ENBREL®

Etanercept (rch)

NAME OF THE MEDICINE

ENBREL (Etanercept) 25 mg and 50 mg powder for injection and water for injections

ENBREL (Etanercept) 25 mg* and 50 mg solution for injection in 0.5 mL pre-filled syringe

DESCRIPTION

Powder for solution for injection (powder and solvent for solution for injection). Following reconstitution with water for injections, ENBREL is a clear colourless solution, with a pH of 7.1-7.7. ENBREL powder for injection also contains mannitol, sucrose and trometamol as excipients.

ENBREL solution for injection in a pre-filled syringe is a clear, colourless or pale yellow solution with a pH of 6.1-6.5. ENBREL solution for injection also contains sucrose, sodium chloride, L-arginine hydrochloride, sodium phosphate-monobasic dihydrate, sodium phosphate-dibasic dihydrate and water.

Etanercept is a human tumour necrosis factor receptor p75 Fc fusion protein produced by recombinant DNA technology in a Chinese hamster ovary (CHO) mammalian expression system. Etanercept is a dimer of a protein genetically engineered by fusing the extracellular ligand binding domain of human tumour necrosis factor receptor-2 (TNFR2/p75) to the Fc domain of human IgG1. This Fc component contains the hinge, CH₂ and CH₃ regions but not the CH₁ region of IgG1. Etanercept contains 934 amino acids and has an apparent molecular weight of approximately 150 kilodaltons.

The potency is determined by measuring the ability of etanercept to neutralise the TNFα-mediated growth inhibition of A375 cells. The specific activity of etanercept is 1.7 x 10⁶ units/mg.

PHARMACOLOGY

Pharmacodynamics

Etanercept binds specifically to tumour necrosis factor (TNF) and blocks its interaction with cell surface TNF receptors. Etanercept did not induce complement-mediated cytolysis of murine T cells that expressed TNF on the cell surface. TNF is a naturally occurring cytokine that is involved in normal inflammatory and immune responses. TNF is a dominant cytokine in the inflammatory process of rheumatoid arthritis. Elevated levels of TNF are also found in the synovium and psoriatic plaques of patients with psoriatic arthritis and in serum and synovial tissue of patients with ankylosing spondylitis. In plaque psoriasis, infiltration by inflammatory cells including T-cells leads to increased TNF levels in psoriatic lesions, compared with levels in uninvolved skin.

Two distinct receptors for TNF (TNFRs), a 55 kilodalton protein (p55) and a 75 kilodalton protein (p75), exist naturally as monomeric molecules on cell surfaces and in soluble forms. Biological activity of TNF is dependent upon binding to either cell surface TNFR.

Etanercept is a dimeric soluble form of the p75 TNF receptor that can bind to two TNF molecules. It inhibits the activity of TNF in vitro and has been shown to affect several animal models of inflammation, including murine collagen-induced arthritis. Etanercept inhibits binding of both TNFα and TNFβ (lymphotoxin alpha [LTα]) to cell surface TNFRs, rendering TNF biologically inactive. Cells expressing transmembrane TNF that bind ENBREL are not lysed in vitro in the presence or absence of complement.

Mechanism of action

Pro-inflammatory molecules that are linked in a network controlled by TNF mediate much of the joint pathology in rheumatoid arthritis and ankylosing spondylitis and skin pathology in plaque psoriasis. The mechanism of action of etanercept is thought to be its competitive inhibition of TNF binding to cell surface TNFR, preventing TNF-mediated cellular responses by rendering TNF biologically inactive. Etanercept may also modulate biological responses controlled by additional downstream molecules (e.g., cytokines, adhesion molecules, or proteinases) that are induced or regulated by TNF.

Pharmacokinetics

Etanercept is slowly absorbed from the site of subcutaneous (SC) injection, reaching maximum concentration between 24 and 96 hours after a single dose. The absolute bioavailability is 76% as calculated in a population pharmacokinetic analysis of several studies. With twice weekly doses, it is anticipated that steady-state concentrations may be two to five-fold greater than those observed after single doses. After a single SC dose of 25 mg ENBREL, the average maximum serum concentration observed in healthy volunteers was 1.65 ± 0.66 mg/L, and area under the curve was 235 ± 96.6 mg.hr/L. Dose proportionality has not been formally evaluated, but there is no apparent saturation of clearance across the dosing range.

A bi-exponential curve is required to describe the concentration time curve of etanercept. The central volume of distribution of etanercept is 7.6 L, while the volume of distribution at steady state is 10.4 L.

After continued dosing of RA patients (n = 25) with ENBREL for 6 months with 25 mg twice weekly, the median observed level was 3.0 mg/L (range 1.7 to 5.6 mg/L).

Etanercept is cleared slowly from the body. The half-life is long, approximately 70 hours. Clearance is approximately 0.066 L/hr in patients with RA, somewhat lower than the value of 0.11 L/hr observed in healthy volunteers. Additionally, the pharmacokinetics of etanercept in rheumatoid arthritis patients, plaque psoriasis and ankylosing spondylitis patients are similar.

Serum concentration profiles at steady state were comparable among patients with RA treated with 50 mg ENBREL powder for injection once weekly and those treated with 25 mg ENBREL powder for injection twice weekly. A single 50 mg/mL injection of ENBREL was also found to be bioequivalent to two simultaneous injections of 25 mg/mL. The mean (± standard deviation) Cmax, Cmin and partial AUC were 2.4 ± 1.5 mg/L, 1.2 ± 0.7 mg/L and 297 ± 166 mg.h/L, respectively, for patients treated with 50 mg ENBREL once weekly (n = 21); and 2.6 ± 1.2 mg/L, 1.4 ± 0.7 mg/L and 316 ± 135 mg.h/L for patients treated with 25 mg ENBREL twice weekly (n = 16). Serum concentrations in patients with RA have not been measured for periods of dosing that exceed 6 months. In an open-label, single-dose, two treatment crossover study in healthy volunteers, etanercept administered as a single injection of ENBREL 50 mg solution for injection was found to be bioequivalent to two simultaneous injections of ENBREL 25 mg powder for injection. The mean (± standard deviation) Cmax and AUC(0-T) are expressed in the table below

Although there is elimination of radioactivity in urine after administration of radiolabelled etanercept to patients and volunteers, increased etanercept concentrations were not observed in patients with acute renal or hepatic failure. The presence of renal and hepatic impairment should not require a change in dosage. There is no apparent pharmacokinetic difference between men and women.

No formal pharmacokinetic studies have been conducted to examine the metabolism of etanercept or the effects of renal or hepatic impairment. Methotrexate has no effect on the pharmacokinetics of etanercept. The effect of ENBREL on the human pharmacokinetics of methotrexate has not been investigated.

Geriatric patients

The impact of advanced age was studied in the population pharmacokinetic analysis of etanercept serum concentrations. Clearance and volume estimates in patients aged 65 to 87 years were similar to estimates in patients less than 65 years of age.

Patients with juvenile chronic arthritis

In a polyarticular-course juvenile chronic arthritis trial with ENBREL, 69 patients (age 4 to 17 years) were administered 0.4 mg ENBREL/kg twice weekly for three months. Serum concentration profiles were similar to those seen in adult rheumatoid arthritis patients. The youngest children (4 years of age) had reduced clearance (increased clearance when normalised by weight) compared with older children (12 years of age) and adults. Simulation of dosing suggests that while older children (10-17 years of age) will have serum levels close to those seen in adults, younger children will have appreciably lower levels.

