in a phase 2b randomized trial, Kim A. Papp, MD, PhD, reported at the annual congress of the European Academy of Dermatology and Venereology.
A nanobody is a tiny antibody fragment with a much smaller molecular weight than the monoclonal antibodies utilized today in treating psoriasis or atopic dermatitis. The sonelokinab nanobody, derived from animals in the camel family, is a recombinant sequence-optimized nanobody specific for human IL-17F, IL-17A, the heterodimer IL-17A/F, and serum albumin. The binding to serum albumin give sonelokinab a lengthy half-life of 10-12 hours, which may be therapeutically relevant, explained Dr. Papp, president and founder of Probity Medical Research in Waterloo, Ont.
He presented the 24-week results of a multicenter, double-blind, double-dummy randomized trial including 313 North American and European adults with an average 18-year history of psoriasis and a baseline Psoriasis Area and Severity Index (PASI) score of about 21. They were randomized to one of six treatment arms for the first 12 weeks: subcutaneous injection of sonelokinab at 30, 60, or 120 mg at weeks 0, 2, 4, and 8; enhanced–loading-dose sonelokinab at 120 mg every 2 weeks through week 10; the IL-17A inhibitor secukinumab (Cosentyx) at its standard dosing as an active comparator; or placebo. Data analysis was by rigorous nonresponder imputation, meaning anyone who didn’t complete the study was scored as a nonresponder.
“This yields a conservative data analysis somewhat biased against sonelokinab,” the dermatologist pointed out.
The primary outcome in the trial was the week-12 rate of an Investigator’s Global Assessment score of 0 or 1, indicative of clear or almost clear skin. This was achieved in 88.2% of patients in the highest-dose arm of sonelokinab. That group also had a week-12 PASI 90 response rate of 76.5% and a PASI 100 response rate of 33.3%. By comparison, patients on standard-dose secukinumab had a less robust week-12 IGA 0/1 rate of 77.4%, a PASI 90 of 64.2%, and a PASI 100 of 28.3%. Of note, however, this secukinumab performance was better than seen in the 30-mg sonelokinab group, and comparable to outcomes with 60 mg of sonelokinab.
Dose escalation was performed from weeks 12-24. Patients with a week-12 IGA score greater than 1 after being on sonelokinab at 30 or 60 mg were upgraded to 120 mg at week 12 and again every 4 weeks thereafter. Placebo-treated controls were switched to 120 mg at weeks 12, 14, 16, and every 4 weeks thereafter. The group on the enhanced–loading-dose sonelokinab moved to 120 mg every 4 weeks, while those who had gotten four doses of sonelokinab at 120 mg during the first 12 weeks were switched to 120 mg every 8 weeks. The secukinumab group remained on the approved dosing through week 24.
At week 24, superior outcomes were seen in the enhanced–loading-dose sonelokinab group, with an IGA 0/1 response rate of 94.2%, a PASI 90 of 90.4%, and a PASI 100 of 56.9%. The corresponding week-24 rates in patients on 120 mg of sonelokinab every 8 weeks from week 12 on were 80.4%, 79.2%, and 40.4%, outcomes similar to those seen with secukinumab.
The rapidity of response to sonelokinab at 120 mg was striking, with approximately one-third of treated patients achieving a PASI 90 response by week 4.
“This could reflect the smaller molecular profile. There is possibly rapid increased absorption or bioavailability, quicker time to achieving serum half-life, better penetration into target tissue, and perhaps more effective engagement at the target. All of those things are possibilities. These are things that are yet to be explored, but it’s very enticing to see that uncharacteristically rapid initial response. It’s all very gratifying – and tantalizing,” Dr. Papp said in response to an audience question.
The safety profile of sonelokinab was reassuring. The most common adverse events were nasopharyngitis in 13.5% of patients and pruritus in 6.7%, with most cases being mild or moderate. As with other IL-17 blockers, there was an increase in oral candidiasis. This side effect appeared to occur in dose-dependent fashion: The incidence was zero in the 30-mg group, 1.9% with 60 mg, 3.8% with sonelokinab at 120 mg without an enhanced loading dose, and 5.9% with the enhanced loading dose.
The study was conducted by Avillion in partnership with Merck. Dr. Papp reported receiving research funding from and serving as a consultant to those and numerous other pharmaceutical companies.