medwireNews: Patients with active psoriatic arthritis (PsA) continue to derive clinical benefit from the interleukin-23 inhibitor guselkumab over around a year of treatment, indicate follow-up results from a phase IIa trial.
Additionally, the treatment was well tolerated, with no unanticipated safety signals with the extended exposure, said lead author Atul Deodhar (Oregon Health & Science University, Portland, USA) presenting the research at the 2017 ACR/ARHP Annual Meeting, held in San Diego, California, USA.
He explained that guselkumab previously demonstrated “robust efficacy” at the 24-week mark, improving outcomes relative to placebo for PsA patients with at least 3% of body surface area involvement who had an inadequate response to current or prior standard of care therapies, and met all primary and secondary endpoints.
The trial design allowed for participants who had been randomly assigned to receive guselkumab to continue treatment after the assessment of the primary endpoint at 24 weeks, while those originally allocated to the placebo arm could crossover to the guselkumab arm, with treatment given until week 56.
The current analysis reports on the outcomes of these patients, finding that the proportion of patients achieving a 20%, 50%, or 70% improvement in ACR criteria or a 75%, 90%, or 100% reduction in the Psoriasis Area and Severity Index (PASI) scores increased in the crossover group (n=29) after the 24-week mark, while the response rates were maintained in the continuation group (n=86).
For example, a 50% improvement in ACR criteria was seen at 56 weeks in 53.0% of patients continuing guselkumab, compared with 39.5% at week 24, and the corresponding rates for patients switching to guselkumab were 66.7% and 17.2%.
Similarly, a 90% reduction in PASI scores was seen in 78.0% of patients continuing guselkumab at week 56, compared with 70.9% at week 24, and in a respective 74.1% and 10.3% of patients who switched.
The crossover group also demonstrated improvements in terms of the severity of enthesitis and dactylitis, with increases in the rates of complete resolution of these symptoms from week 24 through to week 56. And once again, the rates were sustained in the guselkumab continuation group during the additional follow-up.
For the safety analysis over the extended follow-up, the researchers included the 29 patients who had crossed over to guselkumab and all 100 patients originally assigned to receive guselkumab, with adverse events rates through week 56 of 17.2% and 46.0%, respectively.
Infections and infestations were the most common side effects, occurring in 3.4% of crossover participants and 26.0% of those given guselkumab throughout.
Of note, post-week 24, there was no disproportionate increase in the overall incidence of adverse events, or infections and infestations, among guselkumab-treated patients with longer exposure, the presenting author commented.
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