Final MINT Study Results Highlight Real-World Benefits of Mogamulizumab in Mycosis Fungoides and Sézary Syndrome
Kyowa Kirin International plc, a wholly owned subsidiary of Kyowa Kirin Co., Ltd. (TSE: 4151), has announced the final results of the German MINT study, which evaluated the real-world use of mogamulizumab in patients with mycosis fungoides (MF) and Sézary syndrome (SS). The findings were presented at the 2026 Annual Meeting of the European Organisation for Research and Treatment of Cancer Cutaneous Lymphoma Tumour Group (EORTC-CLTG) in Berlin, Germany.
The results add to the growing body of evidence supporting the use of mogamulizumab in routine clinical practice and represent one of the largest real-world evaluations of the treatment among patients with MF and SS in Germany. The study assessed treatment outcomes across a broad patient population, including individuals with advanced disease and clinically relevant subtypes that may be underrepresented in controlled clinical trials.
The final analysis demonstrated a median time-to-next-treatment (TTNT) of 14.9 months, a best overall response rate (ORR) of 62.4%, and a median progression-free survival (PFS) of 20.2 months. These findings provide further insights into treatment durability, disease control, and patient outcomes in everyday clinical settings.
The MINT study also examined treatment outcomes across different disease stages and specific patient subgroups, including those with large cell transformation (LCT) and folliculotropic mycosis fungoides (fMF). In addition, the analysis assessed quality-of-life outcomes and the safety profile of mogamulizumab, helping clinicians better understand its potential role in the management of these uncommon and challenging lymphomas.
Evaluating Mogamulizumab in Routine Clinical Practice
MINT was conducted as a company-sponsored, multicentre, non-interventional, combined retrospective and prospective real-world study across 18 centres throughout Germany. The study brought together specialists in cutaneous T-cell lymphoma (CTCL) to investigate clinical outcomes among patients receiving mogamulizumab outside the controlled environment of a clinical trial.
The primary endpoint was time-to-next-treatment, a clinically meaningful measure that helps assess how long patients remain on a treatment strategy before another therapy becomes necessary. Unlike endpoints that focus exclusively on tumour response, TTNT can provide a broader picture of treatment benefit in routine practice, where clinical decisions may be influenced by disease progression, tolerability, symptoms, and individual patient circumstances.
The study included patients with different disease characteristics and clinical histories, providing a heterogeneous population that reflects the complexity of CTCL management. Researchers evaluated outcomes according to disease stage and mogamulizumab-associated rash (MAR) status, alongside exploratory assessments in patients with LCT and fMF.
By investigating these groups, MINT sought to complement findings from controlled clinical studies with evidence reflecting the experiences of patients treated in everyday healthcare settings. Real-world studies can help identify patterns of treatment use and outcomes across populations that may differ from those enrolled in clinical trials.
The final analysis included 109 patients, consisting of 56 individuals with MF and 53 with SS. The median follow-up period was 25.2 months. Most patients had advanced disease at the start of mogamulizumab treatment, with 83.5% classified as stage IIB or higher.
The inclusion of a substantial proportion of patients with advanced-stage disease is particularly relevant because treatment decisions can become more complex as CTCL progresses. These patients may require sustained disease management, careful monitoring of treatment response, and consideration of alternative therapies when clinical benefit is no longer sufficient.
Understanding Mycosis Fungoides and Sézary Syndrome
Mycosis fungoides and Sézary syndrome are forms of cutaneous T-cell lymphoma, a type of non-Hodgkin lymphoma that primarily affects the skin. Although the skin is the principal site of disease manifestation, CTCL can also involve the blood, lymph nodes, and internal organs.
MF commonly presents with persistent skin changes, including patches, plaques, and, in more advanced cases, tumours. Patients may experience itching, scaling, changes in skin colour, and other symptoms that can persist over extended periods.
Sézary syndrome is a more aggressive form of CTCL characterised by the presence of malignant T cells in the blood, often accompanied by widespread skin involvement. The disease can present with extensive redness, itching, and other symptoms that can be physically uncomfortable and difficult to manage.
