MADRID – The lessening of the signs and symptoms of psoriatic arthritis that occurs during the first 6 months of ustekinumab treatment persisted and improved further at the end of 1 year, with a favorable safety profile, according to 52-week data from the PSUMMIT II trial.
The sustained benefits in American College of Rheumatology (ACR) 20 responses and other efficacy endpoints were evident even in patients who had been treated previously with anti-tumor necrosis factor (anti-TNF) agents and among those who were anti-TNF naïve, although the benefits were greater in the latter group patients, according to Dr. Christopher T. Ritchlin, a professor in the department of medicine, allergy/immunology, and rheumatology at the University of Rochester (N.Y.). This includes beneficial effects on skin and enthesitis, Dr. Ritchlin said at the annual European Congress of Rheumatology.
The PSUMMIT II study is a follow-up to the PSUMMIT I study, the findings of which showed that ustekinumab, a human interleukin (IL)-12 and IL-23 antagonist, showed significant effectiveness in patients with psoriatic arthritis (PsA) who had not been exposed to anti-TNF drugs.
Ustekinumab is currently approved for treating moderate to severe plaque psoriasis in adults who are candidates for phototherapy or systemic therapy in the United States, or those who have failed to respond to, have a contraindication to, or are intolerant of other systemic therapies in Europe. In December 2012, the manufacturer, Janssen, announced that it had filed for further approval for ustekinumab in both the United States and Europe for the treatment of active disease.
The PSUMMIT II study enrolled 312 patients with active PsA who had five or more tender and five or more swollen joints, and a C-reactive protein level of 0.3 mg/dL or higher. Patients who had been treated previously with anti-TNF therapy (n = 180) and those naive to anti-TNF therapy (n = 132) were included and randomized to one of two doses of ustekinumab (45 mg or 90 mg) or placebo administered at week 0, 4, and 12. At 16 weeks, patients with less than a 5% improvement in tender and swollen joint counts on placebo were switched to active treatment, those on 45 mg ustekinumab had their dose upped to 90 mg, and those on 90 mg remained on that dose.
Dr. Christopher Ritchlin
At 6 months, significantly more patients treated with ustekinumab than placebo achieved the primary endpoint of an ACR 20, and more patients on active treatment had an ACR 50, and at least a 75% improvement in the Psoriasis Area and Severity Index (PASI 75).
These results were sustained at 1 year, with 47%-48% of those on 45 mg and 90 mg, and 56% of those who switched from placebo to the 45-mg dose, achieving an ACR 20. In addition, 26%-29% achieved an ACR 50 (29% for those switched from placebo), and 13%-18% achieved an ACR 70 (15% for placebo). There were also improvements associated with treatment in HAQ-DI (Health Assessment Questionnaire-Disability Index) scores at week 52, according to Dr. Ritchlin. The mean change in HAQ-DI scores from baseline to week 52 were -0.21 for placebo, -0.20 for the 45-mg dose of ustekinumab, and -0.28 for the 90-mg dose.
Among those who had not been treated before with an anti-TNF agent, 59%-60% of those on ustekinumab (73% for those switched from placebo) achieved an ACR 20 at week 52, compared with 37%-41% of those who had taken an anti-TNF agent previously before being treated with ustekinumab (30% for placebo). Although responses among anti-TNF naive patients were superior, the responses among those who had been treated with these agents previously were still significantly improved, an indication that ustekinumab "offers an alternative for patients who cannot take or fail anti-TNF agents," Dr. Ritchlin said in the interview.
Treatment was "very effective" for skin symptoms and for enthesitis, he noted. Compared with baseline, dactylitis was improved by a median of 95% among those on the 45-mg dose, 91% among those on the 90-mg dose, and 100% in those who switched from placebo to the 45-mg dose of ustekinumab. Similar improvements in enthesitis were seen, with the highest improvement (60%) seen with the highest dose of ustekinumab. PASI scores at baseline ranged from 11 to 13 and improved by 56%-64% by follow-up at week 52.
In general, ustekinumab was well tolerated, with no deaths or cases of tuberculosis reported and with similar rates of adverse events and serious adverse events between the two doses (just under 6%). There were two malignancies: one breast cancer and one squamous cell carcinoma in two patients taking the 90-mg dose of ustekinumab, who had both been treated with anti-TNFs previously. The rate of serious infections was less than 1% among those treated with ustekinumab. Through 60 weeks of treatment, there were three major adverse cardiovascular events, all myocardial infarctions, in patients treated with ustekinumab. These patients all had multiple cardiovascular risk factors, Dr. Ritchlin said. They had also been exposed previously to anti-TNF treatment.