Reported Reactions

Drugs › Kinase inhibitor

Brand name · Idelalisib

Zydelig: adverse event reports filed with FDA

1,650 reports list it as a suspect or interacting product, 2014–2026. Class: Kinase inhibitor.

1,650
reports as suspect product
0% of all reports · about 135 a year
10
reports, 12 months to June 2026
22 in the 12 months before
90.9%
marked serious by the reporter
70.8% across the class
19.2%
record death among outcomes, as reported
317 reports · not verified by FDA

Between April 2014 and June 2026, 1,650 adverse event reports received by FDA list the brand name Zydelig (idelalisib) as a suspect or interacting product. Reports that mention it only as a concomitant medication (99) are left out of every figure here.

In the 12 months to June 2026, 10 reports listed it, down 55% from 22 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 135 reports a year and 0% of the 20,646,523 reports in the database, and 0.2% of the reports for the kinase inhibitor 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 diarrhoea (16.5%), disease progression (9.8%) and off label use (7.5%). A report can list several reactions, so shares add to more than 100%; 404 different terms appear across these reports. Diarrhoea is recorded in 16.5% of these reports, a larger share than in the median kinase inhibitor drug (6.9%).

90.9% of the reports are marked serious by the reporter (70.8% across the class); 19.2% record death among the outcomes and 48.8% record hospitalisation, as reported. 63.2% of the reports came from physicians, and the largest patient age group is 65 to 74 (26.5%). 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

0510Jul 2021: 10Aug 2021: 2Sep 2021: 4Oct 2021: 4Nov 2021: 1Dec 2021: 22022Jan 2022: 2Feb 2022: 1Mar 2022: 1Apr 2022: 1May 2022: 3Jun 2022: 2Jul 2022: 3Aug 2022: 1Sep 2022: 0Oct 2022: 5Nov 2022: 4Dec 2022: 12023Jan 2023: 2Feb 2023: 0Mar 2023: 0Apr 2023: 3May 2023: 3Jun 2023: 5Jul 2023: 0Aug 2023: 0Sep 2023: 0Oct 2023: 2Nov 2023: 2Dec 2023: 72024Jan 2024: 5Feb 2024: 2Mar 2024: 0Apr 2024: 1May 2024: 7Jun 2024: 1Jul 2024: 5Aug 2024: 3Sep 2024: 0Oct 2024: 0Nov 2024: 1Dec 2024: 32025Jan 2025: 1Feb 2025: 7Mar 2025: 1Apr 2025: 1May 2025: 0Jun 2025: 0Jul 2025: 1Aug 2025: 0Sep 2025: 0Oct 2025: 1Nov 2025: 0Dec 2025: 02026Jan 2026: 0Feb 2026: 0Mar 2026: 0Apr 2026: 0May 2026: 4Jun 2026: 4

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

02054092014: 2820142015: 3162016: 40920162017: 2432018: 27220182019: 1572020: 7920202021: 502022: 2420222023: 242024: 2820242025: 122026: 82026

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Zydelig reports recording the termmedian drug in kinase inhibitor

  1. Diarrhoealoose or frequent stools16.5%272
  2. Disease progressionthe disease advanced9.8%162
  3. Off label useused for a purpose or in a way not on the label7.5%123
  4. Pyrexiafever6.4%106
  5. Colitisinflamed bowel5.7%94
  6. Pneumonialung infection5.7%94
  7. Neutropenialow neutrophils, a type of white blood cell4.7%77
  8. Dehydrationdehydration4.1%68
  9. Deaththe patient died; cause not stated by this term3.3%54
  10. Dyspnoeashortness of breath2.9%48
  11. Lung disordera lung problem, type not specified2.9%48
  12. Fatiguetiredness2.8%46
  13. Rashskin rash2.7%45
  14. Renal failurekidney failure2.5%42
  15. Weight decreasedweight loss2.5%41
  16. Coughcough2.4%39
  17. Sepsisa severe body-wide response to infection2.3%38
  18. Acute kidney injurysudden loss of kidney function2.2%37
  19. Vomitingbeing sick2.2%36
  20. Chronic lymphocytic leukaemia2%33
  21. Drug ineffectivethe medicine did not work as expected2%33
  22. Thrombocytopenialow platelets1.9%32
  23. Interstitial lung diseasescarring or inflammation of lung tissue1.9%31
  24. Astheniaweakness or lack of energy1.6%27
  25. Infectionan infection, type not specified1.6%27
  26. Decreased appetitereduced appetite1.6%26
  27. Pancytopenialow counts of all blood cells1.6%26
  28. Atrial fibrillationan irregular heart rhythm1.5%25

