Difference in skin toxicities observed in patients with metastatic melanoma treated with combined pembrolizumab and ipilimumab vs pembrolizumab alone

Introduction: Recent studies demonstrated combination therapy with anti-programmed death-1 (anti-PD1) and ipilimumab increase tumour response rate at the expense of increased toxicity. We aim to compare the cutaneous manifestations between the combination and anti-PD1 monotherapy.
Methods: We prospectively reviewed all patients with metastatic melanoma receiving combination of ipilimumab and pembrolizumab from January 2015 to February 2016 at Westmead Hospital, Sydney, Australia. This cohort was compared to our previously published cohort on pembrolizumab monotherapy.
Results: Of the 25 included patients on combination therapy, 88% of patients developed new cutaneous lesions. Frequently observed lesions were lichenoid reaction (64%), pruritus (60%) and vitiligo (28%). The cumulative incidence of lichenoid reaction and pruritus increased rapidly in the first 3 months of treatment. The hazard ratio compared to anti-PD1 monotherapy was 5.6 (95% CI 2.7-11.7, P <0.001) for lichenoid reaction, 7.8 (3.3-18.4, P <0.001) for pruritus, and 2.3 (0.9-6.1, P = 0.09) for vitiligo.
Conclusion: The time taken to develop immune related cutaneous toxicities was shorter for those on combination therapy versus anti-PD1 monotherapy.

Dr. Shelley Ji Eun Hwang

Westmead Hospital, Sydney, Australia

My name is Shelley Ji Eun Hwang, a first year dermatology registrar currently working at Skin and Cancer Foundation at Darlinghurst and St Vincent's hospital. I have previously worked as a dermatology research fellow at Westmead Hospital, Sydney under the supervision of A/Prof Fernandez-Penas.