Phase II Study of STEMVAC Vaccine with Hormone Therapy or Chemotherapy for Metastatic Hormone Receptor Positive, HER2 Negative Breast Cancer

What this Trial Is About

Researchers are evaluating how well the vaccine STEMVAC works when combined with standard hormone therapy or chemotherapy in treating patients with hormone receptor-positive, HER2-negative metastatic breast cancer. This phase II trial explores STEMVACs potential to boost the immune system to target aggressive cancer cells that have spread from the original tumor site. The study includes patients with endocrine therapy-sensitive and endocrine therapy-resistant disease, aiming to understand how these combinations affect cancer progression and immune response. Participants are divided into two groups Cohort 1 includes patients who have completed at least two cycles of standard endocrine therapy plus a CDK46 inhibitor or abemaciclib alone, and Cohort 2 includes patients who have completed at least one cycle of the chemotherapy drug capecitabine after progression on endocrine therapies. Both groups receive STEMVAC vaccine injections intradermally on a schedule of three priming doses every 28 days, followed by two booster doses at 6 and 9 months, and additional boosters every 6 months if the disease does not worsen or cause unacceptable side effects. Imaging biopsies, blood collections, and CT or PET scans are performed regularly during the trial. Throughout the study, participants undergo various assessments including image-guided biopsies, blood sample collections, and PET or CT scans to monitor safety and immune response. After completing the vaccine treatment, patients are followed every six months for three years to track adverse events, immune response, progression-free survival, circulating tumor DNA, and cancer cell elimination. This comprehensive monitoring helps researchers evaluate the vaccines impact and safety over time.

A Vaccine (STEMVAC) With Standard Endocrine-Based Therapy or Chemotherapy for the Treatment of Metastatic Hormone Receptor Positive, HER2 Negative Breast Cancer