Clinical trials

This section presents data from 5 randomised controlled trials in rheumatoid arthritis, 1 study in polyarticular-course juvenile chronic arthritis, 2 trials in ankylosing spondylitis, 1 trial in psoriatic arthritis and 2 trials in plaque psoriasis.

Adult rheumatoid arthritis

Placebo-controlled studies

The efficacy of ENBREL was assessed in a randomised, double-blind, placebo-controlled study. The study evaluated 234 adult patients with active rheumatoid arthritis who had failed therapy with at least one but no more than four disease-modifying antirheumatic drugs (DMARDs). Doses of 10 mg or 25 mg ENBREL or placebo were administered subcutaneously twice a week for 6 consecutive months. The results of this controlled trial were expressed in percentage improvement in rheumatoid arthritis using American College of Rheumatology (ACR) response criteria. The primary endpoint was achievement of an ACR 20 response at month 3. Subjects who failed to respond based on pre-specified criteria for lack of efficacy before month 3 were allowed to drop out early and were considered treatment failures. By definition, an ACR 20 response is achieved if a patient experiences a 20% improvement in their tender joint count and swollen joint count plus ≥ 20% improvement in at least three of the following five criteria: (1) patient pain assessment, (2) patient global assessment, (3) physician global assessment, (4) patient self-assessed disability and (5) acute-phase reactant (erythrocyte sedimentation rate or C-reactive protein). ACR 50 and 70 responses are defined using the same criteria with a 50% improvement or a 70% improvement, respectively. ACR 20 and 50 responses were higher in patients treated with ENBREL at 3 and 6 months than in patients treated with placebo, at all time points as seen in the table below.

Approximately 15% of subjects who received ENBREL achieved an ACR 70 response at month 3 and month 6 compared to fewer than 5% of subjects in the placebo arm. Among patients receiving ENBREL, the clinical responses generally appeared within 1 to 2 weeks after initiation of therapy and nearly always occurred by 3 months. A dose response was seen; results with 10 mg were intermediate between placebo and 25 mg. ENBREL was significantly better than placebo in all components of the ACR criteria as well as other measures of rheumatoid arthritis disease activity not included in the ACR response criteria, such as morning stiffness. A Health Assessment Questionnaire (HAQ), which included disability, vitality, mental health, general health status and arthritis-associated health status sub-domains, was administered every 3 months during the trial. All sub-domains of the HAQ were improved in patients treated with ENBREL compared to controls at 3 and 6 months.

After discontinuation of ENBREL, symptoms of arthritis generally returned within a month. Reintroduction of treatment with ENBREL after discontinuations of up to 24 months resulted in the same magnitudes of response as patients who received ENBREL without interruption of therapy based on results of open-label studies. Continued durable responses have been seen in open-label extension treatment trials when patients received ENBREL without interruption.

A second randomised, double-blind, placebo-controlled study also compared the safety and efficacy of ENBREL (25 mg) against placebo (SC, twice a week over 6 months) in 89 RA patients in addition to a stable dose of methotrexate. The ACR response criteria were used to assess efficacy. The primary endpoint was achievement of an ACR 20 response at 6 months. Responses were higher in patients treated with ENBREL at 3 and 6 months. Clinical responses in ENBREL-treated patients generally appeared after 1-2 weeks of therapy. In addition, approximately 15% of ENBREL-treated patients achieved an ACR 70 response at month 3 and month 6, compared to less than 5% of subjects in the placebo arm. ENBREL-treated patients experienced significantly greater improvements in all components of the ACR criteria, compared to patients in the placebo arm.

The safety and efficacy of 50 mg ENBREL (two 25 mg SC injections) administered once weekly were evaluated in a double-blind, placebo-controlled study of 420 patients with active RA. In this study, 53 patients received placebo, 214 patients received 50 mg ENBREL once weekly and 153 patients received 25 mg ENBREL twice weekly. The safety and efficacy profiles of the two ENBREL treatment regimens were comparable in their effect on signs and symptoms of RA.

Active-Controlled Studies

A randomised, active-controlled study with blinded radiographic evaluations as a primary endpoint compared the efficacy of ENBREL to oral methotrexate in 632 adult patients with active rheumatoid arthritis (<3 years duration) who had never received treatment with methotrexate. The patients had to have >12 tender joints, >10 swollen joints and either ESR >28 mm/hr, CRP >2.0 mg/dL, or morning stiffness for >45 minutes. Patients were at high risk of erosive disease defined as being rheumatoid factor positive or having at least three erosions at baseline. Doses of 10 mg or 25 mg ENBREL were administered SC twice a week for up to 24 months. Methotrexate doses were escalated from 7.5 mg/week to a maximum of 20 mg/week over the first 8 weeks of the trial and continued for up to 24 months. Clinical improvement including onset of action within 2 weeks with ENBREL 25 mg was similar to that seen in the previous 2 trials and was maintained for up to 24 months. At baseline, patients had a moderate degree of disability, with mean HAQ scores of 1.4 to 1.5. Treatment with ENBREL 25 mg resulted in substantial improvement at 12 months, with about 44% of patients achieving a normal HAQ score (less than 0.5). This benefit was maintained in Year 2 of this study.

In this study, structural joint damage was assessed radiographically and expressed as change in Total Sharp Score (TSS) and its components, the erosion score and joint space narrowing score (JSN). Radiographs of hands/wrists and feet were read at baseline and 6, 12 and 24 months. The 10 mg ENBREL dose had consistently less effect on structural damage than the 25 mg dose. ENBREL 25 mg was significantly superior to methotrexate for erosion scores at both 12 and 24 months. The differences in TSS and JSN were not statistically significant between methotrexate and ENBREL 25 mg. The results are shown in the figure below.

Radiographic Progression over 24 Months

In another active-controlled, double-blind, randomised study, clinical efficacy, safety and radiographic progression in RA patients treated with ENBREL alone (25 mg twice weekly), methotrexate alone (7.5 to 20 mg weekly, median dose 20 mg) and of the combination of ENBREL and methotrexate initiated concurrently were compared in 682 adult patients with active rheumatoid arthritis of 6 months to 20 years duration (median 5 years) who had a less than satisfactory response to at least 1 DMARD other than methotrexate. Forty-three percent of patients had previously received MTX a mean of 2 years prior to the trial at a mean dose of 12.9mg/week. Patients were excluded from this study if MTX had been discontinued for lack of efficacy or for safety considerations.

Patients in the ENBREL in combination with methotrexate therapy group had significantly higher ACR 20, ACR 50, ACR 70 responses and improvement for disease activity scores (DAS) at both 24 and 52 weeks than patients in either of the single therapy groups (results shown in table below).

The percentage of patients who achieved low disease activity (defined as DAS < 2.4) at 52 weeks was 39%, 35% and 61% for patients in the ENBREL alone group, methotrexate alone group and the ENBREL combination group, respectively. Remission (defined as DAS < 1.6) was experienced by 18%, 14% and 37% of patients administered ENBREL alone, methotrexate alone and combination therapy respectively.

