Cetuximab

12.1 Mechanism of Action The epidermal growth factor receptor (EGFR, HER1, c-ErbB-1) is a transmembrane glycoprotein that is a member of a subfamily of type I receptor tyrosine kinases including EGFR, HER2, HER3, and HER4. The EGFR is constitutively expressed in many normal epithelial tissues, including the skin and hair follicle. Expression of EGFR is also detected in many human cancers including those of the head and neck, colon, and rectum. Cetuximab binds specifically to the EGFR on both normal and tumor cells, and competitively inhibits the binding of epidermal growth factor (EGF) and other ligands, such as transforming growth factor-alpha. In vitro assays and in vivo animal studies have shown that binding of cetuximab to the EGFR blocks phosphorylation and activation of receptor-associated kinases, resulting in inhibition of cell growth, induction of apoptosis, and decreased matrix metalloproteinase and vascular endothelial growth factor production. Signal transduction through the EGFR results in activation of wild-type Ras proteins, but in cells with activating Ras somatic mutations, the resulting mutant Ras proteins are continuously active regardless of EGFR regulation. In vitro , cetuximab can mediate antibody-dependent cellular cytotoxicity (ADCC) against certain human tumor types. In vitro assays and in vivo animal studies have shown that cetuximab inhibits the growth and survival of tumor cells that express the EGFR. No anti-tumor effects of cetuximab were observed in human tumor xenografts lacking EGFR expression. The addition of cetuximab to radiation therapy or irinotecan in human tumor xenograft models in mice resulted in an increase in anti-tumor effects compared to radiation therapy or chemotherapy alone. In the setting of BRAF-mutant CRC, induction of EGFR-mediated MAPK pathway activation has been identified as a mechanism of resistance to BRAF inhibitors. Combinations of a BRAF inhibitor and agents targeting EGFR have been shown to overcome this

1 INDICATIONS AND USAGE ERBITUX ® is an epidermal growth factor receptor (EGFR) antagonist indicated for treatment of: Head and Neck Cancer Locally or regionally advanced squamous cell carcinoma of the head and neck in combination with radiation therapy. ( 1.1 , 14.1 ) Recurrent locoregional disease or metastatic squamous cell carcinoma of the head and neck in combination with platinum-based therapy with fluorouracil. ( 1.1 , 14.1 ) Recurrent or metastatic squamous cell carcinoma of the head and neck progressing after platinum-based therapy. ( 1.1 , 14.1 ) Colorectal Cancer K-Ras wild-type, EGFR-expressing, metastatic colorectal cancer as determined by an FDA-approved test in combination with FOLFIRI for first-line treatment, in combination with irinotecan in patients who are refractory to irinotecan-based chemotherapy, as a single-agent in patients who have failed oxaliplatin- and irinotecan-based chemotherapy or who are intolerant to irinotecan. ( 1.2 , 5.7 , 12.1 , 14.2 ) Limitations of Use: ERBITUX is not indicated for treatment of Ras-mutant colorectal cancer or when the results of the Ras mutation tests are unknown. ( 5.7 ) BRAF V600E Mutation-Positive Metastatic Colorectal Cancer (CRC) in combination with encorafenib, for the treatment of adult patients with metastatic colorectal cancer (CRC) with a BRAF V600E mutation, as detected by an FDA-approved test, after prior therapy. ( 1.3 ) 1.1 Squamous Cell Carcinoma of the Head and Neck (SCCHN) ERBITUX ® is indicated: in combination with radiation therapy for the initial treatment of locally or regionally advanced squamous cell carcinoma of the head and neck (SCCHN). in combination with platinum-based therapy with fluorouracil for the first-line treatment of patients with recurrent locoregional disease or metastatic SCCHN. as a single-agent for the treatment of patients with recurrent or metastatic SCCHN for whom prior platinum-based therapy has failed. 1.2 K-Ras Wild-type, EGFR-expressing Colorectal Cancer (CRC)

