BTK inhibitors in cancer patients with COVID19: "The winner will be the one who controls that chaos" (Napoleon Bonaparte).

Chong, Elise A; Roeker, Lindsey E; Shadman, Mazyar; Davids, Matthew S; Schuster, Stephen J; Mato, Anthony R

As the SARS-CoV-2 (COVID19) pandemic spreads and the number of Bruton's tyrosine kinase inhibitor (BTKi)-treated COVID19 affected patients grows, we must consider the pros and cons of BTKi discontinuation for our patients. In favor of BTKi continuation, BTK plays an active role in macrophage polarization. By modulating key transcription factors, BTK may regulate macrophage polarization downstream of classic M1 and M2 polarizing stimuli and mitigate the hyperinflammatory state associated with COVID19. In favor of BTKi discontinuation, we note a potentially increased risk of secondary infections or impaired humoral immunity. We hypothesize that the potential benefit of blunting a hyper-inflammatory response to SARS-CoV-2 through attenuation of M1 polarization outweighs the potential risk of impaired humoral immunity, not to mention the risk of rapid progression of B-cell malignancy following BTKi interruption. Based on this, we suggest continuing BTKi in patients with COVID19.