Enbrel is indicated for the treatment of adults with severe active AS who have had an inadequate response to conventional therapy.¹

• Hypersensitivity to the active substance or to any of the excipients¹
• Sepsis or risk of sepsis¹
• Treatment with Enbrel should not be initiated in patients with active infections, including chronic or localised infections¹

The recommended dose of Enbrel in adults is 25 mg administered twice weekly, or 50 mg administered once weekly.¹

Data suggest that a clinical response is usually achieved within 12 weeks of treatment. Continued therapy should be carefully reconsidered in a patient not responding within this time period.<sup>1    

Patients treated with Enbrel should be given the Patient Card.</sup>

The efficacy of Enbrel in AS was assessed in a randomised, double-blind study comparing twice-weekly administration of 25 mg Enbrel with placebo. The study enrolled 277 patients between 18–70 years of age with active AS, defined as VAS scores of ≥ 30 for average 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 BASFI. Patients receiving DMARDs, NSAIDs, or corticosteroids could continue them on stable doses. Doses of 25 mg of Enbrel or placebo were administered SC twice a week for 6 months in 138 patients.¹

The primary measure of efficacy (ASAS 20) was a ≥ 20% improvement in at least 3 of the 4 ASAS domains (patient global assessments, back pain, BASFI, and inflammation) and absence of deterioration in the remaining domain. ASAS 50 and 70 responses used the same criteria with a 50% improvement or a 70% improvement, respectively.¹

Compared to placebo, treatment with Enbrel resulted in significant improvements in the ASAS 20, ASAS 50 and ASAS 70 as early as 2 weeks after the initiation of therapy.¹

Among patients with AS who received Enbrel, the clinical responses were apparent at the time of the first visit (2 weeks) and were maintained through 6 months of therapy. Responses were similar in patients who were or were not receiving concomitant therapies at baseline.¹

The efficacy of Enbrel in patients with non-radiographic axial spondyloarthritis (nr-AxSpA) was assessed in a randomised, 12-week double-blind, placebo-controlled study. The study evaluated 215 adult patients (modified intent-to-treat population) with active nr-AxSpA (18 to 49 years of age),  defined as those patients meeting the ASAS classification criteria of axial spondyloarthritis but did not meet the modified New York criteria for AS. Patients were also required to have an inadequate response or intolerance to two or more NSAIDs. In the double-blind period, patients received Enbrel 50 mg weekly or placebo for 12 weeks. The primary measure of efficacy (ASAS 40) was a 40% improvement in at least three of the four ASAS domains and absence of deterioration in the remaining domain. The double-blind period was followed by an open-label period during which all patients received Enbrel 50 mg weekly for up to an additional 92 weeks. MRIs of the sacroiliac joint and spine were obtained to assess inflammation at baseline and at weeks 12 and 104.¹

Compared to placebo, treatment with Enbrel resulted in statistically significant improvement in the ASAS 40, ASAS 20 and ASAS 5/6. Significant improvement was also observed for the ASAS partial  remission and BASDAI 50. Week 12 results are shown in the table below.¹

At week 12, there was a statistically significant improvement in the SPARCC (Spondyloarthritis Research Consortium of Canada) score for the sacroiliac joint (SIJ) as measured by MRI for patients  receiving Enbrel. Adjusted mean change from baseline was 3.8 for Enbrel treated (n=95) versus 0.8 for placebo treated (n=105) patients (p<0.001). At week 104, the mean change from baseline in the  SPARCC score measured on MRI for all Enbrel-treated subjects was 4.64 for the SIJ (n=153) and 1.40 the spine (n=154).¹ 

Enbrel showed statistically significantly greater improvement from baseline to week 12 compared to placebo in most health-related quality of life and physical function assessments, including BASFI 
(Bath Ankylosing Spondylitis Functional Index), EuroQol 5D Overall Health State Score and SF-36 Physical Component Score.¹

Clinical responses among nr-AxSpA patients who received Enbrel were apparent at the time of the first visit (2 weeks) and were maintained through 2 years of therapy. Improvements in health-related quality of life and physical function were also maintained through 2 years of therapy. The 2 year data did not reveal any new safety findings. At week 104, 8 subjects had progressed to a score of bilateral Grade 2 on spinal X-ray according to the modified New York Radiological Grade, indicative of axial spondyloarthropathy.

Please refer to Enbrel summary of product characteristics for additional efficacy data.

The most commonly reported adverse reactions are injection site reactions (such as pain, swelling, itching, reddening and bleeding at the puncture site), infections (such as upper respiratory infections, bronchitis, bladder infections and skin infections), headache, allergic reactions, development of autoantibodies, itching, and fever.¹

Serious adverse reactions have also been reported for Enbrel. TNF-antagonists, such as Enbrel, affect the immune system and their use may affect the body's defenses against infection and cancer. Serious infections affect fewer than 1 in 100 patients treated with Enbrel. Reports have included fatal and life-threatening infections and sepsis. Various malignancies have also been reported with use of Enbrel, including cancers of the breast, lung, skin and lymph glands (lymphoma).¹

Serious haematological, neurological and autoimmune reactions have also been reported. These include rare reports of pancytopenia and very rare reports of aplastic anaemia. Central and peripheral demyelinating events have been seen rarely and very rarely, respectively, with Enbrel use. There have been rare reports of lupus, lupus-related conditions, and vasculitis.¹

Before prescribing Enbrel refer to the full Summary of Product Characteristics which is linked below.