Long-Term Safety and Efficacy of Ixekizumab in Japanese Patients with Psoriasis

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Investigators have evaluated the long-term, real-world use of ixekizumab in Japanese patients with psoriasis for up to 3 years.¹ The study included patients with psoriasis vulgaris, psoriatic arthritis, generalized pustular psoriasis, and erythrodermic psoriasis.

Psoriasis has a 0.34% prevalence in Japan with up to 23% of cases being psoriatic arthritis.² This literature is the first to collect real-world safety data past 52 weeks in Japanese patients taking the IL-17A blocker.

“Real-world evidence has become increasingly important for health-care decision making, with real-world data complementing clinical trial findings and providing additional data outside the constraints of clinical trial guidelines,” the authors wrote.

The single-arm, post-marketing, observational study was conducted at 163 sites in Japan from November 2016 to September 2022. Approximately 804 patients who previously had not responded to conventional systemic therapies were included. Secukinumab and adalimumab were the most commonly used biologics prior to this trial. About 68% of participants were male. The median age was 54 with a mean disease duration of 11.8 years.

Most patients had psoriasis vulgaris (72.9%) but 37.7% had psoriatic arthritis, 7.8% had generalized pustular psoriasis, and 3.7% had erythrodermic psoriasis. Some patients also had more than one subtype. Other commonly reported comorbidities include hepatitis B and hypertension. Dosage was split up by Q2/Q2 (n = 137) and Q2/Q4 (n = 550). Patients with psoriatic arthritis were more likely to utilize the Q2/Q2 dosing.

Researchers assessed the long-term safety and effectiveness at baseline, weeks 4, 12, 24, and 52 through the Psoriasis Area and Severity Index (PASI). The impact on patients’ quality of life via the Dermatology Life Quality Index (DLQI) was also measured at baseline, weeks 12, 24, and 52. Additional safety data regarding malignancies and other serious infections was collected for a follow-up period of 2 years.

The amount of participants who reached PASI 50, PASI 75, PASI 90, and PASI 100 at week 52 in the overall population were 90.7%, 80.2%, 70.6%, and 56.9%, respectively. This was observed in all subtypes of psoriasis as well as in both dosing groups (p < 0.001). A PASI of 100 was achieved by 52.6% in the Q2/Q2 group and 57.6% in the Q2/Q4 group. Reductions in absolute body surface area were also demonstrated in both cohorts. Total patient-reported DLQI scores decreased in the overall population as well as in each of the doses.

About 25% of patients (n = 203) experienced adverse events in the first year of treatment. These included injection site reactions and fungal infections such as oral candidiasis and tinea pedis. Thirty-six of these were serious in nature and included cellulitis, pneumonia, and sepsis. Less than 1% of patients (n = 7) developed malignancy. A higher proportion of these were observed in patients with generalized pustular psoriasis.

Patients receiving the Q2/Q2 dose had a lower incidence of adverse effects compared to those who took the Q2/Q4 dose. Nonetheless, all events were resolved by week 52. According to the subgroup analyses, sex, age, body mass index, disease duration, and prior treatments did not impact the incidence of adverse effects. These findings align with the existing safety profile of ixekizumab.

In the long-term safety analysis, less than 1% of patients developed malignancies after 2 years (n = 6) and 3 years (n = 4). Additionally, patients who had previously received biologic therapy saw more malignancies, but this needs to be investigated further in larger studies.

The lack of a control group, the potential for selection bias, and the lower number of patients in certain subgroups may be considered limitations. Further research can better define how treatment ineffectiveness or adverse events may impact discontinuation of ixekizumab. There is also a citrate-free formulation of ixekizumab, which could be tested in a future study.

References

1. Torii H, Morita A, Yamamoto C, et al. Safety and effectiveness of ixekizumab in Japanese patients with psoriasis vulgaris, psoriatic arthritis, generalized pustular psoriasis, and erythrodermic psoriasis: Post-marketing surveillance. J Dermatol. Published online March 13, 2025. doi:10.1111/1346-8138.17695

2. Ohara Y, Kishimoto M, Takizawa N, et al. Prevalence and Clinical Characteristics of Psoriatic Arthritis in Japan. J Rheumatol. 2015;42(8):1439-1442. doi:10.3899/jrheum.141598