Mean HAQ scores improved from baseline levels of (1.7, 1.7 and 1.8) to (1.0, 1.1 and 0.8) at 52 weeks in the ENBREL, methotrexate and ENBREL in combination with methotrexate treatment groups, respectively (combination versus both methotrexate and etanercept, p<0.01).

Radiographic progression as measured by Total Sharp Score (TSS) was significantly less in the ENBREL group than in the methotrexate group at week 52. Significantly less radiographic progression (TSS) was observed with ENBREL in combination with methotrexate compared with ENBREL alone or methotrexate alone at week 52. The results for radiographic results (TSS), joint erosion and joint space narrowing (JSN) at week 52 are shown in the figure below. There was a significant decrease in TSS compared with baseline in the combination of ENBREL with methotrexate group.

Radiographic Progression: Comparison of ENBREL vs. Methotrexate vs. ENBREL in Combination with Methotrexate in Patients with RA of 6 Months to 20 Years Duration (52-Week Results)

Pairwise comparison p-values: * = p < 0.05 for comparisons of ENBREL vs. methotrexate, ^,† = p < 0.05 for comparisons of ENBREL + methotrexate vs. methotrexate and ^Φ = p < 0.05 for comparisons of ENBREL + methotrexate vs. ENBREL

The percentage of patients without progression (TSS change ≤ 0.5) was higher in the ENBREL in combination with methotrexate and ENBREL groups compared with methotrexate at week 24 (74%, 68% and 56%, respectively; p<0.05) and week 52 (80%, 68% and 57%, respectively; p<0.05).

The safety and efficacy of 50 mg ENBREL (two 25 mg SC injections) administered once weekly were evaluated in a double-blind, placebo-controlled study of 420 patients with active RA. In this study, 53 patients received placebo, 214 patients received 50 mg ENBREL once weekly and 153 patients received 25 mg ENBREL twice weekly. The safety and efficacy profiles of the two ENBREL treatment regimens were comparable at week 8 in their effect on signs and symptoms of RA.

Juvenile rheumatoid arthritis

The safety and efficacy of ENBREL were assessed in a two-part study of 69 children with polyarticular-course JRA who had a variety of JRA onset types. Patients aged 4 to 17 years with moderately to severely active polyarticular-course JRA refractory to or intolerant of methotrexate were enrolled; patients remained on a stable dose of a single non-steroidal anti-inflammatory drug and/or prednisone (≤ 0.2 mg/kg/day or 10 mg maximum). In part 1, all patients received 0.4 mg/kg (maximum 25 mg per dose) ENBREL SC twice weekly. In part 2, patients with a clinical response at day 90 were randomised to remain on ENBREL or receive placebo for four months and assessed for disease flare. Responses were measured using the JRA Definition of Improvement (DOI), defined as ≥ 30% improvement in at least three of six and ≥ 30% worsening in no more than one of six JRA core set criteria, including active joint count, limitation of motion, physician and patient/parent global assessments, functional assessment and ESR. Disease flare was defined as a ≥ 30% worsening in three of six JRA core set criteria and ≥ 30% improvement in not more than one of six JRA core set criteria and a minimum of two active joints.

In part 1 of the study, 51 of 69 (74%) patients demonstrated a clinical response and entered part 2. In part 2, 6 of 25 (24%) patients remaining on ENBREL experienced a disease flare compared to 20 of 26 (77%) patients receiving placebo (p=0.007). From the start of part 2, the median time to flare was ≥ 116 days for patients who received ENBREL and 28 days for patients who received placebo. Each component of the JRA core set criteria worsened in the arm that received placebo and remained stable or improved in the arm that continued on ENBREL. The data suggested the possibility of a higher flare rate among those patients with a higher baseline ESR. Of patients who demonstrated a clinical response at 90 days and entered part 2 of the study, some of the patients remaining on ENBREL continued to improve from month 3 through month 7, while those who received placebo did not improve.

Adults with psoriatic arthritis

The efficacy of ENBREL was assessed in a randomised, double-blind, placebo-controlled study of 205 patients with psoriatic arthritis. Patients were between 18 and 70 years of age and had active psoriatic arthritis (≥ 3 swollen joints and ≥ 3 tender joints) in at least one of the following forms: (1) distal interphalangeal (DIP) involvement; (2) polyarticular arthritis (absence of rheumatoid nodules and presence of psoriasis); (3) arthritis mutilans; (4) asymmetric psoriatic arthritis; or (5) spondylitis-like ankylosis. Patients also had plaque psoriasis with a qualifying target lesion ≥ 2cm in diameter. Patients currently on methotrexate therapy (stable for ≥ 2 months) could continue at a stable dose of ≤25mg/week methotrexate. Doses of 25mg ENBREL or placebo were administered SC twice a week for 6 months. At the end of the double-blind study, patients could enter a long-term open-label extension study for a total duration of up to 2 years.

The clinical responses were expressed as percentages of patients achieving the ACR 20, 50 and 70 response and percentages with improvement in Psoriatic Arthritis Response Criteria (PsARC). The PsARC endpoint comprises of four measures: (1) patient global assessment, (2) physician global assessment, (3) joint pain/tenderness score and (4) joint swelling score. Achievement of the PsARC endpoint requires improvement in at least two of the four measures, one of which must be joint pain/tenderness or swelling and no worsening in any of the four measures. Data have not been evaluated to establish whether ENBREL inhibits progressive joint destruction in psoriatic arthritis. Results are summarised in the Table below.

In this study, the psoriatic skin lesions of patients with active arthritis were also improved with ENBREL treatment compared with placebo. In a subset of patients with psoriasis involvement ≥3% of body surface area, improvements in the Psoriasis Area and Severity Index (PASI) were assessed at Month 3 and Month 6. The PASI is a composite score calculated from disease activity scores and the fraction of body surface area involvement. PASI results are presented in the Table below.

PASI Responses of Patients with Psoriatic Arthritis in Placebo-Controlled Trial

a: 25 mg ENBREL SC twice weekly
b: p < 0.001, ENBREL vs. placebo
c: p < 0.01, ENBREL vs. placebo

Among patients with psoriatic arthritis who received ENBREL, the clinical responses were apparent at the time of the first visit (4 weeks) and were maintained through 6 months of therapy. ENBREL was significantly better than placebo in all measures of disease activity (p < 0.001) and responses were similar with and without concomitant methotrexate therapy.

In this study, structural joint damage was assessed radiographically and expressed as change in modified Total Sharp Score (TSS) and its components, the erosion score and joint space narrowing score (JSN). The possible range for the modified TSS was 0 to 370. Radiographs of hands and wrists were obtained at baseline and months 6, 12 and 24.

The 1-year analyses as shown in the table below indicates that the difference between treatment groups was significant for mean annualized rate of change from baseline in TSS, erosion scores and for JSN. In addition, significantly more subjects in the etanercept group had no progression (≤0 change) in TSS from baseline, compared with subjects in the placebo group.

The modified TSS at 6, 12 and 24 months are presented in the following table for those patients who entered year 2 and provided radiographs during the second year of the study.

In subjects who received placebo during the controlled part of the study and etanercept in the open-label part, further radiographic progression was inhibited after subjects began receiving etanercept. ENBREL treatment resulted in improvement in physical function during the double-blind period and this benefit was maintained during the longer-term exposure of up to 2 years.

