Tisagenlecleucel side effects: what 4,557 FDA adverse event reports show

Tisagenlecleucel · Kymriah · 172 reaction terms · 12,654 drug–reaction co-reports · data 2026-09-14

Drug class

CD19-directed Chimeric Antigen Receptor, Genetically-modified Autologous T Cells

FDA label (Established Pharmacologic Class)

Brand names

Kymriah

openFDA label

Who reports

4,557 reports · 94% serious · 1,317 with death outcome · 38% female

openFDA FAERS counts, all years, deduplication not applied

Used for

KYMRIAH is a CD19-directed genetically modified autologous T cell immunotherapy indicated for the treatment of: Patients up to 25 years of age with B-cell precursor acute lymphoblastic leukemia (ALL) that is refractory or in second or later relapse. ( .

FDA label, Indications and Usage

What it is

KYMRIAH (tisagenlecleucel) is a CD19-directed genetically modified autologous T cell immunotherapy comprised of autologous T cells that are genetically modified using a lentiviral vector to encode an anti-CD19 chimeric antigen receptor (CAR).

FDA label, Description section

Boxed warning

CYTOKINE RELEASE SYNDROME, NEUROLOGICAL TOXICITIES, and SECONDARY HEMATOLOGICAL MALIGNANCIES Cytokine Release Syndrome (CRS), including fatal or life-threatening reactions, occurred in patients receiving KYMRIAH. Do not administer KYMRIAH to patients with active infection or inflammatory disorders.

FDA label

How to read this page. FAERS is a spontaneous-reporting system: counts are not incidence rates and a signal is not proof of causation. Each reaction below is run through an automated screen — is the term in the FDA label (known), in the indications (the disease being treated), an administrative/coding term, or none of these (unlabeled)? That screen is mechanical text matching, not a causality assessment. The 30 hand-written Bradford Hill assessments are on the causality assessment page. Not medical advice.

Causality screen of the 40 strongest signals

Labeled — boxed warning 5Labeled adverse reaction 11Labeled (related wording) 6Reporting / coding artifact 2Lab value / disease marker 4Not in label — unassessed 12

What the badges mean

Labeled — boxed warning The term (or its clinical synonym) appears in the FDA boxed warning: causality is regulator-recognised and considered serious.
Labeled adverse reaction The exact term appears in the label's warnings or adverse-reactions sections: a known, expected effect. The FAERS signal confirms the label rather than discovering anything.
Labeled (related wording) The label describes this effect under different wording (e.g. 'neutropenia' for 'neutrophil count decreased'). Treated as known.
Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
Lab value / disease marker A laboratory result, investigation or disease-activity marker (antibody positive, CRP abnormal, swollen joint count) not described in the label. These usually mirror the monitored disease or testing protocol rather than a drug effect; not screened further.
Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.

Strongest disproportionality signals

Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only and flags pairs whose reports are unusually skewed by sex or come mostly from consumers rather than clinicians. 132 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.

Show: hide coding/lab/outcome terms hide indication terms unlabeled only hide PRR-only

