concentrations of meloxicam, whereas itraconazole, unexpectedly, decreases plasma meloxicam concentrations, possibly by impairing its absorption.

Anti-tumour necrosis factor therapy in rheumatoid arthritis and risk of malignant lymphomas: relative risks and time trends in the Swedish Biologics Register.

BACKGROUND: Tumour necrosis factor (TNF) antagonists have proved effective as treatment against rheumatoid arthritis (RA), but the unresolved issue of whether the use of anti-TNF therapy increases the already elevated risk of lymphoma in RA remains a concern. METHODS: Using the Swedish Biologics Register (ARTIS), the Swedish Cancer Register, pre-existing RA cohorts and cross-linkage with other national health and census registers, a national RA cohort (n = 67,743) was assembled and patients who started anti-TNF therapy between 1998 and July 2006 (n = 6604) were identified. A general population comparator (n = 471,024) was also assembled and the incidence of lymphomas from 1999 to 31 December 2006 was assessed and compared in these individuals. RESULTS: Among the 6604 anti-TNF-treated RA patients, 26 malignant lymphomas were observed during 26,981 person-years of follow-up, which corresponded to a relative risk (RR) of 1.35 (95% CI 0.82 to 2.11) versus anti-TNF-naive RA patients (336 lymphomas during 365,026 person-years) and 2.72 (95% CI 1.82 to 4.08) versus the general population comparator (1568 lymphomas during 3,355,849 person-years). RA patients starting anti-TNF therapy in 1998-2001 accounted for the entire increase in lymphoma risk versus the two comparators. By contrast, RR did not vary significantly by time since start of first treatment or with the accumulated duration of treatment, nor with the type of anti-TNF agent. CONCLUSION: Overall and as used in routine care against RA, TNF antagonists are not associated with any major further increase in the already elevated lymphoma occurrence in RA. Changes in the selection of patients for treatment may influence the observed risk.

Cytochrome P450 induction by rifampicin in healthy subjects: determination using the Karolinska cocktail and the endogenous CYP3A4 marker 4beta-hydroxycholesterol.

The Karolinska cocktail, comprising caffeine, losartan, omeprazole, and quinine, was given before and after administration of rifampicin (20, 100, or 500 mg daily) to measure induction of cytochrome P450 (P450) enzymes. Rifampicin was given for 14 days to eight healthy subjects (all of whom possessed at least one wild-type CYP2C9 and one wild-type CYP2C19 gene) in each dose group. 4beta-hydroxycholesterol was assessed as an endogenous marker of CYP3A4 induction. A fourfold induction of CYP3A4 was seen at the highest dose by both quinine:3'-hydroxyquinine and 4beta-hydroxycholesterol measurements (P < 0.001). CYP3A4 was also induced at the two lower doses of rifampicin when measured by these two markers (P < 0.01 or P < 0.001). CYP1A2, CYP2C9, and CYP2C19 were induced after 500 mg rifampicin daily (1.2-fold, P < 0.05; 1.4-fold, P < 0.05; and 4.2-fold, P < 0.01, respectively). In conclusion, we have shown that the Karolinska cocktail and 4beta-hydroxycholesterol can be used for an initial screening of the induction properties of a drug candidate.

CYP3A induction and inhibition by different antiretroviral regimens reflected by changes in plasma 4beta-hydroxycholesterol levels.

OBJECTIVE AND METHODS: A member of the major human cytochrome P450 superfamily of hemoproteins, CYP3A4/5, converts cholesterol into 4beta-hydroxycholesterol. We studied plasma 4beta-hydroxycholesterol levels prior to and 4 weeks after initiating antiretroviral therapy that included efavirenz, ritonavir-boosted atazanavir or ritonavir-boosted lopinavir with the aim of exploring the usefulness of plasma 4beta-hydroxycholesterol levels as an endogenous biomarker of CYP3A activity. Efavirenz is an inducer of CYP3A, whereas the ritonavir-boosted regimens are net inhibitors of CYP3A. RESULTS: In patients treated with efavirenz, the median plasma 4beta-hydroxycholesterol level increased by 46 ng/mL (p = 0.004; n = 11). In contrast, patients given ritonavir-boosted atazanavir showed a median decrease in plasma 4beta-hydroxycholesterol of -9.4 ng/mL (p = 0.0003; n = 22), and those given ritonavir-boosted lopinavir showed a median change from baseline of -5.8 ng/mL (p = 0.38; n = 19). There were significant between-group differences in the effects of antiretroviral treatment on plasma 4beta-hydroxycholesterol levels (p < 0.0001). CONCLUSION: Changes in plasma 4beta-hydroxycholesterol following the initiation of efavirenz- or atazanavir/ritonavir-based antiretroviral therapy reflected the respective net increase and decrease of CYP3A activity of these regimens. The plasma 4beta-hydroxycholesterol level did not indicate a net CYP3A inhibition in the lopinavir/ritonavir arm, possibly because of concomitant enzyme induction.

