a new randomized trial showed.
The results suggested adding an ACE inhibitor doesn’t affect cardiac injury or cardiac function outcomes “and should not be used as a preventative strategy” in these patients, David Austin, MD, consultant cardiologist, Academic Cardiovascular Unit, The James Cook University Hospital, Middlesbrough, England, and chief investigator for the PROACT study, told this news organization.
But while these negative results are disappointing, he said, “we now have a definitive result in a robustly conducted trial that will take the field forward.”
The findings were presented on April 8, 2024, at the American College of Cardiology (ACC) Scientific Session 2024.
Anthracyclines, which are extracted from Streptomyces bacterium, are chemotherapy drugs widely used to treat several types of cancer. Doxorubicin is among the most clinically important anthracyclines.
While extremely effective, anthracyclines can cause irreversible damage to cardiac cells and ultimately impair cardiac function and even cause heart failure, which may only be evident years after exposure. “Cardiac injury is very common in patients treated with high dose anthracyclines,” noted Dr. Austin.
The open-label PROACT study included 111 adult patients, mean age 58 years and predominantly White and women, being treated for breast cancer (62%) or NHL (38%) at National Health Service hospitals in England with high-dose anthracycline-based chemotherapy.
Patients were randomized to standard care (six cycles of high-dose doxorubicin-equivalent anthracycline-based chemotherapy) plus the ACE inhibitor enalapril maleate or standard care alone. The mean chemotherapy dose was 328 mg/m2; any dose greater than 300 is considered high.
The starting dose of enalapril was 2.5 mg twice a day, which was titrated up to a maximum of 10 mg twice a day. The ACE inhibitor was started at least 2 days before chemotherapy began and finished 3 weeks after the last anthracycline dose.
During the study, enalapril was titrated to 20 mg in more than 75% of patients, with the mean dose being 17.7 mg.
Myocardial Injury Outcome
The primary outcome was myocardial injury measured by the presence (≥ 14 ng/L) of high sensitivity cardiac troponin T (cTnT) during anthracycline treatment and 1 month after the last dose of anthracycline.
cTnT is highly expressed in cardiomyocytes and has become a preferred biomarker for detecting acute myocardial infarction and other causes of myocardial injury.
Blood sampling for cTnT and cardiac troponin I (cTnI) was performed at baseline, within 72 hours prior to chemotherapy and at trial completion. All patients had negative troponin results at baseline, indicating no heart damage.
A majority of patients experienced elevations in troponin (78% in the enalapril group and 83% in the standard of care group), but there was no statistically significant difference between groups (adjusted odds ratio [OR], 0.65; 95% CI, 0.23-1.78; P = .405).
There was also no significant difference between groups in terms of cTnI, a secondary endpoint. However, the proportion of patients testing positive for cTnI (47% in the enalapril group and 45% in controls) was substantially lower than that for cTnT.