Zolbetuximab

1 INDICATIONS AND USAGE VYLOY, in combination with fluoropyrimidine- and platinum-containing chemotherapy, is indicated for the first-line treatment of adults with locally advanced unresectable or metastatic human epidermal growth factor receptor 2 (HER2)‑negative gastric or gastroesophageal junction (GEJ) adenocarcinoma whose tumors are claudin (CLDN) 18.2 positive as determined by an FDA-approved test [see Dosage and Administration ( 2.1 ) and Clinical Studies ( 14 )]. VYLOY is a claudin 18.2-directed cytolytic antibody and is indicated in combination with fluoropyrimidine- and platinum-containing chemotherapy for the first-line treatment of adults with locally advanced unresectable or metastatic human epidermal growth factor receptor 2 (HER2)-negative gastric or gastroesophageal junction adenocarcinoma whose tumors are claudin (CLDN) 18.2 positive as determined by an FDA-approved test ( 1 ).

12.1 Mechanism of Action Zolbetuximab-clzb is a claudin 18.2 (CLDN18.2)-directed cytolytic antibody that depletes CLDN18.2-positive cells via antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). Zolbetuximab-clzb in combination with chemotherapy had increased antitumor activity in CLDN18.2-expressing mouse tumor models compared to zolbetuximab-clzb or chemotherapy alone.

2 DOSAGE AND ADMINISTRATION • Administer by intravenous infusion only . Do not administer VYLOY as an intravenous push or bolus. ( 2.6 ) • The recommended first dose of VYLOY is 800 mg/m 2 followed by 600 mg/m 2 every 3 weeks or 400 mg/m 2 every 2 weeks. ( 2.3 ) 2.1 Patient Selection Select adult patients with locally advanced unresectable or metastatic HER2-negative gastric or GEJ adenocarcinoma whose tumors are CLDN18.2 positive (defined as ≥75% of tumor cells demonstrating moderate to strong membranous CLDN18 immunohistochemical staining) for treatment with VYLOY in combination with fluoropyrimidine- and platinum-containing chemotherapy using an FDA-approved test [see Clinical Studies ( 14 )]. Information on FDA-approved tests for the detection of CLDN18.2 is available at https://www.fda.gov/CompanionDiagnostics . 2.2 Prior to Administration If a patient is experiencing nausea and/or vomiting prior to administration of VYLOY, the symptoms should be resolved to Grade ≤1 before administering the first infusion. Premedication Prior to each infusion of VYLOY, premedicate patients with a combination of antiemetics (e.g., NK-1 receptor blockers and/or 5-HT3 receptor blockers, as well as other drugs as indicated) for the prevention of nausea and vomiting [see Warnings and Precautions ( 5.2 )]. 2.3 Recommended Dosage Administer VYLOY in combination with fluoropyrimidine- and platinum-containing chemotherapy as follows: • First dose: 800 mg/m 2 intravenously. • Subsequent doses: o 600 mg/m 2 intravenously every 3 weeks, or o 400 mg/m 2 intravenously every 2 weeks. • Continue treatment until disease progression or unacceptable toxicity. 2.4 Dosage Modifications for Adverse Reactions No dose reduction for VYLOY is recommended. Adverse reactions for VYLOY are managed by reducing the infusion rate, interruption of the infusion, withholding the dose, and/or permanently discontinuing VYLOY as described in Table 1 . Table 1. Recommended Dose Modifications for VYLOY for Adverse Reactions Adverse Reaction Severity Toxicity was graded per National Cancer Institute Common Terminology Criteria for Adverse Events Version 5.0 (NCI-CTCAE v5.0). Dose Modification Hypersensitivity or Infusion-related reactions [see Warnings and Precautions ( 5.1 )]. Grade 2 • Interrupt the infusion until Grade ≤1, then resume at a reduced infusion rate for the remaining infusion. • Premedicate and administer the next infusion per the infusion rates in Table 2. Grade 3 Follow Grade 2 management for Grade 3 infusion-related nausea and vomiting. or 4 or anaphylaxis • Immediately stop the infusion and permanently discontinue. 2.5 Preparation Reconstitution • Calculate the recommended dose based on the patient’s body surface area as described in Section 2.3 to determine the total volume and number of vials needed. • Reconstitute each vial of VYLOY to achieve a concentration of 20 mg/mL as follows: o 100 mg vial add 5 mL of Sterile Water for Injection. o 300 mg vial add 15 mL of Sterile Water for Injection. • Slowly add the Sterile Water for Injection into the VYLOY vial, and direct the stream toward the inside wall of the vial. Do not inject directly onto the lyophilized powder. • Slowly swirl each vial until the contents are completely dissolved. Allow the reconstituted vial(s) to settle until the bubbles are gone. Do not shake the vial . • Visually inspect the reconstituted solution for particulate matter and discoloration. The reconstituted solution should be clear to slightly opalescent, colorless to slight yellow and free of visible particles. Discard any vial with visible particles or discoloration. • Store reconstituted vial(s) at room temperature 15°C to 30°C (59°F to 86°F) for up to 5 hours if not used immediately. This product does not contain a preservative . Dilution • Withdraw the required volume of reconstituted VYLOY vial(s) and transfer into an infusion bag containing 0.9% Sodium Chloride Injection, to a final concentration of 5 mg/mL. o The diluted solut

