PARIS – Dermatologists are likely to do a double-take when they see the long-term efficacy and safety data for tildrakizumab (Ilumya), a high-affinity humanized monoclonal antibody targeting interleukin-23 p19, relative to the performance of older and more familiar biologic agents with other targets in psoriasis, Diamant Thaçi, MD, predicted at the annual congress of the European Academy of Dermatology and Venereology.
Dr. Diamant Thaçi
“The time to relapse [off tildrakizumab] is very different from what we are used to with other biologics; for example, the tumor necrosis factor inhibitors,” observed Dr. Thaçi, professor and chairman of the department of dermatology at the University of Lübeck (Germany).
He presented the 148-week, follow-up results of a pooled analysis of the open-label extension studies of reSURFACE 1 and reSURFACE 2, two pivotal phase 3 randomized double-blind international trials of 1,862 patients with moderate to severe chronic plaque psoriasis. The primary outcomes through week 12, which were instrumental in gaining marketing approval for tildrakizumab for treating psoriasis in 2018 from the Food and Drug Administration and the European Medicines Agency, have been published in the Lancet (2017 Jul 15;390[10091]:276-88).
Dr. Thaçi’s analysis of the 148-week outcomes was restricted to the patients who had at least a 75% improvement from baseline in Psoriasis Area and Severity Index scores (PASI 75) at week 28. Nearly 80% of patients on tildrakizumab reached that threshold at week 28 in reSURFACE 1, as did 73% in reSURFACE 2.
The question asked in the extension study was, How do responders to tildrakizumab at 28 weeks fare after nearly 3 years on the drug? And the answer was: very well. Maintenance of at least a PASI 75 response was observed at 148 weeks in 91% of patients on tildrakizumab at the approved 100-mg dose and 92% of those on the 200-mg dose. The FDA-approved regimen is 100 mg by subcutaneous injection at weeks 0 and 4, and then every 12 weeks after that.
An intriguing feature of reSURFACE 1 was that a subset of PASI 75 responders at week 28 got taken off tildrakizumab at that point and switched to double-blind placebo, then restarted on their earlier dose of tildrakizumab upon relapse, which was defined as loss of at least 50% of the achieved on-drug PASI improvement.
At week 64, fully 48 weeks after their last dose of tildrakizumab, the relapse rate was 54% in the group formerly on 100 mg of tildrakizumab and slightly better at 47% in those formerly on 200 mg. The median time to relapse was 226 days in the 100-mg group and 258 days in the higher-dose arm. Those are exceptionally long times to relapse, and it’s useful information to file away in the event a psoriasis patient needs to discontinue biologic therapy for a period of time, Dr. Thaçi observed.
At week 64 – again, off active treatment since week 16 – 63% of the tildrakizumab 100-mg group had lost their previous PASI 75 response, as had 52% who were formerly on tildrakizumab at 200 mg.
The long-term safety profile of tildrakizumab paralleled that of placebo. For example, the exposure-adjusted adverse event rates of serious infections and major adverse cardiovascular events were closely similar in the placebo, tildrakizumab 100 mg, and tildrakizumab 200 mg groups.
There were two notable between-group differences in adverse events of interest: injection site reactions occurred at a rate of 5.36 per 100 person-years with placebo, compared with 1.94 and 2.3 per 100 person-years with tildrakizumab at 100 and 200 mg, respectively; and the incidence of nonmelanoma skin cancer was 0.97 cases per 100 person-years in the placebo arm, versus 0.5 and 0.49 cases per 100 person-years in the two tildrakizumab arms.
Dr. Thaçi did not present PASI 90 response outcomes because, at the time the reSURFACE trials were planned, PASI 75 was considered state of the art. The PASI 90 data are still being crunched but will be available soon. The 4- and 5-year follow-up data from the long-term extension studies are also on their way.
The reSURFACE 1 and reSURFACE 2 trials and their extension studies were funded by Sun Pharma and Merck. Dr. Thaçi reported receiving research grants from and serving as a consultant and paid scientific advisor to those pharmaceutical companies and more than a dozen others.