
Global Study Confirms Survival Advantage of Mogamulizumab in Advanced Mycosis Fungoides and Sézary Syndrome
Key Takeaways
- Mogamulizumab offers a significant survival advantage for advanced CTCL patients, with median overall survival of 64 months versus 54 months for non-recipients.
- The PROCLIPI registry, covering 19 countries, provides robust prognostic data for CTCL, enhancing global understanding of this rare disease.
New findings from the PROgnostic Cutaneous Lymphoma International Prognostic Index (PROCLIPI) Study provide additional evidence that mogamulizumab, marketed under the brand name Poteligeo by Kyowa Kirin International (KKI), a wholly owned subsidiary of Japan-based specialty pharmaceutical company Kyowa Kirin, may offer a meaningful overall survival advantage for patients with advanced cutaneous T-cell lymphoma (CTCL), including mycosis fungoides (MF) and Sézary syndrome (SS). The analysis, presented at the European Organization for Research and Treatment of Cancer’s
The PROCLIPI registry is one of the largest of its kind, spanning 19 countries and including more than 2000 patients. The registry was established to generate robust prognostic data for CTCL subtypes, and it now provides one of the most comprehensive views of global outcomes in this rare disease area (2).
Among 371 patients with advanced MF and SS, the study reported a median overall survival (OS) of 64 months for those treated with mogamulizumab, compared with 54 months for patients who did not receive the therapy (p<0.01). In the subgroup of patients with Sézary syndrome, median OS reached approximately six-and-a-half years for those given mogamulizumab versus three years for those on other systemic treatments (p<0.01). These findings align with earlier evidence suggesting potential OS advantages of using mogamulizumab in advanced CTCL, KKI and UHB noted in the release (1).
What does this new global data mean for biopharma development in rare disease oncology?
These results underscore the importance of real-world data in complementing clinical trials for rare malignancies, for which limited patient populations can constrain traditional study designs. “The PROCLIPI Study demonstrates the power of global collaboration in rare diseases,” said Professor Julia Scarisbrick, chief investigator of the PROCLIPI Study and honorary professor of dermatology at University Hospitals Birmingham NHS Foundation Trust, in the press release (1). “By bringing together data from across the world, we can generate insights that simply wouldn’t be possible in isolation.”
Now in its tenth year, PROCLIPI collects extensive data encompassing clinical, pathological, imaging, and treatment parameters to refine prognostic understanding of MF and SS. A recently developed Cutaneous Lymphoma International Prognostic Index (CLIPI) has introduced a more precise system for risk stratification, enabling researchers and clinicians to identify which patient subgroups are most likely to benefit from specific therapies (1).
Such large-scale registries are increasingly shaping biopharmaceutical strategies for rare diseases by bridging gaps between controlled trials and real-world patient experiences. These insights can inform clinical development programs, guide regulatory discussions, and ultimately influence manufacturing priorities for biologics such as monoclonal antibodies (1).
Can international collaboration redefine how evidence is built in rare conditions?
For the biopharmaceutical community, the PROCLIPI findings highlight the growing role of collaborative data networks in driving translational research. “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,” said Dr. Nick Kronfeld, head of medical affairs, Kyowa Kirin International, in the release.
The partnership between KKI and UHB exemplifies how industry and academia can jointly advance understanding of rare cancers through real-world evidence generation. “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,” Susan Thornton, CEO, Cutaneous Lymphoma Foundation, said in the release.
As biologics and targeted therapies continue to evolve, integrating longitudinal registry data with molecular profiling and treatment outcomes may accelerate development pathways for other low-prevalence malignancies (3). For manufacturers, this type of data-driven insight not only refines understanding of therapeutic benefit but also informs production planning, clinical trial design, and health policy frameworks that enable better access for patients worldwide (4).
References
1. Kirin International.
2. Scarisbrick, J. J. The PROCLIPI international Registry, an Important Tool to Evaluate the Prognosis of Cutaneous T-Cell Lymphomas. Presse Med. 2022, 51 (1), 104123. DOI:
3. Okuma, H. S.; Yonemori, K.; Narita, S. N.; et al. MASTER KEY Project: Powering Clinical Development for Rare Cancers Through a Platform Trial. Clin. Pharmacol. Ther. 2020, 108 (3), 596–605. DOI:
4. Costa, V.; Custodio, M. G.; Gefen, E.; Fregni, F. The Relevance of the Real-World Evidence in Research, Clinical, and Regulatory Decision Making. Front Public Health 2025, 18 (13), 1512429. DOI:
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