Dr Beylot-Barry on Patient Selection, Follow-up of Moga-Stop in Sézary Syndrome

This discussion is rather for the patients who are advanced-age patients for whom we will not discuss allogeneic transplantation. I think that the patients who will have allogeneic transplantation are not good candidates for this strategy, because for those patients we will do the treatment, obtain complete remission, and then propose allogeneic transplantation.

Marie Beylot-Barry, MD, PhD, professor and head of the Department of Dermatology at CHU de Bordeaux in Bordeaux, France, discussed patient selection and the limitations of the Moga-Stop strategy of mogamulizumab (Poteligeo) discontinuation in Sézary syndrome.

At the 6th World Congress of Cutaneous Lymphoma (WCCL), Beylot-Barry and colleagues presented extended follow-up from Moga-Stop, which evaluated patients with Sézary syndrome who discontinued mogamulizumab after a good response for reasons other than progression. In the first part of this discussion, Beylot-Barry detailed the study design and the efficacy of mogamulizumab retreatment at relapse.¹ Here, she addressed which patients are suited to a treatment break and what the analysis can and cannot yet prove.

For patients weighing indefinite therapy against a planned treatment break, Beylot-Barry framed the decision as one of patient selection. A monitored discontinuation — ideally a gradual spacing of infusions rather than an abrupt stop — is most appropriate for those in a sustained complete or partial response, with the explicit understanding that mogamulizumab can be resumed if disease recurs. The potential advantages she described are practical: limiting cumulative toxicity from prolonged exposure, reducing treatment cost, and possibly mitigating the risk of resistance, though she cautioned that the resistance benefit remains unproven.

Crucially, she distinguished the population for whom this strategy fits. The discontinuation approach is best suited to older patients, or those who are not candidates for allogeneic transplant. Patients being bridged toward transplant represent a different pathway, she noted. There, the goal is to achieve complete remission and then proceed to allogeneic transplant, rather than to stop therapy and monitor.

The Moga-Stop study is retrospective, with a relatively small control cohort of patients who continued mogamulizumab; while progression-free survival did not differ between those who stopped and those who continued, she emphasized that retrospective design constrains how firmly such conclusions can be drawn. A meaningful group of patients remained in remission well beyond stopping, at a long median follow-up.

Beylot-Barry said clinicians currently lack criteria to identify which patients in remission will relapse after stopping and which will not. Closing that gap — work that intersects with ongoing efforts to define response and resistance biomarkers for the agent² — and converting the Moga-Stop observations into a formal treatment-break recommendation will require a large, prospective cohort.

References

1. Dr Beylot-Barry on Moga-Stop and Mogamulizumab Retreatment in Sézary Syndrome. OncLive. Accessed June 25, 2026. https://www.onclive.com/view/dr-beylot-barry-on-moga-stop-and-mogamulizumab-retreatment-in-sezary-syndrome

2. Analysis Identifies Potential Response, Resistance Biomarkers to Mogamulizumab in R/R Mycosis Fungoides/Sézary Syndrome. OncLive. Published June 25, 2026. Accessed June 25, 2026. https://www.onclive.com/view/analysis-identifies-potential-response-resistance-biomarkers-to-mogamulizumab-in-r-r-mycosis-fungoides-s-zary-syndrome