What the label lists and what reports show
Nirogacestat side effects
Nirogacestat's FDA label: “The most common ( > 15 %) adverse reactions are diarrhea, ovarian toxicity, rash, nausea, fatigue, stomatitis, headache, abdominal pain, cough, alopecia, upper respiratory tract infection and dyspnea.” FAERS holds 838 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is diarrhoea (305 reports).
- No generic listed
Check it at the source: the nirogacestat FDA label on DailyMed (effective September 1, 2026, SpringWorks Therapeutics, Inc.); the FDA FAERS public dashboard.
What does the patient leaflet say about side effects?
From the patient leaflet: What are the possible side effects of OGSIVEO?OGSIVEO can cause serious side effects, including: Diarrhea. Diarrhea is common during treatment with OGSIVEO and may sometimes be severe. Your healthcare provider may tell you to drink more fluids or may tell you to take antidiarrheal medicines. Tell your healthcare provider right away if you have diarrhea that lasts longer than a few days and does not get better after taking antidiarrheal medicines. Ovarian problems. Females who are able to become pregnant may have ovarian problems and changes in their menstrual cycle during treatment with OGSIVEO. OGSIVEO may affect fertility which may affect your ability to have a child. Tell your healthcare provider if you have any changes in your menstrual cycle or any hot flashes, night sweats or vaginal dryness during treatment with OGSIVEO. Liver problems. OGSIVEO can cause an increase in liver enzymes. […]
Source: FDA drug label, SpringWorks Therapeutics, Inc., effective September 1, 2026 (SPL set f172e6ff-3190-41b0-b95a-58a7ef9e9e1e), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsThe most common ( > 15 %) adverse reactions are diarrhea, ovarian toxicity, rash, nausea, fatigue, stomatitis, headache, abdominal pain, cough, alopecia, upper respiratory tract infection and dyspnea.
Table 2. Adverse Reactions (≥ 15%) in Patients with Desmoid Tumor Who Received OGSIVEO with a Difference Between Arms of ≥ 5% Compared to Placebo on DeFi
| Reaction | All Grades (%) | Grade 3 (%) | All Grades (%) | Grade 3 (%) |
|---|---|---|---|---|
| Diarrhea | 84 | 16 | 35 | 1.4 |
| Nausea | 54 | 1.4 | 39 | 0 |
| Stomatitis a | 39 | 4 | 4 | 0 |
| Abdominal pain a | 22 | 1.4 | 14 | 1.4 |
| Rash a | 68 | 6 | 14 | 0 |
| Alopecia | 19 | 0 | 1.4 | 0 |
| Fatigue a | 54 | 2.9 | 38 | 0 |
| Headache a | 30 | 0 | 15 | 0 |
| Cough a | 20 | 0 | 6 | 0 |
| Dyspnea | 16 | 0 | 6 | 0 |
| Upper respiratory tract | 17 | 0 | 2.8 | 0 |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedThe following serious adverse reactions are described elsewhere in the labeling: Diarrhea [ see Warnings and Precautions ( 5.1 )] Ovarian Toxicity [ see Warnings and Precautions ( 5.2 )] Hepatotoxicity [see Warnings and Precautions ( 5.3 )] Non-Melanoma Skin Cancers [see Warnings and Precautions ( 5.4 )] Electrolyte Abnormalities [ see Warnings and Precautions ( 5.5 )] Hypersensitivity Reactions [see Warnings and Precautions (5.6) ] The most common ( > 15 %) adverse reactions are diarrhea, ovarian toxicity, rash, nausea, fatigue, stomatitis, headache, abdominal pain, cough, alopecia, upper respiratory tract infection and dyspnea. ( 6.1 ) The most common laboratory abnormalities (≥15%) are decreased phosphate, increased urine glucose, increased urine protein, increased AST, increased ALT, and decreased potassium. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact SpringWorks Therapeutics Inc. at 1-888-400-7989 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. …
Source: FDA drug label, SpringWorks Therapeutics, Inc., effective September 1, 2026 (SPL set f172e6ff-3190-41b0-b95a-58a7ef9e9e1e), via openFDA; the full label on DailyMed
What do FAERS reports show?
838 reports list nirogacestat among the medicines taken, each a report of something that happened, not proof the medicine caused it; 8 are coded as a death and 113 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 20 reactions below, 10 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Nirogacestat: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions