INTRODUCTION:Copanlisib is a phosphoinositol 3-kinase (PI3K) inhibitor approved for the third-line treatment of follicular non-Hodgkin lymphoma. Although the drug is generally well-tolerated, it can be associated with several unique and potentially serious adverse effects (AEs). Two of the most common toxicities not seen with other PI3K inhibitors include hyperglycemia and hypertension, which primarily occur during infusion and resolve shortly thereafter, and likely relate to targeting the PI3K alpha isoform. Other toxicities less commonly observed with copanlisib than with other approved drugs in this class include non-infectious pneumonitis, infections, diarrhea and colitis, and hepatobiliary toxicity. MATERIALS AND METHODS:A panel composed of experts in lymphoma, diabetes, and hypertension convened to develop guidance pertaining to the administration of copanlisib and the management of the AEs associated with copanlisib treatment. RESULTS:Recommendations were formulated pertaining to the management of AEs associated with copanlisib treatment, particularly infusion-related hyperglycemia and hypertension, noninfectious pneumonitis, infections, diarrhea, and colitis. The recommendations herein reflect the consensus of the members of this panel, all of whom contributed to these suggested approaches to patient supportive care. CONCLUSION:There are a number of challenges associated with the use of copanlisib. Infusion-related hypertension and hyperglycemia occur frequently, although they are transient, reversible, and rarely of clinical significance; this report provides guidance as to their management.