Effect of terbinafine and voriconazole on the pharmacokinetics of the antidepressant venlafaxine.

This study investigated the effect of terbinafine and voriconazole on the pharmacokinetics of venlafaxine in healthy volunteers. Plasma concentrations of venlafaxine and O-desmethylvenlafaxine (ODV) were measured after ingestion of 75 mg venlafaxine without pretreatment (control), after terbinafine pretreatment, or after voriconazole pretreatment. During the terbinafine phase, the area under the plasma concentration-time curve (AUC(0-infinity)) of venlafaxine was on average 490% (P<0.001) and that of ODV 57% (P<0.001) of the corresponding control value. Terbinafine decreased the AUC(0-infinity) ratio of ODV over venlafaxine by 82% (P<0.001). Voriconazole slightly increased the sum of AUC(0-infinity) of venlafaxine plus AUC(0-infinity) of ODV (active moiety) by 31% (P<0.001). The most likely mechanism for the interaction between terbinafine and venlafaxine is the inhibition of CYP2D6-mediated O-demethylation of venlafaxine, whereas the minor effects of voriconazole are probably due to the inhibition of CYP3A4-, CYP2C9-, or CYP2C19-mediated metabolism of venlafaxine.

Metabolism of antidepressant and neuroleptic drugs by cytochrome p450s: clinical and interethnic aspects.

Early after the introduction of the classical tricyclic antidepressants and neuroleptics, it was shown that the plasma concentrations of these drugs varied between patients given the same dose. This variation is to a major extent due to the variation in the activity of cytochrome P450 (CYP) enzymes (cf. review by Bertilsson et al.1) During recent year(s), the different CYP enzymes catalyzing the metabolism of these drugs have been identified and the clinical relevance has also been identified. This brief review highlights the clinical importance and ethnic differences in the metabolism of these drugs.

CYP3A5 genotype has an impact on the metabolism of the HIV protease inhibitor saquinavir.

CYP3A is the main enzyme subfamily involved in the metabolism of the HIV protease-inhibitor saquinavir. We hypothesized that individuals homozygous for CYP3A5*1 might have a higher oral clearance of saquinavir, compared with subjects lacking functional CYP3A5 alleles. A single-dose pharmacokinetic trial of saquinavir soft gel capsules, 1,200 mg, was performed in 16 black Tanzanian healthy volunteers with two functional CYP3A5 alleles (*1/*1) and in 18 volunteers without functional CYP3A5 alleles (both alleles being either *3, *6, or *7). The median area under the plasma concentration-time curve (AUC)0-24 reached among subjects with two functional alleles was 1,410 ng h/ml (interquartile range (IQR) 826-1,929), whereas it was 2,138 ng h/ml (IQR 1,380-3,331) in subjects without (P=0.0533, Mann-Whitney U-test). The median ratio of saquinavir over its M2 plus M3 hydroxy metabolites in urine was 64 (IQR 52-73) in subjects with two functional alleles, whereas it was 145 (IQR 89-181) in those without (P=0.000078, Mann-Whitney U-test). In conclusion, saquinavir is metabolized by CYP3A5. The median AUC0-24 for saquinavir among individuals with two functional CYP3A5 alleles was 34% lower than among those with no functional alleles. To clarify the clinical importance of the CYP3A5 polymorphism, further studies should be conducted on saquinavir, dosed to steady state, in the presence of ritonavir boosting.

Risks of solid cancers in patients with rheumatoid arthritis and after treatment with tumour necrosis factor antagonists.

