Kyowa Kirin Regains Control of Rocatinlimab Development Following Amgen Partnership Termination
Key Insights
Kyowa Kirin has terminated its rocatinlimab development collaboration with Amgen and will regain full control of the global program, including regulatory filings and commercialization.
The anti-OX40 (search) monoclonal antibody demonstrated positive results in Phase 3 trials involving nearly 1,500 adults with moderate-to-severe atopic dermatitis (search), meeting all co-primary and key secondary endpoints.
Regulatory submission is planned for the first half of 2026, with the U.S. filing expected first, followed by Japan and other global markets.
Kyowa Kirin Co., Ltd. announced the termination of its rocatinlimab development and commercialization collaboration with Amgen, marking a significant strategic shift for the Japanese pharmaceutical company's lead atopic dermatitis (search) asset. The decision, driven by Amgen's strategic portfolio prioritization, will see Kyowa Kirin regain full control of the global rocatinlimab program, including regulatory filings and future commercialization.
The transition comes as rocatinlimab, an anti-OX40 (search) monoclonal antibody, has demonstrated promising clinical results in treating moderate-to-severe atopic dermatitis (search). Despite the partnership termination, Amgen will continue to manufacture the investigational therapy, ensuring continuity for the more than 3,300 patients currently enrolled across the comprehensive clinical development program.
Strong Phase 3 Clinical Results Drive Confidence
Landmark findings from the Phase 3 ROCKET-IGNITE and ROCKET-HORIZON studies, published in The Lancet in November 2025, provide the foundation for Kyowa Kirin's confidence in proceeding independently. Both studies evaluated rocatinlimab monotherapy in nearly 1,500 adults with moderate-to-severe atopic dermatitis (search) and met all co-primary and key secondary endpoints.
The trials achieved the US regulatory submission requirement for the revised Investigator's Global Assessment (rIGA) score of 0/1, defined as achieving a vIGA-AD score of 0 (clear skin) or 1 (almost clear skin) with only presence of barely perceptible erythema and ≥2-point reduction from baseline. For the more stringent rIGA score of 0 or 1 endpoint, patients with a score of 1 could not have any induration, papulation, or lichenification.
"Kyowa Kirin is confident in the potential of rocatinlimab to address critical unmet needs for patients with moderate-to-severe atopic dermatitis (search) who are looking for new, long-lasting options that may address the chronic nature of unpredictable flares," said Abdul Mullick, Ph.D., President and Chief Operating Officer of Kyowa Kirin.
Novel Mechanism Targets Disease Pathophysiology
Rocatinlimab represents a potentially first-in-class T-cell rebalancing therapy that directly targets the OX40 (search) receptor expressed on pathogenic T-cells. This mechanism of action distinguishes it from existing treatments by inhibiting and reducing pathogenic effector and memory T-cells responsible for driving systemic and local inflammatory responses in atopic dermatitis (search).
The OX40 (search) receptor serves as a co-stimulatory receptor critical in disease pathophysiology, with effector T-cells expressing OX40 present in lesions of patients with atopic dermatitis (search). This targeted approach aims to address the underlying drivers of chronic inflammatory disease rather than merely treating symptoms.
Comprehensive Safety Profile Established
The long-term safety extension study ROCKET-ASCEND demonstrated the potential for sustained therapeutic effect and extended dosing intervals. The most frequent treatment-emergent adverse events (≥5 per 100 patient-years in any rocatinlimab group and greater than placebo) included upper respiratory infections (including nasopharyngitis and pharyngitis), aphthous ulcers, headache, influenza, cough, and rhinitis, consistent with observations from previous ROCKET trials.
"Based on the data available to-date, rocatinlimab has demonstrated a generally favorable benefit-risk profile across its Phase 3 clinical program," said Takeyoshi Yamashita, Ph.D., Executive Vice President and Chief Medical Officer of Kyowa Kirin. "The potential to provide a meaningful and sustained clinical response may be important, particularly for patients who continue to experience symptoms despite existing therapies."
Broad Clinical Development Program
The Phase 3 ROCKET program represents one of the most comprehensive clinical development initiatives in atopic dermatitis (search), consisting of eight pivotal studies evaluating both long-term efficacy and safety. The program includes diverse patient populations spanning adults and adolescents, systemic treatment-naïve patients, and those previously treated with biologics and JAK inhibitors.
This broad clinical approach underscores rocatinlimab's potential as a meaningful treatment option across various clinical scenarios for patients living with atopic dermatitis (search). The extensive patient enrollment of more than 3,300 participants provides substantial data to support the therapy's clinical profile.
Regulatory Timeline and Market Strategy
Kyowa Kirin plans to file for regulatory approval in the United States first during the first half of 2026, followed by submissions in Japan before expanding to other global markets. This strategic approach leverages the company's extensive clinical and commercial expertise developed over more than 70 years of drug discovery and biotechnology innovation.
The company's decision to proceed independently reflects confidence in rocatinlimab as a key strategic priority and life-changing differentiated asset with significant market potential. Rocatinlimab was originally discovered and advanced by Kyowa Kirin, drawing on the company's deep expertise in immunology and antibody engineering in collaboration with La Jolla Institute for Immunology.
Beyond atopic dermatitis (search), rocatinlimab is also being investigated for moderate to severe uncontrolled asthma (search), prurigo nodularis (search), and potentially other conditions where T-cell imbalance drives inflammation, suggesting broader therapeutic applications for this novel mechanism of action.