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New Drug for Psoriatic Arthritis and Axial Spondyloarthritis

The Medicines and Healthcare products Regulatory Agency (MHRA) has granted marketing authorisation for bimekizumab (Bimzelx, UCB) for patients with active psoriatic arthritis and adult patients with active axial spondyloarthritis.

Bimekizumab is a humanised monoclonal IgG1 antibody designed to inhibit both IL-17A and IL-17F – two key cytokines driving inflammatory disease - selectively and directly. It was first approved in the UK in August 2021 for the treatment of adults with moderate to severe plaque psoriasis who were candidates for systemic therapy.

Psoriatic arthritis affects over 600,000 people in the UK, and often affects the small joints of the hands and feet. Axial Spondyloarthritis, which includes ankylosing spondylitis, affects 220,000 people in the UK and causes significant and long-lasting pain in the lower back, buttocks, and hips.

Professor Karl Gaffney, consultant rheumatologist at The Norfolk and Norwich University Hospital NHS Foundation Trust, explained that psoriatic arthritis and axial spondyloarthritis were chronic, painful conditions "with no cure". He pointed out that "the unfortunate reality for many patients is that they will have to cycle through a number of treatments before eventually finding one that works for them". 

He welcomed the possibility of a new treatment option potentially to improve the quality of life of people living with these conditions.

Commenting for Medscape News UK, Dr Benjamin Ellis, consultant rheumatologist and senior clinical policy adviser to Versus Arthritis, stressed that far too many people with these conditions were prevented from going to school or work, caring for family, and living independently, due to their painful symptoms.

"Current treatments do not work for everyone," he pointed out, so the MHRA approval of a new medicine would be welcomed by people with these conditions, who needed "more and better options to control their symptoms".

Approval Supported By Positive Study Findings

The MHRA has approved bimekizumab, alone or in combination with methotrexate, for the treatment of adults with active psoriatic arthritis who have had an inadequate response or have been intolerant to one or more disease-modifying antirheumatic drugs. 

In active axial spondyloarthritis, the MHRA has approved bimekizumab for the treatment of adults with active non-radiologic axial spondyloarthritis with objective signs of inflammation, as indicated by elevated C-reactive protein and/or magnetic resonance imaging, who have responded inadequately or are intolerant to non-steroidal anti-inflammatory drugs, and for the treatment of adults with active ankylosing spondylitis (also now known as radiographic axial spondyloarthritis) who have responded inadequately or are intolerant to conventional therapy.

The approvals by the MHRA are based on data from the Phase 3 BE COMPLETE and BE OPTIMAL (psoriatic arthritis) studies and data from the Phase 3 BE MOBILE 1 (non-radiologic axial spondyloarthritis) and BE MOBILE 2 (ankylosing spondylitis) studies. 

In the psoriatic arthritis studies, bimekizumab showed improvements compared with placebo in joint and skin symptoms across biologic naïve and TNF inhibitor-inadequate responder populations.

In the axial spondyloarthritis studies, bimekizumab showed improvements compared with placebo in signs, symptoms, and disease activity across the spectrum of disease.

Exercise Caution

The most frequently reported adverse reactions with bimekizumab were upper respiratory tract infections (14.5%) — most frequently nasopharyngitis — and oral candidiasis (7.3%). 

The manufacturers stressed that bimekizumab is contraindicated in patients with clinically important active infections, such as active tuberculosis, and said that "prior to initiating treatment with bimekizumab, patients should be evaluated for tuberculosis infection". 

In addition, "caution should be exercised" when considering the use of bimekizumab in patients with a chronic infection or a history of recurrent infection, and the drug should not be initiated in patients with any clinically important active infection until the infection resolved or was adequately treated. 

The drug was not recommended in patients with inflammatory bowel disease, as cases of new or exacerbations of inflammatory bowel disease had been reported with bimekizumab.

The MHRA emphasised that "this medicinal product is subject to additional monitoring".

Asked to comment for Medscape News UK, Laura Stevenson, deputy chief executive at the Psoriasis Association described how psoriatic arthritis could have a "significant life impact". She emphasised that it was "hugely important" to have access to new therapies such as bimekizumab, which could make a "real difference" for eligible people.

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This article was updated on 5 September to include a comment from consultant rheumatologist Dr Benjamin Ellis.