Zanidatamab

1 INDICATIONS AND USAGE ZIIHERA is a bispecific HER2-directed antibody indicated for: Gastroesophageal Adenocarcinoma (GEA) • in combination with fluoropyrimidine- and platinum-containing chemotherapy, and tislelizumab-jsgr, as first-line treatment of adult patients with HER2-positive (IHC 3+ or IHC 2+/ISH+) unresectable locally advanced or metastatic gastric, gastroesophageal junction, or esophageal adenocarcinoma, as detected by an FDA-authorized test. ( 1.1 ) • in combination with fluoropyrimidine- and platinum-containing chemotherapy, as first-line treatment of adult patients with HER2-positive (IHC 3+) unresectable locally advanced or metastatic gastric, gastroesophageal junction, or esophageal adenocarcinoma, as detected by an FDA-authorized test. ( 1.1 ) Biliary Tract Cancer (BTC) • for the treatment of adults with previously treated, unresectable or metastatic HER2-positive (IHC 3+) BTC, as detected by an FDA-authorized test.* ( 1.2 ) *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 ) 1.1 Gastroesophageal Adenocarcinoma (GEA) • ZIIHERA, in combination with fluoropyrimidine- and platinum-containing chemotherapy and tislelizumab-jsgr, is indicated for the first-line treatment of adult patients with HER2-positive (IHC 3+ or IHC 2+/ISH+) unresectable locally advanced or metastatic gastric, gastroesophageal junction, or esophageal adenocarcinoma, as detected by an FDA-authorized test [see Dosage and Administration ( 2.1 )] . • ZIIHERA, in combination with fluoropyrimidine- and platinum-containing chemotherapy, is indicated for the first-line treatment of adult patients with HER2-positive (IHC 3+) unresectable locally advanced or metastatic gastric, gastroesophageal junction, or esophageal adenocarcinoma, as detected by an FDA-authorized test [see Dosage and Administration ( 2.1 )] . 1.2 Biliary Tract Cancer (BTC) ZIIHERA, as a single agent, is indicated for the treatment of adults with previously treated, unresectable or metastatic HER2-positive (IHC 3+) biliary tract cancer (BTC), as detected by an FDA-authorized test [see Dosage and Administration ( 2.1 )] . This indication is approved under accelerated approval based on overall response rate and duration of response [see Clinical Studies ( 14.2 )] . Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial(s).

12.1 Mechanism of Action Zanidatamab-hrii is a bispecific HER2-directed antibody that binds to extracellular domains 2 (ECD2) and 4 (ECD4) on HER2. Similar to other HER2-directed antibodies, in vitro binding of zanidatamab-hrii with HER2 causes clustering and results in internalization leading to a reduction of the receptor on the tumor cell surface. Zanidatamab-hrii induces complement-dependent cytotoxicity (CDC), antibody-dependent cellular cytotoxicity (ADCC), and antibody-dependent cellular phagocytosis (ADCP). These mechanisms result in tumor growth inhibition and cell death in vitro and in vivo.

