Bimekizumab is well-suited to long-term control of psoriatic arthritis (PsA), a long-term extension of two Phase 3 trials has suggested.

The study, which was funded by UCB and co-authored by company representatives, showed that three years of monthly bimekizumab treatment offered safe and sustained disease control in PsA patients who were biologic (b)DMARD-naïve or who had an inadequate response or intolerance to tumour necrosis factor inhibitors (TNFi-IR).

At three years, the majority of patients had achieved swollen joint count resolution and showed improvements in skin outcomes, regardless of their prior treatment.

“Bimekizumab demonstrated sustained high levels of efficacy and tolerability to three years, supporting its suitability for long-term treatment in bDMARD-naïve and TNFi-IR patients with PsA,” wrote the authors, including Dr Laura Coates, an NIHR Research Professor at the University of Oxford.

The open-label extension study, published in Rheumatology [link here], recruited participants from two Phase 3 trials in which PsA patients who were bDMARD-naïve (n=712) or TNFi-IR (n=400) had received 160mg bimekizumab every four weeks.

Participants continued four-weekly bimekizumab treatment, with 546 bDMARD-naïve patients and 299 TNFi-IR patients completing a total of 160 weeks of treatment.

After 160 weeks, the incidence of treatment-emergent adverse events (TEAEs) was 164.2 and 88.6 per 100 patient-years in bDMARD-naïve and TNFi-IR patients, respectively, while the incidence rates of serious TEAEs were 6.5 and 5.7 per 100 patient-years, respectively.

The most common TEAEs were SARS-CoV-2 infection, nasopharyngitis and upper respiratory tract infection, and the authors noted that incidence rates decreased with each year of exposure.

Efficacy data also showed positive outcomes. For bDMARD-naïve and TNFi-IR patients, respectively:

• 56.1% and 50.4% achieved ACR50 after year one, continuing to 53.2% and 55.2% at year three
• 61.8% and 58.2% achieved swollen joint count resolution after year one, continuing to 59.5% and 59.1% at year three
• 64.7% and 66.2% showed 100% improvement from baseline in Psoriasis Area and Severity Index, continuing to 61.9% and 67.5% at year three
• 30.0% and 23.6% achieved very low disease activity after three years.

A subset of bDMARD-naïve participants had received 52 weeks of adalimumab in the preceding trial, before switching to bimekizumab, and these patients “showed sustained efficacy in joint symptoms and improved efficacy in skin symptoms up to two years after the switch, reflecting the improvements seen in patients receiving bimekizumab from baseline at two years,” the authors noted.

“Evaluation of the long-term safety and efficacy of bimekizumab in a real-world clinical setting would be valuable, alongside the examination of safety and efficacy in different patient subgroups such as ‘difficult-to-treat’ patients and patients with different disease durations, comorbidities, or co-medications,” they concluded.

Adding GLP-1 receptor agonist to biologic further boosts PsA outcomes 

Meanwhile, a separate study has shown that adding a GLP-1 receptor agonist to biologic treatment can significantly improve outcomes for overweight PsA patients.

The research, which was funded by Eli Lilly and co-authored by company representatives, found that overweight or obese PsA patients who received tirzepatide and ixekizumab were more likely to achieve ACR50 than those given ixekizumab alone, with significant differences seen after just four weeks.

As well as the expected weight loss, additional tirzepatide resulted in widespread benefits to patient-reported outcomes of disease activity and quality of life.

“Participants with active PsA and complex inflammatory-metabolic disease achieved clinically meaningful improvement of PsA, physical function, weight reduction, and quality of life when treated with ixekizumab + tirzepatide compared to ixekizumab alone, with no new safety concerns,” wrote the authors, including Dr Coates.

In the study, published in Arthritis & Rheumatology [link here], PsA patients who were overweight with at least one weight-related comorbidity, or who were obese, were randomised to receive 52 weeks of ixekizumab plus tirzepatide (n=138) or ixekizumab alone (n=133).

Significantly more patients achieved ACR50 when given additional tirzepatide compared to ixekizumab alone (33.5% vs 20.4%, p=0.020).

In addition, substantially more patients achieved both ACR50 and at least a 10% weight reduction when given ixekizumab plus tirzepatide compared to ixekizumab alone (31.7% vs 0.8%), with rates of simultaneous ACR20 and at least 5% weight reduction also far higher (69.7% vs 10.3%).

Patients treated with ixekizumab plus tirzepatide also reported significantly greater improvements in the Health Assessment Questionnaire–Disability Index (p<0.001) and Functional Assessment of Chronic Illness Therapy–Fatigue (p<0.001).

There were no new safety signals, although gastrointestinal adverse events were most common and were more prevalent with additional tirzepatide than ixekizumab alone, particularly nausea (29.7% vs 3.0%), diarrhoea (18.1% vs 3.8%), constipation (16.7% vs 3.0%), and vomiting (10.9% vs 0.8%).

“These data strengthen the EULAR and GRAPPA treatment guidelines, which recommend that clinicians consider comorbidities in the patient’s treatment approach to achieve low disease activity or remission,” the authors suggested.

“The addition of tirzepatide to ixekizumab represents a potential paradigm shift to optimise comprehensive clinical outcomes and patient quality of life in the appropriate patient population,” they added.