DANYELZA

1 INDICATIONS AND USAGE DANYELZA is indicated, in combination with granulocyte-macrophage colony-stimulating factor (GM-CSF), for the treatment of pediatric patients 1 year of age and older and adult patients with relapsed or refractory high-risk neuroblastoma in the bone or bone marrow who have demonstrated a partial response, minor response, or stable disease to prior therapy. This indication is approved under accelerated approval based on overall response rate and duration of response [see Clinical Studies (14) ] . Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial(s). DANYELZA is a GD2-binding monoclonal antibody indicated, in combination with granulocyte-macrophage colony-stimulating factor (GM-CSF), for the treatment of pediatric patients 1 year of age and older and adult patients with relapsed or refractory high-risk neuroblastoma in the bone or bone marrow who have demonstrated a partial response, minor response, or stable disease to prior therapy. This indication is approved under accelerated approval based on overall response rate and duration of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial(s). ( 1 )

2 DOSAGE AND ADMINISTRATION The recommended dosage of DANYELZA is 3 mg/kg/day (up to 150 mg/day), administered as an intravenous infusion after dilution on Days 1, 3, and 5 of each treatment cycle. Treatment cycles are repeated every 4 weeks until complete response or partial response, followed by 5 additional cycles every 4 weeks. Subsequent cycles may be repeated every 8 weeks. Discontinue DANYELZA and GM-CSF for disease progression or unacceptable toxicity. Administer GM-CSF subcutaneously prior to and during each treatment cycle as recommended. ( 2.1 ) 2.1 Recommended Dosage The recommended dosage of DANYELZA is 3 mg/kg/day (up to 150 mg/day) on Days 1, 3, and 5 of each treatment cycle, administered as an intravenous infusion after dilution [see Dosage and Administration (2.4 and 2.5) ] in combination with GM-CSF subcutaneously as shown in Table 1. Refer to the GM-CSF Prescribing Information for recommended dosing information. Treatment cycles are repeated every 4 weeks until complete response or partial response, followed by 5 additional cycles every 4 weeks. Subsequent cycles may be repeated every 8 weeks. Discontinue DANYELZA and GM-CSF for disease progression or unacceptable toxicity. Administer pre-infusion medications and supportive treatment, as appropriate, during infusion. [see Dosage and Administration (2.2) ] The recommended dosage regimen for each treatment cycle is described below and in Table 1: Days -4 to 0: administer GM-CSF 250 µg/m 2 /day by subcutaneous injection, beginning 5 days prior to DANYELZA infusion. Days 1 to 5: administer GM-CSF 500 µg/m 2 /day by subcutaneous injection. Administer at least 1 hour prior to DANYELZA administration on Days 1, 3, and 5. Days, 1, 3, and 5: administer DANYELZA 3 mg/kg/day (up to 150 mg/day) by intravenous infusion. Table 1 Dose and Schedule of GM-CSF and DANYELZA Within One Treatment Cycle Day -4 -3 -2 -1 0 1 2 3 4 5 Subcutaneous GM-CSF 250 µg/m 2 /day 500 µg/m 2 /day Intravenous DANYELZA 3 mg/kg/day 3 mg/kg/day 3 mg/kg/day Missed Dose If a DANYELZA dose is missed, administer the missed dose the following week by Day 10. Administer GM-CSF 500 µg /m 2 /day on the first day of the DANYELZA infusion, and on the day before and on the day of the second and third infusion, respectively (i.e. a total of 5 days with 500 µg /m 2 /day). 2.2 Premedications and Supportive Medications Pain Management Prior to and During Infusion [see Warnings and Precautions (5.2) ]: Five days prior to the first infusion of DANYELZA in each cycle, initiate a 12-day course (Day -4 through Day 7) of prophylactic medication for neuropathic pain, such as gabapentin. Administer oral opioids 45-60 minutes prior to initiation of each DANYELZA infusion and additional intravenous opioids as needed for breakthrough pain during the infusion. Consider use of ketamine for pain that is not adequately controlled by opioids. Premedication: Reduce Risk of Infusion-Related Reactions and Nausea/Vomiting [see Warnings and Precautions (5.1) and Adverse Reactions (6.1) ] . Administer intravenous corticosteroids (e.g. methylprednisolone 2 mg/kg with maximum dose of 80 mg or equivalent corticosteroid dose) 30 minutes to 2 hours prior to the first infusion of DANYELZA. Administer corticosteroid premedication for subsequent infusions if a severe infusion reaction occurred with the previous infusion or during the previous cycle. Administer an antihistamine, an H2 antagonist, acetaminophen and an antiemetic 30 minutes prior to each infusion. 2.3 Dosage Modifications for Adverse Reactions The recommended dosage modifications for DANYELZA for adverse reactions are presented in Table 2. Table 2. Recommended DANYELZA Dosage Modifications for Adverse Reactions Adverse Reaction Severity Based on Common Terminology Criteria for Adverse Events (CTCAE) v 5.0 Dosage Modifications Infusion-related reactions [see Warnings and Precautions (5.1) ] Grade 2 Defined as: Therapy or infusion interruption indicated but responds promptly to sy…

