Imfinzi: adverse event reports filed with FDA

12,098

reports as suspect product

0.1% of all reports · about 1,345 a year

2,560

reports, 12 months to June 2026

1,683 in the 12 months before

93.6%

marked serious by the reporter

94.8% across the class

32.5%

record death among outcomes, as reported

3,934 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 Imfinzi reports recording the termmedian drug in programmed death ligand-1 blocker

1. Deaththe patient died; cause not stated by this term22.2%2,682
2. Malignant neoplasm progression9.1%1,101
3. Radiation pneumonitis6%720
4. Pneumonitis4.5%543
5. Interstitial lung diseasescarring or inflammation of lung tissue3%359
6. Diarrhoealoose or frequent stools3%358
7. Neutrophil count decreased2.5%308
8. Pyrexiafever2.5%308
9. Dyspnoeashortness of breath2.2%267
10. Rashskin rash2.2%263
11. Metastases to central nervous system2%246
12. Pneumonialung infection2%246
13. Off label useused for a purpose or in a way not on the label1.9%234
14. Fatiguetiredness1.8%213
15. Anaemialow red blood cells1.6%199
16. Platelet count decreasedlow platelet count1.6%198
17. Myelosuppression1.6%192
18. Astheniaweakness or lack of energy1.5%184
19. Decreased appetitereduced appetite1.4%173
20. Colitisinflamed bowel1.3%162
21. Cholangitis1.3%161
22. Disease progressionthe disease advanced1.3%161
23. Malaisegeneral feeling of being unwell1.3%160
24. Febrile neutropeniafever with low white blood cells1.3%157
25. Hypothyroidismunderactive thyroid1.3%157
26. Nauseafeeling sick1.3%157
27. Liver disorder1.2%150
28. Cytokine release syndrome1.2%148
29. Hepatic function abnormal1.1%139
30. Coughcough1.1%135

Top 30 of 934 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 4 drugs in the programmed death ligand-1 blocker 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 23,488 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. 18.1% 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 12,098 reports.

Drugs most often listed in the same reports

Other products listed in reports where Imfinzi 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 programmed death ligand-1 blocker 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 Imfinzi as a suspect or interacting product; reports listing it only as a concomitant medication (92) 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.