Affibody Reclaims Autoimmune Drug Izokibep from Acelyrin, Citing Untapped Potential

Affibody, a Swedish biopharmaceutical company, has regained full rights to the autoimmune drug candidate izokibep from its former partner Acelyrin. This development marks a significant shift in the drug's trajectory and highlights the challenges faced in bringing novel therapies to market.

Acelyrin's Retreat from Izokibep

California-based Acelyrin, which initially licensed izokibep in 2021 for $25 million upfront, has decided to terminate its agreement with Affibody. This move follows Acelyrin's gradual retreat from the once-promising IL-17A inhibitor, which began with the cessation of development in two disease areas in August of last year.

The biotech's journey with izokibep has been tumultuous. After securing the license, Acelyrin raised an impressive $540 million in an IPO to fund late-phase trials across multiple indications. However, the company's enthusiasm for the drug waned over time, culminating in this complete divestment.

Clinical Trial Results and Strategic Decisions

Izokibep has shown mixed results in clinical trials, contributing to Acelyrin's changing stance:

• A phase 3 trial in hidradenitis suppurativa met its primary endpoint, with 33% of izokibep-treated patients achieving a 75% or greater reduction in abscesses and inflammatory nodules, compared to 21% in the placebo group.
• Despite this success, Acelyrin halted investment in the hidradenitis suppurativa indication.
• The drug scored a win in a phase 2b/3 trial for psoriatic arthritis earlier in 2024, but Acelyrin subsequently pulled back from this indication as well.
• A phase 2b/3 uveitis trial missed both its primary and secondary endpoints late last year.

These mixed outcomes led Acelyrin to narrow its focus, ultimately deciding to exit the izokibep program entirely.

Affibody's Perspective and Future Plans

Affibody's CEO, David Bejker, expressed confidence in izokibep's potential, particularly in dermatology. "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 stated.

The Swedish company believes that Acelyrin "has not been able to fully capitalize" on izokibep's potential, especially given the positive phase 3 data in hidradenitis suppurativa. Affibody now faces the challenge of advancing the drug's development and potential commercialization, a task that Acelyrin's CEO Mina Kim previously suggested might be better suited for a larger company with an established presence in the indication.

As Affibody takes full control of izokibep, the pharmaceutical industry will be watching closely to see if the company can unlock the drug's full potential and navigate the complex landscape of autoimmune disease treatment.