Month long treatment with Imiquimod may induce regression of lentigo maligna melanoma

A new study by Marie Daude and team showed that after a month of therapy, imiquimod lowers the lentigo maligna surface, without increasing the risk of intralesional excision, and with favorable cosmetic results. The findings of this study were published in the European Academy of Dermatology and Venereology.

On photoexposed skin, lentigo maligna (LM) is a melanocytic proliferation that has the potential to develop into LM melanoma. The suggested initial course of therapy is surgery. Without international agreement, excision margins of 5 to 10 mm still exist. Numerous investigations have demonstrated that the immunomodulator imiquimod causes LM regression. In order to compare the effects of imiquimod and a placebo in neoadjuvant situations, this research was conducted.

A phase III prospective, multicenter, randomized clinical research was conducted. In a 1:1 ratio, patients were randomly randomized to take imiquimod or a placebo for 4 weeks, after which they underwent LM excision 4 weeks later. Extra-lesional excision was the primary objective, with a margin of 5 mm from the remaining pigmentation following imiquimod or vehicle. Secondary outcomes were relapse-free duration, number of complete remissions, number of revision procedures to acquire extra-lesional excisions, and gain on surface excised between the two groups.

The key findings of this study were:

1. 283 patients in all took part in the trial; 247 of them made up the modified ITT population, along with 121 placebo recipients and 126 imiquimod recipients.

2. In 116 (92%) imiquimod patients and 102 (84%) placebo patients, the first extralesional extirpation was done; the difference between the two groups was not statistically significant (p = 0.0743).

3. Regarding the surface of LM, imiquimod considerably (p 0.001) decreased the LM surface (4.6-3.1 cm2) more than the placebo (3.9-4.1 cm2) did.

Before performing excision on big lentigo maligna lesions in potentially disfiguring places, healthcare professionals should think about using imiquimod as a neoadjuvant.

Reference:

Daude, M., Dinulescu, M., Nguyen, J., Maillard, H., Le Duff, F., Machet, L., Beylot‐Barry, M., Legoupil, D., Wierzbicka‐Hainaut, E., Bedane, C., Leccia, M. T., Debarbieux, S., Meyer, N., Khammari, A., & Dréno, B. (2023). Efficacy of imiquimod in the management of lentigo maligna. In Journal of the European Academy of Dermatology and Venereology. Wiley. https://doi.org/10.1111/jdv.19141