Anti-HER2 cardiotoxicity reports with other cardiovascular events carried much worse outcomes

Design

Pharmacovigilance disproportionality and cluster analysis of FAERS

Population

Spontaneous reports of cardiac dysfunction with anti-HER2 therapies (589 in cluster analysis)

Primary outcome

Reporting odds ratio; severe outcome by co-reported cardiovascular events

Effect

ROR 26.64 (95% CI 25.61–27.71); severe outcome 41.7% vs 17.5%, aOR 3.24 (2.14–4.95)

This pharmacovigilance study used the US FDA Adverse Event Reporting System (FAERS). Echocardiography-related cardiac dysfunction — typically a fall in ejection fraction — was reported far more often with anti-HER2 therapies than with other drugs (reporting odds ratio 26.6, 95% CI 25.6–27.7), across the individual agents and groupings.

In 589 detailed reports, 35% also recorded another cardiovascular event, such as arrhythmia or heart failure. Severe outcomes (death, hospitalisation, life-threatening event or disability) occurred in 41.7% of those versus 17.5% of reports with cardiac dysfunction alone (adjusted OR 3.24, 2.14–4.95). A cluster of left ventricular dysfunction with cardiovascular co-reporting had the highest proportion of severe outcomes (52%).

The mechanism of trastuzumab cardiotoxicity — loss of HER2-mediated cardiomyocyte survival signalling — is largely reversible, which is why monitoring and treatment interruption work. But this analysis suggests the reversible-dysfunction picture does not hold when a patient develops symptoms or other cardiovascular events. Spontaneous reports cannot give incidence, only patterns.

• Arrange baseline and serial echocardiography during anti-HER2 therapy according to the oncology protocol.
• Treat a fall in ejection fraction plus any other cardiovascular event — arrhythmia, heart failure symptoms — as high risk and involve cardiology.
• Optimise blood pressure and start ACE inhibitors or beta-blockers when ejection fraction falls, as cardio-oncology guidance advises.
• Asymptomatic ejection fraction decline often recovers with interruption; do not assume it is permanent.
• Report suspected cardiotoxicity to the pharmacovigilance programme — in India, PvPI.

Why it matters

It separates the usually reversible asymptomatic ejection-fraction dip from the pattern that more often ends in hospitalisation or death.

Don't overread it

Spontaneous reports show disproportionate reporting, not incidence or causation, and severity may reflect what gets reported.

The statistics, in plain English

A reporting odds ratio of 26.6 means cardiac dysfunction was about 27 times more likely to be reported with anti-HER2 drugs than with other drugs in the database — a strong signal, but not a measure of how often it happens to patients.

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