5 WARNINGS AND PRECAUTIONS Neurotoxicity: Peripheral neuropathy, neurological disorders of the eye, and prolonged urinary retention have also occurred. Permanently discontinue as recommended. ( 2.3 , 5.2 ) Myocarditis: Withhold, reduce dose, or discontinue based on severity. ( 2.3 , 5.3 ) Hypertension: Monitor blood pressure during and after infusion as recommended. Withhold, reduce infusion rate, or discontinue based on severity. ( 2.3 , 5.4 ) Orthostatic Hypotension: Severe orthostatic hypotension, including cases requiring hospitalization, have occurred. Withhold, reduce dose, or discontinue based on severity. ( 2.3 , 5.5 ) Embryo-Fetal Toxicity: May cause fetal harm. Advise females of reproductive potential of potential risk to a fetus and to use effective contraception. ( 5.6 ) 5.1 Serious Infusion-Related Reactions DANYELZA can cause serious infusion reactions requiring urgent intervention including fluid resuscitation, administration of bronchodilators and corticosteroids, intensive care unit admission, infusion rate reduction or interruption of DANYELZA infusion. Infusion-related reactions included hypotension, bronchospasm, hypoxia, and stridor [see Adverse Reactions (6.1) ]. Serious infusion-related reactions occurred in 4% of patients in Study 201 and in 18% of patients in Study 12-230. Infusion-related reactions of any Grade occurred in 100% of patients in Study 201 and 94% of patients in Study 12-230. Hypotension of any grade occurred in 100% of patients in Study 201 and 89% of patients in Study 12-230. In Study 201, 68% of patients experienced Grade 3 or 4 infusion reactions; and in Study 12-230, 32% of patients experienced Grade 3 or 4 infusion reactions. Anaphylaxis occurred in 12% of patients and 2 patients (8%) permanently discontinued DANYELZA due to anaphylaxis in Study 201. One patient in Study 12-230 (1.4%) experienced a Grade 4 cardiac arrest 1.5 hours following completion of DANYELZA infusion. In Study 201, infusion reactions generally occurred within 24 hours of completing a DANYELZA infusion, most often within 30 minutes of initiation. Infusion reactions were most frequent during the first infusion of DANYELZA in each cycle. Eighty percent of patients required reduction in infusion rate and 80% of patients had an infusion interrupted for at least one infusion-related reaction. Caution is advised in patients with pre-existing cardiac disease, as this may exacerbate the risk of severe hypotension. Premedicate with an antihistamine, acetaminophen, an H2 antagonist and corticosteroid as recommended [see Dosage and Administration (2.2) ]. Monitor patients closely for signs and symptoms of infusion reactions during and for at least 2 hours following completion of each DANYELZA infusion in a setting where cardiopulmonary resuscitation medication and equipment are available. Reduce the rate, interrupt infusion, or permanently discontinue DANYELZA based on severity and institute appropriate medical management as needed [see Dosage and Administration (2.3) and Contraindications (4) ]. 5.2 Neurotoxicity DANYELZA can cause severe neurotoxicity, including severe neuropathic pain, transverse myelitis, and reversible posterior leukoencephalopathy syndrome. Pain Pain, including abdominal pain, bone pain, neck pain, and extremity pain, occurred in 100% of patients in Study 201 and 94% of patients in Study 12-230. Grade 3 pain occurred in 72% of patients in Study 201. One patient in Study 201 (4%) required interruption of an infusion due to pain. Pain typically began during the infusion of DANYELZA and lasted a median of less than one day in Study 201 (range less than one day and up to 62 days) [see Adverse Reactions (6.1) ] . Premedicate with drugs that treat neuropathic pain (e.g., gabapentin) and oral opioids. Administer intravenous opioids as needed for breakthrough pain [see Dosage and Administration (2.2) ]. Permanently discontinue DANYELZA based on severity [see Dosage and Administration (2.3) ]. Transverse Myel…

