Poteligeo May Result in Antitumor Activity in Adult T-Cell Leukemia/Lymphoma

Treatment with Poteligeo (mogamulizumab) resulted in clinically meaningful antitumor activity in patients with adult T-cell leukemia/lymphoma, according to results from the MIMOGA study published in Blood Advances.

The study also found that a patient’s immune system status before initiating Poteligeo, a targeted drug known as a monoclonal antibody, was significantly associated with treatment outcome.

In this prospective observational study, study authors enrolled 101 patients (mean age, 69 years; 42% women) with adult T-cell leukemia/lymphoma who were not previously treated with Poteligeo. All patients were treated with Poteligeo and underwent immune monitoring before, during and after treatment.

The primary goal of this study was to clarify the immune dynamics of lymphocyte subsets in blood after treatment with Poteligeo. This included regulatory T cells, which regulate or suppress foreign cells within the immune system, contributing to immune response. A secondary goal included identifying molecular and immunological mechanisms that determine the efficacy of treatment or the occurrence of side effects.

Upon enrollment, study authors observed a significant inverse correlation, or a negative relationship, between serum soluble interleukin-2 receptor levels, which are associated with immune system activation, and the percentage of Tax-specific cytotoxic T lymphocytes, or cells within the immune system that can potentially kill other cells. This was not observed with cytomegalovirus pp65-specific cytotoxic T lymphocytes, which can protect the body from infection.

Treatment with Poteligeo resulted in an overall response rate, meaning all partial and complete responses, of 65%. In addition, patients had a median progression-free survival, meaning the time from the start of treatment until disease worsened, of 7.4 months and an overall survival (OS), meaning the time from the start of treatment until death, of 16 months. Patients with a higher percentage of Tax-specific cytotoxic T lymphocytes were more likely to have longer survival. This was not seen with cytomegalovirus pp65-specific cytotoxic T lymphocytes.

Several factors were considered significant independent unfavorable prognostic factors for OS, including higher soluble interleukin-2 receptor levels, clinical subtype (either acute or lymphoma type) and a lower percentage of particular B cells — CD2-CD19+ — within peripheral blood mononuclear cells, or cells that deliver responses to the immune system. This may signify that patients with more B cells have somewhat of a favorable immune status, which may lead to better outcomes with this particular treatment.

“On the basis of the present study focusing on the patients’ immunological status before mogamulizumab and its influence on outcome, further time series analysis, in addition to comprehensive genomic analysis, is warranted to establish predictive markers for treatment success and to better understand the mechanisms of action of mogamulizumab,” the study authors wrote.

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