6 ADVERSE REACTIONS The following serious adverse reactions are described elsewhere in the labeling: • Hypersensitivity Reactions, including anaphylaxis, and infusion related reactions [see Warnings and Precautions ( 5.1 )] . • Severe Nausea and Vomiting [see Warnings and Precautions ( 5.2 )] . The most common adverse reactions (≥15%) for VYLOY in combination with mFOLFOX6 or CAPOX were nausea, vomiting, fatigue, decreased appetite, diarrhea, peripheral sensory neuropathy, abdominal pain, constipation, decreased weight, hypersensitivity reactions, and pyrexia. The most common laboratory abnormalities (≥15%) for VYLOY in combination with mFOLFOX6 or CAPOX were decreased neutrophil count, decreased leucocyte count, decreased albumin, increased creatinine, decreased hemoglobin, increased glucose, decreased lymphocyte count, increased aspartate aminotransferase, decreased platelets, increased alkaline phosphatase, increased alanine aminotransferase, decreased glucose, decreased sodium, decreased phosphate, decreased potassium, and decreased magnesium ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Astellas Pharma US, Inc. at 1-800-727-7003 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 pooled safety population described in the WARNINGS AND PRECAUTIONS reflect exposure to VYLOY in 533 patients at an 800 mg/m 2 initial dose followed by subsequent doses of 600 mg/m 2 every 3 weeks in combination with fluoropyrimidine- and platinum-containing chemotherapy in the SPOTLIGHT (279) and GLOW (254) studies. Among 533 patients who received VYLOY in these studies, 47% were exposed for ≥6 months and 20% were exposed for ≥12 months. In this pooled population, the most common (≥15%) adverse reactions, were nausea, vomiting, fatigue, decreased appetite, diarrhea, peripheral sensory neuropathy, abdominal pain, constipation, decreased weight, hypersensitivity reactions, and pyrexia. The most common (≥15%) laboratory abnormalities in the pooled population were decreased neutrophil count, decreased leucocyte count, decreased albumin, increased creatinine, decreased hemoglobin, increased glucose, decreased lymphocyte count, increased aspartate aminotransferase, decreased platelets, increased alkaline phosphatase, increased alanine aminotransferase, decreased glucose, decreased sodium, decreased phosphate, decreased potassium, and decreased magnesium. SPOTLIGHT The safety of VYLOY was evaluated in SPOTLIGHT in patients with locally advanced unresectable or metastatic gastric or GEJ cancer who received at least one dose of VYLOY at an 800 mg/m 2 initial dose followed by 600 mg/m 2 subsequent doses every 3 weeks in combination with mFOLFOX6 [see Clinical Studies ( 14 )] . The median duration of exposure to VYLOY in combination with mFOLFOX6 was 6.2 months (range: 1 day to 40.9 months). Serious adverse reactions occurred in 45% of patients treated with VYLOY in combination with mFOLFOX6; the most common serious adverse reactions (≥2%) were vomiting (8%), nausea (7%), neutropenia (2.9%), febrile neutropenia (2.9%), diarrhea (2.9%), intestinal obstruction (3.2%), pyrexia (2.5%), pneumonia (2.5%), respiratory failure (2.2%), pulmonary embolism (2.2%), decreased appetite (2.1%) and sepsis (2.0%). Fatal adverse reactions occurred in 5% of patients who received VYLOY in combination with mFOLFOX6 including sepsis (1.4%), pneumonia (1.1%), respiratory failure (1.1%), intestinal obstruction (0.7%), acute hepatic failure (0.4%), acute myocardial infarction (0.4%), death (0.4%), disseminated intravascular coagulation (0.4%), encephalopathy (0.4%), and upper gastrointestinal hemorrhage (0.4%). Permanent discontinuation of VYLOY due to an adverse reaction occurred

