Long term apremilast monotherapy can result in sustained improvement in psoriatic arthritis out to five years in DMARD-naive patients, Australian-led research shows.
PALACE 4 comprised 527 patients randomised to apremilast (20 or 30mg) or placebo for 16-24 weeks, before placebo patients were re-randomised to apremilast to week 52. The results at week 52 were previously reported in the limbic in 2018.
Patients then entered a four-year open label extension to evaluate long term exposure.
The study, co-authored by Associate Professor Paul Bird from the University of NSW, found 58% patients on 30 mg apremilast achieved ACR20 at week 52 and 65.8% of those who continued therapy achieved ACR 20 at week 260.
“Similarly, ACR50 and ACR70 responses increased from baseline and were sustained over 260 weeks with continued treatment,” the study said.
Mean swollen joint and tender joint counts reduced 76.1% and 59.4% respectively at week 52 and further (84.8% and 76.4%) at week 260.
Improvement in enthesitis and dactylitis seen in affected patients at 52 weeks were also maintained at week 260 as were improvements in physical function and plaque psoriasis in affected patients.
The study said similar improvements were seen with the 20 mg dose.
“At the end of the study, 24.8% of patients remaining in the trial reported using a csDMARD or steroid for any reason, suggesting that approximately 75% of patients responded sufficiently with apremilast alone whereas concomitant csDMARD or steroid could have contributed to treatment response in the remaining 25%,” the study said.
“These findings suggest that apremilast may offer long-term benefits to DMARD-naive patients with active PsA who initiate apremilast early in the course of their treatment paradigm.”
Common adverse events to both doses included diarrhoea and nausea which usually resolved within four weeks. There were no new safety concerns with long term exposure.
Serious infections were rare and apremilast was not associated with an increased risk of basal or squamous cell carcinoma.
The investigators said a limitation of the study was that long-term efficacy results may be biased by non-random discontinuation of patients due to lack or loss of response, adverse events and the absence of a control arm.
“Open-label extensions do, however, offer insight into the efficacy and safety of therapies in those patients who remain on longer-term therapy.”
“The findings from the open-label extension phase of the PALACE 4 study demonstrate that apremilast offers sustained efficacy in DMARD-naive PsA patients continuing treatment as well as a favourable safety profile.”
Disclosure: The study was funded by Celgene.