The study was terminated early based on an imbalance in worsening Crohn's disease in active treatment groups.

The purpose of this study is to evaluate the safety and efficacy of long-term treatment with brodalumab in adults with Crohn's disease.

This study is an open-label extension of study 20090072 (NCT01150890) in adults with Crohn's disease.

Inclusion Criteria:

• Subject was randomized into study 20090072 (NCT01150890) and completed the week 12 evaluation.
• Subject completed the week 12 evaluation in study 20090072 no more than 1 year prior to the planned first visit of AMG 827 in 20100008.
• Subject or subject's legally acceptable representative has provided informed consent.
• Subject meets regional recommendations for immunizations, eg, United States Centers for Disease Control and Prevention recommendations for subjects enrolled in the United States.
• For subjects with ≥ 3 months between the week 12 visit of 20090072 and the planned first dose of AMG 827 in 20100008: If testing is clinically indicated in the opinion of the investigator (eg, because of known recent exposure), then subject has negative test for hepatitis B, hepatitis C, and/or human immunodeficiency virus (HIV).
• For female subjects with ≤ 4 weeks between the week 12 visit of 20090072 and the planned first dose of AMG 827 in 20100008: Subject has a negative urine pregnancy test at baseline prior to the first dose of AMG 827 in the open-label extension (except those at least 2 years post menopausal or surgically sterile).
• For female subjects with > 4 weeks between the week 12 visit of 20090072 and the planned first dose of AMG 827 in 20100008: Subject has a negative serum pregnancy test within 28 days before initiating AMG 827 and a negative urine pregnancy test at baseline prior to the first dose of AMG 827 in the open-label extension (except those at least 2 years post menopausal or surgically sterile).
• For subjects with ≥ 3 months between the week 12 visit of 20090072 and the planned first dose of AMG 827 in 20100008, if clinically indicated in the opinion of the investigator (eg, because of known recent exposure) please assess the following:
• If the subject entered 20090072 with a negative purified protein derivative (PPD) test: Subject must have a negative PPD test within 30 days prior to the planned first dose of AMG 827. Tuberculin skin tests should be considered positive when they have greater than or equal to 5 mm of induration at 48-72 hours after test is placed.
• If the subject entered 20090072 with a positive PPD: Subject must have a negative Quantiferon test within 30 days prior to the planned first dose of AMG 827.

Exclusion Criteria:

• Subject had any serious adverse event reported during study 20090072 and considered to be related to investigational product.
• Subject experienced an adverse event or laboratory abnormality in study 20090072 that, in the opinion of the investigator, could cause extension of treatment to be detrimental to the subject, prevent the subject from completing the study, or interfere with the interpretation of the study results.
• Subject has known sensitivity to any of the products to be administered during dosing.

Other medical conditions

• Subject is currently experiencing an infection of Common Terminology Criteria for Adverse Events grade 2 (if requiring oral medication) or higher. Subject is ineligible until the infection resolves.
• Subject has a serious infection, defined as requiring hospitalization or intravenous antibiotics, within 8 weeks before the first dose of AMG 827 in 20100008.
• For subjects with ≥ 3 months between the week 12 visit of 20090072 and the planned first dose of AMG 827 in 20100008: Subject has recurrent or chronic infections, defined as ≥ 3 infections requiring anti-microbials over the past 12 months prior to screening.
• Subject has a significant concurrent medical condition, including
• Type 1 diabetes
• Uncontrolled type 2 diabetes
• Moderate to severe heart failure (New York Heart Association class III or IV)
• Myocardial infarction within the last year
• Current or history of unstable angina pectoris within the last year
• Uncontrolled hypertension as defined by resting blood pressure ≥ 150/90 mmHg prior to first investigational product dose (confirmed by a repeat assessment)
• Severe chronic pulmonary disease (eg, requiring oxygen therapy)
• Major chronic inflammatory disease or connective tissue disease other than Crohn's disease (eg, systemic lupus erythematosus, rheumatoid arthritis, psoriasis)
• Active malignancy, including evidence of cutaneous basal or squamous cell carcinoma or melanoma
• History of cancer (except successfully treated in situ cervical cancer or squamous or basal cell carcinoma of the skin).
• Any condition that, in the opinion of the investigator, might cause this study to be detrimental to the subject
• Laboratory abnormalities
• For subjects with > 4 weeks between the week 12 visit of 20090072 and the planned first dose of AMG 827 in 20100008, subject has laboratory abnormalities at screening, including
• Elevated aspartate aminotransferase or alanine aminotransferase (> 2x upper limit of normal)
• Serum direct bilirubin ≥ 1.5x upper limit of normal
• Hemoglobin < 10 g/dL
• Hemoglobin A1c > 8.0 (for subjects with type 2 diabetes)
• Platelet count < 125,000 /mm^3
• White blood cell count < 3,000 cells/mm^3
• Absolute neutrophil count < 2,000/mm^3
• Creatinine clearance < 50 mL/min (Cockroft-Gault formula, central lab will calculate value and provide to sites)
• Any other laboratory abnormality, which, in the opinion of the investigator, could cause extension of treatment to be detrimental to the subject, prevent the subject from completing the study, or interfere with the interpretation of the study results
• Washouts and non-permitted drugs
• Subject has used Tysabri (natalizumab) subsequent to study 20090072.
• Subject received an anti-tumor necrosis factor agent within 8 weeks prior to the first dose of AMG 827 in 20100008.
• Subject received other commercially available biologic agent (eg, ustekinumab) within 12 weeks prior to the first dose of AMG 827 in 20100008.
• Subject received an investigational agent (other than AMG 827), investigational procedure, or participated in an investigational device study subsequent to study 20090072.
• Subject received live vaccines within 12 weeks prior to the first dose of AMG 827 in 20100008.
• Subject received cyclosporine, mycophenolate mofetil, sirolimus (rapamycin), thalidomide, or tacrolimus within 4 weeks prior to the first dose of AMG 827 in 20100008.
• General or other
• Female subject is not willing to use highly effective contraception during treatment with AMG 827 (except if at least 2 years postmenopausal or surgically sterile).
• Subject is pregnant or breast feeding, or planning to become pregnant while enrolled in the study.
• Subject has any kind of disorder that, in the opinion of the investigator, may compromise the ability of the subject to give written informed consent and/or to comply with all required study procedures.
• Subject will not be available for protocol required study visits, to the best of the subject and investigator's knowledge.