Quality of life in psoriatic arthritis patients was assessed using the Health Assessment Questionnaire (HAQ) and SF-36 instruments. There was a statistically significant improvement in mean HAQ score from 1.1 to 0.5 on a scale of 0 to 3 for patients treated with ENBREL. The SF-36 showed improvements in the physical but not the mental components of the quality of life score.

Adults with ankylosing spondylitis

The efficacy of ENBREL was assessed in 2 randomised, double-blind, placebo-controlled studies in 361 patients with ankylosing spondylitis. The largest of these trials (n= 277) enrolled patients who were between 18 and 70 years of age and had active ankylosing spondylitis as defined by the modified New York Criteria for Ankylosing Spondylitis. Patients were to have evidence of active disease based on visual analog scale (VAS) scores of ≥ 30 for average of duration and intensity of morning stiffness plus VAS scores of ≥ 30 for at least 2 of the following 3 parameters: patient global assessment; average of VAS values for nocturnal back pain and total back pain; average of 10 questions on the Bath Ankylosing Spondylitis Functional Index (BASFI). The duration of this study was up to 24 weeks and patients had a mean diagnosis of AS for 10 years. Patients with complete ankylosis of the spine were excluded from study participation. Patients taking hydroxychloroquine, sulfasalazine, methotrexate or prednisolone (≤10 mg/day) or equivalent, could continue these drugs at stable doses for the duration of the study. Doses of 25 mg of ENBREL (based on dose-finding studies in patients with rheumatoid arthritis) or placebo were administered subcutaneously twice a week for 6 months.

The primary measure of efficacy was a 20% improvement in the Assessment in Ankylosing Spondylitis (ASAS 20) response criteria. Compared to placebo, treatment with ENBREL resulted in significant improvements in clinical response as early as 2 weeks after the initiation of therapy (see figure below).

ASAS 20 Response in Patients with Ankylosing Spondylitis in a Placebo-Controlled Trial

*p < 0.001 for ENBREL vs. placebo.

At 12 weeks, the ASAS 20/50/70 responses were achieved by 60%, 45% and 29%, respectively, of patients receiving ENBREL, compared to 27%, 13% and 7%, respectively, of patients receiving placebo (p<0.001 for ENBREL vs placebo). Similar results were seen at week 24.

Components of Ankylosing Spondylitis Disease Activity

a p < 0.0015 for all comparisons between ENBREL and placebo at 6 months. P-values for continuous endpoints were based on percent change from baseline.

b Measured on a Visual Analog Scale (VAS) scale with 0 = "none" and 100 = "severe."

c Average of total nocturnal and back pain scores, measured on a VAS scale with 0 = "no pain" and 100 = "most severe pain."

d Bath Ankylosing Spondylitis Functional Index (BASFI), average of 10 questions.

e Inflammation represented by the average of the last 2 questions on the 6-question Bath Ankylosing Spondylitis Disease Activity Index (BASDAI).

f C-reactive protein (CRP) normal range: 0 - 1.0 mg/dL.

Adults with plaque psoriasis

The safety and efficacy of ENBREL were assessed in two randomised, double-blind, placebo-controlled studies. Study 1 evaluated 652 patients with chronic plaque psoriasis who were ≥ 18 years old, had active but clinically stable plaque psoriasis involving ≥ 10% of the body surface area and had a minimum psoriasis area and severity index (PASI) of 10 at screening. ENBREL was administered subcutaneously at doses of 25 mg once a week, 25 mg twice a week or 50 mg twice a week for 6 consecutive months. During the first 12 weeks of the double-blind treatment period, patients received placebo or one of the above three ENBREL doses. After 12 weeks of treatment, patients in the placebo group began treatment with blinded ENBREL (25 mg twice weekly); patients in the active treatment groups continued to week 24 on the dose to which they were originally randomised. This study also had a drug withdrawal period during which patients who achieved PASI improvement of at least 50% at week 24 had treatment stopped. Patients were observed off treatment for the occurrence of rebound (PASI ≥ 150% of baseline) and for the time to relapse (defined as a loss of at least half of the improvement achieved between baseline and week 24). Upon relapse, patients were retreated with ENBREL in a blinded fashion at the dose they had been receiving at week 24.

Study 2 evaluated 583 patients and had the same inclusion criteria as study 1. Patients in this study received a dose of 25 mg or 50 mg ENBREL, or placebo subcutaneously twice a week for 12 weeks and then all patients received open-label 25 mg ENBREL twice weekly for an additional 24 weeks.

The primary efficacy endpoint in both studies was the proportion of patients in each treatment group that achieved the PASI 75 (i.e., at least a 75% improvement in the PASI score from baseline) at 12 weeks. The results of the primary and secondary endpoints of both studies are shown below.

Among patients with plaque psoriasis who received ENBREL, significant responses relative to placebo were apparent at the time of the first visit (2 weeks) for the mean percent improvement in PASI, Dermatologist Static Global Assessment of Psoriasis, Dermatology Life Quality Index and Patient Global Assessment of Psoriasis and were maintained through 24 weeks of therapy.

During the withdrawal period in study 1, symptoms of psoriasis gradually returned with a median time to disease relapse of 3 months. No rebound flare of disease and no psoriasis-related adverse events were observed. Retreatment with ENBREL resulted in a similar magnitude of response as was seen during the initial double-blind portion of the study.

At weeks 4, 8 and 12 of study 2, the 50 mg twice weekly group had a significantly higher PASI 75 response rate than the 25 mg twice weekly group (p < 0.05, see figure below). The majority of patients who were initially randomised to 50 mg twice weekly and had their ENBREL dose decreased at week 12 to 25 mg twice weekly maintained their PASI 75 response through week 36. For patients who received 25 mg twice weekly throughout the study, the PASI 75 response continued to improve between weeks 12 and 36.

PASI 75 Response of Patients with Plaque Psoriasis in Study 2

x: = p< 0.001 compared with placebo, y = p < 0.05 for 50 mg BIW compared with 25 mg BIW.
P-values were only calculated for the double-blind period (up to week 12).

Immunocompetence

Evaluations of immunocompetence were performed on 49 ENBREL-treated patients with active RA. No evidence of immunosuppression was found in evaluations of delayed-type hypersensitivity skin testing, enumeration of immune effector cell populations and immunoglobulins and in vitro testing of neutrophil and T cell function.

Antibodies

Antibodies to ENBREL, all non-neutralising, were detected in 4 out of 96 RA patients who received ENBREL at a dose of 25 mg twice a week for up to 3 months in a placebo-controlled trial. Results from JCA patients were similar to those seen in adult RA patients treated with ENBREL. No apparent correlation of antibody development to clinical response or adverse events was seen. Of 98 patients with psoriatic arthritis who have been tested, no patient has developed antibodies to ENBREL. Among 175 ankylosing spondylitis patients treated with ENBREL, 3 patients were reported with antibodies to ENBREL, none were neutralising. In double-blind studies up to 6 months duration in plaque psoriasis, about 1% of the 1084 patients developed antibodies to ENBREL, none were neutralising.

