Dr Haverkos on the Management of Mogamulizumab-Associated Rash in CTCL

Some studies suggest that patients who have a rash actually are the ones [who] respond better. We really try not to make [rashes] a dose-limiting toxicity, and if there's a way to treat through them, we certainly try to do that.

Brad Haverkos, MD, an associate professor of medicine and hematology at the University of Colorado Anschutz, discussed approaches for the management of mogamulizumab-kpkc (Poteligeo)–associated rash (MAR) in patients with cutaneous T-cell lymphoma (CTCL).

Haverkos discussed MAR as a common and particularly challenging toxicity associated with mogamulizumab, noting that MAR could occur early in treatment or emerge after many months of therapy with a wide range of clinical manifestations. A key challenge was that MAR often closely resembles CTCL progression, making differentiation based on clinical appearance alone difficult. To help distinguish MAR from disease progression, Haverkos said skin biopsies represent a routine approach, although he acknowledged that histopathologic interpretation could remain difficult and that biopsies do not always provide a definitive answer. He emphasized that skin biopsy remained the most valuable tool for evaluating the underlying cause of a new rash in patients receiving mogamulizumab.

Regarding management, Haverkos noted that substantial variability existed in clinical practice and that no universally accepted approach had been established for treating MAR. He highlighted emerging evidence suggesting that patients who develop the treatment-related rash may experience improved treatment responses, reinforcing the importance of avoiding unnecessary treatment discontinuation when feasible.

Haverkos described the use of systemic corticosteroids and oral methotrexate in his clinic as strategies for controlling MAR while maintaining treatment adherence. He also acknowledged that other oncologists have employed additional treatment approaches beyond prednisone and methotrexate. He characterized MAR management as an evolving area in which clinical experience continues to guide decision-making, with the expectation that future research and accumulating evidence will further refine diagnostic and therapeutic strategies for this adverse effect.