My CLL Immunity is Impaired in Both My B and T Cells

By August 2025, I’ll be two years on epcoritamab, effective against my CLL but also suppressing my normal T and B cells and increasing my infection risk.

Infections are the leading cause of death in chronic lymphocytic leukemia or CLL, accounting for between one-third and half of all mortality. Patients on treatment are often at even higher risk.

In the case of my trial of epcoritamab, of the four deaths recorded, three were from infection and one was from skin cancer that may well have been related to the immune suppression caused by both the CLL itself and the epcoritamab.

While I have so far dodged any infections or second cancers other than one basal cell carcinoma easily cured with a Mohs procedure, specialized method of surgically excising the cancer, I don’t plan to test my luck anymore.

What cinched my decision to stop the trial was the results of my T cell subsets blood test. I already knew that the bispecific antibody had for the most part wiped out all my all my B cells, the cancerous ones that had mutated to form my clonal CLL, but also all my healthy antibody producing B cells. Epcoritamab targets the surface marker CD20 found on all B lymphocytes, so no surprise there. In this way it is similar to other monoclonal antibodies used to treat CLL such as rituximab and obinutuzumab in that it depletes cells that are normal or cancerous. And while not having any antibody forming B cells is not ideal, it is rarely life threatening.

Low or no T cells is a whole different story. Think AIDS. Epcoritamab is a bispecific antibody. It works its magic by engaging my healthy T lymphocytes to kill the B lymphocytes, but in doing so, the T lymphocytes exhaust themselves and die.

My T cell counts are low. They weren’t six months ago. My helper CD4 T cell count is 350. Normal is >500. AIDS range in <200. My cytotoxic or CD8 killer T cell count is also low. Obviously, my total T cell count is low. It might be even lower now as the blood was drawn before I received another and likely last epcoritamab injection. And the T cell counts only address the quantity of cells. Their quality is almost certainly impaired. 

Time to quit. The risk benefit ratio has tilted in the wrong direction. The likelihood of getting much more benefit from one more shot in the belly is small, the chances of a long treatment free remission are already high if I stop now, and the future looks bright with the number of great new therapeutic options available when the time inevitably comes that I’ll need treatment again growing every year.

Definitely time to say thanks and move on. In a follow-up post here, I’ll talk more about the psychological impact of going off therapy. At least in my case, while it will be wonderful to not have to engage with my cancer so often through all the regular trial visits, there was some real reassurance in checking in monthly with my doctor and knowing all was going well. I will miss that.