Drugs › B lymphocyte stimulator-specific inhibitor
Generic name
Belimumab: adverse event reports filed with FDA
4,254 reports list it as a suspect or interacting product, 2011–2026. Class: B lymphocyte stimulator-specific inhibitor. Also reported as Belimumab Solution For Injection.
- 4,254
- reports as suspect product
- 0% of all reports · about 290 a year
- 654
- reports, 12 months to June 2026
- 669 in the 12 months before
- 90.6%
- marked serious by the reporter
- 41.8% across the class
- 5.7%
- record death among outcomes, as reported
- 241 reports · not verified by FDA
Between November 2011 and June 2026, 4,254 adverse event reports received by FDA list belimumab, a generic name as a suspect or interacting product. Reports that mention it only as a concomitant medication (329) are left out of every figure here.
In the 12 months to June 2026, 654 reports listed it, close to the 669 of the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Over its reporting history that is about 290 reports a year and 0% of the 20,646,523 reports in the database, and 14.1% of the reports for the b lymphocyte stimulator-specific inhibitor class. How many people take it is not in the data, so a count is not a rate of occurrence.
The reactions recorded most often are systemic lupus erythematosus (27.3%), product dose omission issue (12.8%) and drug ineffective (9.9%). A report can list several reactions, so shares add to more than 100%; 826 different terms appear across these reports. Systemic lupus erythematosus is recorded in 27.3% of these reports, a larger share than in the median b lymphocyte stimulator-specific inhibitor drug (18.8%).
90.6% of the reports are marked serious by the reporter (41.8% across the class); 5.7% record death among the outcomes and 29.6% record hospitalisation, as reported. 39% of the reports came from consumers, and the largest patient age group is 18 to 44 (24.8%). FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event."
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 Belimumab reports recording the termmedian drug in b lymphocyte stimulator-specific inhibitor
- Systemic lupus erythematosuslupus, an autoimmune disease27.3%1,160
- Product dose omission issuea dose was missed12.8%545
- Drug ineffectivethe medicine did not work as expected9.9%421
- Painpain, site not specified6.1%261
- Fatiguetiredness6%256
- Off label useused for a purpose or in a way not on the label6%256
- Inappropriate schedule of product administrationthe product was taken at the wrong times6%255
- Condition aggravatedthe condition being treated got worse5.3%226
- Arthralgiajoint pain5.3%224
- Lupus nephritis5.1%218
- Malaisegeneral feeling of being unwell4.4%187
- Headachehead pain4.3%183
- Pyrexiafever4.1%176
- Nauseafeeling sick4%172
- Urinary tract infectionbladder or urinary infection3.6%152
- Pneumonialung infection3.4%145
- Rashskin rash3%128
- Exposure during pregnancythe medicine was taken during pregnancy2.8%121
- Covid-19COVID-19 infection2.8%118
- Influenzaflu2.7%115
- Illness2.6%112
- Deaththe patient died; cause not stated by this term2.5%105
- Nasopharyngitisa cold2.4%104
- Coughcough2.4%100
- Diarrhoealoose or frequent stools2.3%97
- Astheniaweakness or lack of energy2.2%95
- Foetal exposure during pregnancythe unborn baby was exposed to the medicine2.2%95
- Hospitalisationadmission to hospital2.2%94
- Herpes zostershingles2.1%89
- Pain in extremitypain in an arm or leg2.1%88
Top 30 of 826 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 2 drugs in the b lymphocyte stimulator-specific inhibitor 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 30,275 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
Patient age
Patient sex
Who reported
Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 47.8% of reports give the United States as the country of the event or reporter.
Reason for use recorded
| Indication as recorded (MedDRA) | Reports | Share |
|---|---|---|
| Systemic lupus erythematosus | 2,994 | 70.4% |
| Lupus nephritis | 220 | 5.2% |
| Chronic cutaneous lupus erythematosus | 55 | 1.3% |
| Immunosuppression | 25 | 0.6% |
| Immunosuppressant drug therapy | 16 | 0.4% |
| Sjogren's syndrome | 15 | 0.4% |
The indication field is filled in by the reporter and is often blank; shares are of all 4,254 reports.
Drugs most often listed in the same reports
| Drug (any role in the report) | Reports | Share of Belimumab reports |
|---|---|---|
| Hydroxychloroquine | 846 | 19.9% |
| Prednisone | 683 | 16.1% |
| Mycophenolate mofetil | 597 | 14% |
| Methotrexate | 456 | 10.7% |
| Azathioprine | 455 | 10.7% |
| Prednisolone | 452 | 10.6% |
| Rituximab | 304 | 7.1% |
| Cyclophosphamide | 254 | 6% |
| Plaquenil | 182 | 4.3% |
| Tacrolimus | 174 | 4.1% |
Other products listed in reports where Belimumab 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
| Measure | Belimumab | B lymphocyte stimulator-specific inhibitor | All reports |
|---|---|---|---|
| Reports as suspect product | 4,254 | 30,275 | 20,646,523 |
| Share of that pool | — | 14.1% | 0% |
| Reports, latest 12 months | 654 | — | 1,332,454 |
| Marked serious | 90.6% | 41.8% | 57.4% |
| Death recorded among outcomes, per 1,000 reports | 57 | 29 | 91 |
| Hospitalisation recorded, per 1,000 reports | 296 | 142 | 213 |
| Consumer-filed share | 39% | 67.6% | 45.8% |
| Top term, share of reports | Systemic lupus erythematosus 27.3% | median 18.8% | 0.2% |
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 b lymphocyte stimulator-specific inhibitor class
| Drug | Name type | Reports | Latest 12 months | Marked serious |
|---|---|---|---|---|
| Benlysta | brand | 26,021 | 3,218 | 33.8% |
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.
Questions about Belimumab reports
How many adverse event reports has FDA received for Belimumab?
4,254 reports list Belimumab as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 654 of them arrived in the latest 12 months. Another 329 list it only as a concomitant medication.
What reactions are recorded in Belimumab reports?
systemic lupus erythematosus (27.3%), product dose omission issue (12.8%), drug ineffective (9.9%), pain (6.1%) and fatigue (6%). These are MedDRA preferred terms coded from what the reporter described; a report can list several, and a term's presence is not a finding that Belimumab was responsible.
How serious are the reports?
90.6% are marked serious by the reporter. Among the outcomes recorded, 5.7% of reports include death and 29.6% include hospitalisation. FDA has not verified these outcomes and states that the reports "cannot be used to estimate the incidence" of the events.
Who files these reports?
consumer or non-health professional (39%), physician (36.1%) and other health professional (21.9%). Most reports reach FDA through the manufacturer, which must forward reports it receives.
Are reports for Belimumab rising?
654 reports in the 12 months to June 2026, close to the 669 of the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Counts also move with how many people take a product, its time on the market and publicity.
Do these reports show that Belimumab was responsible for these reactions?
No. FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event." The reaction may relate to the condition being treated, to other medicines, or to something else.
Is this a list of the side effects of Belimumab?
No. It is a count of what was reported to FDA. The adverse reactions observed in clinical studies are printed on the FDA-approved label, which a pharmacist or clinician can go through with you.
How do I report an adverse event?
Consumers and health professionals can report to FDA through MedWatch (Form FDA 3500 online, or 1-800-FDA-1088), or to the manufacturer, which must pass reports on. See the guide on how to report.
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 Belimumab as a suspect or interacting product; reports listing it only as a concomitant medication (329) 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.
Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.