Top 30 of 404 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 100 drugs in the kinase 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

Death19.2%317
Life-threatening7.1%117
Hospitalisation (initial or prolonged)48.8%806
Disability2.5%42
Congenital anomaly0%0
Other serious74.5%1,230
Not serious9.1%150

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 849,161 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

Under 20%0
2 to 110.1%1
12 to 170%0
18 to 441.5%25
45 to 6418.7%309
65 to 7426.5%437
75 and over23.7%391
Age not given29.5%487

Patient sex

Female33.9%560
Male61.7%1,018
Not given4.4%72

Who reported

Physician63.2%1,042
Pharmacist8.1%133
Other health professional16.9%279
Lawyer0.1%1
Consumer or non-health professional11.4%188
Not given0.4%7

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 22.7% of reports give the United States as the country of the event or reporter.

Reason for use recorded

Indication as recorded (MedDRA)ReportsShare
Chronic lymphocytic leukaemia71843.5%
B-cell lymphoma22613.7%
Non-hodgkin's lymphoma432.6%
Follicular lymphoma311.9%
Lymphoma281.7%
Chronic lymphocytic leukaemia recurrent211.3%

The indication field is filled in by the reporter and is often blank; shares are of all 1,650 reports.

In context

MeasureZydeligKinase inhibitorAll reports
Reports as suspect product1,650849,16120,646,523
Share of that pool—0.2%0%
Reports, latest 12 months10—1,332,454
Marked serious90.9%70.8%57.4%
Death recorded among outcomes, per 1,000 reports19219091
Hospitalisation recorded, per 1,000 reports488264213
Consumer-filed share11.4%42.3%45.8%
Top term, share of reportsDiarrhoea 16.5%median 6.9%3.1%

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 kinase inhibitor class

DrugName typeReportsLatest 12 monthsMarked serious
Ibrancebrand81,9122,38047.1%
Imbruvicabrand67,0392,28374.4%
Cabometyxbrand41,8184,90440.4%
Sutentbrand33,21517574.5%
Afinitorbrand30,70616171.3%
Sprycelbrand27,25555749.7%
Tasignabrand24,91132870.9%
Kisqalibrand24,6033,41379.2%
Ofevbrand23,9072,43466.9%
Gleevecbrand23,1328174.7%
Tagrissobrand23,0851,41092.3%
Lenvimabrand22,3502,64387.3%
Votrientbrand22,08411960.9%
Mekinistbrand17,07091664%
Inlytabrand15,69638860.9%

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 Zydelig reports

How many adverse event reports has FDA received for Zydelig?

1,650 reports list Zydelig as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 10 of them arrived in the latest 12 months. Another 99 list it only as a concomitant medication.

What reactions are recorded in Zydelig reports?

diarrhoea (16.5%), disease progression (9.8%), off label use (7.5%), pyrexia (6.4%) and colitis (5.7%). 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 Zydelig was responsible.

How serious are the reports?

90.9% are marked serious by the reporter. Among the outcomes recorded, 19.2% of reports include death and 48.8% 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 (63.2%), other health professional (16.9%) and consumer or non-health professional (11.4%). Most reports reach FDA through the manufacturer, which must forward reports it receives.

Are reports for Zydelig rising?

10 reports in the 12 months to June 2026, down 55% from 22 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 Zydelig 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 Zydelig?

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 Zydelig as a suspect or interacting product; reports listing it only as a concomitant medication (99) 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.