Popular Heart Medications May Curb Cardiac Toxicity in Patients With Breast Cancer

Patients with breast cancer face a wide array of side effects but, most importantly, a commonly used chemotherapy drug in women with HER2-positive disease is known to cause cardiac toxicity.

Herceptin (trastuzumab), which is a targeted therapy, is effective in improving survival and reducing recurrence, but that benefit comes at a risk of potentially dangerous heart problems, such as heart muscle damage and heart failure. The risk is greater when Herceptin is given with other chemotherapy drugs like Adriamycin (doxorubicin), which can also cause heart damage, according to the American Cancer Society.

However, findings from a new study presented at the American College of Cardiology’s 67th Annual Scientific Session showed that adding two popular heart medications to the chemotherapy regimen may prevent heart damage from happening in these patients.

“(HER2-positive breast cancer) is so widespread and deadly,” Maya Guglin, M.D., Ph.D., professor of medicine and director of Mechanical Assisted Circulation at the University of Kentucky’s Gill Heart Institute said in an interview with CURE. “Currently, oncologists are limited in (treatment) options because the combination of anthracyclines and Herceptin produces the highest rate of toxic cardiac effect. If they feel safer about using anthracyclines on their patients it will increase the utilization of the most aggressive anticancer management.”

The large multi-center trial included 468 patients from 167 sites and examined the effectiveness of ACE inhibitors — drugs that widen blood vessels to increase the amount of blood the heart pumps – and beta blockers – drugs that reduce blood pressure – to preserve a patient's heart function during chemotherapy. Patients were either treated with Herceptin alone or Herceptin after receiving Adriamycin.

University of Kentucky researchers found a significant reduction in heart issues for patients on ACE inhibitors or beta blockers who received Adriamycin then Herceptin. In the placebo group, cardiac event rates were 47 percent compared with 37 percent in patients who received ACE inhibitors and 31 percent in patients who received beta blockers.

“Patients may now have less anxiety that cancer may also be silently killing their heart. That’s how they feel sometimes,” said Guglin. “Usually they have an echocardiogram every three months during treatment and every time there is the anxiety that ejection fraction may drop below 50 percent and their oncologist may stop treatment. Meaning the heart will be healing but cancer will continue to grow. Knowing that we can largely eliminate these side effects, I think will give them some peace of mind.”

Ejection fraction is a measure of the heart’s ability to pump blood. When it drops below 50 percent that is viewed as abnormal. “Basically, this is how we judge some degree of damage to the heart muscle,” said Guglin. “The lower the ejection fraction is, the worse it is. It means the heart is impaired.” In the study, neither ACE inhibitors nor beta blockers helped preserve ejection fraction in patients who received only Herceptin.

According to the researchers, 1 in 4 women develop potentially dangerous heart problems from Herceptin. The American Heart Association recently issued a warning to doctors and patients recommending that they weigh the risks when choosing a treatment plan for HER2-positive breast cancer, noted the researchers.

The study findings may give oncologists more flexibility and choices without worrying so much about toxicity, according to Guglin. “It was significant to find that using cheap and widely utilized drugs for heart failure we can, to great extent, minimize the damage to the heart,” she said.