4 CONTRAINDICATIONS DANYELZA is contraindicated in patients with a history of severe hypersensitivity reaction to naxitamab-gqgk. Reactions have included anaphylaxis [see Warnings and Precautions (5.1) ]. History of severe hypersensitivity reaction to naxitamab-gqgk. ( 4 )

8.1 Pregnancy Risk Summary Based on its mechanism of action, DANYELZA may cause fetal harm when administered to pregnant women [see Clinical Pharmacology (12.1) ]. There are no available data on the use of DANYELZA in pregnant women and no animal reproduction studies have been conducted with DANYELZA. IgG1 monoclonal antibodies are transported across the placenta in a linear fashion as pregnancy progresses, with the largest amount transferred during the third trimester. Advise pregnant women of potential risk to a fetus. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.

6 ADVERSE REACTIONS The following clinically significant adverse reactions are also described elsewhere in the labeling: Serious Infusion-Related Reactions [see Warnings and Precautions (5.1) ] Neurotoxicity [see Warnings and Precautions (5.2) ] Myocarditis [see Warnings and Precautions (5.3) ] Hypertension [see Warnings and Precautions (5.4) ] Orthostatic Hypotension [see Warnings and Precautions (5.5) ] The most common adverse reactions (≥25%) are infusion-related reaction, pain, tachycardia, vomiting, cough, nausea, diarrhea, decreased appetite, hypertension, fatigue, erythema multiforme, peripheral neuropathy, urticaria, pyrexia, headache, injection site reaction, edema, anxiety, localized edema, and irritability ( 6.1 ). The most common Grade 3 or 4 laboratory abnormalities (≥5%) are decreased lymphocytes, decreased neutrophils, decreased hemoglobin, decreased platelet count, decreased potassium, increased alanine aminotransferase, decreased glucose, decreased calcium, decreased albumin, decreased sodium, and decreased phosphate ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Y-mAbs Therapeutics, Inc, at 1-833-339-6227 (1-833-33YMABS), 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. The safety of DANYELZA in combination with GM-CSF was evaluated in patients with refractory or relapsed high-risk neuroblastoma in bone or bone marrow who had demonstrated a partial response, minor response, or stable disease following initial or subsequent therapy, and in patients who were in second complete remission, from two open-label, single arm studies, Study 201 (n=25) and Study 12-230 (n=72). Patients received DANYELZA 9 mg/kg/cycle administered as three separate intravenous infusions of 3 mg/kg (Day 1, 3 and 5) in the first week of each cycle. Patients also received GM-CSF 250 µg/m 2 /day subcutaneously on Days -4 to 0 and GM-CSF 500 µg/m 2 /day subcutaneously on Days 1 to 5 [see Clinical Studies (14) ]. The most common adverse reactions in Studies 201 and 12-230 (≥25% in either study) were infusion-related reaction, pain, tachycardia, vomiting, cough, nausea, diarrhea, decreased appetite, hypertension, fatigue, erythema multiforme, peripheral neuropathy, urticaria, pyrexia, headache, injection site reaction, edema, anxiety, localized edema and irritability. The most common Grade 3 or 4 laboratory abnormalities (≥5% in either study) were decreased lymphocytes, decreased neutrophils, decreased hemoglobin, decreased platelet count, decreased potassium, increased alanine aminotransferase, decreased glucose, decreased calcium, decreased albumin, decreased sodium and decreased phosphate. Study 201 In Study 201, among 25 patients who received DANYELZA in combination with GM-CSF, 12% were exposed for 6 months or longer and none were exposed for greater than one year. Serious adverse reactions occurred in 32% of patients who received DANYELZA in combination with GM-CSF. Serious adverse reactions in more than one patient included anaphylactic reaction (12%) and pain (8%). Permanent discontinuation of DANYELZA due to an adverse reaction occurred in 12% of patients. Adverse reactions resulting in permanent discontinuation of DANYELZA included anaphylactic reaction (8%) and respiratory depression (4%). Dosage interruptions of DANYELZA due to an adverse reaction occurred in 84% of patients. Adverse reactions requiring dosage interruption in > 10% of patients included hypotension and bronchospasm. Table 4 summarizes adverse reactions in Study 201. Table 4. Adverse Reactions (>10%) in Patients with Refractory or Relapsed High-Risk Neuroblastoma in Bone or Bone Marrow Who Received DANYELZA with GM-CSF in Study 201 DANYELZA with GM-CSF Adverse reactio…