INDICATIONS

ENBREL is indicated for the treatment of:

• active, rheumatoid arthritis (RA) in adults where classical antirheumatic therapy is insufficient or inappropriate. ENBREL treatment decreases disease activity, increases functional ability, and improves health-related quality of life. ENBREL is also effective in combination with methotrexate.
• active, adult rheumatoid arthritis to slow progression of disease-associated structural damage as measured by X-ray.
• active polyarticular-course juvenile chronic arthritis in patients (4 to 17 years) who have had inadequate response to one or more disease-modifying anti-rheumatic drugs. ENBREL has not been studied in children less than 4 years of age.
• active and progressive psoriatic arthritis in adults, when the response to previous disease-modifying antirheumatic therapy has been inadequate. ENBREL has been shown to reduce the rate of progression of joint damage as measured by X-ray and to improve physical function.
• active ankylosing spondylitis in adults.
• adult patients with moderate to severe plaque psoriasis.

CONTRAINDICATIONS

1. Known hypersensitivity to etanercept or to any of its excipients.
2. Patients with, or at risk of, sepsis.
3. Treatment with ENBREL should not be initiated in patients with serious, active infection including chronic or localised infections.
4. Concurrent treatment with Interleukin-1 antagonists.

PRECAUTIONS

Infections

Patients should be evaluated for infections before, during and after treatment with ENBREL, taking into consideration that the mean elimination half-life of etanercept is 80 hours (standard deviation of 28 hours; range from 7 to 300 hours).

Serious infections including sepsis and tuberculosis, have been reported with the use of ENBREL. Some of these infections have been fatal. These infections were due to bacteria, mycobacteria, fungi and viruses. Opportunistic infections have also been reported. Many of these serious events have occurred in patients with underlying diseases that, in addition to their RA, could predispose them to infections. Patients who develop a new infection while undergoing treatment with ENBREL should be monitored closely. Administration of ENBREL should be discontinued if a patient develops a serious infection (e.g., tuberculosis or atypical mycobacterium infection) or sepsis.

Opportunistic infections, including invasive fungal infections, have been reported in patients receiving etanercept. In some cases, fungal and other opportunistic infections are not recognised and this has resulted in delays in approriate treatment, sometimes resulting in death. In many of the reports, patients have also received concomitant medicines including immunosuppressants. In evaluating patients for infections, physicians should consider the patient's risk for relevant opportunistic infections (e.g., exposure to endemic mycoses).

Physicians should exercise caution when considering the use of ENBREL in patients with a history of recurring or chronic infections or with underlying conditions, which may predispose patients to infections such as advanced or poorly controlled diabetes (see CONTRAINDICATIONS). Caution should be exercised in patients at high risk of developing serious infection, including patients undergoing major surgery.

Tuberculosis

Tuberculosis (including disseminated or extrapulmonary presentation) has been observed in patients receiving TNF-blocking agents, including etanercept. Tuberculosis may be due to reactivation of latent TB infection or to new infection.

Before initiation of therapy with ENBREL, any patient at increased risk for TB should be evaluated for active or latent infection. Prophylaxis of latent TB infection should be initiated prior to therapy with ENBREL. Treatment of latent tuberculosis in patients with a reactive tuberculin test reduces the risk of tuberculosis reactivation in patients receiving TNF blockers.

Some patients who tested negative for latent tuberculosis prior to receiving ENBREL have developed active tuberculosis. Physicians should monitor patients receiving ENBREL for signs and symptoms of active tuberculosis, including patients who tested negative for latent tuberculosis infection. Applicable local guidelines should be consulted. Patients with RA appear to have an increased rate of TB infection.

Cases of tuberculosis and atypical mycobacterium infection including mycobacterium avium complex in patients on treatment with etanercept have been reported. Treatment should be ceased immediately if mycobacterial infection is suspected.

Reactivation of hepatitis B

Reactivation of hepatitis B virus (HBV) in patients who are chronic carriers of this virus who are receiving TNF blockers including ENBREL has been reported. A causal relationship has not been established for ENBREL. In some instances, HBV reactivation occurring in conjunction with TNF blocker therapy has been fatal. The majority of these reports have occurred in patients concomitantly receiving other medications that suppress the immune system, which may also contribute to HBV reactivation. Patients at risk for HBV infection should be evaluated for evidence of prior HBV infection before initiating TNF blocker therapy. Prescribers should exercise caution in prescribing TNF blockers for patients identified as carriers of HBV. Patients who are carriers of HBV and require treatment with TNF blockers should be closely monitored for signs and symptoms of active HBV infection throughout therapy and for several months following termination of therapy. Adequate data are not available on the safety or efficacy of treating patients who are carriers of HBV with anti-viral therapy in conjunction with TNF blocker therapy to prevent HBV reactivation. If HBV reactivation should develop in patients who are receiving ENBREL, treatment should be stopped and effective anti-viral therapy with appropriate supportive treatment should be initiated.

Worsening of hepatitis C

There have been reports of worsening of hepatitis C in patients receiving ENBREL, although a causal relationship with ENBREL has not been established.

Alcoholic hepatitis

In a study of 48 hospitalised patients treated with etanercept or placebo for moderate to severe alcoholic hepatitis, etanercept was not efficacious and the mortality rate in pateints treated with etanercept was significantly higher after 6 months. Infections were also higher in the etanercept group. The use of etanercept in patients for the treatment of alcoholic hepatitis is not recommended. Physicians should use caution whhen using etanercept in patients who also have moderate to severe alcoholic hepatitis.

Concurrent administration of TNF inhibitors and anakinra

Concurrent administration of etanercept and anakinra (a recombinant, non-glycosilated form of the human Interleukin-1 receptor antagonist) has been associated with an increased risk of serious infection, an increased risk of neutropenia and no additional benefit compared to etanercept alone. The safety and efficacy of anakinra used in combination with etanercept has not been established. Therefore, combination of etanercept and anakinra is contraindicated (see also CONTRAINDICATIONS and Interactions with other medicines).

Concurrent administration of etanercept and abatacept

In clinical studies, concurrent administration of abatacept and etanercept therapy resulted in increased incidences of serious adverse events. This combination has not demonstrated increased clinical benefit; such use is not recommended.

Haematological reactions

Rare cases of pancytopenia and very rare cases of aplastic anaemia, some with fatal outcome, have been reported in patients treated with ENBREL. Caution should be exercised in patients being treated with ENBREL who have a previous history of blood dyscrasias. All patients should be advised that if they develop signs and symptoms suggestive of blood dyscrasias or infections (eg, persistent fever, sore throat, bruising, bleeding, paleness) whilst on ENBREL, they should seek immediate medical advice. Such patients should be evaluated urgently, including full blood count; if any blood dyscrasias are confirmed, ENBREL should be discontinued.

Allergic reactions

Parenteral administration of any biological product should be attended by appropriate precautions in case an allergic or untoward reaction occurs. Allergic reactions associated with ENBREL administration have been reported commonly. Allergic reactions have included angioedema and urticaria, serious reactions have occurred. If any serious allergic or anaphylactic reaction occurs, ENBREL therapy should be discontinued immediately and appropriate therapy initiated.

