A Phase III readout in September 2024 for rocatinlimab, on which Amgen and Kyowa Kirin were collaborating in atopic dermatitis, appeared underwhelming to analysts, with Jefferies noting that the data “came in at the lower end of efficacy and expectations.”
Amgen has walked away from an autoimmune agreement with Kyowa Kirin, handing back rights to the anti-OX40 antibody rocatinlimab.
The termination “is the result of a strategic portfolio prioritization by Amgen,” according to a press announcement from Kyowa Kirin on Friday. The companies will ensure continuity for patients currently being treated in clinical trials, and Amgen will continue to manufacture the drug for these programs.
Analysts appear split on Amgen’s decision to cut off rocatinlimab. Writing to investors on Friday, William Blair called the move “somewhat of a surprise,” given the recent completion of the drug’s broad late-stage program and an impending regulatory submission.
On the other hand, analysts at Leerink Partners said in their own note on Friday that they are not surprised with the move, particularly given “long-standing questions about [rocatinlimab’s] efficacy and tolerability profile.” Amgen, the firm pointed out, did not indicate its intent to file for rocatinlimab’s approval even after late-stage testing was completed.
In September 2024, Amgen and Kyowa Kirin released Phase III data for rocatinlimab, demonstrating that 32.8% of treated patients hit 75% improvement in eczema disease severity, as opposed to 13.7% of placebo comparators. Analysts, however, appeared underwhelmed by the outcome, with Jefferies telling investors at the time that the data were “modest” and “came in at the lower end of efficacy and expectations.”
The companies released long-term safety data a year later, in September 2025, covering 24 weeks of initial treatment plus 32 weeks of long-term follow-up in a separate late-stage extension study. They said at the time that the dropout rate was “low” across all treated arms, with no new safety signals of concern.
But a readout from March that same year revealed that patients treated with rocatinlimab showed higher rates of both chills and pyrexia—elevated body temperature—compared to placebo counterparts, a safety profile that according to William Blair on Friday, “was going to be a commercial challenge in treating chronic conditions like atopic dermatitis, and also potentially limiting dose intensity and therefore efficacy.”
“Ultimately, rocatinlimab’s unique side effects were always going to be a headwind to commercialization,” the analysts added.
Still, Kyowa Kirin said Friday that it maintains confidence in rocatinlimab and its potential to “address critical needs for patients with moderate-to-severe atopic dermatitis.” The Japanese company plans to file an approval application with the FDA in the first half of this year.
