IMPORTANT SAFETY INFORMATION
Severe and Fatal Immune-Mediated Adverse Reactions
Important immune-mediated adverse reactions listed may not be inclusive of all possible severe and fatal
Immune-mediated adverse reactions, which may be severe or fatal, can occur in any organ system or
tissue, can occur at any time after starting or discontinuing treatment with a PD-1/PD-L1–blocking
antibody, and can affect more than one body system simultaneously.
Monitor patients closely for symptoms and signs that may be clinical manifestations of such reactions.
Early identification and management of immune‐mediated adverse reactions are essential to ensure safe
use of PD-1/PD-L1–blocking antibodies. Evaluate liver enzymes, creatinine, and thyroid function at
baseline and periodically during treatment. If suspected, initiate appropriate workup to exclude alternative
etiologies, including infection. Institute medical management promptly, including specialty consultation
Withhold or permanently discontinue ZYNYZ depending on severity. In general, if ZYNYZ requires
interruption or discontinuation, administer systemic corticosteroid therapy (1-2 mg/kg/day prednisone or
equivalent) until improvement to ≤ Grade 1. Then, initiate corticosteroid taper and continue to taper over
at least 1 month. Consider administration of other systemic immunosuppressants in patients whose
adverse reactions are not controlled with corticosteroids.
ZYNYZ can cause immune-mediated pneumonitis. Immune-mediated pneumonitis occurred in 3%
(13/440) of patients, including fatal (0.2%), Grade 3 (0.9%), and Grade 2 (1.4%) reactions. Pneumonitis
led to permanent discontinuation of ZYNYZ in 1 patient and withholding in 0.9%.
Systemic corticosteroids were required in 77% (10/13) of patients. Pneumonitis resolved in 10 of the 13
ZYNYZ can cause immune-mediated colitis. Cytomegalovirus infections/reactivations have occurred in
patients with corticosteroid-refractory immune-mediated colitis treated with PD-1/PD-L1–blocking
antibodies. In cases of corticosteroid-refractory colitis, consider repeating infectious workup to exclude
Immune-mediated colitis occurred in 1.6% (7/440) of patients, including Grade 4 (0.2%), Grade 3 (0.2%),
and Grade 2 (0.7%). Colitis led to permanent discontinuation of ZYNYZ in 1 patient and withholding in
Systemic corticosteroids were required in 71% (5/7) of patients. Colitis resolved in 4/7 patients.
ZYNYZ can cause immune-mediated hepatitis. Immune-mediated hepatitis occurred in 3% (13/440) of
patients, including Grade 4 (0.2%), Grade 3 (2.3%), and Grade 2 (0.5%). Hepatitis led to permanent
discontinuation of ZYNYZ in 1.4% of patients and withholding in 0.9%.
Systemic corticosteroids were required in 85% (11/13) of patients. Hepatitis resolved in 6/13 patients.
ZYNYZ can cause primary or secondary adrenal insufficiency. For ≥ Grade 2 adrenal insufficiency,
initiate symptomatic treatment per institutional guidelines, including hormone replacement as clinically
indicated. Withhold or permanently discontinue ZYNYZ depending on severity.
Adrenal insufficiency occurred in 0.7% (3/440) of patients, including Grade 3 (0.5%) and Grade 2 (0.2%).
ZYNYZ was permanently discontinued in no patients and was withheld for 1 patient with adrenal
All patients required systemic corticosteroids. Adrenal insufficiency resolved in 1 of the 3 patients.
ZYNYZ can cause immune-mediated hypophysitis. Hypophysitis can present with acute symptoms
associated with mass effect such as headache, photophobia, or visual field cuts, and can cause
hypopituitarism. Initiate hormone replacement as clinically indicated. Withhold or permanently
discontinue ZYNYZ depending on severity.
Hypophysitis occurred in 0.5% (2/440, both Grade 2) of patients. No patients discontinued or withheld
ZYNYZ due to hypophysitis.
All patients required systemic steroids. Hypophysitis resolved in 1 of the 2 patients.
ZYNYZ can cause immune-mediated thyroid disorders. Thyroiditis can present with or without
endocrinopathy. Hypothyroidism can follow hyperthyroidism. Initiate hormone replacement or medical
management of hyperthyroidism as clinically indicated. Withhold or permanently discontinue ZYNYZ
depending on severity.
Thyroiditis occurred in 0.7% (3/440, all Grade 1) of patients. No patients discontinued or withheld
ZYNYZ due to thyroiditis. Thyroiditis resolved in 1 of the 3 patients.
Hypothyroidism occurred in 10% (42/440) of patients receiving ZYNYZ, including Grade 2 (4.8%). No
patients discontinued due to hypothyroidism. ZYNYZ was withheld in 0.5% of patients.
Systemic corticosteroids were required for 1 patient, and 79% (33/42) of patients received endocrine
Hyperthyroidism occurred in 6% (24/440) of patients receiving ZYNYZ, including Grade 2 (2.5%).
ZYNYZ was not discontinued in any patient and was withheld in 1 patient. Systemic corticosteroids were
required for 13% (3/24) of patients, and 46% (11/24) of patients received endocrine therapy.
Type 1 Diabetes Mellitus, Which Can Present with Diabetic Ketoacidosis
Monitor patients for hyperglycemia or other signs and symptoms of diabetes. Initiate treatment with
insulin as clinically indicated. Withhold ZYNYZ depending on severity.