Beyond the clinical manifestations, these conditions can substantially affect patients’ daily lives. Visible skin lesions and persistent symptoms may interfere with work, relationships, social activities, and emotional well-being. Because the symptoms can be difficult to conceal, patients may experience additional challenges in their personal and professional lives.
Disease progression can also affect long-term outcomes, making effective treatment and ongoing monitoring important components of care. For patients with advanced disease, treatment goals may include controlling malignant cell growth, alleviating symptoms, maintaining quality of life, and delaying the need to change therapies.
Against this background, real-world evidence is valuable in helping clinicians understand how treatments perform across different patient groups and disease stages.
Study Demonstrates Durable Treatment Outcomes
The final MINT results showed that patients treated with mogamulizumab experienced encouraging treatment outcomes across the study population.
The median TTNT was 14.9 months, indicating the duration before patients required another treatment approach. The best overall response rate was 62.4%, while median progression-free survival reached 20.2 months.
Median overall survival was not estimable at the time of analysis because the number of deaths observed was limited. Some patients had been followed for as long as 71 months, but the available number of events was insufficient to establish a median overall survival estimate.
These results offer complementary perspectives on treatment effectiveness. Overall response rate measures the proportion of patients who achieve a defined response, while progression-free survival evaluates the time patients remain alive without disease progression. TTNT provides another measure of clinical benefit by examining the interval before a subsequent treatment becomes necessary.
Together, these endpoints help characterise treatment outcomes in a real-world setting, although they measure different aspects of disease management and should not be interpreted as interchangeable measures of efficacy.
Professor Chalid Assaf, Director of the Department of Dermatology and Venereology at Helios Klinikum Krefeld, Health and Medical University Düsseldorf-Krefeld, Germany, highlighted the importance of understanding treatment performance beyond clinical trials.
“For patients living with mycosis fungoides and Sézary syndrome, understanding how treatments perform outside the controlled setting of clinical trials is critically important. The final MINT results demonstrate meaningful clinical outcomes across a broad patient population treated in routine practice and highlight the value of collaborative real-world research in helping clinicians make informed treatment decisions,” Professor Assaf said.
His comments underscore the role of real-world research in complementing clinical trial findings and providing additional information to support individualised treatment decisions for patients with rare lymphomas.
Findings Across Clinically Relevant Patient Subgroups
In addition to evaluating the overall study population, the MINT investigators conducted exploratory analyses to examine treatment response in clinically relevant subgroups.
Among patients with large cell transformation, the best overall response rate was 54.5%. This subgroup included 11 patients, with a 95% confidence interval (CI) of 23.4% to 83.3%.
For patients with folliculotropic mycosis fungoides, the best overall response rate was 50.0%. This analysis included 12 patients, with a 95% CI of 21.1% to 78.9%.
These findings provide preliminary real-world insights into treatment outcomes in patient populations with distinct disease characteristics. However, the small subgroup sizes and wide confidence intervals mean the results should be interpreted cautiously. Further evidence may be needed to establish the consistency of these outcomes across larger populations.
The researchers also examined outcomes according to disease stage. Among patients with early-stage disease, the best overall response rate was 50.0%, based on 18 patients, with a 95% CI of 26.0% to 74.0%.
In the advanced-stage group, which included 91 patients, the best overall response rate was 64.8%, with a 95% CI of 54.1% to 74.6%.
These exploratory results demonstrate that responses were observed across both early- and advanced-stage disease groups. Nevertheless, the study was not designed to establish that treatment is more effective in one stage than another, and the subgroup findings should not be interpreted as evidence of comparative superiority.
The study also reported a disease control rate of 95.7% among patients who developed mogamulizumab-associated rash. This analysis included 47 patients.
MAR is an important clinical consideration when treating patients with mogamulizumab, as skin reactions can require evaluation and management. The disease control finding provides additional information about outcomes in this subgroup, although it does not establish that the development of MAR causes improved disease control.
By examining these distinct patient groups, MINT contributes to a broader understanding of how mogamulizumab is used in routine clinical care and how treatment outcomes may vary according to individual clinical characteristics.
Time to Next Treatment and Quality of Life
Time-to-next-treatment was a central focus of the MINT study because it offers practical information about the duration of a treatment strategy before another therapy is required.
