MADRID – Apremilast improves the signs and symptoms of psoriatic arthritis in about 60% of patients at 1 year, according to long-term data from the PALACE 1 trial.
At week 52, a 20% improvement in disease symptoms according to American College of Rheumatology (ACR 20) response criteria was achieved by 57%-63% of patients treated with apremilast, providing evidence of sustained treatment effects.
The PALACE 1 trial’s primary endpoint of an ACR 20 at 16 weeks, already reported last year, was achieved by 31% of patients treated with apremilast 20 mg and 40% of those given apremilast 30 mg, compared with 19% of those given placebo.
"Oral apremilast demonstrated long-term efficacy, including improvement in signs and symptoms and physical function, and skin manifestations," Dr. Arthur Kavanaugh, professor of medicine at the University of California, San Diego, said at the annual European Congress of Rheumatology.
Apremilast is an oral phosphodiesterase 4 inhibitor under investigation as a treatment for active psoriatic arthritis (PsA). It is being evaluated as a possible treatment for skin psoriasis, ankylosing spondylitis, rheumatoid arthritis, and Behçet’s disease.
PALACE 1 was a phase III, multicenter, double-blind, placebo-controlled study of apremilast for the treatment of active PsA. A total of 504 patients with a documented diagnosis of PsA for at least 6 months were recruited into the study (Ann. Rheum. Dis. 2013;72[Suppls3]:163).
Functional outcomes improved
Physical function improved according to measurements on the Health Assessment Questionnaire–Disability Index (HAQ-DI). At baseline, HAQ-DI scores were 1.21, and "we saw that patients improved by –0.35, which is certainly the level that patients can say, ‘I feel better and I can do my daily activities better,’ " Dr. Kavanaugh said.
Additionally, 25% and 37% of patients treated with apremilast 20 mg and 30 mg, respectively, achieved a 75% improvement in the Psoriasis Area and Severity Index at 52 weeks, which is a "very high bar" to achieve, he noted.
The main side effect seen was diarrhea, affecting 11%-19% of patients given apremilast and 2.4% given placebo. However, diarrhea occurred mainly in the first 6 months of therapy and could be managed by taking appropriate measures on an individual patient basis, Dr. Kavanaugh said. This might include prescription of an antidiarrheal agent.
"Prolonged exposure to apremilast did not result in any unexpected increased incidence of adverse events or laboratory abnormalities," he noted. The latter could mean that, if approved, apremilast might not need routine laboratory monitoring.
Sara Freeman/IMNG Medical Media
Dr. Arthur Kavanaugh
The PALACE development program
PALACE 1 is one of several clinical trials that have investigated the efficacy and safety of apremilast in active PsA. In these studies, 24 weeks’ treatment with one of two oral doses (20 mg or 30 mg twice daily) of apremilast was compared to placebo. The primary endpoint of the studies was the percentage of patients achieving ACR 20 at 16 weeks.
For inclusion in the trials, patients had to have active disease despite prior therapy with disease-modifying antirheumatic drugs (DMARDs), biologic agents, or both. Dr. Kavanaugh noted that the majority of patients had failed DMARD therapy in PALACE 1, with almost one-quarter receiving prior biologic therapy.
Patients who had a less than 20% reduction from baseline in swollen/tender joint counts at 16 weeks were re-randomized to receive apremilast 20 mg or 30 mg if they had originally been treated with placebo, while patients originally randomized to active treatment stayed on their initial dose if they failed to respond significantly. At the end of the planned 24-week treatment period, all remaining patients on placebo were re-randomized to apremilast 20 mg or 30 mg until 1 year of follow up.
PALACE 3 data also reported
The results of PALACE 3 and combined 6-month safety data from the PALACE 1, PALACE 2, and PALACE 3 trials were also reported at the congress.
In PALACE 3 (Ann. Rheum. Dis. 2013;72[Suppl. 3]:685), significantly more patients achieved the primary endpoint of an ACR 20 at 16 weeks if they were treated with either the 20-mg dose (29.4%, P = .02) or 30-mg dose (42.8%, P less than .0001) of apremilast, compared with those given placebo (18.9%). There was also statistically significant and "clinically meaningful" improvement in physical function and pain. "The results of PALACE 3 support the efficacy and safety findings of the PALACE 1 study and help establish the profile of apremilast in PsA," the PALACE 3 investigators concluded.
The pooled safety findings revealed no new safety concerns and showed apremilast was generally well tolerated (Ann. Rheum. Dis. 2013;72[Suppl. 3]:85). Rates of diarrhea at 24 weeks were 12.6% and 16.5% for the 20-mg and 30-mg doses of apremilast, and 2.8% for placebo, respectively. Other side effects of note included nausea (10% and 16.1% vs. 4.6%), headache (8.4% and 11.5% vs. 4.6%), and upper respiratory tract infection (7% and 6% vs. 3%).