What the label lists and what reports show
Nipocalimab side effects
Nipocalimab's FDA label: “The most common adverse reactions (≥10%) in patients with gMG treated with IMAAVY were respiratory tract infections, peripheral edema, and muscle spasms.” FAERS holds 227 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 headache (15 reports).
- No generic listed
Check it at the source: the nipocalimab FDA label on DailyMed (effective August 21, 2026); 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 IMAAVY?IMAAVY can cause serious side effects, including: Infections. IMAAVY may increase your risk of infections, including serious infections. If you have an infection, your healthcare provider will treat your infection or delay your infusion until your infection is gone. Tell your healthcare provider right away if you get any of the following symptoms of infection: fever chills shivering cough sore throat fever blisters burning when you urinate trouble breathing Allergic (hypersensitivity) reactions. Allergic reactions can happen during or up to a few weeks after your IMAAVY infusion. Tell your healthcare provider and get emergency medical help right away if you get any of these symptoms during or after your IMAAVY infusion: swelling of your face, lips, mouth, tongue, or throat trouble swallowing or breathing hives itchy rash chest pain or tightness Infusion-related reactions. […]
Source: FDA drug label, Janssen Biotech, Inc., effective August 21, 2026 (SPL set 8886274c-f2b2-48af-85c1-2f90bfe304b8), via openFDA; the full label on DailyMed
What does the label list?
From the label: adverse reactionsThe most common adverse reactions (≥10%) in patients with gMG treated with IMAAVY were respiratory tract infections, peripheral edema, and muscle spasms.
Table 3: Adverse Reactions (≥ 5%) of Patients Treated with IMAAVY and More Frequently than in Placebo in gMG Study 1
| Adverse Reaction | IMAAVY N=98 % | Placebo N=98 % |
|---|---|---|
| Respiratory tract infection COVID-19 (and other related terms), pneumonia, bronchitis,… | 18 | 13 |
| Urinary tract infection other related terms | 6 | 3 |
| Herpes zoster and Herpes simplex | 6 | 2 |
| Oral infection glossitis, oral candidiasis, pericoronitis, pulpitis dental, tooth… | 5 | 3 |
| Peripheral edema | 12 | 2 |
| Muscle spasm | 12 | 3 |
| Hypersensitivity reaction angioedema, dermatitis atopic, eczema, gingival swelling, rash… | 8 | 7 |
| Abdominal pain | 8 | 3 |
| Back pain | 8 | 5 |
| Pyrexia | 7 | 1 |
| Diarrhea | 7 | 3 |
| Cough | 7 | 3 |
| Anemia | 6 | 4 |
| Dizziness | 5 | 1 |
| Nausea | 5 | 2 |
| Hypertension | 5 | 2 |
| Insomnia | 5 | 2 |
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 clinically significant adverse reactions are described elsewhere in the labeling Infections [see Warnings and Precautions (5.1) ] Hypersensitivity Reactions [see Warnings and Precautions (5.2) ] Infusion-related Reactions [see Warnings and Precautions (5.3) ] The most common adverse reactions (≥10%) in patients with gMG treated with IMAAVY were respiratory tract infections, peripheral edema, and muscle spasms. ( 6.1 ) The most common adverse reactions (≥10%) in patients with wAIHA treated with IMAAVY were peripheral edema, diarrhea and pyrexia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Janssen Biotech, Inc. at 1-800-526-7736 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. Adults with gMG In gMG Study 1 and its extension study, the safety of IMAAVY was evaluated in 186 patients with gMG who received at least one dose of IMAAVY. Of those patients, 168 patients were exposed to IMAAVY every 2 weeks for at least 6 months, and 140 patients were exposed for at least 12 months. …
Source: FDA drug label, Janssen Biotech, Inc., effective August 21, 2026 (SPL set 8886274c-f2b2-48af-85c1-2f90bfe304b8), via openFDA; the full label on DailyMed
What do FAERS reports show?
227 reports list nipocalimab among the medicines taken, each a report of something that happened, not proof the medicine caused it; 2 are coded as a death and 41 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, 15 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.
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?
- Nipocalimab: 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