A phase 1 trial suggests that the multipeptide T-cell activator iTAC-XS15-CLL could be a safe and promising immunotherapy for patients with chronic lymphocytic leukemia receiving BTK inhibitors. The study enrolled 20 patients with minimal residual disease who were in partial remission after treatment with ibrutinib, acalabrutinib, or zanubrutinib. Each patient received three doses of a personalized vaccine targeting leukemia-specific antigens.
The therapy was well tolerated, with no grade 4 adverse events reported. Most side effects were mild to moderate local reactions such as skin nodules, redness, and swelling. About 45% of patients experienced flu-like symptoms. Rare cases of back pain and atrial flutter were reported, but these were not clearly linked to the treatment.
The vaccine induced strong and durable immune responses. By the end of treatment, 95% of patients showed T-cell activation, with most maintaining responses at six months. Increased immune activity was associated with reduced leukemia cells, supporting further clinical trials.