2 DOSAGE AND ADMINISTRATION • Premedicate all patients to reduce the risk of infusion-related reactions (IRRs). ( 2.2 ) • Administer loperamide during the first cycle to patients receiving ZIIHERA in combination with fluoropyrimidine- and platinum-containing chemotherapy for diarrhea prophylaxis. ( 2.2 ) Gastroesophageal Adenocarcinoma (GEA): • Patients weighing less than 70 kg: ZIIHERA 1,800 mg intravenously every 3 weeks or 1,200 mg every 2 weeks infusion in combination with fluoropyrimidine- and platinum-containing chemotherapy, with or without tislelizumab-jsgr. ( 2.3 ) • Patients weighing 70 kg or greater: ZIIHERA 2,400 mg intravenously every 3 weeks or 1,600 mg every 2 weeks in combination with fluoropyrimidine- and platinum-containing chemotherapy, with or without tislelizumab-jsgr. ( 2.3 ) Biliary Tract Cancer: ZIIHERA 20 mg/kg intravenously every 2 weeks. ( 2.3 ) 2.1 Patient Selection HER2-Positive Gastroesophageal Adenocarcinoma (GEA) Select patients for treatment of unresectable locally advanced or metastatic GEA based on HER2-positive status (IHC 3+ or IHC 2+/ISH+), as detected by FDA-authorized tests [see Clinical Studies ( 14.1 )] . Information on FDA-authorized tests for HER2 protein expression and gene amplification in gastric, gastroesophageal junction, or esophageal adenocarcinoma is available at: http://www.fda.gov/CompanionDiagnostics . Biliary Tract Cancer (BTC) Select patients for treatment of unresectable or metastatic biliary tract cancer based on HER2-positive (IHC 3+) tumor specimens, as detected by an FDA-authorized test [see Clinical Studies ( 14.2 )] . Information on FDA-authorized tests for HER2 protein expression in biliary tract cancers is available at: http://www.fda.gov/CompanionDiagnostics. 2.2 Premedications and Important Administration Information Premedicate all patients 30 to 60 minutes prior to each dose of ZIIHERA to reduce the risk of infusion-related reactions [see Warnings and Precautions ( 5.4) ] : • Administer acetaminophen, an antihistamine (such as diphenhydramine) and a corticosteroid (such as hydrocortisone). ZIIHERA in combination with fluoropyrimidine- and platinum-containing chemotherapy with or without tislelizumab-jsgr Antidiarrheal prophylaxis: • Administer loperamide 4 mg twice daily beginning on Day 1 and continue for at least 7 days during the first cycle of treatment. • If patients experience Grade 1 or higher diarrhea during the first cycle, continue prophylaxis with loperamide 4 mg twice daily for at least the first 7 days of each subsequent cycle [see Warnings and Precautions ( 5.1 )]. Fluorouracil-containing regimens: • When ZIIHERA is administered in combination with fluorouracil-containing regimens, administer fluorouracil as an intravenous infusion. Do NOT administer fluorouracil as an intravenous bolus due to the potential increase in diarrhea [see Warnings and Precautions ( 5.1 )] . Missed dose ZIIHERA in combination with fluoropyrimidine- and platinum-containing chemotherapy with or without tislelizumab-jsgr If a planned dose of ZIIHERA is delayed or missed, administer the dose as soon as possible if 7 days or fewer have passed since the scheduled time. If more than 7 days have passed since the planned dose, withhold ZIIHERA and resume on day 1 of the next cycle. ZIIHERA as a single agent If a planned dose of ZIIHERA is delayed or missed, administer the dose as soon as possible; do not wait until the next planned dose. Adjust the administration schedule to maintain a 2-week interval between doses. 2.3 Recommended Dosage Gastroesophageal Adenocarcinoma (GEA) Administer ZIIHERA as an intravenous infusion until disease progression or unacceptable toxicity at the recommended dosages presented in Table 1: Table 1: Dosage recommendations for patients with GEA Patient body weight Dosage < 70 kg: • 1,800 mg every 3 weeks or • 1,200 mg every 2 weeks ≥ 70 kg: • 2,400 mg every 3 weeks or • 1,600 mg every 2 weeks Refer to the Prescribing Information of each of the indiv