The analysis reported a median TTNT of 12.0 months among patients with MF and 20.2 months among patients with SS.
These findings provide disease-specific information that may help clinicians assess treatment patterns in real-world practice. However, the observed differences between the MF and SS groups should be interpreted carefully, as the study was non-interventional and was not designed to establish the reasons for differences in TTNT between the two populations.
Quality of life was another important component of the evaluation. Patients with CTCL may experience substantial physical and emotional burdens because of persistent itching, skin lesions, visible changes, and the ongoing demands of disease management.
The MINT investigators assessed quality of life using the Skindex-29 questionnaire, a dermatology-specific instrument designed to evaluate the effects of skin conditions on patients’ well-being.
Among the patients included in the reported analysis, the median Skindex-29 score improved by 38.5%, declining from 49.1 at treatment initiation, based on 21 patients, to 30.2 at Month 12, based on seven patients.
The reduction in scores indicates an improvement in the measured quality-of-life burden among the patients assessed. However, the smaller number of patients available at the 12-month evaluation should be considered when interpreting the result.
These findings are relevant because successful CTCL management extends beyond clinical response alone. Treatment decisions also need to account for symptom burden, treatment tolerability, daily functioning, and the patient’s overall experience of living with the disease.
The quality-of-life results therefore add another dimension to the clinical outcomes reported in MINT, while highlighting the importance of continued patient-reported outcome assessments in real-world research.
Safety Profile Consistent With Previous Clinical Evidence
The investigators concluded that mogamulizumab demonstrated a safety profile comparable to that observed in the pivotal Phase 3 MAVORIC study, while providing clinical benefits in treatment response and quality of life in patients with MF and SS.
In the final MINT analysis, grade 3 or higher treatment-related adverse events were reported in 38.5% of patients. The most frequently reported events included drug eruption and lymphopenia.
Serious treatment-related adverse events that led to treatment discontinuation occurred in 22.0% of patients.
These safety findings highlight the importance of monitoring patients throughout treatment. Drug eruption and other skin-related reactions require clinical assessment because they may overlap with the manifestations of the underlying skin lymphoma. Lymphopenia also warrants appropriate monitoring and management based on the patient’s clinical circumstances.
The proportion of patients who discontinued treatment because of serious treatment-related adverse events further emphasises the need to balance potential clinical benefits against tolerability and individual patient needs.
Although the investigators considered the overall safety profile comparable to that observed in MAVORIC, real-world findings should be interpreted within the context of the study population, follow-up period, and methods used to collect safety data.
The MINT results add to the evidence available to clinicians when discussing treatment expectations, potential adverse events, and monitoring requirements with patients.
Kyowa Kirin Continues to Support Real-World CTCL Research
Kyowa Kirin International has continued to support real-world evidence generation in CTCL through collaborations with investigators and treatment centres across Europe. The MINT study forms part of a broader effort to improve understanding of treatment outcomes among patients receiving mogamulizumab in routine clinical practice.
Dr. Azeem Danish, Medical Affairs Director, DACH, at Kyowa Kirin, emphasised the importance of the study’s findings for clinicians managing this heterogeneous patient population.
“MINT provides valuable real-world evidence from Germany on the use of mogamulizumab across the heterogeneous population of patients with mycosis fungoides and Sézary syndrome, including clinically relevant subgroups that are often underrepresented in clinical trials. By evaluating time-to-next-treatment as a clinically meaningful outcome, the study offers practical insights that can support CTCL specialists in making informed, individualised treatment decisions,” Dr. Danish said.
The company’s support for MINT reflects the importance of collaboration between pharmaceutical developers, clinical investigators, and specialist treatment centres in rare cancer research.
Because CTCL encompasses multiple disease presentations and clinical trajectories, evidence from routine practice can help complement findings from controlled studies. Real-world analyses may also identify areas where additional research is needed, including the management of specific disease subtypes, the interpretation of treatment-related skin reactions, and the relationship between clinical response and quality of life.
