VYLOY

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 ).

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 solution of VYLOY is compatible with intravenous infusion bags composed of polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC) [with either Di(2-ethylhexyl) phthalate (DEHP) or, Trioctyl trimellitate (TOTM) plasticizers], ethylene propylene copolymer, ethylene-vinyl acetate (EVA) copolymer, PP and styrene-ethylene-butylene-styrene copolymer. o The diluted solution of VYLOY is compatible with infusion tubing composed of PE, PVC [with DEHP, TOTM or Di(2-ethylhexyl) terephthalate plasticizers], polybutadiene (PB), or elastomer modified polypropylene with in-line filter membranes composed of polyethersulfone (PES) or polysulfone. • Mix diluted solution by gentle inversion. Do not shake the bag . • Visually inspect the infusion bag for any particulate matter prior to use. The diluted solution should be free of visible particles. Do not use the infusion bag if particulate matter is observed. • Discard any unused portion left in the single-dose vials. Storage of diluted infusion • Store the prepared infusion bag: o At room temperature 15°C to 30°C (59°F to 86°F) for no longer than 6 hours from the end of the preparation of the infusion bag to the completion of the infusion. o Under refrigeration at 2°C to 8°C (36°F to 46°F) for no longer than 16 hours from the end of the preparation of the infusion bag to the completion of the infusion. Do not freeze. 2.6 Administration • Administer VYLOY as an intravenous infusion only. Do NOT administer as an intravenous push or bolus. • If VYLOY and fluoropyrimidine- and platinum-containing chemotherapy are administered on the same day, VYLOY must be administered first. • No incompatibilities have been observed with o closed system transfer devices composed of PP, PE, stainless steel, silicone (rubber/oil/resin), polyisoprene, PVC with TOTM plasticizer, acrylonitrile-butadiene-styrene (ABS) copolymer, methyl methacrylate-ABS copolymer, thermoplastic elastomer, polytetrafluoroethylene, polycarbonate, PES, acrylic copolymer, polybutylene terephthalate, PB, or EVA copolymer. o central ports composed of silicone rubber, titanium alloy or PVC with TOTM plasticizer. • In-line filters (pore size of 0.2 μm composed of materials listed above) are recommended to be used during administration. • Do NOT co-administer other drugs through the same infusion line. • Immediately administer the infusion as described in Table 2 . To minimize the risk of adverse reactions, begin each infusion at a slower rate for 30 to 60 minutes; if tolerated, gradually increase the rate as described in Table 2 . • If the infusion time exceeds the recommended storage time (6 hours from end of preparation of infusion solution at room temperature or 16 hours from end of preparation of infusion solution under refrigeration), the infusion bag must be discarded and a new infusion bag prepared to continue the infusion. Infusion Rate Recommendations Table 2. Infusion Rates Recommended for Each VYLOY Infusion VYLOY Dose Initial Infusion Rate (first 30-60 minutes ) In the absence of adverse reactions after 30 to 60 minutes, the infusion rate can be increased to the subsequent infusion rate as tolerated. Subsequent Infusion Rate First Dose 800 mg/m 2 100 mg/m 2 /hr 200-265 mg/m 2 /hr Subsequent Doses 600 mg/m 2 every 3 weeks 75 mg/m 2 /hr 150-265 mg/m 2 /hr or or or 400 mg/m 2 every 2 weeks 50 mg/m 2 /hr 100-200 mg/m 2 /hr

4 CONTRAINDICATIONS None. None. ( 4 )

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 antiemetics prior to each infusion of VYLOY [see Dosage and Administration ( 2.2 )] . Manage patients during and after infusion with antiemetics or fluid replacement. Interrupt the infusion, or permanently discontinue VYLOY based on severity [see Dosage and Administration ( 2.4 )] .