6 ADVERSE REACTIONS The following clinically significant adverse reactions are described in greater detail in other sections of the labeling: • Diarrhea [see Warnings and Precautions ( 5.1 )] • Embryo-Fetal Toxicity [see Warnings and Precautions ( 5.2) ] • Left Ventricular Dysfunction [see Warnings and Precautions (5.3 )] • Infusion-Related Reactions [see Warnings and Precautions ( 5.4 )] • Most common adverse reactions (≥ 20%) with ZIIHERA in combination with chemotherapy and tislelizumab-jsgr were diarrhea, nausea, decreased appetite, vomiting, hypokalemia, fatigue, rash, peripheral neuropathy, and IRR. ( 6.1 ) • Most common adverse reactions (≥ 20%) with ZIIHERA in combination with chemotherapy were diarrhea, nausea, vomiting, decreased appetite, fatigue, hypokalemia, peripheral neuropathy, IRR, and rash. ( 6.1 ) • Most common adverse reactions (≥ 20%) with ZIIHERA as a single agent were diarrhea, IRR, abdominal pain, and fatigue. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Jazz Pharmaceuticals, Inc. at 1‑800‑520‑5568 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. Gastroesophageal Adenocarcinoma (GEA) The pooled safety population of ZIIHERA described in WARNINGS AND PRECAUTIONS, reflects exposure to ZIIHERA in combination with chemotherapy, with or without tislelizumab-jsgr, in 725 patients with GEA from four open-label studies, including HERIZON-GEA-01 (N=605), ZWI-ZW25-201 (N=46), ZWI-ZW25-101 (N=41), and BGB-A317-ZW25-101 (N=33) at doses of 1,800 mg every 3 weeks (< 70 kg), 2,400 mg every 3 weeks (≥ 70 kg), 1,200 mg every 2 weeks (< 70 kg), 1,600 mg every 2 weeks (≥ 70 kg), or other doses. Among the 330 patients who received ZIIHERA in combination with chemotherapy and tislelizumab-jsgr for GEA, 64% were exposed for 6 months or longer, and 41% were exposed for 1 year or more. Among the 395 patients who received ZIIHERA in combination with chemotherapy for GEA, 57% were exposed for 6 months or longer, and 34% were exposed for 1 year or more. Biliary Tract Cancer (BTC) The pooled safety population of ZIIHERA administered 20 mg/kg intravenously as a single agent, described in WARNINGS AND PRECAUTIONS reflects exposure in 233 patients in two single-arm, open-label studies (ZWI-ZW25-101 and HERIZON-BTC-01): 109 patients with biliary tract cancer, and 124 patients with other cancers. Among 233 patients who received ZIIHERA as a single agent, 39% were exposed for 6 months or longer, and 17% were exposed for greater than one year. Gastroesophageal Adenocarcinoma (GEA) (HERIZON-GEA-01) The safety of ZIIHERA administered in combination with chemotherapy, with or without tislelizumab-jsgr for the treatment of GEA was evaluated in 901 patients [see Clinical Studies ( 14.1 )] . Patients received ZIIHERA by IV infusion every 3 weeks at 1,800 mg (< 70 kg body weight) or 2,400 mg (≥ 70 kg), with or without tislelizumab-jsgr and an investigator choice of a fluoropyrimidine- and platinum-based chemotherapy (CAPOX or FP) or trastuzumab with CAPOX or FP [see Clinical Studies ( 14.1 )] . Treatment in each arm continued until disease progression or unacceptable toxicity. ZIIHERA in combination with tislelizumab-jsgr and chemotherapy Sixty-three percent (63%) of patients were exposed to ZIIHERA for 6 months or longer and 39% 1 year or longer). Serious adverse reactions occurred in 59% of patients who received ZIIHERA. Serious adverse reactions in > 2% of patients included diarrhea (17%), infusion-related reactions (5%), vomiting (4.8%), hypokalemia (4.4%), acute kidney injury (3.7%), pneumonia (3.7%), nausea (2.4%), decreased appetite (2.4%), and anemia (2.4%). Fatal adverse reactions occurred in 2.4% of patients who received ZIIHERA in com

