Copanlisib Products | Cleanchem - Copanlisib is a kinase inhibitor used in the treatment of relapsed or refractory follicular lymphoma, a type of non-Hodgkin lymphoma. It works by inhibiting phosphoinositide 3-kinase (PI3K), which is involved in cell survival and proliferation. Copanlisib is typically used when other treatment options have failed. Common side effects include hypertension, diarrhea, and infection.