After receiving Tecvayli and achieving a complete response, how long should treatment continue and is risk of infection present as long as treatment continues?
Bispecific antibody therapy is administered to myeloma patients until their disease progresses or side effects of the treatment become intolerable. Prolonged treatment like this is similar to how most other myeloma treatments are administered with the exception of CAR T-cell therapy. Ongoing studies with bispecific antibody therapy are investigating different approaches to shortening the duration of administration. For example, some studies are investigating a fixed duration of treatment, that is, treatment is administered for a set period of time and then stopped. Other studies are investigating a guided therapy approach in which treatment is stopped only in patients who achieve a complete response and minimal residual disease (MRD) negativity and maintain that response for a period of time.
And, yes, the risk of infection continues for as long as a patient is on treatment.
What are the effects of missing doses of bispecific antibody treatment and infection risk?
Unlike traditional chemotherapy (for example, Cytoxan) where a patient’s white blood cell counts are immediately reduced and then bounce back to normal levels within weeks, the effects of bispecific antibody therapy on the immune system are long-lasting. As a result, patients may take longer to clear an infection (like COVID-19). Therefore, if a myeloma patient has an active infection, doctors will stop the administration of bispecific antibody therapy so as to not further diminish a patient’s ability to fight an infection. Some myeloma patients have been able to maintain their response to bispecific antibody therapy even after being off treatment.
Is risk of infection higher with bispecific antibody therapy than with CAR T-cell therapy?
Both CAR T-cell therapy and bispecific antibody therapy are associated with a high risk of infection. Infection may be easier to manage in a patient receiving CAR T-cells because they are administered as a fixed duration—it is a “one and done” infusion and a patient’s immune system can eventually recover within a year after infusion. With bispecific antibody therapy, the effect on the immune system lasts for the entire time a patient is on treatment—keeping them at risk of infection during that time.