Kesimpta: adverse event reports filed with FDA

29,257

reports as suspect product

0.1% of all reports · about 2,811 a year

2,658

reports, 12 months to June 2026

3,867 in the 12 months before

38.3%

marked serious by the reporter

77% across the class

1.1%

record death among outcomes, as reported

326 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 Kesimpta reports recording the termmedian drug in cd20-directed cytolytic antibody

1. Fatiguetiredness18.3%5,366
2. Headachehead pain15.4%4,507
3. Painpain, site not specified11.9%3,478
4. Chillschills or shivering11.7%3,427
5. Pyrexiafever11.4%3,333
6. Influenza like illnessflu-like symptoms9.8%2,855
7. Nauseafeeling sick5.9%1,718
8. Multiple sclerosis relapsea flare of multiple sclerosis5.5%1,609
9. Astheniaweakness or lack of energy4.9%1,425
10. Covid-19COVID-19 infection4.9%1,425
11. Gait disturbancedifficulty walking4.7%1,381
12. Multiple sclerosis4.7%1,377
13. Hypoaesthesianumbness4.6%1,356
14. Feeling abnormalfeeling odd or not right4.5%1,322
15. Malaisegeneral feeling of being unwell4.5%1,302
16. Dizzinesslight-headedness or unsteadiness4.3%1,247
17. Nasopharyngitisa cold4.3%1,244
18. Pain in extremitypain in an arm or leg3.9%1,136
19. Drug ineffectivethe medicine did not work as expected3.8%1,115
20. Injection site painpain where the injection was given3.4%998
21. Inappropriate schedule of product administrationthe product was taken at the wrong times3.3%974
22. Coughcough3.2%949
23. Falla fall3.2%936
24. Arthralgiajoint pain3.2%931
25. Accidental exposure to product3.1%920
26. Urinary tract infectionbladder or urinary infection3.1%915
27. Back painback pain3%872
28. Myalgiamuscle pain3%866
29. Vomitingbeing sick2.8%832
30. Illness2.8%825

Top 30 of 1,691 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 12 drugs in the cd20-directed cytolytic antibody 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 316,120 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. 82.4% 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 29,257 reports.

Drugs most often listed in the same reports

Other products listed in reports where Kesimpta 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 cd20-directed cytolytic antibody 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 Kesimpta as a suspect or interacting product; reports listing it only as a concomitant medication (576) 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.