Herceptin: adverse event reports filed with FDA

30,399

reports as suspect product

0.2% of all reports · about 1,351 a year

934

reports, 12 months to June 2026

2,443 in the 12 months before

81.2%

marked serious by the reporter

86.6% across the class

14.2%

record death among outcomes, as reported

4,310 reports · not verified by FDA

Reports by month, five years

Reports by the month FDA received them. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

By year received

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Herceptin reports recording the termmedian drug in her2/neu receptor antagonist

1. Diarrhoealoose or frequent stools8.6%2,609
2. Deaththe patient died; cause not stated by this term8%2,428
3. Fatiguetiredness6.4%1,942
4. Nauseafeeling sick6.1%1,846
5. Disease progressionthe disease advanced5.8%1,773
6. Myelosuppression4.4%1,349
7. Dyspnoeashortness of breath4.3%1,303
8. Off label useused for a purpose or in a way not on the label4%1,231
9. Vomitingbeing sick4%1,211
10. Pyrexiafever3.7%1,137
11. Astheniaweakness or lack of energy3.5%1,049
12. Rashskin rash3%917
13. Ejection fraction decreased3%901
14. Alopeciahair loss2.9%896
15. No adverse eventno adverse event was reported2.9%868
16. Neuropathy peripheralnerve damage in hands or feet2.8%854
17. Headachehead pain2.7%835
18. Chillschills or shivering2.7%831
19. Painpain, site not specified2.6%793
20. Arthralgiajoint pain2.3%711
21. Malaisegeneral feeling of being unwell2.3%701
22. Metastases to central nervous system2.3%696
23. Decreased appetitereduced appetite2.1%648
24. Coughcough1.9%590
25. Anaemialow red blood cells1.9%589
26. Neutropenialow neutrophils, a type of white blood cell1.9%585
27. Palmar-plantar erythrodysaesthesia syndrome1.9%569
28. Drug ineffectivethe medicine did not work as expected1.9%564
29. Dizzinesslight-headedness or unsteadiness1.8%560
30. White blood cell count decreasedlow white cell count1.8%556

Top 30 of 1,977 MedDRA preferred terms recorded across these reports, with a plain-language gloss where one is available. One report can record several terms. The hollow bar is the median share across the 6 drugs in the her2/neu receptor antagonist class; it describes the reports, not the patients. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Outcomes recorded

Outcome flags as the reporter set them; a report can carry several, and "other serious" is FDA's own category for serious reports outside the named outcomes. Grey bar: all 85,553 reports in the class. FDA has not verified any outcome and states that the reports "cannot be used to estimate the incidence of these events."

Patients and reporters

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 32.9% of reports give the United States as the country of the event or reporter.

Reason for use recorded

The indication field is filled in by the reporter and is often blank; shares are of all 30,399 reports.

Drugs most often listed in the same reports

Other products listed in reports where Herceptin is a suspect product, whatever their own role. Co-listing means the two were recorded together; it says nothing about either product's part in the event. Only the 2,500 most-reported names are counted here.

In context

Shares are of reports, not of patients treated. The number of people taking a product is not in the data, so none of these figures is a rate, and differences between columns reflect who takes a product, who reports and how long it has been sold. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Other drugs in the her2/neu receptor antagonist class

Ordered by report count for navigation only. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic." A brand and its generic are separate rows because reporters name them separately.

Where this comes from. Counts are built from the openFDA Drug Adverse Event (FAERS) bulk export released 28 Sep 2026, which holds reports FDA received through 30 Jun 2026. Drug names are as reported, resolved to the brand or generic name on the FDA label where openFDA's harmonisation matched them; classes are the pharmacologic class (EPC) from the label and the National Drug Code Directory of 17 Sep 2026. A report counts here when it lists Herceptin as a suspect or interacting product; reports listing it only as a concomitant medication (6,643) are excluded. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.