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Cytokine release syndrome	1,757	467.9 449.7–486.8ROR 760.9 · χ² 742,377 / p <1e-300	422.3 EB05 406.0 · IC025 +8.5 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 262.0 · 92% clinician	no trial data cached
Neurotoxicity	426	115.7 105.5–126.8ROR 127.5 · χ² 47,145 / p <1e-300	112.2 EB05 103.6 · IC025 +6.5 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 69.8	no trial data cached
Lymphocyte count decreased	372	98.9 89.6–109.1ROR 107.6 · χ² 35,202 / p <1e-300	96.3 EB05 88.4 · IC025 +6.3 3/3 methods agree	Lab value / disease marker	serious PRR 71.6 · 92% clinician	no trial data cached
Cytopenia	230	90.3 79.5–102.5ROR 95.0 · χ² 19,838 / p <1e-300	87.9 EB05 78.8 · IC025 +6.0 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 56.2	no trial data cached
Haematocrit decreased	270	63.1 56.1–70.9ROR 67.0 · χ² 16,225 / p <1e-300	62.0 EB05 56.0 · IC025 +5.6 3/3 methods agree	Lab value / disease marker	serious PRR 42.7	no trial data cached
Neutrophil count decreased	372	42.6 38.7–47.0ROR 46.3 · χ² 14,974 / p <1e-300	42.2 EB05 38.7 · IC025 +5.2 3/3 methods agree	Labeled — boxed warning synonym match	serious PRR 29.6 · 91% clinician	no trial data cached
Hypoxia (low oxygen)	236	31.2 27.5–35.3ROR 32.8 · χ² 6,826 / p <1e-300	30.9 EB05 27.7 · IC025 +4.6 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 19.3 · 92% clinician	no trial data cached
Myelodysplastic syndrome	88	28.1 22.9–34.6ROR 28.7 · χ² 2,264 / p <1e-300	27.8 EB05 23.3 · IC025 +4.2 3/3 methods agree	Not in label — unassessed	serious PRR 17.3 · 93% clinician	no trial data cached
Malignant neoplasm progression	607	27.6 25.6–29.7ROR 31.7 · χ² 15,504 / p <1e-300	27.4 EB05 25.6 · IC025 +4.6 3/3 methods agree	Reporting / coding artifact	serious PRR 17.2 · 92% clinician	no trial data cached
Disseminated intravascular coagulation	65	21.3 16.7–27.1ROR 21.6 · χ² 1,231 / p 6e-270	21.1 EB05 17.1 · IC025 +3.8 3/3 methods agree	Not in label — unassessed	serious PRR 13.0	no trial data cached
Coagulopathy	73	20.3 16.2–25.5ROR 20.6 · χ² 1,315 / p 2e-288	20.1 EB05 16.5 · IC025 +3.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 13.0 · 92% clinician	no trial data cached
Platelet count decreased	417	18.1 16.5–19.8ROR 19.8 · χ² 6,720 / p <1e-300	18.0 EB05 16.6 · IC025 +4.0 3/3 methods agree	Labeled (related wording) related wording	serious PRR 13.6 · 91% clinician	no trial data cached
Encephalopathy	94	17.7 14.5–21.7ROR 18.1 · χ² 1,463 / p <1e-300	17.6 EB05 14.8 · IC025 +3.7 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 10.9 · 91% clinician	no trial data cached
Multiple organ dysfunction syndrome	105	17.4 14.4–21.0ROR 17.8 · χ² 1,600 / p <1e-300	17.3 EB05 14.7 · IC025 +3.7 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 10.5 · 91% clinician	no trial data cached
White blood cell count decreased	403	17.2 15.6–18.8ROR 18.7 · χ² 6,122 / p <1e-300	17.1 EB05 15.7 · IC025 +3.9 3/3 methods agree	Labeled (related wording) related wording	serious PRR 14.7 · 92% clinician	no trial data cached
Haemoglobin decreased	369	16.6 15.0–18.3ROR 17.9 · χ² 5,385 / p <1e-300	16.5 EB05 15.1 · IC025 +3.8 3/3 methods agree	Labeled (related wording) related wording	serious PRR 11.4 · 91% clinician	no trial data cached
Tachypnoea	46	15.7 11.8–20.9ROR 15.8 · χ² 616 / p 3e-136	15.5 EB05 12.0 · IC025 +3.3 3/3 methods agree	Not in label — unassessed	serious PRR 9.9 · 91% clinician	no trial data cached
Acute myeloid leukaemia	52	15.4 11.8–20.2ROR 15.6 · χ² 685 / p 3e-151	15.2 EB05 12.0 · IC025 +3.3 3/3 methods agree	Labeled (related wording) related wording	serious PRR 9.5 · 94% clinician	no trial data cached
Blood lactate dehydrogenase increased	50	14.5 11.0–19.1ROR 14.6 · χ² 612 / p 2e-135	14.3 EB05 11.1 · IC025 +3.2 3/3 methods agree	Lab value / disease marker	serious PRR 9.1 · 92% clinician	no trial data cached
