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Causality: well established
Causality assessment · Causality: well established
Trastuzumab and Cardiotoxicity / heart failure: is the FAERS signal real?
A written Bradford Hill assessment of one drug–event pair. The grade is a judgement about the signal, not a statement that this drug causes this event in any one person; FAERS counts are reports, not rates.
Trastuzumab ↔ Cardiotoxicity / heart failure
n=1,080 co-reports · PRR 4.2 · ROR 4.2
Trastuzumab, a HER2-targeted breast-cancer drug, can cause a usually reversible decline in heart function and, less often, heart failure — especially when used with anthracyclines or in older patients. Because HER2 signalling helps the heart, blocking it can impair heart-muscle function, so heart function is measured before and during treatment. The 1,080 co-reports (PRR 4.2) reflect both the real effect and the drug's widespread use in HER2-positive breast and gastric cancer.
Regulatory basis: trastuzumab prescribing information (boxed warning for cardiomyopathy/heart failure; cardiac monitoring).
| Bradford Hill viewpoint | Status | Note |
|---|---|---|
| Temporality (necessary) | met | Heart function may decline during therapy and often recovers after withdrawal |
| Strength | partial | PRR 4 on a large co-report count |
| Consistency | met | Reproduced across breast-cancer trials |
| Specificity | met | A recognised trastuzumab effect, worse with anthracyclines |
| Biological gradient | partial | Risk rises with anthracycline co-therapy, age, and prior cardiac disease |
| Plausibility | met | HER2 blockade impairing heart-muscle survival signalling is the mechanism |
| Coherence | met | Coheres with the boxed warning and cardiac monitoring |
| Experiment | partial | Dechallenge (withdrawal) frequently improves heart function; no randomized trial |
| Analogy | met | Analogous to cardiotoxicity with anthracyclines and other HER2-targeted drugs |
This page's own qualitative read, not an automated/citation-gated assessment.
✗ A results-posting trastuzumab trial (NCT02947685) recorded ejection-fraction decreases in both arms, but its arm structure does not isolate trastuzumab; the boxed-warning evidence base is the anthracycline-trial literature and cardiac monitoring rather than this single AE table.