Endometrial cancer (EC) is a common gynecological
malignancy and the fourth most common
malignancy in European and North American women. Amongst EC, the advanced serous, p53-mutated, and pMMR subtypes have the highest risk of relapse despite optimal standard of care
therapy. At present, there is no standard of care maintenance treatment to prevent relapse among these high-risk patients.
Vaccines are a form of
immunotherapy that can potentially increase the immunogenicity of pMMR, serous, and p53-mutated
tumors to render them responsive to check point inhibitor-based
immunotherapy. We demonstrate, for the first time, the feasibility of generating a personalized dendritic cell
vaccine pulsed with
peptide neoantigens in a patient with pMMR, p53-mutated, and serous endometrial
adenocarcinoma (SEC). The personalized
vaccine was administered in combination with systemic
chemotherapy to treat an inoperable metastatic recurrence. This treatment association demonstrated the safety and immunogenicity of the personalized dendritic cell
vaccine. Interestingly, a complete oncological response was obtained with respect to both radiological assessment and the
tumor marker CA-125.