This phase 2 trial will investigate the safety of experimental treatment zanidatamab (ZW25) in combination with palbociclib (Ibrance) and fulvestrant (Faslodex) in patients with advanced breast cancer (BC). The main outcomes evaluated will be the rate of side effects and survival without cancer worsening. This trial is recruiting in the United States and Spain.
Breast cancer (BC) is one of the most common types of cancer. Survival rates with BC have improved in recent years. This is because we know more about the different types of BC tumors. Certain tumor markers (TM) can be used to identify and treat BC. Human epidermal growth factor receptor 2 (HER2) is one of these TMs. Another is the hormone receptor (HR). These are proteins that can be found on certain BC cells and help BC cells grow.
Zanidatamab (ZW25) is an experimental drug. It is an antibody-drug. It can bind to HER2 positive (+) tumor cells. Animal experiments suggest that ZW25 can slow tumor cell growth. It is unknown if ZW25 is safe in humans.
Palbociclib is a targeted therapy that is approved in combination with hormonal treatment fulvestrant in patients with advanced HR+, HER2+ BC. This trial will investigate the safety of ZW25 in combination with palbociclib and fulvestrant in patients with HER+/HR+ BC. The main outcome will be the rate of side effects and survival without cancer worsening.
Who are they looking for?
86 patients with metastatic or unresectable (cannot be removed by surgery) HER2+/HR+ BC will be recruited to this trial. Patients previously treated with other HER2+ and HR+ drugs and who had cancer worsen can take part. Participants must have adequate organ function, including normal heart function.
Patients treated with HER2+ or HR+ or chemotherapy drugs in the last 3 weeks cannot take part in the trial. Patients cannot have been treated with palbociclibbefore. Patients who had a heart attack, uncontrolled high blood pressure, uncontrolled heart disease or lung diseases cannot participate. Other exclusion criteria are infections including HIV, hepatitis B, C, uncontrolled kidney or liver disease, and brain tumors.
How will it work
All patients will be treated with ZW25 in combination with fulvestrant and palbociclib. ZW25 will be administered intravenously (into the veins). Side effects will be recorded over 4 weeks. The long-term safety will be monitored for up to 3.5 years. Survival will also be measured at 6 months.