Latex (dry natural rubber) is present in the rubber closure of the diluent syringe (vial presentation) and also in the needle cover of the pre-filled syringe presentation. This may cause hypersensitivity reactions when handled by, or when ENBREL is administered to, persons with known or possible latex sensitivity. Patients or caregivers should contact their doctor before using ENBREL if these latex components will be handled by, or if ENBREL will be given to, someone with a known hypersensitivity to latex.

Cardiac disorders

There have been post-marketing reports of worsening of congestive heart failure (CHF), with and without identifiable precipitating factors, in patients taking etanercept. Two large clinical trials evaluating the use of etanercept in the treatment of CHF were terminated early due to lack of efficacy. Although not conclusive, data from one of these trials suggests a possible tendency towards worsening CHF in those patients assigned to etanercept treatment. Physicians should use caution when using etanercept in patients who also have CHF.

CNS disorders

Although no clinical trials have been performed evaluating etanercept therapy in patients with multiple sclerosis, clinical trials of other TNF antagonists in patients with multiple sclerosis have shown increases in disease activity. There have been rare reports of CNS demyelinating disorders, including multiple sclerosis, in patients treated with etanercept (see ADVERSE EFFECTS); the causal relationship to etanercept therapy remains unclear. A careful risk/benefit evaluation, including a neurological assessment, is recommended when prescribing etanercept therapy to patients with pre-existing or recent onset of CNS demyelinating disease, or to those who are considered to have an increased risk of developing demyelinating disease.

Use in psoriasis

The safety and efficacy of etanercept in combination with other immunosuppressive agents used in psoriasis or with phototherapy have not been studied. Etanercept should not be used in combination with such agents because of the possibility of excessive immunosuppression.

Monitoring

Based on the results of clinical studies in rheumatoid arthritis, normally no special laboratory evaluations are necessary in addition to careful medical management and supervision of patients.

Immunosuppression and malignancy

TNF modulates immune responses and has a protective effect against the development of some tumours. The impact of treatment with ENBREL, on the course of development of malignancies, including those caused by immunosuppressive agents, is not understood and has not been studied. The possibility exists for anti-tumour necrosis factor (TNF) therapies, including ENBREL, to affect host defences against infections and malignancies since TNF mediates inflammation and modulates cellular immune responses. The impact of treatment with ENBREL on the development and course of malignancies and active and/or chronic infections is not fully understood (see ADVERSE REACTIONS). Reports of malignancies affecting various sites have been received in the post-marketing period including breast and lung carcinoma and lymphoma.

In the controlled portions of clinical trials of all the TNF blocking agents, more cases of lymphoma have been observed among patients receiving the TNF blocker compared to control patients. During the controlled portions of ENBREL trials, 3 lymphomas were observed among 4509 ENBREL-treated patients versus 0 among 2040 control patients (duration of controlled treatment ranged from 3 to 24 months). In the controlled and open-label portions of clinical trials of ENBREL, 9 lymphomas were observed in 5723 patients over approximately 11201 patient-years of therapy. This is 3-fold higher than that expected in the general population. While patients with rheumatoid arthritis or psoriasis, particularly those with highly active disease, may be at a higher risk (up to several fold) for the development of lymphoma, a possible risk for the development of lymphomas or other malignancies in patients treated with a TNF-antagonist cannot be excluded.

In a study of 49 patients with RA treated with ENBREL, there was no evidence of depression of delayed-type hypersensitivity, depression of immunoglobulin levels, or change in enumeration of effector cell populations. The safety and efficacy of ENBREL, in patients with immunosuppression or chronic infections have not been evaluated.

Two juvenile chronic arthritis patients developed varicella infection and signs and symptoms of aseptic meningitis, which resolved without sequelae. Patients with a significant exposure to varicella virus should temporarily discontinue ENBREL therapy and be considered for prophylactic treatment with Varicella Zoster Immune Globulin.

In a placebo-controlled study of 180 patients with Wegener's granulomatosis, the addition of etanercept to standard treatment (including cyclophosphamide and high-dose steroids) was no more efficacious than standard treatment alone. The group of patients who received etanercept experienced more non-cutaneous malignancies of various types than the patient group receiving standard treatment alone. The use of etanercept for treatment of Wegener's granulomatosis is not recommended.

Non-melanoma skin cancer has been reported in patients treated with TNF-antagonists including etanercept. Combining the results of controlled portions of clinical trials of etanercept, more cases of non-melanoma skin cancer were observed in patients taking etanercept compared with control patients, particularly in patients with psoriasis. Periodic skin examination is recommended for all patients who are at risk for non-melanoma skin cancer.

Vaccinations

Most psoriatic patients receiving ENBREL were able to mount an effective B-cell immune response to pneumococcal polysaccharide vaccine, but titers in aggregate were moderately lower and fewer patients had two-fold rises in titers compared to patients not receiving ENBREL. Live vaccines should not be given concurrently with ENBREL. No data are available on the secondary transmission of infection by live vaccines in patients receiving ENBREL. If possible, bring juvenile chronic arthritis patients up to date with all immunisations in agreement with current immunisation guidelines prior to initiating ENBREL therapy.

Autoantibody formation

Treatment with ENBREL may result in the formation of autoimmune antibodies (see ADVERSE EFFECTS).

Genotoxicity and effects on fertility

Genotoxicity studies showed no evidence of gene mutations or chromosomal damage. Long-term animal studies have not been conducted to evaluate the carcinogenic potential of ENBREL or its effects on fertility.

Use in pregnancy

Category B2

The safe use of etanercept during pregnancy has not been established. Therefore, ENBREL should be used during pregnancy only if clearly needed.

Developmental toxicity studies have been performed in rats and rabbits at doses resulting in AUC-based systemic exposure levels of etanercept that were at least 12-fold higher than in humans at the highest proposed therapeutic dose of 50 mg and have revealed no evidence of harm to the foetus due to ENBREL. There are, however, no studies in pregnant women. Animal studies are not always predictive of human response.

Use in lactation

The safe use of etanercept during lactation has not been established. It is not known whether etanercept is excreted in human milk or absorbed systemically after ingestion. There are no animal studies assessing the effects of ENBREL on the neonate. Because many drugs and immunoglobulins are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from ENBREL, a decision should be made whether to discontinue nursing or discontinue the drug.

Use in children

ENBREL has not been studied in children less than 4 years of age.

Studies have not been done in patients with polyarticular-course JRA to assess the effects of continued ENBREL therapy in patients who do not respond within 3 months of initiating ENBREL therapy or to assess the combination of ENBREL with methotrexate.

The safety and efficacy of ENBREL in paediatric patients (i.e. <18 years) with chronic plaque psoriasis have not been established.

Use in the elderly

A total of 123 RA patients aged 65 years or older have been studied in clinical trials. No overall differences in safety or effectiveness were observed between these patients and younger patients. Greater sensitivity of some older individuals cannot be ruled out.

Interactions with other medicines

Methotrexate

ENBREL may be administered in combination with methotrexate for the treatment of rheumatoid arthritis. In a safety and efficacy clinical trial, methotrexate had no effect on the pharmacokinetics of etanercept. The effect of ENBREL on the human pharmacokinetics of methotrexate has not been investigated. The safety and efficacy of etanercept in combination with methotrexate for the treatment of psoriasis have not been studied. ENBREL should not be administered in combination with methotrexate for the treatment of psoriasis (See PRECAUTIONS). Product Information for methotrexate should be consulted when etanercept is administered with methotrexate.