BACKGROUND: Existing studies of solid cancers in rheumatoid arthritis (RA) reflect cancer morbidity up until the early 1990s in prevalent cohorts admitted to hospital during the 1980s. OBJECTIVE: To depict the cancer pattern of contemporary patients with RA, from updated risk data from prevalent and incident RA populations. To understand the risk of solid cancer after tumour necrosis factor (TNF) treatment by obtaining cancer data from cohorts treated in routine care rather than trials. METHODS: A population based study of three RA cohorts (one prevalent, admitted to hospital 1990-2003 (n = 53,067), one incident, diagnosed 1995-2003 (n = 3703), and one treated with TNF antagonists 1999-2003 (n = 4160)), which were linked with Swedish nationwide cancer and census registers and followed up for cancer occurrence through 2003. RESULTS: With 3379 observed cancers, the prevalent RA cohort was at marginally increased overall risk of solid cancer, with 20-50% increased risks for smoke related cancers and +70% increased risk for non-melanoma skin cancer, but decreased risk for breast (-20%) and colorectal cancer (-25%). With 138 cancers, the incident RA cohort displayed a similar cancer pattern apart from non-decreased risks for colorectal cancer. TNF antagonist treated patients displayed solid cancer (n = 67) risks largely similar to those of other patients with RA. CONCLUSION: The cancer pattern in patients treated with TNF antagonists mirrors those of other contemporary as well as historic RA cohorts. The consistent increase in smoking associated cancers in patients with RA emphasises the potential for smoking cessation as a cancer preventive measure in RA.

Haematopoietic malignancies in rheumatoid arthritis: lymphoma risk and characteristics after exposure to tumour necrosis factor antagonists.

BACKGROUND: Patients with rheumatoid arthritis (RA) are at increased risk of malignant lymphomas, and maybe also of leukaemia and multiple myeloma. The effect of tumour necrosis factor (TNF) antagonists on lymphoma risk and characteristics is unclear. OBJECTIVE: To assess expected rates and relative risks of haematopoietic malignancies, especially those associated with TNF antagonists, in large population based cohorts of patients with RA. METHODS: A population based cohort study was performed of patients with RA (one prevalent cohort (n = 53,067), one incident cohort (n = 3703), and one TNF antagonist treated cohort 1999 through 2003 (n = 4160)), who were linked with the Swedish Cancer Register. Additionally, the lymphoma specimens for the 12 lymphomas occurring in patients with RA exposed to TNF antagonists in Sweden 1999 through 2004 were reviewed. RESULTS: Study of almost 500 observed haematopoietic malignancies showed that prevalent and incident patients with RA were at increased risk of lymphoma (SIR = 1.9 and 2.0, respectively) and leukaemia (SIR = 2.1 and 2.2, respectively) but not of myeloma. Patients with RA treated with TNF antagonists had a tripled lymphoma risk (SIR = 2.9) compared with the general population. After adjustment for sex, age, and disease duration, the lymphoma risk after exposure to TNF antagonists was no higher than in the other RA cohorts. Lymphomas associated with TNF antagonists had characteristics similar to those of other RA lymphomas. CONCLUSION: Overall, patients with RA are at equally increased risks for lymphomas and leukaemias. Patients with RA treated with TNF antagonists did not have higher lymphoma risks than other patients with RA. Prolonged observation is needed to determine the long term effects of TNF antagonists on lymphoma risk.

Results from a nationwide postmarketing cohort study of patients in Sweden treated with etanercept.

OBJECTIVES: To describe a nationwide system for postmarketing follow up of new antirheumatic drugs in Sweden, and to analyse safety and effectiveness in an etanercept treated patient cohort. METHODS: Etanercept became available in Sweden for prescribing on a named patient basis in 1999. All patients treated were included in a follow up of intensified adverse event reporting and recording of clinical outcome during 24 months, according to the EULAR core set. RESULTS: The mean (SD) disease activity score (DAS 28) value at inclusion among 820 patients recruited on a named patient basis during year 1 was 5.99 (1.19). After two years, 21% (n = 172) of these patients had discontinued the treatment. Of the remaining 648 patients, 68% (n = 442) responded to the treatment. However, in 55% of the responders, the disease activity was intermediate or high (mean DAS 28, 3.37 (1.20)). In all, 540 adverse events were reported in 421 adverse drug reaction (ADR) reports, in 294 patients. The events in 80 reports (19%) were serious. Twenty two per cent of the events were infections, of which 24% (n = 29) were serious. The incidence of serious adverse events remained constant over time. CONCLUSIONS: At start of etanercept treatment, patients had high disease activity. Activity remained high in a large proportion of the responding patients. Although serious ADRs occurred during late phases of treatment, no unexpected safety problems arose. No specific indicators of ADR risk were found. The monitoring system that was established may be useful in future postmarketing surveillance.