Pyrexia (fever)	1,043	13.9 13.2–14.7ROR 17.7 · χ² 12,646 / p <1e-300	13.9 EB05 13.2 · IC025 +3.7 3/3 methods agree	Labeled (related wording) related wording	serious PRR 10.2	no trial data cached
Bone marrow failure	60	13.5 10.5–17.4ROR 13.7 · χ² 682 / p 1e-150	13.3 EB05 10.6 · IC025 +3.2 3/3 methods agree	Labeled (related wording) related wording	serious PRR 8.3	no trial data cached
Clostridium difficile colitis	28	12.2 8.4–17.6ROR 12.2 · χ² 275 / p 4e-62	11.6 EB05 8.1 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious PRR 7.6 · 93% clinician	no trial data cached
Bacteraemia	31	12.1 8.5–17.3ROR 12.2 · χ² 305 / p 1e-68	11.6 EB05 8.3 · IC025 +2.8 3/3 methods agree	Not in label — unassessed	serious PRR 7.5	no trial data cached
Lymphopenia	36	11.8 8.5–16.3ROR 11.9 · χ² 345 / p 3e-77	11.3 EB05 8.3 · IC025 +2.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 7.8 · 97% clinician	no trial data cached
Aphasia (loss of speech)	77	11.7 9.4–14.6ROR 11.9 · χ² 744 / p 4e-164	11.5 EB05 9.4 · IC025 +3.1 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 8.4 · 91% clinician	no trial data cached
Febrile neutropenia	167	11.6 10.0–13.5ROR 12.0 · χ² 1,613 / p <1e-300	11.5 EB05 10.1 · IC025 +3.2 3/3 methods agree	Labeled — boxed warning synonym match	serious PRR 7.1 · 98% clinician	no trial data cached
C-reactive protein increased	88	11.2 9.1–13.7ROR 11.4 · χ² 803 / p 6e-177	11.0 EB05 9.1 · IC025 +3.0 3/3 methods agree	Lab value / disease marker	serious PRR 7.0 · 98% clinician	no trial data cached
Brain oedema	30	11.0 7.7–15.7ROR 11.0 · χ² 261 / p 5e-59	10.3 EB05 7.3 · IC025 +2.6 3/3 methods agree	Not in label — unassessed	serious PRR 6.8	no trial data cached
Motor dysfunction	24	10.9 7.3–16.3ROR 11.0 · χ² 207 / p 4e-47	10.1 EB05 6.8 · IC025 +2.5 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 8.4 · 92% clinician	no trial data cached
Cytomegalovirus infection	39	10.8 7.9–14.8ROR 10.9 · χ² 337 / p 1e-75	10.3 EB05 7.7 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious PRR 6.7 · 92% clinician	no trial data cached
Candida infection (yeast infection)	39	10.8 7.9–14.7ROR 10.9 · χ² 336 / p 3e-75	10.3 EB05 7.7 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious PRR 9.5 · 95% clinician	no trial data cached
Hypotension (low blood pressure)	446	10.3 9.4–11.2ROR 11.3 · χ² 3,749 / p <1e-300	10.2 EB05 9.4 · IC025 +3.2 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 7.3 · 91% clinician	no trial data cached
Nephropathy toxic	24	9.9 6.7–14.8ROR 10.0 · χ² 184 / p 4e-42	9.1 EB05 6.2 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious PRR 5.7 · ♀ 0% (drug 38%) · 92% clinician	no trial data cached
Depressed level of consciousness	85	9.9 8.0–12.3ROR 10.1 · χ² 673 / p 1e-148	9.7 EB05 8.0 · IC025 +2.9 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 6.2	no trial data cached
Staphylococcal infection	67	9.3 7.4–11.8ROR 9.5 · χ² 490 / p 8e-109	9.0 EB05 7.3 · IC025 +2.7 3/3 methods agree	Not in label — unassessed	serious PRR 6.3	no trial data cached
Disease progression	225	8.8 7.7–10.0ROR 9.2 · χ² 1,552 / p <1e-300	8.7 EB05 7.8 · IC025 +2.9 3/3 methods agree	Reporting / coding artifact	serious PRR 6.1 · 95% clinician	no trial data cached
Atelectasis	18	8.6 5.4–13.6ROR 8.6 · χ² 112 / p 1e-26	7.4 EB05 4.8 · IC025 +2.0 3/3 methods agree	Not in label — unassessed	serious PRR 5.3	no trial data cached
Thrombocytopenia (low platelets)	203	8.4 7.3–9.6ROR 8.7 · χ² 1,319 / p 5e-289	8.3 EB05 7.4 · IC025 +2.8 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 5.3 · 91% clinician	no trial data cached
Clostridium difficile infection	39	8.3 6.1–11.3ROR 8.4 · χ² 243 / p 5e-55	7.7 EB05 5.8 · IC025 +2.4 3/3 methods agree	Not in label — unassessed	serious PRR 5.3	no trial data cached
Lymphoma	27	8.0 5.5–11.7ROR 8.1 · χ² 159 / p 9e-37	7.3 EB05 5.2 · IC025 +2.2 3/3 methods agree	Labeled — boxed warning synonym match	serious PRR 5.0	no trial data cached