Anakinra

Patients treated with ENBREL and anakinra were observed to have a higher rate of serious infection when compared with patients who were treated with ENBREL alone (historical data). In addition, in a double-blind placebo-controlled trial, in patients receiving background methotrexate, patients treated with ENBREL and anakinra were observed to have a higher rate of serious infection and neutropenia than patients who were treated with ENBREL alone (see PRECAUTIONS).

Live vaccines

No safety data are available on the effects of live vaccine when used in combination with ENBREL. Live vaccines should therefore not be given concurrently with ENBREL.

Sulfasalazine

In a clinical study of patients who were receiving established doses of sulfasalazine, to which etanercept was added, patients in the combination group experienced a statistically significant decrease in mean white blood cell counts in comparison to groups treated with etanercept or sulfasalazine alone.

Digoxin

Etanercept does not significantly affect digoxin exposure. There was a reduction in etanercept exposure in the presence of digoxin, however there was significant inter-subject variability. The clinical significance of this reduced exposure is uncertain.

Warfarin

Etanercept does not significantly affect warfarin exposure. There was a slight reduction in etanercept exposure in the presence of warfarin, however there was significant inter-subject variability. The clinical significance of this reduced exposure is uncertain.

Other

In clinical trials, no apparent interactions have been observed when ENBREL was administered with glucocorticoids, non-steroidal anti-inflammatory drugs (NSAIDs) or analgesics.

Effects on laboratory tests

No effects on laboratory tests have been reported in adults. An analysis of 54 JCA patients in an open-label study demonstrated low haemoglobin, low albumin and low lymphocyte counts in 63%, 39% and 30% of juvenile patients, respectively. These observations, however, appear to be attributed to the underlying disease, rather than treatment with ENBREL.

Ability to drive or operate machinery

No studies on the effects on the ability to drive and use machines have been performed.

ADVERSE Effects

Injection site reactions

Patients with rheumatic diseases in controlled trials treated with ENBREL had a significantly higher incidence (37% cf. 10%) of injection site reactions (erythema and/or itching, pain or swelling) compared with placebo-treated patients. The frequency of injection site reactions was greatest in the first month and subsequently decreased in frequency. Mean duration was 3 to 5 days. No treatment was given for the majority of injection site reactions in the ENBREL treatment groups, and the majority of those patients who were given treatment received topical preparations such as corticosteroids, or oral antihistamines. Some patients who experienced injection site reactions also experienced reactions at previous injection sites. In post-marketing experience, injection site bleeding and bruising have also been observed in conjunction with etanercept therapy.

Infections

Serious and fatal infections have been reported; reported pathogens include bacteria, mycobacteria, viruses and fungi. Opportunistic infections have also been reported. Mycobacterium infections include tuberculosis (incidences are rare) and atypical mycobacterium infection (including mycobacterium avium complex).

In clinical trials in rheumatic disorders, upper respiratory infections ("colds") and sinusitis were the most frequently reported infections in patients receiving ENBREL or placebo. In placebo-controlled trials, the incidence of upper respiratory tract infections was 17% in the placebo treatment group and 22% in the group treated with ENBREL. In rheumatoid arthritis patients participating in placebo controlled trials, there were 0.68 events per patient year in the placebo group and 0.82 events per patient year in the group treated with ENBREL when the longer observation of patients on ENBREL was accounted for.

In controlled trials in patients with rheumatoid arthritis, the rates of reported serious (fatal, life-threatening, or required hospitalisation or intravenous antibiotics) and non-serious infection were similar for ENBREL and placebo when adjusted for duration of exposure. Some infections have occurred within a few weeks after initiating treatment with ENBREL in patients who have underlying conditions (e.g., diabetes, congestive heart failure, history of active or chronic infections) in addition to their rheumatoid arthritis. (See PRECAUTIONS). Data from a sepsis clinical trial not specifically in patients with rheumatoid arthritis suggest that ENBREL treatment may increase mortality in patients with established sepsis.

In placebo-controlled psoriatic arthritis and plaque psoriasis trials of up to 24 weeks duration, there were no differences in rates of infection among patients treated with ENBREL and those treated with placebo. In the double-blind and open-label psoriatic arthritis trials, one patient reported a serious infection (pneumonia). The risk of infection with long-term treatment cannot be estimated from this data.

Malignancies

Reports of malignancies affecting various sites have been received in the post-marketing period. The observed rates and incidences of new malignancies in clinical trials with ENBREL were similar to those expected for the population studied. Patients have been observed in clinical trials with ENBREL for over five years. Among 4462 rheumatoid arthritis patients treated with ENBREL in clinical trials for a mean of 27 months (approximately 10000 patient-years of therapy), 9 lymphomas were observed for a rate of 0.09 cases per 100 patient-years. This is 3-fold higher than the rate of lymphomas expected in the general population based on the Surveillance, Epidemiology and End Results Database. An increased rate of lymphoma up to several fold has been reported in the rheumatoid arthritis patient population and may be further increased in patients with more severe disease activity. (see PRECAUTIONS: Immunosuppression and malignancy).

There have been reports of malignancies in a clinical trial of patients being treated for Wegener's granulomatosis (see PRECAUTIONS: Immunosuppression and malignancy).

Autoantibody formation

In controlled trials, the percentage of patients who developed new positive antinuclear antibodies (ANA) (≥ 1:40), new positive anti-double-stranded DNA antibodies and new anticardiolipin antibodies were increased compared to placebo-treated patients. Rare reports have been described in clinical trials and post-marketing experience, including patients with rheumatoid factor positive RA, who have developed additional antibodies in conjunction with a lupus-like syndrome or rashes compatible with subacute cutaneous lupus or discoid lupus by clinical presentation and biopsy (see Other adverse reactions, below). The impact of long-term treatment with ENBREL on the development of autoimmune diseases is unknown.

Other adverse reactions

Events reported in at least 3% of all patients with higher incidence in patients treated with ENBREL compared to controls in placebo-controlled RA trials (including the combination methotrexate trial) and events per patient year are summarised in the next table.

Percent of Rheumatoid Arthritis Patients Reporting Adverse Events and Events per Patient Year in Placebo-Controlled Clinical Trialsa

Based on the results of clinical studies in rheumatoid arthritis, normally no special laboratory evaluations are necessary in addition to careful medical management and supervision of patients.

The following table of suspected adverse reactions is based on clinical trials and/or spontaneous post-marketing reports.

Adverse reaction frequencies are listed below in CIOMS frequency categories:

Very common: ≥ 10%

Common: ≥ 1% and < 10%

Uncommon: ≥ 0.1% and < 1%

Rare: ≥ 0.01% and < 0.1%

Very rare: < 0.01%

*see additional information, under "Infections" above.

** Uveitis has been reported in clinical trials and post-marketing experience. The reported frequency for placebo-treated patients in clinical trials was similar to the reported frequency for etanercept-treated patients.

Paediatric patients with juvenile chronic arthritis

In general, the adverse events in paediatric patients were similar in frequency and type to those seen in adult patients.

Juvenile chronic arthritis patients treated with ENBREL has a significantly higher incidence of injection sites reactions (erythema and/or itching, pain or swelling) compared with placebo-treated patients in controlled clinical trials.

