Zolbetuximab

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.

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 • Stor

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