Trial evidence (ClinicalTrials.gov)

Trial cross-check not yet run for this drug (ClinicalTrials.gov pull covers the 800 most-reported drugs first).

Most frequently reported reactions

By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.

Reaction	Reports	PRR 95% CI · ROR · χ²/p	EBGM EB05 · IC025	Label screen	Serious-only & strata	Trial cross-check
Cytokine release syndrome	1,757	467.9 449.7–486.8ROR 760.9 · χ² 742,377 / p <1e-300	422.3 EB05 406.0 · IC025 +8.5 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 262.0 · 92% clinician	no trial data cached
Pyrexia (fever)	1,043	13.9 13.2–14.7ROR 17.7 · χ² 12,646 / p <1e-300	13.9 EB05 13.2 · IC025 +3.7 3/3 methods agree	Labeled (related wording) related wording	serious PRR 10.2	no trial data cached
Malignant neoplasm progression	607	27.6 25.6–29.7ROR 31.7 · χ² 15,504 / p <1e-300	27.4 EB05 25.6 · IC025 +4.6 3/3 methods agree	Reporting / coding artifact	serious PRR 17.2 · 92% clinician	no trial data cached
Hypotension (low blood pressure)	446	10.3 9.4–11.2ROR 11.3 · χ² 3,749 / p <1e-300	10.2 EB05 9.4 · IC025 +3.2 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 7.3 · 91% clinician	no trial data cached
Neurotoxicity	426	115.7 105.5–126.8ROR 127.5 · χ² 47,145 / p <1e-300	112.2 EB05 103.6 · IC025 +6.5 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 69.8	no trial data cached
Platelet count decreased	417	18.1 16.5–19.8ROR 19.8 · χ² 6,720 / p <1e-300	18.0 EB05 16.6 · IC025 +4.0 3/3 methods agree	Labeled (related wording) related wording	serious PRR 13.6 · 91% clinician	no trial data cached
White blood cell count decreased	403	17.2 15.6–18.8ROR 18.7 · χ² 6,122 / p <1e-300	17.1 EB05 15.7 · IC025 +3.9 3/3 methods agree	Labeled (related wording) related wording	serious PRR 14.7 · 92% clinician	no trial data cached
Neutrophil count decreased	372	42.6 38.7–47.0ROR 46.3 · χ² 14,974 / p <1e-300	42.2 EB05 38.7 · IC025 +5.2 3/3 methods agree	Labeled — boxed warning synonym match	serious PRR 29.6 · 91% clinician	no trial data cached
Lymphocyte count decreased	372	98.9 89.6–109.1ROR 107.6 · χ² 35,202 / p <1e-300	96.3 EB05 88.4 · IC025 +6.3 3/3 methods agree	Lab value / disease marker	serious PRR 71.6 · 92% clinician	no trial data cached
Haemoglobin decreased	369	16.6 15.0–18.3ROR 17.9 · χ² 5,385 / p <1e-300	16.5 EB05 15.1 · IC025 +3.8 3/3 methods agree	Labeled (related wording) related wording	serious PRR 11.4 · 91% clinician	no trial data cached
Death	295	1.6 1.4–1.8ROR 1.6 · χ² 64 / p 6e-16	1.6 EB05 1.4 · IC025 +0.5	Outcome field, not a reaction boxed warning mentions mortality	serious PRR 1.0	no trial data cached
Haematocrit decreased	270	63.1 56.1–70.9ROR 67.0 · χ² 16,225 / p <1e-300	62.0 EB05 56.0 · IC025 +5.6 3/3 methods agree	Lab value / disease marker	serious PRR 42.7	no trial data cached
Hypoxia (low oxygen)	236	31.2 27.5–35.3ROR 32.8 · χ² 6,826 / p <1e-300	30.9 EB05 27.7 · IC025 +4.6 3/3 methods agree	Labeled adverse reaction exact term	serious PRR 19.3 · 92% clinician	no trial data cached
Cytopenia	230	90.3 79.5–102.5ROR 95.0 · χ² 19,838 / p <1e-300	87.9 EB05 78.8 · IC025 +6.0 3/3 methods agree	Labeled — boxed warning exact term	serious PRR 56.2	no trial data cached
Disease progression	225	8.8 7.7–10.0ROR 9.2 · χ² 1,552 / p <1e-300	8.7 EB05 7.8 · IC025 +2.9 3/3 methods agree	Reporting / coding artifact	serious PRR 6.1 · 95% clinician	no trial data cached

