Acelyrin has punted the autoimmune drug prospect izokibep back to Affibody, completing a retreat from its former lead candidate that began with the axing of development in two diseases in August. The news led Affibody to claim its former partner “has not been able to fully capitalize” on the asset’s potential.
California-based Acelyrin licensed izokibep in 2021 for $25 million upfront. The biotech, which agreed to pay up to $280 million in milestones, had no significant operations before striking the deal for the IL-17A inhibitor. Less than two years later, Acelyrin raised $540 million in an IPO to bankroll late-phase trials of izokibep in multiple indications.
The biotech subsequently soured on izokibep. Now, Acelyrin has cut its ties to the molecule. Once the termination is effective, Affibody will regain all rights to the candidate, and its CEO David Bejker thinks his company can make better use of them than its former partner.
“We are convinced that izokibep, with its clear path to approval and competitive profile, can become a game-changing drug in the dermatology field, particularly for the significant number of patients debilitated by [hidradenitis suppurativa],” Bejker said in a statement. “It is clear that Acelyrin has not been able to fully capitalize on the potential demonstrated by izokibep’s best-in-class phase 3 data.”
A phase 3 trial of izokibep in hidradenitis suppurativa, a skin condition characterized by abscesses, met its primary endpoint last year. Acelyrin found 33% of patients who took izokibep had a 75% or greater reduction in abscesses and inflammatory nodules, compared to 21% of people on placebo. Yet, having hit the primary and secondary endpoints, Acelyrin simultaneously stopped investing in the indication.
At the same time, the biotech pulled back from psoriatic arthritis—a disease in which it scored a phase 2b/3 win earlier in 2024—to leave uveitis as its last remaining area of active izokibep development. The phase 2b/3 uveitis trial missed its primary and secondary endpoints late last year.
With Inmagene Biopharmaceuticals recently ending a deal covering Asian countries including China and South Korea, responsibility for izokibep will fall squarely on Sweden’s Affibody. Acelyrin CEO Mina Kim has framed getting izokibep to market in hidradenitis suppurativa as a job for a big company with an existing footprint in the indication. Izokibep failed an earlier trial in the indication in 2023.