Drugs › Asparagine-specific enzyme
Brand name · Calaspargase pegol
Asparlas: adverse event reports filed with FDA
564 reports list it as a suspect or interacting product, 2022–2026. Class: Asparagine-specific enzyme.
- 564
- reports as suspect product
- 0% of all reports · about 141 a year
- 152
- reports, 12 months to June 2026
- 110 in the 12 months before
- 89.5%
- marked serious by the reporter
- 97.7% across the class
- 4.1%
- record death among outcomes, as reported
- 23 reports · not verified by FDA
564 adverse event reports received by FDA list the brand name Asparlas (calaspargase pegol) as a suspect or interacting product, from July 2022 to June 2026. A further 3 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, 152 reports listed it, up 38% from 110 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 141 reports a year and 0% of the 20,646,523 reports in the database, and 4.7% of the reports for the asparagine-specific enzyme class. How many people take it is not in the data, so a count is not a rate of occurrence.
The MedDRA terms listed most often are hypersensitivity (33.5%), anaphylactic reaction (15.6%) and pancreatitis (10.8%). A report can list several reactions, so shares add to more than 100%; 100 different terms appear across these reports. Hypersensitivity is recorded in 33.5% of these reports, a larger share than in the median asparagine-specific enzyme drug (4.5%).
89.5% of the reports are marked serious by the reporter (97.7% across the class); 4.1% record death among the outcomes and 34% record hospitalisation, as reported. 43.1% of the reports came from other health professionals, and the largest patient age group is 2 to 11 (13.8%). 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 Asparlas reports recording the termmedian drug in asparagine-specific enzyme
- Hypersensitivityan allergic-type reaction33.5%189
- Anaphylactic reactiona severe, sudden allergic reaction15.6%88
- Pancreatitisinflammation of the pancreas10.8%61
- Infusion related reactiona reaction during or soon after an infusion10.6%60
- Vomitingbeing sick5%28
- Febrile neutropeniafever with low white blood cells3.9%22
- Hypertriglyceridaemia3.7%21
- Tachycardiafast heart rate3.5%20
- Coughcough3.2%18
- Nauseafeeling sick2.8%16
- Neutropenialow neutrophils, a type of white blood cell2.3%13
- Urticariahives2.3%13
- Hyperglycaemiahigh blood sugar2%11
- Pancreatitis acute1.8%10
- Septic shockshock arising from infection1.8%10
- Abdominal painstomach or belly pain1.6%9
- Flushingsudden reddening or warmth of the skin1.6%9
- Pancreatitis necrotising1.6%9
- Venoocclusive liver disease1.6%9
- Dyspnoeashortness of breath1.4%8
- Pancytopenialow counts of all blood cells1.4%8
- Treatment delayed1.4%8
- Acute kidney injurysudden loss of kidney function1.2%7
- Drug level increaseda raised blood level of the medicine1.2%7
- Thrombocytopenialow platelets1.2%7
- Hypotensionlow blood pressure1.1%6
- Pyrexiafever1.1%6
- Angioedemadeep swelling of skin or mucous membranes0.9%5
Top 30 of 100 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 3 drugs in the asparagine-specific enzyme 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 12,068 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. 95.9% 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 | 170 | 30.1% |
| B-cell type acute leukaemia | 96 | 17% |
| T-cell type acute leukaemia | 40 | 7.1% |
| B precursor type acute leukaemia | 18 | 3.2% |
| Leukaemia | 15 | 2.7% |
| T-cell lymphoma | 6 | 1.1% |
The indication field is filled in by the reporter and is often blank; shares are of all 564 reports.
In context
| Measure | Asparlas | Asparagine-specific enzyme | All reports |
|---|---|---|---|
| Reports as suspect product | 564 | 12,068 | 20,646,523 |
| Share of that pool | — | 4.7% | 0% |
| Reports, latest 12 months | 152 | — | 1,332,454 |
| Marked serious | 89.5% | 97.7% | 57.4% |
| Death recorded among outcomes, per 1,000 reports | 41 | 126 | 91 |
| Hospitalisation recorded, per 1,000 reports | 340 | 605 | 213 |
| Consumer-filed share | 0.9% | 3% | 45.8% |
| Top term, share of reports | Hypersensitivity 33.5% | median 4.5% | 0.9% |
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 asparagine-specific enzyme class
| Drug | Name type | Reports | Latest 12 months | Marked serious |
|---|---|---|---|---|
| Pegaspargase | generic | 6,294 | 259 | 99.5% |
| Oncaspar | brand | 5,210 | 166 | 96.4% |
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 Asparlas reports
How many adverse event reports has FDA received for Asparlas?
564 reports list Asparlas as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 152 of them arrived in the latest 12 months. Another 3 list it only as a concomitant medication.
What reactions are recorded in Asparlas reports?
hypersensitivity (33.5%), anaphylactic reaction (15.6%), pancreatitis (10.8%), infusion related reaction (10.6%) and vomiting (5%). 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 Asparlas was responsible.
How serious are the reports?
89.5% are marked serious by the reporter. Among the outcomes recorded, 4.1% of reports include death and 34% 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?
other health professional (43.1%), pharmacist (40.2%) and physician (14.7%). Most reports reach FDA through the manufacturer, which must forward reports it receives.
Are reports for Asparlas rising?
152 reports in the 12 months to June 2026, up 38% from 110 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 Asparlas 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 Asparlas?
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 Asparlas as a suspect or interacting product; reports listing it only as a concomitant medication (3) 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.