Characterization of Cutaneous Adverse Events Associated With PI3K Inhibitors in 11 Patients.

Introduction: Phosphoinositide 3-kinase (PI3K) inhibitors are a new class of cancer therapeutics that inhibits one or more enzymes in the PI3K/AKT/mTOR tumor growth pathway. As compared to other tyrosine kinase inhibitors, there is evidence that PI3K inhibitors have a higher incidence of severe cutaneous adverse events (CAEs) ranging from 2-21%. There is a lack of further characterization of clinical trials and management options for these CAEs.

Methods: A retrospective chart review of our institution's records between January 2015 and May 2019 was conducted; electronic medical records were queried by using a pharmacy database and ICD-10 codes for patients receiving PI3K inhibitor who experienced CAEs during therapy. These CAEs were characterized by two board-certified dermatologists at a major cancer center.

Results: Eleven patients were identified as having 12 cumulative CAEs. Average time to rash onset was 4 weeks, and the most common identified rashes were eczematous (25%) and morbilliform (17%). Four patients experienced a dose delay, and one patient immediately discontinued their PI3K inhibitor.

Conclusion: Although most CAEs caused by PI3K inhibitors in this study were limited to grade 1-2 and were controlled with topical corticosteroids and oral antihistamines, a number of patients experienced dose impact. This highlights the dermatologist's role in managing and minimizing interruption of therapy while maintaining quality of life.