Drugs › CD22-directed immunoconjugate
Brand name · Inotuzumab ozogamicin
Besponsa: adverse event reports filed with FDA
669 reports list it as a suspect or interacting product, 2017–2026. Class: CD22-directed immunoconjugate.
- 669
- reports as suspect product
- 0% of all reports · about 76 a year
- 42
- reports, 12 months to June 2026
- 57 in the 12 months before
- 88%
- marked serious by the reporter
- 96% across the class
- 45.9%
- record death among outcomes, as reported
- 307 reports · not verified by FDA
669 adverse event reports received by FDA list the brand name Besponsa (inotuzumab ozogamicin) as a suspect or interacting product, from September 2017 to May 2026. A further 35 reports list it only as a concomitant medication, and those are not counted in the figures on this page.
In the 12 months to June 2026, 42 reports listed it, down 26% from 57 in 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 76 reports a year and 0% of the 20,646,523 reports in the database, and 27.7% of the reports for the CD22-directed immunoconjugate 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 death (20.3%), neoplasm progression (17%) and venoocclusive liver disease (11.8%). A report can list several reactions, so shares add to more than 100%; 147 different terms appear across these reports. Death is recorded in 20.3% of these reports, a larger share than in the median CD22-directed immunoconjugate drug (14.3%).
88% of the reports are marked serious by the reporter (96% across the class); 45.9% record death among the outcomes and 23.8% record hospitalisation, as reported. 66.7% of the reports came from physicians, and the largest patient age group is 18 to 44 (21.2%). 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 Besponsa reports recording the termmedian drug in cd22-directed immunoconjugate
- Deaththe patient died; cause not stated by this term20.3%136
- Neoplasm progression17%114
- Venoocclusive liver disease11.8%79
- Off label useused for a purpose or in a way not on the label7.2%48
- Platelet count decreasedlow platelet count6.4%43
- Pyrexiafever6.4%43
- Febrile neutropeniafever with low white blood cells4.5%30
- White blood cell count decreasedlow white cell count4.5%30
- Thrombocytopenialow platelets4.2%28
- Venoocclusive disease3.9%26
- Ascitesfluid in the abdomen3.6%24
- Sepsisa severe body-wide response to infection2.5%17
- Neutropenialow neutrophils, a type of white blood cell2.4%16
- Infectionan infection, type not specified2.2%15
- Multiple organ dysfunction syndromeseveral organs failing2.2%15
- Myelosuppression2.2%15
- Nauseafeeling sick2.1%14
- Neoplasm recurrence1.8%12
- Weight increasedweight gain1.8%12
- Alanine aminotransferase increasedraised liver enzyme (ALT)1.5%10
- Fatiguetiredness1.5%10
- Mucosal inflammation1.5%10
- Tumour lysis syndrome1.5%10
- Aspartate aminotransferase increasedraised liver enzyme (AST)1.3%9
- Anaemialow red blood cells1.2%8
Top 30 of 147 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 cd22-directed immunoconjugate 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 2,419 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. 29.1% of reports give the United States as the country of the event or reporter.
Reason for use recorded
| Indication as recorded (MedDRA) | Reports | Share |
|---|---|---|
| Acute lymphocytic leukaemia | 209 | 31.2% |
| Acute lymphocytic leukaemia recurrent | 71 | 10.6% |
| B-cell type acute leukaemia | 28 | 4.2% |
| Acute lymphocytic leukaemia refractory | 11 | 1.6% |
| B precursor type acute leukaemia | 8 | 1.2% |
| B-cell prolymphocytic leukaemia | 8 | 1.2% |
The indication field is filled in by the reporter and is often blank; shares are of all 669 reports.
Drugs most often listed in the same reports
| Drug (any role in the report) | Reports | Share of Besponsa reports |
|---|---|---|
| Cytarabine | 42 | 6.3% |
| Methotrexate | 42 | 6.3% |
| Blincyto | 28 | 4.2% |
| Ursodiol | 28 | 4.2% |
| Prednisolone | 26 | 3.9% |
| Acyclovir | 25 | 3.7% |
| Cyclophosphamide | 25 | 3.7% |
| Methotrexate sodium | 23 | 3.4% |
| Sulfamethoxazole, trimethoprim | 23 | 3.4% |
| Acetaminophen | 22 | 3.3% |
Other products listed in reports where Besponsa 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 | Besponsa | CD22-directed immunoconjugate | All reports |
|---|---|---|---|
| Reports as suspect product | 669 | 2,419 | 20,646,523 |
| Share of that pool | — | 27.7% | 0% |
| Reports, latest 12 months | 42 | — | 1,332,454 |
| Marked serious | 88% | 96% | 57.4% |
| Death recorded among outcomes, per 1,000 reports | 459 | 340 | 91 |
| Hospitalisation recorded, per 1,000 reports | 238 | 433 | 213 |
| Consumer-filed share | 12.6% | 12.3% | 45.8% |
| Top term, share of reports | Death 20.3% | median 14.3% | 4.1% |
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 cd22-directed immunoconjugate class
| Drug | Name type | Reports | Latest 12 months | Marked serious |
|---|---|---|---|---|
| Inotuzumab ozogamicin | generic | 1,750 | 137 | 99% |
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 Besponsa reports
How many adverse event reports has FDA received for Besponsa?
669 reports list Besponsa as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 42 of them arrived in the latest 12 months. Another 35 list it only as a concomitant medication.
What reactions are recorded in Besponsa reports?
death (20.3%), neoplasm progression (17%), venoocclusive liver disease (11.8%), off label use (7.2%) and platelet count decreased (6.4%). 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 Besponsa was responsible.
How serious are the reports?
88% are marked serious by the reporter. Among the outcomes recorded, 45.9% of reports include death and 23.8% 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?
physician (66.7%), consumer or non-health professional (12.6%) and pharmacist (10.3%). Most reports reach FDA through the manufacturer, which must forward reports it receives.
Are reports for Besponsa rising?
42 reports in the 12 months to June 2026, down 26% from 57 in 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 Besponsa 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 Besponsa?
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 Besponsa as a suspect or interacting product; reports listing it only as a concomitant medication (35) 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.