5 WARNINGS AND PRECAUTIONS • Left Ventricular Dysfunction: Assess left ventricular ejection fraction (LVEF) prior to initiation of ZIIHERA and at regular intervals during treatment. Withhold or permanently discontinue ZIIHERA based on severity. ( 2.4 , 5.3 ) • Infusion-Related Reactions (IRRs): Premedicate before each infusion of ZIIHERA. Interrupt the infusion, decrease the infusion rate, and/or permanently discontinue ZIIHERA based on severity. ( 2.2 , 2.4 , 5.4 ) 5.1 Diarrhea ZIIHERA can cause severe diarrhea. When ZIIHERA is used in combination with fluoropyrimidine- and platinum-containing chemotherapy with or without tislelizumab-jsgr, severe, life threatening, and fatal cases of diarrhea can occur despite loperamide prophylaxis [see Adverse Reactions ( 6.1 ), Use in Specific Populations ( 8.5 )] . The risk of severe and life threatening diarrhea is higher when ZIIHERA is administered with chemotherapy and tislelizumab-jsgr, with a higher risk in patients aged 65 years or older compared to younger patients [see Geriatric Use ( 8.5 )] . Advise patients to increase oral fluids, begin antidiarrheals, and notify their healthcare provider immediately if diarrhea occurs [see Patient Counseling Information ( 17 )] . Administer antidiarrheal prophylaxis with loperamide in cycle 1 for all patients receiving ZIIHERA in combination with fluoropyrimidine- and platinum-containing chemotherapy with or without tislelizumab-jsgr. Begin loperamide at the first loose stool when ZIIHERA is administered in combination with chemotherapy or as a single agent. Administer fluids, electrolytes, and additional antidiarrheal agents as necessary. When ZIIHERA was used in combination with chemotherapy with or without tislelizumab-jsgr, 9% of patients had a dose reduction of ZIIHERA due to diarrhea and concomitant agents were dose reduced in 22% of patients. Before modifying the dose of ZIIHERA, evaluate, modify or discontinue drug(s) contributing to diarrhea in accordance with their respective prescribing information. Withhold, reduce the dose, or permanently discontinue ZIIHERA based on severity [see Dosage and Administration ( 2.2 , 2.4 )] . In a Phase 2 study evaluating ZIIHERA in combination with FOLFOX in patients with GEA, 57% of patients who received a fluorouracil bolus without loperamide prophylaxis (N=14), experienced Grade 3 diarrhea, while 30% of patients who did not receive a fluorouracil bolus but received loperamide prophylaxis (N=10) experienced Grade 3 diarrhea. If treating patients with ZIIHERA in combination with FOLFOX, do not administer the fluorouracil bolus. Gastroesophageal Adenocarcinoma (GEA) In Combination with fluoropyrimidine- and platinum-containing chemotherapy and tislelizumab: When ZIIHERA was used in combination with fluoropyrimidine- and platinum-containing chemotherapy and tislelizumab-jsgr, diarrhea was reported in 85% of 330 patients treated in clinical studies, including Grade 4 (2.1%), Grade 3 (24%), and Grade 2 (31%) events. Fatal outcomes resulting from diarrhea occurred in 1.5% of patients. Diarrhea leading to dose reduction of ZIIHERA occurred in 10% of patients, and permanent discontinuation of ZIIHERA occurred in 3.9% of patients. In cycle 1, diarrhea at Grade 4 severity occurred in 1.5% and Grade 3 severity occurred in 15% of patients despite use of loperamide prophylaxis. The median time to onset for cycle 1 diarrhea was 6 days and median time to resolution was 18 days. In Combination with fluoropyrimidine- and platinum-containing chemotherapy: When ZIIHERA was used in combination with fluoropyrimidine- and platinum-containing chemotherapy , diarrhea was reported in 81% of 395 patients treated in clinical studies, including Grade 4 (1.3%), Grade 3 (20%) and Grade 2 (33%). Diarrhea leading to dose reduction of ZIIHERA occurred in 10% of patients, and permanent discontinuation of ZIIHERA occurred in 1.8% of patients. In cycle 1, diarrhea at Grade 4 severity occurred in 0.8% and Grade 3 severity occurred

4 CONTRAINDICATIONS None. • None. ( 4 )