Unlabeled candidate signals

These flagged terms were not found in the FDA label text and do not match an artifact pattern. They are the pairs that would merit a structured assessment (temporality, dose-response, biological plausibility, consistency across databases, trial or cohort evidence). The screen has not done that; string-matching misses label wording, and a strong PRR can still be stimulated reporting, co-medication, or the disease itself.

Myelodysplastic syndrome — n=88, PRR 28.1
Disseminated intravascular coagulation — n=65, PRR 21.3
Tachypnoea — n=46, PRR 15.7
Clostridium difficile colitis — n=28, PRR 12.2
Bacteraemia — n=31, PRR 12.1
Brain oedema — n=30, PRR 11.0
Cytomegalovirus infection — n=39, PRR 10.8
Candida infection — n=39, PRR 10.8
Nephropathy toxic — n=24, PRR 9.9
Staphylococcal infection — n=67, PRR 9.3

Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.

Common questions

What are the most reported side effects of Tisagenlecleucel?

In FDA FAERS, the most frequently co-reported reaction terms for Tisagenlecleucel are cytokine release syndrome, pyrexia, hypotension, neurotoxicity, platelet count decreased, white blood cell count decreased. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.

Does Tisagenlecleucel have an FDA boxed warning?

Yes. The current FDA label carries a boxed warning: CYTOKINE RELEASE SYNDROME, NEUROLOGICAL TOXICITIES, and SECONDARY HEMATOLOGICAL MALIGNANCIES Cytokine Release Syndrome (CRS), including fatal or life-threatening reactions, occurred in patients receiving KYMRIAH. Do not administer KYMRIAH to patients with active infection or inflammatory disorders.

Do FAERS signals prove that Tisagenlecleucel causes these side effects?

No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.

Sources & methods

FDA label via openFDA (set ID aad3ba54-dfd3-4cb3-9e2b-c5ef89559189, effective 20251216; matched on openfda.generic_name.exact:"TISAGENLECLEUCEL")
Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA count= aggregation, field patient.drug.openfda.generic_name.exact, 172 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction
Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
Seriousness and sex counts from openFDA count=serious, patient.patientsex, seriousnessdeath

Page generated 2026-10-08. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.