Adoptive cell transfer of autologous TILs in metastatic breast cancer

Metastatic breast cancer is most often an incurable disease with only modest responses to available immunotherapies. A study at the National Cancer Institute (Bethesda, MD) investigated the immunogenicity of somatic mutations in breast cancer and explored the therapeutic efficacy in a pilot phase 2 trial of mutation-reactive tumor-infiltrating lymphocytes (TILs) in patients with metastatic disease refractory to previous lines of treatment. Most patients with breast cancer generated a natural immune response targeting the expressed products of their cancer mutations. Objective tumor regression was noted in three of six patients included in the phase 2 trial, including one complete response (ongoing over 5.5 years) and two partial responses (6 and 10 months).