Pharmacologic class (EPC) · 3 drug pages

Asparagine-specific enzyme: adverse event reports filed with FDA

12,068 reports list a drug in this class as a suspect or interacting product, 2004–2026.

Read first · FDA's statement on these data

Adverse event reports submitted to FDA do not undergo extensive validation or verification. Therefore, a causal relationship cannot be established between product and reactions listed in a report. While a suspected relationship may exist, it is not medically validated and should not be the sole source of information for clinical decision making or other assumptions about the safety or efficacy of a product. Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product. openFDA, FDA

FDA adds: "There is no certainty that the reported event (adverse event or medication error) was actually due to the product. FDA does not require that a causal relationship between a product and event be proven, and reports do not always contain enough detail to properly evaluate an event." The information in these reports "cannot be used to estimate the incidence of these events."

Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated.

Not medical advice. This site counts what was reported to FDA. Questions about a medicine or device belong with a pharmacist or clinician.

12,068
reports across the class: 0.1% of all reports; 577
reports, 12 months to June 2026: 689 in the 12 months before; 97.7%
marked serious by the reporter: 57.4% across all reports; 3
drugs with a page: brand and generic names counted separately

Asparagine-specific enzyme is a pharmacologic class (an FDA Established Pharmacologic Class) with 3 drug pages on this site. Together those drugs are listed as a suspect or interacting product in 12,068 adverse event reports received by FDA, 0.1% of the database, from January 2004 to June 2026.

577 reports arrived in the 12 months to June 2026, down 16% from 689 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. 97.7% of the class's reports are marked serious, 12.6% record death among the outcomes and 60.5% record hospitalisation, as reported.

Across the class the reactions recorded most often are febrile neutropenia (12.9%), pyrexia (6%) and febrile bone marrow aplasia (5.6%). The class median share shown beside each term is the middle value across the member drugs; it is the comparison used on every drug page in this class.

The members table is 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."

Drugs in the class

Drug	Name type	Reports	Latest 12 months	Marked serious	Top term recorded
Pegaspargase	generic	6,294	259	99.5%	Febrile neutropenia
OncasparPegaspargase	brand	5,210	166	96.4%	Febrile neutropenia
AsparlasCalaspargase pegol	brand	564	152	89.5%	Hypersensitivity

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."

Reports by month, five years

FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

Reactions recorded across the class

share of class reports recording the termmedian drug in the class

Febrile neutropeniafever with low white blood cells12.9%1,554
Pyrexiafever6%729
Febrile bone marrow aplasia5.6%675
Vomitingbeing sick4.9%589
Neutropenialow neutrophils, a type of white blood cell4.4%533
Sepsisa severe body-wide response to infection4.4%528
Hypersensitivityan allergic-type reaction4.2%505
Abdominal painstomach or belly pain4.1%495
Pancreatitisinflammation of the pancreas3.7%445
Hypotensionlow blood pressure3.7%443
Hypertriglyceridaemia3.4%415
Nauseafeeling sick3.3%397
Thrombocytopenialow platelets3.1%375
Hyperbilirubinaemia3%368
Bacterial infectiona bacterial infection2.9%355
Tachycardiafast heart rate2.7%331
Pneumonialung infection2.7%330
Septic shockshock arising from infection2.7%328
Anaphylactic reactiona severe, sudden allergic reaction2.6%318
Hypofibrinogenaemia2.4%294
Off label useused for a purpose or in a way not on the label2.4%294
Anaemialow red blood cells2.4%284
Mucosal inflammation2.4%284
Viral infectiona viral infection2.3%282
Clostridium difficile colitisa bowel infection with C. difficile2.2%269

Solid bar: share of all class reports. Hollow bar: the median share across the 3 member drugs, the reference used on each member's page. One report can record several terms.

Outcomes, patients and reporters

Outcomes recorded

Death12.6%1,522

Life-threatening12.5%1,513

Hospitalisation (initial or prolonged)60.5%7,306

Disability1.2%139

Congenital anomaly0.1%18

Other serious54.5%6,575

Not serious2.3%277

Patient age

Under 22.6%319

2 to 1125.5%3,077

12 to 1712.4%1,495

18 to 4410.2%1,225

45 to 642.7%323

65 to 740.7%80

75 and over0.2%29

Age not given45.7%5,520

Who reported

Physician55.9%6,745

Pharmacist9.6%1,161

Other health professional26%3,132

Lawyer0%3

Consumer or non-health professional3%360

Not given5.5%667

Grey bar: all 20,646,523 reports in the database. Outcome flags are as the reporter set them and are not verified by FDA.

Questions about Asparagine-specific enzyme reports

Which drugs are in the Asparagine-specific enzyme class on this site?

Pegaspargase, Oncaspar and Asparlas. Class membership comes from the pharmacologic class (EPC) on the drug's FDA label.

How many reports does the class have?

12,068 reports through June 2026, 577 of them in the latest 12 months. A report listing two drugs of the class counts once for each.

What reactions are recorded most often?

febrile neutropenia (12.9%), pyrexia (6%), febrile bone marrow aplasia (5.6%), vomiting (4.9%) and neutropenia (4.4%).

Can the members table be used to rank the drugs?

No. 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." Drugs differ in how many people take them, in the conditions they treat, in time on the market and in how diligently reports are collected.

How do I report an adverse event?

Through FDA MedWatch (Form FDA 3500, or 1-800-FDA-1088) or to the manufacturer. 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 class is the Established Pharmacologic Class most often attached to a drug's reports by openFDA's label harmonisation, or from the NDC Directory where reports carry none. 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.