The government has announced that access to ixekizumab on the PBS will be expanded for adults with active ankylosing spondylitis.
The government has announced that access to ixekizumab (Taltz, Eli Lilly) on the PBS will be expanded for adults with active ankylosing spondylitis (AS) from 1 December.
Ixekizumab is also PBS-subsidised for the treatment of plaque psoriasis and psoriatic arthritis, and was approved for AS earlier this year. It’s an IgG4 monoclonal antibody that binds to interleukin-17A (IL-17A), a key pro-inflammatory cytokine in the pathophysiology of AS.
Other current treatment options in Australia for AS include NSAIDs, secukinumab, which is also an IL-17A antibody, and five tumour necrosis factor inhibitor (TNFi) drugs: adalimumab, certolizumab pegol, etanercept, golimumab and infliximab.
The Australian Therapeutic Guidelines consider NSAIDs for symptom control as first line therapy for AS, in conjunction with an appropriate exercise program and other lifestyle changes. Biologic disease-modifying antirheumatic drugs (bDMARDs) can be used in cases of persistent axial inflammation and enthesitis not responding to NSAIDs. Conventional DMARDs, including methotrexate, sulfasalazine and leflunomide, aren’t considered useful for axial inflammation.
Ixekizumab is administered as a subcutaneous injection of 80 mg every four weeks, and can be used concurrently with cDMARDs, corticosteroids, anti-inflammatories and analgesics for the treatment of adults with active AS.
The most common side effects include injection site reactions, upper respiratory tract infections, nausea and tinea.
In applying to extend the indications for ixekizumab to AS, the sponsor submitted two phase III efficacy and safety studies – COAST-V and COAST-W. The studies were primarily designed to demonstrate the efficacy of ixekizumab versus placebo, after 16 weeks of treatment, on the signs and symptoms of AS in adults, with additional descriptive efficacy data submitted for up to 52 weeks of treatment.
The COAST-V study included bDMARD-naïve patients, while the COAST-W studied TNFi-experienced patients. The COAST-V study included an adalimumab active reference group, but wasn’t powered to demonstrate superiority or non-inferiority.
Both studies demonstrated statistically significant and clinically meaningful improvements in signs and symptoms, as defined by the ASAS40 response. In COAST-V, 48% of the ixekizumab-treated patients achieved ASAS40 responses vs 18% of the placebo group, and in COAST-W 25% of patients achieved ASAS40 compared with 13% of the placebo group.
