A retrospective analysis of eosinophilia as a predictive marker of response and toxicity to cancer immunotherapy

Tharani Krishnan; Yoko Tomita; Rachel Roberts-Thomson

doi:10.2144/fsoa-2020-0070

A retrospective analysis of eosinophilia as a predictive marker of response and toxicity to cancer immunotherapy

Future Sci OA. 2020 Aug 3;6(10):FSO608. doi: 10.2144/fsoa-2020-0070.

Authors

Tharani Krishnan¹, Yoko Tomita², Rachel Roberts-Thomson²

Affiliations

¹ Medical Oncology, Royal Adelaide Hospital, South Australia 5000, Australia.
² Medical Oncology, The Queen Elizabeth Hospital, South Australia 5011, Australia.

Abstract

Aim: To investigate eosinophilia as a potential on-treatment biomarker for patients receiving cancer immunotherapy.

Materials & methods: We evaluated the association between eosinophilia and treatment response and toxicity in a retrospective cohort of patients receiving cancer immunotherapy.

Results: The study involved 146 patients. Eosinophilia developed in 22%. Patients who developed eosinophilia were more likely to achieve disease control (p = 0.009), with every 0.1 × 10⁹/l rise in eosinophil count, while receiving treatment was associated with a 28% relative increased chance achieving disease control. Although there was a trend toward improved survival, there was no significant association between eosinophilia and improved overall survival (p = 0.136). Patients with eosinophilia were more likely to develop toxicity (p = 0.042).

Conclusion: Eosinophilia is a potentially useful biomarker warranting further prospective clinical investigation.

Keywords: biomarker; cancer; eosinophilia; immune checkpoint inhibitors; response; toxicity.