TOPLINE:

Treatment with loncastuximab tesirine-lpyl was associated with the development of dermatologic adverse events (dAEs) in 20% of patients with relapsed or refractory diffuse large B‑cell lymphoma; these events were predominantly photodistributed erythematous patches, usually mild, and resolved with topical care.

METHODOLOGY:

• Comprehensive data on dAEs associated with loncastuximab tesirine-lpyl (Zynlonta), a CD19-directed antibody-drug conjugate approved by the FDA in 2021 for treating relapsed or refractory diffuse large B-cell lymphoma, remains limited outside of clinical trials and case series.
• Researchers conducted a retrospective multicenter cohort study that involved 98 patients (mean age, 67.7 years; 31% women; 85% White) with relapsed or refractory diffuse large B-cell lymphoma who received loncastuximab tesirine-lpyl between January 2021 and December 2024 at two tertiary care centers in the US.
• Data were collected on demographics, cancer diagnosis, prior or concurrent oncologic treatments, dAE details, and any modifications to cancer therapy.
• Researchers evaluated the severity of dAEs, their associations with prior radiation exposure and concurrent photosensitizing medication use, and clinical features and management strategies associated with the AEs.

TAKEAWAY:

• Overall, 20 patients (20%) experienced dAEs, most commonly (95%) photodistributed erythematous patches with a median onset of 34 days; most of the rashes were grade 1 (10/19) or grade 2 (8/19) in severity.
• Prior radiation exposure and concurrent photosensitizing medications were not associated with development of photodistributed eruptions.
• Most photodistributed reactions resolved on their own or with topical corticosteroids, moisturizers, and oral antihistamines. No patients required interruption or discontinuation of loncastuximab because of dermatologic toxicity.
• Among the 20 patients with dAEs, one developed a morbilliform eruption and two developed asymptomatic telangiectatic rashes on their extremities that appeared late in the treatment course or after treatment completion and persisted beyond treatment cessation; histopathology of the telangiectatic lesions demonstrated telangiectasia with mild dermal fibrosis.

IN PRACTICE:

“DAEs with loncastuximab tesirine are generally responsive to conservative management without necessitating dose reduction or treatment interruption,” the authors wrote. “Future studies should explore associations between dAEs and tumor response and evaluate the role of sun protection in mitigating dAEs,” they added, noting that this study is the largest “real-world analysis of dAEs associated with loncastuximab.”

SOURCE:

The study was led by Grant J. Riew, AB, Harvard Medical School and the Department of Dermatology, Brigham and Women’s Hospital, Boston, and was published online on February 21, 2026 in the Journal of the American Academy of Dermatology.

LIMITATIONS:

The findings were limited by the retrospective design.

DISCLOSURES:

The study did not receive any specific funding. The authors reported having no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.