A combination of factors, including financial cost and side effects, warrants a judicious approach for deciding whether patients should receive immune checkpoint inhibitors (ICIs). A research group in Taiwan suspected that ICIs might function differently in Taiwanese patients than in the patient populations who underwent clinical trials in the West, and embarked on a retrospective study to see how Taiwanese patients actually fared on the drugs.
Chiao-En Wu, MD, from the Chang Gung Memorial Hospital in Taiwan, and colleagues reviewed patient records from a single Taiwanese hospital. A total of 80 patients with stage 4 melanoma had ICI treatment for the first time in the time period from 2014 to the last assessment date of January 31, 2020. They had received varying treatment protocols, with some getting combinations of ICIs, and some getting monotherapy with ICIs such as ipilimumab or pembrolizumab. Although the patients started out with standard dosing protocols, their physicians had adjusted dosing based on patient response and appearance of toxicity, which introduced some variability into the study.
The cases of advanced melanoma reflected the distinctly different presentations in Asian patients; they tend to present with acral melanoma (discolored streaks under the nails, or on the palms and soles), while white patients tend to present with the more familiar UV exposure-related melanomas. To the authors, these factors reinforced the need to conduct a study specifically on Asian patients.
Los Angeles-area dermatologist and Mohs surgeon Joanna Chan, MD, of the Huntington Dermatology Medical Group, said, “Acral lentiginous melanoma is the most common type of melanoma among Asians who are not frequently exposed to the sun. Studies have suggested that chronic pressure, physical stress, or a history of trauma may contribute to acral lentiginous melanoma.”
The retrospective study found patients on combination ICI therapy (notably, the 17 patients on ipilimumab plus nivolumab were aggregated with the 5 patients who received ipilimumab plus pembrolizumab) had longer periods of progression-free survival (PFS), but that they suffered more adverse effects, namely skin and endocrine toxicity. This is consistent with prior observations demonstrating higher immunotoxicity with the use of more ICI agents; adverse effects are sometimes used as evidence of the ICI achieving its desired immunologic activity in the body.
Adverse effects are a concern not just because they affect a patient’s quality of life, but because they can interfere with the continued success of ICI treatment in some cases.