A Prospective, US-based Study Assessing Mogamulizumab-associated Rash in Patients Diagnosed With Mycosis Fungoides or Sezary Syndrome and Treated With Standard of Care Mogamulizumab

This study is being done to assess mogamulizumab-associated rash in patients diagnosed with mycosis fungoides or sezary syndrome and treated with standard of care mogamulizumab. One of the most common side effects of mogamulizumab is a rash, currently named mogamulizumab-associated rash (MAR) which can look like MF or SS. However, mogamulizumab-associated rash (MAR) does not indicate failure of mogamulizumab, and may be a sign that the drug is working. If not properly evaluated, mogamulizumab-associated rash (MAR) could be misinterpreted as worsening of mycosis fungoides/sezary syndrome, which could lead doctors to recommend stopping mogamulizumab treatment early. The information learned by doing this research study may help tell the difference between mogamulizumab-associated rash (MAR) (sometimes also called "drug eruption") and worsening of the disease. It may also help to uncover information about the cause of mogamulizumab-associated rash (MAR).

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Key information

Conditions

Recurrent Mycosis Fungoides Hemic and Lymphatic Diseases Immune System Diseases Immunoproliferative Disorders Lymphatic Diseases Lymphoma Lymphoma, Non-Hodgkin Lymphoma, T-Cell Lymphoma, T-Cell, Cutaneous Lymphoproliferative Disorders Mycosis Fungoides Neoplasms Neoplasms by Histologic Type Recurrent Sezary Syndrome Refractory Mycosis Fungoides Refractory Sezary Syndrome Sezary Syndrome Stage IB Mycosis Fungoides and Sezary Syndrome AJCC v8 Stage IIA Mycosis Fungoides and Sezary Syndrome AJCC v8 Stage IIB Mycosis Fungoides and Sezary Syndrome AJCC v8 Stage III Mycosis Fungoides and Sezary Syndrome AJCC v8 Stage IV Mycosis Fungoides and Sezary Syndrome AJCC v8

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

City of Hope Medical Center, Duarte, California, United States

About this study

PRIMARY OBJECTIVE:

I. To assess the incidence of mogamulizumab-associated rash (MAR) and its association with overall response in patients with cutaneous T-cell lymphoma (CTCL); mycosis fungoides [MF] and sezary syndrome [SS] subtypes) treated with mogamulizumab.

OUTLINE: This is an observational study.

Patients complete questionnaires, have photographs of their skin taken, and undergo blood sample collection and skin biopsies on study. Patients' medical records are also reviewed.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

* Adult patients (>= 18 years of age) diagnosed with relapsed/refractory Mycosis Fungoides (MF) stage IB, IIA, IIB, III and IV or Sezary Syndrome(SS), and selected by their treating physician to receive single agent mogamulizumab (newly initiated)

Signed informed consent
Willing to undergo baseline biopsy and during treatment to evaluate for Mogamulizumab-Associated Rash (MAR) if clinically indicated
Willing to provide blood sample at baseline, and if applicable, at onset of Mogamulizumab-Associated Rash (MAR)

Exclusion criteria

* Other concomitant systemic and skin directed Cutaneous T-cell Lymphoma (CTCL) regimens except for topical steroids

Prior treatment with mogamulizumab

Treatment and study plan

Non-Interventional Study

Other

Non-interventional study

Primary outcomes

Binary incidence of mogamulizumab-associated rash (MAR)

Time frame: Up to 3 years

Will be estimated as a binomial proportion along with the 95% exact binomial confidence interval.

Sponsors and collaborators

Lead sponsor

City of Hope Medical Center

Other

Collaborators

National Cancer Institute (NCI)

Registry information

Official study title

A Prospective, US-Based Study Assessing Mogamulizumab-Associated Rash in Patients Diagnosed With Mycosis Fungoides or Sézary Syndrome and Treated With Standard of Care Mogamulizumab

Important dates

Study start: 2024
Primary completion: 2026
Study completion: 2026
First posted: Jun 4, 2025
Registry last updated: Sep 9, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Published trials that share one or more normalized conditions with this study.

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