Type 1 diabetes mellitus occurred in 0.2% (1/440) of patients, including Grade 3 (0.2%) adverse
Immune-Mediated Nephritis with Renal Dysfunction
ZYNYZ can cause immune-mediated nephritis. Immune-mediated nephritis occurred in 1.6% (7/440) of
patients receiving ZYNYZ, including Grade 4 (0.5%), Grade 3 (0.7%), and Grade 2 (0.5%). Nephritis led
to permanent discontinuation of ZYNYZ in 0.9% of patients and withholding in 1 patient.
Systemic corticosteroids were required in 57% (4/7) of patients. Nephritis resolved in 3/7 patients.
Immune-Mediated Dermatologic Adverse Reactions
ZYNYZ can cause immune-mediated rash or dermatitis. Bullous and exfoliative dermatitis, including
Stevens-Johnson syndrome, drug rash with eosinophilia and systemic symptoms, and toxic epidermal
necrolysis, has occurred with PD-1/PD-L1–blocking antibodies. Topical emollients and/or topical
corticosteroids may be adequate to treat mild to moderate non-exfoliative rashes. Withhold or
permanently discontinue ZYNYZ depending on severity.
Immune-mediated skin reactions occurred in 8% (36/440) of patients, including Grade 3 (1.1%) and
Grade 2 (7%). Immune-mediated dermatologic adverse reactions led to permanent discontinuation of
ZYNYZ in 1 patient and withholding in 2.3% of patients.
Systemic corticosteroids were required in 25% (9/36) of patients. Immune-mediated dermatologic adverse
reactions resolved in 75% (27/36) of patients.
Other Immune-Mediated Adverse Reactions
The following clinically significant immune-mediated adverse reactions occurred at an incidence of < 1%
in 440 patients who received ZYNYZ or were reported with the use of other PD-1/PD-L1–blocking
antibodies, including severe or fatal cases.
Cardiac/vascular: myocarditis, pericarditis, vasculitis
Gastrointestinal: pancreatitis, to include increases in serum amylase and lipase levels, gastritis, duodenitis
Musculoskeletal: myositis/polymyositis, rhabdomyolysis (and associated sequelae, including renal
failure), arthritis, polymyalgia rheumatica
Neurological: meningitis, encephalitis, myelitis and demyelination, myasthenic syndrome/myasthenia
gravis (including exacerbation), Guillain-Barré syndrome, nerve paresis, autoimmune neuropathy
Ocular: uveitis, iritis, and other ocular inflammatory toxicities. Some cases can be associated with retinal
detachment. Various grades of visual impairment to include blindness can occur. If uveitis occurs in
combination with other immune-mediated adverse reactions, consider a Vogt-Koyanagi-Harada–like
syndrome, as this may require treatment with systemic steroids to reduce the risk of permanent vision
Other (Hematologic/Immune): hemolytic anemia, aplastic anemia, hemophagocytic lymphohistiocytosis,
systemic inflammatory response syndrome, histiocytic necrotizing lymphadenitis (Kikuchi
lymphadenitis), sarcoidosis, immune thrombocytopenic purpura, solid organ transplant rejection.
A severe infusion-related reaction (Grade 3) occurred in 1 (0.2%) of 440 patients. Monitor patients for
signs and symptoms; interrupt or slow the rate of infusion or permanently discontinue ZYNYZ based on
severity of reaction. Consider premedication with an antipyretic and/or an antihistamine for patients who
have had previous systemic reactions to infusions of therapeutic proteins.
Complications of Allogeneic HSCT
Fatal and other serious complications can occur in patients who receive allogeneic hematopoietic stem
cell transplantation (HSCT) before or after being treated with a PD-1/PD-L1–blocking antibody.
Transplant-related complications include hyperacute graft-versus-host disease (GVHD), acute GVHD,
chronic GVHD, hepatic veno-occlusive disease after reduced intensity conditioning, and steroid-requiring
febrile syndrome (without an identified infectious cause), which may occur despite intervening therapy
between PD-1/PD-L1 blockade and allogeneic HSCT.
Follow patients closely for evidence of transplant-related complications and intervene promptly. Consider
the benefit versus risks of treatment with a PD-1/PD-L1–blocking antibody prior to or after an allogeneic
ZYNYZ can cause fetal harm when administered to a pregnant woman. Animal studies have
demonstrated that inhibition of the PD-1/PD-L1 pathway can lead to increased risk of immune-mediated
rejection of the developing fetus, resulting in fetal death. Advise women of the potential risk to a fetus.
Advise females of reproductive potential to use effective contraception during treatment and for 4 months
after the last dose.
Because of the potential for serious adverse reactions in breastfed children, advise women not to
breastfeed during treatment and for 4 months after the last dose.
The safety of ZYNYZ was evaluated in 105 patients with metastatic or recurrent locally advanced MCC.
Serious adverse reactions occurred in 22% of patients receiving ZYNYZ. The most frequent serious
adverse reactions (≥ 2% of patients) were fatigue, arrhythmia, and pneumonitis.
Permanent discontinuation of ZYNYZ due to an adverse reaction occurred in 11% of patients. These
included asthenia, atrial fibrillation, concomitant disease progression of chronic lymphocytic leukemia,
demyelinating polyneuropathy, eosinophilic fasciitis, increased transaminases, infusion-related reaction,
lung disorder, pancreatitis, polyarthritis, and radiculopathy (1 patient each).
Dosage interruptions due to an adverse reaction occurred in 25% of patients. Adverse reactions or
laboratory abnormalities that required dosage interruption in ≥ 2% of patients were increased
transaminases, increased lipase, increased amylase, pneumonitis, and pyrexia.
The most common (≥ 10%) adverse reactions were fatigue, musculoskeletal pain, pruritus, diarrhea, rash,
pyrexia, and nausea.