Infection was the most common adverse event reported in paediatric patients taking ENBREL and occurred at an incidence similar to placebo. The types of infections reported in juvenile chronic arthritis patients were generally mild and consistent with those commonly seen in outpatient paediatric populations.

In clinical trials, two cases of varicella infection with signs and symptoms suggestive of aseptic meningitis have been reported among juvenile chronic arthritis patients treated with ENBREL.

There were 4 reports of macrophage activation syndrome in juvenile chronic arthritis clinical trials.

DOSAGE AND ADMINISTRATION

Treatment should be initiated and supervised by specialist physicians experienced in the diagnosis and treatment of rheumatoid arthritis, psoriatic arthritis, psoriasis or ankylosing spondylitis. Patients may self-inject only if their physician determines that it is appropriate and with medical follow-up, as necessary, after proper training in injection technique.

Adults

Rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis

The recommended dose of ENBREL is 50 mg per week, given as a subcutaneous injection, EITHER once weekly as a single 50 mg injection OR twice weekly as two separate 25 mg injections given 3-4 days apart.

Plaque psoriasis

The recommended dose of ENBREL is 50 mg per week, given once weekly (single 50 mg injection) or twice weekly (single 25 mg injections given 3-4 days apart) as a subcutaneous injection. Higher responses may be achieved from initial treatment for up to 12 weeks with a dose of 50 mg given twice weekly, after which, the dose should be reduced to the standard dose of 50 mg per week. If re-treatment with ENBREL is indicated, the dose used should be 50 mg per week.

Elderly patients

Elderly RA patients (age ≥ 65 years) show similar safety, efficacy and pharmacokinetic profiles compared to younger adult patients treated with ENBREL. Dose adjustment is not needed for the elderly. However, as with other medicinal products, greater sensitivity in some older patients cannot be ruled out.

Children and adolescents with juvenile chronic arthritis

The recommended dose for children 4-17 years of age is 0.4 mg/kg (up to a maximum of 25 mg) after reconstitution of 25 mg ENBREL in 1 mL of water for injections, given twice weekly as a subcutaneous injection with an interval of 3-4 days between doses.

Instructions for use, handling and disposal

Reconstitution (Powder for injection only)

ENBREL contains no antibacterial preservative and therefore, solutions prepared with water for injections should be administered as soon as possible and within six hours following reconstitution. In the absence of compatibility studies, ENBREL must not be mixed with other medicinal products.

Reconstitute the etanercept powder aseptically by injecting 1 mL of sterile water for injections very slowly into the vial with the vial adaptor attached to the syringe. Gently swirl the contents to avoid excessive foaming. Some foaming will occur, this is normal. To avoid excessive foaming, do not shake or vigorously agitate. Dissolution of ENBREL usually takes less than 10 minutes.

Visually inspect the solution for particulate matter and discolouration prior to administration. The solution should not be used if discoloured or cloudy, or if particulate matter remains. Withdraw the solution into the empty syringe, removing only the dose to be given from the vial. Some foam or bubbles may remain in the vial. Do not filter reconstituted solution during preparation or administration. Do not use ENBREL if all the powder in the vial is not dissolved within 10 minutes. Start again with another vial. Once the ENBREL solution has been aspirated into the syringe, discard the vial adaptor and replace with a needle from the pack for injection. Sites for self-injection include thigh, abdomen, or upper arm.

Before injecting

Sites for self injection include thigh, abdomen or upper arm. Injection sites should be rotated. New injections should be given at least 3cm from an old site and never into areas where the skin is tender, bruised, red, or hard (See Instruction sheet supplied with ENBREL).

Powder for injection: The reconstituted solution should be clear and colourless with no lumps, flakes or particles.

Solution for injection: Before injecting, ENBREL single-use pre-filled syringes should be allowed to reach room temperature (approximately 15 to 30 minutes). The needle cover should not be removed during this period. The solution should be clear, colourless or pale yellow and practically free from visible particles. Otherwise, do not inject the solution. Use a different ENBREL pre-filled syringe, then contact your pharmacist for assistance.

ENBREL is for single use only. Any unused product should be disposed of appropriately.

Administration

If a patient is to self-administer ENBREL, they should be instructed in injection techniques to ensure the safe self-administration of ENBREL (See Instruction sheet supplied with ENBREL). The first injection should be performed under the supervision of a qualified health care professional. The ability of that patient to self-inject subcutaneously should be assessed. A puncture-resistant container for disposal of needles and syringes should be used. Patients should be instructed in the technique and told the importance of proper syringe and needle disposal and be cautioned against reuse of these items.

Disposal

Contains no antimicrobial agent. Product is for single use only in one patient only. Discard any residue.

OVERDOSAGE

The maximum tolerated dose of ENBREL has not been established in humans. Repeat-dose studies have been performed in cynomolgus monkeys at doses resulting in AUC-based systemic exposure levels of etanercept that were over 13-fold higher than in humans at the highest proposed therapeutic dose of 50 mg and have revealed no dose-limiting or target organ toxicity. No dose-limiting toxicities were observed during clinical trials of RA patients. The highest dose level evaluated has been an IV loading dose of 32 mg/m² followed by SC doses of 16 mg/m² administered twice weekly. One RA patient mistakenly self-administered 62 mg ENBREL SC twice weekly for three weeks without experiencing unexpected side effects.

There is no known antidote to ENBREL. For advice on the management of overdosage, please contact the Poisons Information Centre on 131 126.

PRESENTATION

Powder for injection

ENBREL powder for injection contains either 25 mg or 50 mg of etanercept. The content of the diluent is 1 mL of sterile water for injections.

ENBREL powder for injection cartons contain 4 clear glass vials (4 mL, Type 1 glass) with Teflon coated rubber stoppers, aluminium seals and flip-off plastic caps. ENBREL is also supplied with 4 pre-filled syringes containing 1 mL water for injections and 8 alcohol swabs. The pre-filled syringes are also made of Type 1 glass. Four vial adaptors and four 27 gauge needles are provided in the carton.

Solution for injection

ENBREL solution for injection is supplied in a kit containing four single-dose pre-filled glass syringes containing ENBREL solution. Each syringe of ENBREL contains either 25 mg* (in 0.5 mL) or 50 mg (in 1 mL) of the active ingredient, etanercept (rch). The needle cover contains natural rubber (latex). Eight alcohol swabs are also are provided in the carton.

Medicine Classification

PRESCRIPTION ONLY MEDICINE.

Storage

Powder for injection and Solution for injection: Store at 2°C to 8°C. Refrigerate. Do not freeze.

For ENBREL powder for injection, the solution should be used immediately (i.e. within 6 hours) after reconstitution. If not used immediately, ENBREL solution must be refrigerated in the vial at 2°C to 8°C after reconstitution.

NAME AND ADDRESS

Pharmacy Retailing (NZ) Limited
Trading as Healthcare logistics
58 Richard Pearce Drive
Airport Oaks
Auckland

For all enquiries please contact:

Wyeth Australia Pty Limited
17-19 Solent Circuit
Baulkham Hills NSW 2153
AUSTRALIA
Toll free telephone number: 0800 447 400 or email medinfo@wyeth.com

Date of Preparation:

April 2009

® Registered Trade Mark