5 WARNINGS AND PRECAUTIONS • Hypersensitivity reactions including serious anaphylaxis reactions and serious and fatal infusion-related reactions have occurred. Monitor patients during and for at least 2 hours after infusion with VYLOY. Interrupt, slow the rate of infusion or permanently discontinue VYLOY based on severity and type of reaction. Premedicate with antihistamines for subsequent infusions after a hypersensitivity reaction. ( 2.4 , 5.1 ) • Severe nausea and vomiting: Premedicate patients with antiemetics prior to each infusion. Interrupt or permanently discontinue VYLOY based on the severity of the nausea and/or vomiting. Manage patients during and after infusion with antiemetics or fluid replacement. ( 2.4 , 5.2 ) 5.1 Hypersensitivity reactions, including anaphylaxis reactions, and infusion related reactions Hypersensitivity reactions, including serious anaphylaxis reactions, and serious and fatal infusion-related reactions (IRR) have been reported in clinical studies when VYLOY has been administered. Any grade hypersensitivity reactions, including anaphylactic reactions, occurring with VYLOY in combination with mFOLFOX6 or CAPOX was 18%. Severe (Grade 3 or 4) hypersensitivity reactions, including anaphylactic reactions, occurred in 2% of patients. Seven patients (1.3%) permanently discontinued VYLOY for hypersensitivity reactions, including two patients (0.4%) who permanently discontinued VYLOY due to anaphylactic reactions. Seventeen (3.2%) patients required dose interruption, and three patients (0.6%) required infusion rate reduction due to hypersensitivity reactions. All grade IRRs occurred in 3.2% in patients administered VYLOY in combination with mFOLFOX6 or CAPOX. Severe (Grade 3) IRRs occurred in 2 (0.4%) patients who received VYLOY. An IRR led to permanent discontinuation of VYLOY in 2 (0.4%) patients and dose interruption in 7 (1.3%) patients. The infusion rate was reduced for VYLOY for 2 (0.4%) patients due to an IRR. Monitor patients during infusion with VYLOY and for 2 hours after completion of infusion or longer if clinically indicated, for hypersensitivity reactions with symptoms and signs that are highly suggestive of anaphylaxis (urticaria, repetitive cough, wheeze and throat tightness/change in voice). Monitor patients for signs and symptoms of IRRs including nausea, vomiting, abdominal pain, salivary hypersecretion, pyrexia, chest discomfort, chills, back pain, cough and hypertension. If a severe or life-threatening hypersensitivity or IRR reaction occurs, discontinue VYLOY permanently, treat symptoms according to standard medical care, and monitor until symptoms resolve. For any Grade 2 hypersensitivity or IRR, interrupt the VYLOY infusion until Grade ≤1, then resume at a reduced infusion rate for the remaining infusion. Premedicate the patient with antihistamines for the subsequent infusions, administer per the infusion rates in Table 2 and closely monitor the patient for symptoms and signs of a hypersensitivity reaction. The infusion rate may be gradually increased as tolerated [see Dosage and Administration ( 2.4 )] . 5.2 Severe Nausea and Vomiting VYLOY is emetogenic. Nausea and vomiting occurred more often during the first cycle of treatment. All grade nausea and vomiting occurred in 82% and 67%, respectively, of patients treated with VYLOY in combination with mFOLFOX6 and 69% and 66% in combination with CAPOX, respectively. Severe (Grade 3) nausea occurred in 16% and 9% of patients treated with VYLOY in combination with mFOLFOX6 or CAPOX respectively. Severe (Grade 3) vomiting occurred in 16% and 12% of patients treated with VYLOY in combination with mFOLFOX6 or CAPOX. Nausea led to permanent discontinuation of VYLOY in combination with mFOLFOX6 or CAPOX in 18 (3.4%) patients and dose interruption in 147 (28%) patients. Vomiting led to permanent discontinuation of VYLOY in combination with mFOLFOX6 or CAPOX in 20 (3.8%) patients and dose interruption in 150 (28%) patients. Pretreat with ant

4 CONTRAINDICATIONS None. None. ( 4 )