Amgen terminated its collaboration with Kyowa Kirin on rocatinlimab, an anti-OX40 antibody for atopic dermatitis, due to strategic portfolio prioritization.124
The partnership began in 2021 with Amgen paying $400 million upfront and potential for up to $850 million in milestones.256
Phase III data from September 2024 showed 32.8% of patients achieving 75% improvement vs. 13.7% placebo, deemed underwhelming by analysts like Jefferies.1
September 2025 long-term safety data reported low dropout rates and no new safety signals, but concerns persisted over efficacy and tolerability.1
Kyowa Kirin regains full global rights, plans FDA submission in H1 2026, and will continue clinical trials with Amgen manufacturing support.134
Analysts are divided:
William Blair surprised, Leerink not, citing competitive atopic dermatitis market and OX40 target issues.15
Sources:
1. https://www.biospace.com/business/amgen-ends-autoimmune-alliance-with-kyowa-kirin-amid-safety-efficacy-questions
2. https://www.fiercebiotech.com/biotech/amgen-jilts-kyowa-exiting-400m-autoimmune-pact-after-running-vast-pivotal-program
3. https://www.dermatologytimes.com/view/kyowa-kirin-takes-full-control-of-rocatinlimab-program
4. https://www.kyowakirin.com/mediacenter/newsreleases/2026/pdf/e20260130_01.pdf
5. https://finviz.com/news/293884/kyowa-kirin-regains-global-rights-to-atopic-dermatitis-drug-after-amgen-collaboration-ends
6. https://www.biopharmadive.com/news/amgen-return-rocatinlimab-kyowa-kirin-atopic-dermatitis-eczma-ox40/810964/