Mirikizumab Superior to Placebo in Treating Plaque Psoriasis

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At week 16, the static Physician’s Global Assessment scores were significantly greater in the mirikizumab group than in the placebo group.

New research suggest mirikizumab is both an efficacious and safe treatment for patients with plaque psoriasis.

A team, led by Andrew Blauvelt, MD, Oregon Medical Research Center, evaluated the efficacy and safety of mirikizumab in adult patients with moderate-to-severe plaque psoriasis through 52 weeks.

The Treatment

IL-23 treatments are both effective and safe in treating patients with moderate-to-severe plaque psoriasis.

In the double-blind, placebo-controlled phase 3, randomized withdrawal OASIS-1 study, the investigators examined 520 patients treated with either subcutaneous mirikizumab 250 mg or placebo every 4 weeks through week 16.

The investigators sought co-primary endpoints of the superiority of mirikizumab compared to placebo on the static Physician’s Global Assessment, as well as at least a 90% improvement in Psoriasis Area and Severity Index at week 16.

Next, the team rerandomized mirikizumab responders to mirikizumab 250 mg every 8 weeks, mirikizumab 125 mg every 8 weeks, or placebos through week 52. They also evaluated secondary endpoints at weeks 16 and 52 and monitored safety for all patients.

Positive Results

The treatment met all primary and key secondary endpoints.

At week 16, the static Physician’s Global Assessment scores were significantly greater in the mirikizumab group (n = 293; 69.3%) than in the placebo group (n = 7; 6.5%) (P <0.001).

The PASI 90 response was also higher in the mirikizumab group (n = 272; 64.3%) than it was in the placebo group (n = 7; 6.5%) (P <0.001).

There were overall more patients in the mirikizumab arms that achieved PASI 75 and PASI 100 (mirikizumab 349, 825% and 137, 324%; placebo 10, 93% and 1, 09%, respectively; all P < 0001).

At week 52, PASI 90, PASI 100 and sPGA responses were mirikizumab 250/placebo every 8 weeks (n = 91;19%, 10%, 18%), mirikizumab 250 every 4 weeks /125 every 8 weeks (n = 90; 86%, 59%, 86%) and mirikizumab 250 every 4 weeks/250 every 8 weeks (n = 91; 86%, 60%, 82%; all P <0001), respectively.

For the safety analysis, the investigators found the rates of serious adverse events were similar across treatment induction (mirikizumab, 1.2% vs. placebo, 1.9%), maintenance (mirikizumab, 1.2% vs. placebo, 1.9%),maintenance(mirikizumab 250 every 4 weeks/125 every 8 weeks, 1%, mirikizumab 250 every 4 weeks/250 every 8 weeks, 3% vs. placebo, 3%).

No deaths occurred over the course of the study.

“Mirikizumab was superior to placebo at week 16 and maintained efficacy through week 52, with no new safety signals,” the authors wrote.

The study, “Efficacy and safety of mirikizumab in psoriasis: results from a 52-week, double-blind, placebo-controlled, randomized withdrawal, phase III trial (OASIS-1),” was published online in the British Journal of Dermatology.