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 in 20% of patients; the most common adverse reactions leading to discontinuation (≥2%) were nausea and vomiting. Dosage interruptions of VYLOY due to an adverse reaction occurred in 75% of patients; the most common adverse reactions leading to dose interruption (≥5%) were nausea, vomiting, neutropenia, abdominal pain, fatigue, and hypertension. Tables 3 and 4 summarize the most common (≥15%) adverse reactions and laboratory abnormalities with a difference between arms of ≥5%, respectively, compared to placebo in SPOTLIGHT. Table 3. Adverse Reactions (≥15%) in Patients Treated with VYLOY in SPOTLIGHT with a Difference Between Arms of ≥5% Compared to Placebo Adverse Reaction VYLOY with mFOLFOX6 n=279 Placebo with mFOLFOX6 n=278 All Grades % Grade 3 or 4 % All Grades % Grade 3 or 4 % Gastrointestinal disorders Nausea 82 16 61 7 Vomiting 67 16 36 6 Metabolism and nutrition disorders Decreased appetite 47 6 34 3.2 General disorders and administration site conditions Peripheral edema 18 0.7 9 0 Table 4. Laboratory Abnormalities (≥ 15%) in SPOTLIGHT with a Difference Between Arms of ≥ 5% Compared to Placebo Laboratory Abnormality VYLOY with mFOLFOX6 The denominator used to calculate the rate varied from 271 to 272 based on the number of patients with a baseline value and at least one post-treatment value. Placebo with mFOLFOX6 All Grades % Grade 3 or 4 % All Grades % Grade 3 or 4 % Albumin decreased 78 4.4 47 1.1 Potassium decreased 28 11 21 6 Glucose decreased 45 0.4 35 0.4 Sodium decreased 29 5 21 2.9 GLOW The safety of VYLOY was evaluated in GLOW in patients with locally advanced unresectable or metastatic gastric/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 CAPOX [see Clinical Studies ( 14 )] . The median duration of exposure to VYLOY in combination with CAPOX was 4.4 months (range: 0.03 to 30.7 months). Serious adverse reactions occurred in 47% of patients treated with VYLOY in combination with CAPOX; the most common serious adverse reactions (≥2%) were vomiting (6%), nausea (4.3%), decreased appetite (3.9%), decreased platelet count (3.1%), upper gastrointestinal hemorrhage (2.8%), diarrhea (2.8%), pneumonia (2.4%), pulmonary embolism (2.3%), and pyrexia (2.0%). Fatal adverse reactions occurred in 8% of patients who received VYLOY in combination with CAPOX including sepsis (1.2%), pneumonia (0.4%), death (0.8%), upper gastrointestinal hemorrhage (0.8%), cerebral hemorrhage (0.8%), abdominal infection (0.4%), acute respiratory distress syndrome (0.4%), cardio‑respiratory arrest (0.4%), decreased platelet count (0.4%), disseminated intravascular coagulation (0.4%), dyspnea (0.4%), gastric perforation (0.4%), hemorrhagic ascites (0.4%), procedural complication (0.4%), sudden death (0.4%), and syncope (0.4%). Permanent discontinuation of VYLOY due to an adverse reaction occurred in 19% of patients; the most common adverse reaction leading to discontinuation (≥2%) was vomiting. Dosage interruption of VYLOY due to an adverse reaction occurred in 55% of patients; the most common adverse reactions leading to dose interruption (≥2%) were nausea, vomiting, neutropenia, thrombocytopenia, anemia, fatigue, infusion-related reaction, and abdominal pain. Tables 5 and 6 summarize the most common (≥15%) adverse reactions and laboratory abnormalities with a difference between arms of ≥5%, respectively compared to placebo in GLOW. Table 5. Adverse Reactions (≥15%) in Patients Treated with VYLOY in GLOW with a Difference Between Arms of ≥5% Compared to Placebo Adverse Reaction VYLOY with CAPOX n=254 Placebo with CAPOX n=249 All Grades % Grade 3 or 4 % All Grades % Grade 3 or 4 % Gastrointestinal disorders Nausea 69 9 50 2.4 Vomiting 66 12 31 3.6 Metabolism and nutrition disorders Decreased appetite 41 7 34 1.6 Blood and lymphatic system disorders Neutropenia 20 7 14 2.8 Investigations Weight decreased 20 0.4 10 0.4 Other clinically relevant adverse reactions (<15%) in GLOW with a difference between arms of 5% compared to placebo included peripheral edema. Table 6. Laboratory Abnormalities (≥15%) in Patients Treated with VYLOY in GLOW with a Difference Between Arms of ≥5% Compared to Placebo Laboratory Abnormality VYLOY with CAPOX The denominator used to calculate the rate varied from 237 to 238 based on the number of patients with a baseline value and at least one post-treatment value. Placebo with CAPOX All Grades % Grade 3 or 4 % All Grades % Grade 3 or 4 % Albumin decreased 66 3.8 47 1.7 Leukocytes decreased 66 6 60 8 Neutrophils decreased 76 21 70 14 Glucose decreased 24 0 18 0

8.1 Pregnancy Risk Summary There are no data with VYLOY use in pregnant women to inform any drug-associated risks. Embryo-fetal toxicity was not observed in pregnant mice intravenously administered zolbetuximab-clzb [see Data] . VYLOY should only be given to a pregnant woman if the benefit outweighs the potential risk. The background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2%-4% and 15%-20%, respectively. Data Animal Data In an embryo-fetal development toxicity study, zolbetuximab-clzb was intravenously administered to pregnant mice during the period of organogenesis and did not result in embryo-fetal toxicity at doses up to 300 mg/kg (approximately 1.9 times the recommended clinical dose based on AUC). Zolbetuximab-clzb crossed the placental barrier resulting in higher fetal serum concentrations on Day 18 of gestation than maternal serum concentrations on Day 16 of gestation.