Seasonal variation in effect of anti-PD-1 initiation on overall survival among patients with advanced melanoma

Eva Ellebaek, Aimilia Schina, Henrik Schmidt, Charlotte Aaquist Haslund, Lars Bastholt, Inge Marie Svane, Marco Donia*

*Corresponding author for this work

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Melanoma is a highly immunogenic cancer, and circannual rhythms influence the activity of the immune system. We retrospectively collected information on all cases with metastatic melanoma (ocular melanoma excluded) that initiated treatment with BRAF-inhibitor-based therapy (BRAFi) or anti-PD-1 monotherapy (PD-1). Cases were divided in two groups based on treatment initiation in the summer half-year (April to September) or winter half-year (October to March). We collected a total of 1054 (BRAF-i) and 1205 (PD-1) patient cases. Median follow-up was 39.7 (BRAFi) and 47.5 (PD-1) months. We did not observe differences in outcomes across patients who were treated in summer versus winter in the BRAFi cohort. Furthermore, we did not observe significant differences in ORR, CRR, and PFS in the PD-1 cohort. However, in patients with BRAF wild-type disease of the PD-1 cohort, treatment initiation in summer was associated with an improved OS (mOS 39.7 months [summer] versus 21.3 months [winter]; HR 0.70, 95% CI 0.57-0.86, p = .0007). This result remained robust to multivariable proportional hazards adjustment (HR 0.70, 95% CI 0.57-0.87, p = .001). Initiation of immunotherapy in summer is associated with prolonged survival in patients with BRAF wild-type melanoma living in Denmark.

Original languageEnglish
JournalPigment Cell & Melanoma Research
Issue number2
Pages (from-to)224-231
Number of pages8
Publication statusPublished - Mar 2023

Bibliographical note

© 2022 The Authors. Pigment Cell & Melanoma Research published by John Wiley & Sons Ltd.


  • anti-PD-1
  • environment
  • immunotherapy
  • melanoma
  • season


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