Strengthening the Evidence Base for Mogamulizumab
The final MINT study results add to the available real-world evidence on mogamulizumab in patients with mycosis fungoides and Sézary syndrome. Across 109 patients treated at 18 centres in Germany, the study reported a median TTNT of 14.9 months, a best overall response rate of 62.4%, and median progression-free survival of 20.2 months.
Exploratory analyses provided additional insights into outcomes among patients with large cell transformation, folliculotropic mycosis fungoides, and different disease stages. The study also reported improvements in measured quality of life and a safety profile that the investigators considered comparable to that observed in the Phase 3 MAVORIC study.
While the non-interventional design and relatively small subgroup populations limit the conclusions that can be drawn, the findings offer useful information about the treatment’s performance in routine clinical practice.
As research into CTCL continues, real-world studies such as MINT may help clinicians better understand treatment durability, patient experience, and the practical challenges associated with managing these rare lymphomas. The findings reinforce the value of ongoing collaboration between industry and clinical investigators to expand the evidence base and support informed, individualised care for people living with MF and SS.
About the MINT Study
MINT (Mogamulizumab In a Non-interventional study to evaluate the safety and outcome in mycosis fungoides and Sézary syndrome Treatment) is a German multicentric, non-interventional, retro-prospective real-world study evaluating the effectiveness and tolerability of mogamulizumab in patients with mycosis fungoides (MF) and Sézary Syndrome (SS). Data were collected from patient medical records across 18 study sites in Germany. The primary endpoint was time-to-next-treatment, with secondary endpoints including response rate, progression-free survival, overall survival, quality of life and tolerability.1
About Kyowa Kirin
Kyowa Kirin aims to discover novel medicines with life-changing value. As a global specialty pharmaceutical company, we have invested in drug discovery and biotechnology innovation for more than 75 years and are currently working to engineer the next generation of antibodies and cell and gene therapies with the potential to help patients affected by severe and rare diseases. A shared commitment to our values, to sustainable growth, and to making people smile unites us across our three regions: JAPAC, North America, and EMEA.
You can learn more about the business of Kyowa Kirin at: https://kyowakirininternational.com/.
About mycosis fungoides (MF) and Sézary Syndrome (SS)
MF and SS are two subtypes of cutaneous T‑cell lymphoma (CTCL), which is itself a rare form of non-Hodgkin’s lymphoma that presents and persists in the skin.5 CTCL is treatable, but is not generally considered to be curable, and there has been a clear unmet need for novel treatment options. As well as the obvious impact of symptoms upon patients, there can be significant erosions to quality of life for those caring for an individual living with CTCL.11
MF and SS are characterised by localisation of cancerous white blood cells called T lymphocytes (T cells), to the skin.9 These cancerous T cells consistently express a protein called CCR4, which enables them to move from the blood to the skin.12-14 When these cancerous T cells move to the skin, this results in the visible early skin symptoms of red patches or plaques which can resemble psoriasis or eczema in the early stages of the disease.7 Later, for some patients, skin involvement may evolve to include tumours or reddening of the majority of the skin’s surface (erythroderma).7
MF—the most common CTCL subtype—accounts for approximately 60% of all CTCLs15 and is typically indolent, characterised by skin symptoms including patches or plaques, skin redness and tumours. SS is much rarer, accounting for around 5% of CTCLs,6 and is more aggressive,7 with high levels of blood involvement.6 It can cause severe itching, erythroderma, intense scaling of the skin and hair loss.7 CTCL can take, on average, between 2 and 7 years for individuals to receive a confirmed diagnosis.16
About POTELIGEO® (mogamulizumab)
Mogamulizumab is a first-in-class humanised monoclonal antibody (mAb) directed against CC-chemokine receptor 4 (CCR4), a protein consistently expressed on cancerous cells seen in both mycosis fungoides and Sézary syndrome.12-14 Once mogamulizumab binds to CCR4, it increases attraction of immune cells from the immune system to destroy the cancerous cells.17
About POTELIGEO® (mogamulizumab) in Plain Language
Mogamulizumab is a monoclonal antibody designed to recognise and attach to CCR4, a protein commonly found on certain cancerous cells in mycosis fungoides and Sézary syndrome. By targeting these cells, it helps the body’s immune system identify and destroy them.