Reported Reactions

Drugs › Kinase inhibitor

Generic name

Momelotinib: adverse event reports filed with FDA

625 reports list it as a suspect or interacting product, 2015–2026. Class: Kinase inhibitor.

625
reports as suspect product
0% of all reports · about 59 a year
336
reports, 12 months to June 2026
197 in the 12 months before
94.7%
marked serious by the reporter
70.8% across the class
23.8%
record death among outcomes, as reported
149 reports · not verified by FDA

625 adverse event reports received by FDA list momelotinib, a generic name as a suspect or interacting product, from December 2015 to June 2026. A further 23 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, 336 reports listed it, up 71% from 197 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 59 reports a year and 0% of the 20,646,523 reports in the database, and 0.1% 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 reactions recorded most often are thrombocytopenia (12%), myelofibrosis (11.8%) and drug ineffective (9.9%). A report can list several reactions, so shares add to more than 100%; 165 different terms appear across these reports. Thrombocytopenia is recorded in 12% of these reports, a larger share than in the median kinase inhibitor drug (0.9%).

94.7% of the reports are marked serious by the reporter (70.8% across the class); 23.8% record death among the outcomes and 30.9% record hospitalisation, as reported. 73.1% of the reports came from physicians, and the largest patient age group is 75 and over (12.3%). 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

03162Jul 2021: 0Aug 2021: 0Sep 2021: 0Oct 2021: 0Nov 2021: 0Dec 2021: 02022Jan 2022: 0Feb 2022: 0Mar 2022: 0Apr 2022: 0May 2022: 0Jun 2022: 0Jul 2022: 0Aug 2022: 0Sep 2022: 0Oct 2022: 1Nov 2022: 0Dec 2022: 02023Jan 2023: 0Feb 2023: 0Mar 2023: 0Apr 2023: 0May 2023: 0Jun 2023: 0Jul 2023: 0Aug 2023: 1Sep 2023: 1Oct 2023: 8Nov 2023: 14Dec 2023: 72024Jan 2024: 11Feb 2024: 11Mar 2024: 11Apr 2024: 7May 2024: 4Jun 2024: 7Jul 2024: 5Aug 2024: 3Sep 2024: 6Oct 2024: 12Nov 2024: 13Dec 2024: 152025Jan 2025: 14Feb 2025: 11Mar 2025: 20Apr 2025: 14May 2025: 22Jun 2025: 62Jul 2025: 40Aug 2025: 26Sep 2025: 31Oct 2025: 33Nov 2025: 33Dec 2025: 322026Jan 2026: 22Feb 2026: 20Mar 2026: 18Apr 2026: 26May 2026: 32Jun 2026: 23

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

01693382015: 120152016: 120162018: 320182019: 420192022: 120222023: 3120232024: 10520242025: 33820252026: 1412026

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Momelotinib reports recording the termmedian drug in kinase inhibitor

  1. Thrombocytopenialow platelets12%75
  2. Myelofibrosis11.8%74
  3. Drug ineffectivethe medicine did not work as expected9.9%62
  4. Anaemialow red blood cells9.1%57
  5. Deaththe patient died; cause not stated by this term8.3%52
  6. Pneumonialung infection7.5%47
  7. Condition aggravatedthe condition being treated got worse6.6%41
  8. Renal impairmentreduced kidney function5%31
  9. Adverse drug reactiona harmful or unpleasant reaction reported to a medicine4.6%29
  10. Neutropenialow neutrophils, a type of white blood cell4.5%28
  11. Pyrexiafever4.5%28
  12. Diarrhoealoose or frequent stools4.2%26
  13. Neuropathy peripheralnerve damage in hands or feet3.8%24
  14. Dizzinesslight-headedness or unsteadiness3.5%22
  15. Hospitalisationadmission to hospital3.4%21
  16. Platelet count decreasedlow platelet count3.2%20
  17. Fatiguetiredness3%19
  18. Malaisegeneral feeling of being unwell3%19
  19. Cardiac failureheart failure2.9%18
  20. Nauseafeeling sick2.9%18
  21. Astheniaweakness or lack of energy2.6%16
  22. Acute kidney injurysudden loss of kidney function2.2%14
  23. Hypotensionlow blood pressure2.1%13
  24. Haemoglobin decreasedlow haemoglobin1.9%12
  25. Headachehead pain1.9%12
  26. Off label useused for a purpose or in a way not on the label1.9%12
  27. Sepsisa severe body-wide response to infection1.9%12
  28. Urinary tract infectionbladder or urinary infection1.9%12

Top 30 of 165 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

Death23.8%149
Life-threatening4.2%26
Hospitalisation (initial or prolonged)30.9%193
Disability1.1%7
Congenital anomaly0%0
Other serious82.9%518
Not serious5.3%33

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%0
12 to 170%0
18 to 441%6
45 to 644.3%27
65 to 748%50
75 and over12.3%77
Age not given74.4%465

Patient sex

Female18.7%117
Male27.8%174
Not given53.4%334

Who reported

Physician73.1%457
Pharmacist13.1%82
Other health professional4.8%30
Lawyer0%0
Consumer or non-health professional8.8%55
Not given0.2%1

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 23% of reports give the United States as the country of the event or reporter.

Reason for use recorded

Indication as recorded (MedDRA)ReportsShare
Myelofibrosis43068.8%
Primary myelofibrosis6911%
Essential thrombocythaemia40.6%
Anaemia30.5%
Myelodysplastic syndrome20.3%
Myelodysplastic syndrome with ringed sideroblasts20.3%

The indication field is filled in by the reporter and is often blank; shares are of all 625 reports.

In context

MeasureMomelotinibKinase inhibitorAll reports
Reports as suspect product625849,16120,646,523
Share of that pool—0.1%0%
Reports, latest 12 months336—1,332,454
Marked serious94.7%70.8%57.4%
Death recorded among outcomes, per 1,000 reports23819091
Hospitalisation recorded, per 1,000 reports309264213
Consumer-filed share8.8%42.3%45.8%
Top term, share of reportsThrombocytopenia 12%median 0.9%0.5%

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 Momelotinib reports

How many adverse event reports has FDA received for Momelotinib?

625 reports list Momelotinib as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 336 of them arrived in the latest 12 months. Another 23 list it only as a concomitant medication.

What reactions are recorded in Momelotinib reports?

thrombocytopenia (12%), myelofibrosis (11.8%), drug ineffective (9.9%), anaemia (9.1%) and death (8.3%). 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 Momelotinib was responsible.

How serious are the reports?

94.7% are marked serious by the reporter. Among the outcomes recorded, 23.8% of reports include death and 30.9% 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 (73.1%), pharmacist (13.1%) and consumer or non-health professional (8.8%). Most reports reach FDA through the manufacturer, which must forward reports it receives.

Are reports for Momelotinib rising?

336 reports in the 12 months to June 2026, up 71% from 197 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 Momelotinib 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 Momelotinib?

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 Momelotinib as a suspect or interacting product; reports listing it only as a concomitant medication (23) 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.