2 DOSAGE AND ADMINISTRATION Premedicate with an H 1 receptor antagonist. ( 2.4 ) In Combination With Radiation Therapy: Initial dose: 400 mg/m 2 administered as a 120-minute intravenous infusion one week prior to initiating a course of radiation therapy. ( 2.2 ) Subsequent doses: 250 mg/m 2 administered as a 60-minute infusion every week for the duration of radiation therapy (6–7 weeks). ( 2.2 ) Complete ERBITUX administration 1 hour prior to radiation therapy. ( 2.2 ) As Single-Agent or in Combination With Chemotherapy: Weekly: Administer initial dose of 400 mg/m 2 as a 120-minute intravenous infusion, and subsequent doses of 250 mg/m 2 infused over 60 minutes once weekly. ( 2.2 , 2.3 ) Biweekly: Administer 500 mg/m 2 as a 120-minute intravenous infusion every two weeks. ( 2.2 , 2.3 ) Complete ERBITUX administration 1 hour prior to chemotherapy. Continue treatment until disease progression or unacceptable toxicity. ( 2.2 , 2.3 ) See full prescribing information for dosage adjustments for adverse reactions. ( 2.5 ) 2.1 Patient Selection Select patients with metastatic colorectal cancer (CRC) for treatment with ERBITUX based on the presence of: Ras wild-type, EGFR-expressing CRC [see Clinical Studies ( 14.2 )], or BRAF V600E mutation-positive metastatic CRC [see Clinical Studies ( 14.3 )] Information on FDA-approved tests for the detection of K-Ras or BRAF V600E mutations in CRC in patients with metastatic CRC is available at: http://www.fda.gov/CompanionDiagnostics. 2.2 Recommended Dosage for Squamous Cell Carcinoma of the Head and Neck (SCCHN) In combination with radiation therapy Initial dose: 400 mg/m 2 administered as a 120-minute intravenous infusion one week prior to initiating a course of radiation therapy. Subsequent doses: 250 mg/m 2 administered as a 60-minute infusion every week for the duration of radiation therapy (6–7 weeks). Complete ERBITUX administration 1 hour prior to radiation therapy. As a single-agent or in combination with platinum-based therapy and fluorouracil Administer Erbitux as a single-agent or in combination with platinum-based therapy and fluorouracil on a weekly or biweekly schedule. Weekly Dosage Initial dose: 400 mg/m 2 administered as a 120-minute intravenous infusion Subsequent doses: 250 mg/m 2 administered as a 60-minute infusion every week Biweekly Dosage Initial and subsequent doses: 500 mg/m 2 administered as a 120-minute intravenous infusion every 2 weeks Complete ERBITUX administration 1 hour prior to platinum-based therapy with fluorouracil. Continue treatment until disease progression or unacceptable toxicity. 2.3 Recommended Dosage for Colorectal Cancer (CRC) As a single-agent or in combination with irinotecan or FOLFIRI (irinotecan, fluorouracil, leucovorin) Administer Erbitux as a single-agent or in combination with irinotecan or FOLFIRI (irinotecan, fluorouracil, leucovorin) on a weekly or biweekly schedule. Weekly Dosage Initial dose: 400 mg/m 2 administered as a 120-minute intravenous infusion Subsequent doses: 250 mg/m 2 administered as a 60-minute infusion every week Biweekly Dosage Initial and subsequent doses: 500 mg/m 2 administered as a 120-minute intravenous infusion every 2 weeks Complete ERBITUX administration 1 hour prior to irinotecan or FOLFIRI. Continue treatment until disease progression or unacceptable toxicity. In combination with encorafenib The recommended initial dose is 400 mg/m 2 administered as a 120-minute intravenous infusion in combination with encorafenib. The recommended subsequent dosage is 250 mg/m 2 weekly as a 60-minute infusion in combination with encorafenib until disease progression or unacceptable toxicity. Refer to the encorafenib prescribing information for recommended encorafenib dosage information. 2.4 Premedication Premedicate with a histamine-1 (H 1 ) receptor antagonist intravenously 30–60 minutes prior to the first dose or subsequent doses as deemed necessary [see Warnings and Precautions ( 5.1 )] . 2.5 Dosage Modifications for Adverse Reactions Reduce, delay, or discontinue ERBITUX to manage adverse reactions as described in Table 1 . Table 1: Recommended Dosage Modifications for Adverse Reactions Adverse Reaction Severity a Dosage Modification a National Cancer Institute (NCI) Common Toxicity Criteria (CTC), version 2.0. Infusion reactions [see Warnings and Precautions ( 5.1 )] Grade 1 or 2 Reduce the infusion rate by 50%. Grade 3 or 4 Immediately and permanently, discontinue ERBITUX. Dermatologic toxicities and infectious sequelae (e.g., acneiform rash, mucocutaneous disease) [see Warnings and Precautions ( 5.4 )] 1 st occurrence; Grade 3 or 4 Delay infusion 1 to 2 weeks; if condition improves, continue at 250 mg/m 2 . If no improvement, discontinue ERBITUX. 2 nd occurrence; Grade 3 or 4 Delay infusion 1 to 2 weeks; if condition improves, continue at 200 mg/m 2 . If no improvement, discontinue ERBITUX. 3 rd occurrence; Grade 3 or 4 Delay infusion 1 to 2 weeks; if condition improves, continue at 150 mg/m 2 . If

