Guselkumab Response Durable in Psoriatic Arthritis

The efficacy of the monoclonal antibody guselkumab (Tremfya) persisted through 2 years of follow-up among patients with active psoriatic arthritis (PsA), a researcher reported at the virtual American College of Rheumatology (ACR) annual meeting.

Among patients who continued on treatment with guselkumab through week 100, 20% improvements on the ACR’s response criteria (ACR20) were observed in 76% of patients who were given the medication in doses of 100 mg every 4 weeks and in 74% of those treated every 8 weeks, noted Iain McInnes, MD, PhD, of the University of Glasgow in Scotland.

In addition, ACR50 responses were seen at week 100 in 56% and 55% of the groups receiving guselkumab every 4 weeks and every 8 weeks, respectively, while ACR70 responses were seen in 35% and 36%, he said during a poster session.

“Psoriatic arthritis is a heterogeneous disease that requires lifelong treatment, so the durability of response is an important consideration,” he noted.

Guselkumab targets the p19 subunit of interleukin (IL)-23, which is approved for use in plaque psoriasis and PsA. The T helper 17 cell line has been implicated in the pathogenesis of both conditions, and IL-23 promotes the proliferation of T helper cells in psoriatic lesions.

The phase III trial, which was known as DISCOVER-2, initially randomized 739 patients who were biologic-naive to one of the two dose regimens or placebo for 24 weeks. At week 24, participants in the placebo group were switched to guselkumab 100 mg every 4 weeks. Ninety-six percent of patients remained in the study at week 24, 93% were still enrolled at week 52, and 88% at week 100.

Improvements on skin scores were observed at all time points. At week 24, 75% improvements in Psoriasis Area and Severity Index (PASI) scores were seen in 78% of the 4-week group and in 79% of the 8-week group, but in only 23% of the placebo group. But by week 100, the corresponding numbers were 83%, 82%, and 80%. PASI 100 scores at week 100 were observed in 59%, 53%, and 61%.

Radiographic progression, assessed by changes in Sharp-van der Heijde scores, was 0.75 during weeks 52 to 100 in the 4-week group and 0.46 in the 8-week group. In the placebo group, the scores were 1.24 by week 24, 0.51 from weeks 24 to 100 (after switching to guselkumab every 4 weeks), and 0.13 from weeks 52 to 100.

Physical function and quality-of-life measures also showed benefits through week 100.

Serious adverse events were reported throughout the study period in 9% of both guselkumab groups and in 7% of the placebo/4-week group, while serious infections occurred in 2%, 3%, and 3%, respectively. One patient in the placebo/4-week group died in a traffic accident.

“Thus, based on the totality of data, guselkumab shows a favorable risk-benefit ratio through 2 years of follow-up,” McInnes concluded.