Global Study Highlights Survival Benefit of Mogamulizumab in Advanced Cutaneous T-Cell Lymphoma
Birmingham, UK, and Tokyo, Japan – Kyowa Kirin International (KKI), a wholly owned subsidiary of Kyowa Kirin Co., Ltd. (TSE:4151, Kyowa Kirin), a Japan-based global specialty pharmaceutical company, and the University Hospitals Birmingham NHS Foundation Trust today announced new overall survival (OS) insights from the international PROCLIPI (PROgnostic Cutaneous Lymphoma International Prognostic Index) Study. The results align with previous findings suggesting that mogamulizumab (POTELIGEO®) may deliver a meaningful overall survival benefit for patients living with mycosis fungoides (MF) and Sézary syndrome (SS), two rare and advanced subtypes of cutaneous T-cell lymphoma (CTCL).²
The new data were presented during the European Organisation for Research and Treatment of Cancer Cutaneous Lymphoma Tumour Group (EORTC-CLTG) Annual Meeting in Athens, Greece.² These findings contribute to a growing body of global evidence demonstrating the potential for improved long-term outcomes with mogamulizumab in patients with advanced CTCL.
Key findings²:
- Among patients with advanced-stage MF and SS (n=371), median overall survival from the onset of treatment was significantly higher for those receiving mogamulizumab (n=72), at 64 months, compared with 54 months for those not treated with the drug (n=175) (p<0.01).
- Across risk-stratified groups defined by the new Cutaneous Lymphoma International Prognostic Index (CLIPI), mogamulizumab-treated patients showed a consistent trend toward improved overall survival.
- In a subset of patients with Sézary syndrome (n=96), median overall survival reached approximately 6.5 years for those treated with mogamulizumab (n=46), compared with around 3 years for patients who received systemic therapies other than mogamulizumab (n=50) (p<0.01).
These data reinforce the importance of global collaboration in advancing the understanding of rare diseases such as CTCL and underline the potential real-world benefits of innovative therapies.
Professor Julia Scarisbrick, Chief Investigator of the PROCLIPI Study and Honorary Professor of Dermatology at University Hospitals Birmingham NHS Foundation Trust, emphasized the significance of these results:
The PROCLIPI Study demonstrates the power of international collaboration in rare diseases. By bringing together data from across the world, we can generate insights that simply wouldn’t be possible in isolation. We are proud to coordinate this initiative, helping to build robust scientific evidence while giving patients and families a clearer picture of what long-term survival looks like.
Now in its tenth year, the PROCLIPI Study was established to develop prognostic indices for MF and SS, collecting comprehensive data on clinical, haematological, pathological, imaging, treatment response, quality of life, and survival outcomes.¹ Recently, the study introduced a new prognostic index for advanced CTCL—the CLIPI—enabling more precise risk stratification for patients.⁶
Patient advocates have also highlighted the value of these findings for the CTCL community. Susan Thornton, CEO of the Cutaneous Lymphoma Foundation, said:
For those of us in the CTCL community, survival isn’t just about numbers on a chart—it’s about being able to spend more time with our families, plan for the future, and live life with dignity. Initiatives like PROCLIPI are vital because the data reflect real lived experiences and can help drive meaningful improvements in patient care.
The independent, investigator-led PROCLIPI Study aligns closely with Kyowa Kirin International’s commitment to generating real-world insights that advance understanding of CTCL. These efforts aim to translate clinical evidence into improvements in access, policy, and patient care on a global scale.
Cutaneous T-cell lymphoma is a rare and complex form of non-Hodgkin lymphoma, affecting the skin and sometimes the blood, lymph nodes, and internal organs.⁷ Due to its rarity, progress in understanding and treating CTCL has historically been slow.⁸ However, emerging real-world data continue to strengthen the evidence base supporting potential treatment benefits, helping clinicians and researchers refine strategies for improving patient outcomes.
Dr. Nick Kronfeld, Head of Medical Affairs at Kyowa Kirin International, commented on the broader implications of the findings:
These insights into improved overall survival for patients living with CTCL mark an important step forward, providing a stronger clinical evidence base and reinforcing the value of international networks in rare disease research. By working closely with both scientific and patient communities, we can deepen our understanding of real-world outcomes and bring life-changing value to patients and families—not only today but for years to come.
The presentation of these new overall survival data underscores Kyowa Kirin International’s continued support for advancing rare disease research and strengthening collaborations across the CTCL community.
Note to Editors
The overall survival data from the PROCLIPI Study were presented as an oral presentation during the 2025 EORTC CTCL Annual Group Meeting.² KKI did not sponsor the PROCLIPI study or the overall survival analysis.
Key OS results²:
- Median overall survival for patients receiving mogamulizumab (n=72) compared with those not receiving mogamulizumab (n=175) was 64 months versus 54 months.
- Median OS according to CLIPI risk stratification:
- Low-risk: 67 months vs. “not reached” for mogamulizumab versus those not receiving it.
- Medium-risk: 64 months vs. 48 months for mogamulizumab versus those not receiving it.
- High-risk: 26 months vs. 13 months for mogamulizumab versus those not receiving it.
These findings contribute to a growing foundation of evidence suggesting that mogamulizumab may offer a meaningful survival benefit across diverse patient subgroups, further highlighting the importance of precision-based approaches in CTCL treatment.
As the PROCLIPI initiative continues to evolve, it exemplifies the collective effort of clinicians, researchers, and patient advocates working toward a shared goal—improving the lives of those affected by rare and complex diseases. By bridging international data and real-world clinical experience, the study continues to inform future innovations and optimize patient care worldwide.