6 ADVERSE REACTIONS The following adverse reactions are discussed in greater detail in other sections of the label: Infusion reactions [see Warnings and Precautions ( 5.1 )] . Cardiopulmonary arrest [see Warnings and Precautions ( 5.2 )] . Pulmonary toxicity [see Warnings and Precautions ( 5.3 )] . Dermatologic toxicity [see Warnings and Precautions ( 5.4 )] . Hypomagnesemia and Electrolyte Abnormalities [see Warnings and Precautions ( 5.6 )] . The most common adverse reactions (incidence ≥25%) with Erbitux as a single-agent or in combination with radiotherapy or chemotherapy (FOLFIRI, Irinotecan and 5-Fluorouracil/Platinum) are: cutaneous adverse reactions (including rash, pruritus, and nail changes), headache, diarrhea, and infection. ( 6 ) The most common adverse reactions (>25%) for ERBITUX, in combination with encorafenib, are fatigue, nausea, diarrhea, dermatitis acneiform, abdominal pain, decreased appetite, arthralgia, and rash. ( 6 ). To report SUSPECTED ADVERSE REACTIONS, contact Eli Lilly and Company at 1-800-LillyRx (1-800-545-5979) 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 data described in Warnings and Precautions reflect exposure to ERBITUX in 1373 patients with SCCHN or CRC enrolled in clinical trials and treated at the recommended dosage for a median of 7 to 14 weeks [see Clinical Studies ( 14.1 , 14.2 )] . The most common adverse reactions in clinical trials with ERBITUX as a single-agent or in combination with radiotherapy or chemotherapy [FOLFIRI, irinotecan and 5-fluorouracil/platinum] (incidence ≥25%) include cutaneous adverse reactions (including rash, pruritus, and nail changes), headache, diarrhea, and infection. Squamous Cell Carcinoma of the Head and Neck (SCCHN) In Combination with Radiation Therapy The safety of ERBITUX in combination with radiation therapy compared to radiation therapy alone was evaluated in BONNER. The data described below reflect exposure to ERBITUX in 420 patients with locally or regionally advanced SCCHN. ERBITUX was administered at the recommended dosage (400 mg/m 2 initial dose, followed by 250 mg/m 2 weekly). Patients received a median of 8 infusions (range 1 to 11) [see Clinical Studies ( 14.1 )] . Table 2 provides the frequency and severity of adverse reactions in BONNER. Table 2: Selected Adverse Reactions in ≥10% of Patients with Locoregionally Advanced SCCHN (BONNER) a Adverse Reaction ERBITUX with Radiation (n=208) Radiation Therapy Alone (n=212) Grades 1–4 b Grades 3 and 4 Grades 1–4 Grades 3 and 4 a Adverse reactions occurring in ≥10% of patients in the ERBITUX combination arm and at a higher incidence (≥5%) compared to the radiation alone arm. b Adverse reactions were graded using the NCI CTC, version 2.0. c Includes cases also reported as infusion reaction. d Infusion reaction defined as any event described at any time during the clinical study as “allergic reaction” or “anaphylactoid reaction”, or any event occurring on the first day of dosing described as “allergic reaction”, “anaphylactoid reaction”, “fever”, “chills”, “chills and fever”, or “dyspnea”. e Based on laboratory measurements, not on reported adverse reactions, the number of subjects with tested samples varied from 205–206 for ERBITUX with Radiation arm; 209–210 for Radiation alone. f Acneiform rash defined as any event described as “acne”, “rash”, “maculopapular rash”, “pustular rash”, “dry skin”, or “exfoliative dermatitis”. General Asthenia 56 4 49 5 Fever c 29 1 13 1 Headache 19 <1 8 <1 Chills c 16 0 5 0 Infusion Reaction d 15 3 2 0 Infection 13 1 9 1 Gastrointestinal Nausea 49 2 37 2 Emesis 29 2 23 4 Diarrhea 19 2 13 1 Dyspepsia 14 0 9 1 Metabolism and Nutrition Weight Loss 84 11 72 7 Dehydration 25 6 19 8 Increased Alanine Transaminase e 43 2 21 1 Increased Aspartate Transaminase e 38 1 24 1 Increased Alkaline Phosphatase e 33 <1 24 0 Respiratory Pharyngitis 26 3 19 4 Dermatologic Acneiform Rash f 87 17 10 1 Radiation Dermatitis 86 23 90 18 Application Site Reaction 18 0 12 1 Pruritus 16 0 4 0 The overall incidence of late radiation toxicities (any grade) was higher for patients receiving ERBITUX in combination with radiation therapy compared with radiation therapy alone. The following sites were affected: salivary glands (65% versus 56%), larynx (52% versus 36%), subcutaneous tissue (49% versus 45%), mucous membrane (48% versus 39%), esophagus (44% versus 35%), skin (42% versus 33%). The incidence of Grade 3 or 4 late radiation toxicities was similar between the radiation therapy alone and the ERBITUX with radiation treatment groups. In Combination with Platinum-based Therapy and Fluorouracil The safety of a cetuximab product in combination with platinum-based therapy and