An AECOPD is defined as worsening of two or more major symptoms or one major and one minor symptom for two or more consecutive days. The severity of an AECOPD is defined as: Moderate exacerbations require treatment with systemic corticosteroids, and or antibiotics. Severe exacerbations require hospitalization. The AECOPD rate was analyzed using a Poisson Regression model adjusted for over dispersion with number of exacerbations as the outcome and the log of follow-up time as an offset variable, with covariates for treatment group (MEDI8986, placebo), background maintenance therapy and previous exacerbations. Mean exacerbations were presented as number of exacerbations/year.

Modified intent-to-treat (mITT) population included all participants who were randomized into the study and received any investigational product.

An AECOPD is defined as worsening of two or more major symptoms or one major and one minor symptom for two or more consecutive days. Severe exacerbations require hospitalization. The AECOPD rate was analyzed using a Poisson Regression model adjusted for over dispersion with number of exacerbations as the outcome and the log of follow-up time as an offset variable, with covariates for treatment group (MEDI8986, placebo), background maintenance therapy and previous exacerbations. Mean exacerbations were presented as number of exacerbations/year.

The mITT population included all participants who were randomized into the study and received any investigational product.

Time to first worsening of two or more major symptoms or one major and one minor symptom for two or more consecutive days. The severity of an AECOPD is defined as: Mild exacerbations require treatment with an increase in usual therapy, e.g., increase use of short acting bronchodilators. Moderate exacerbations require treatment with systemic corticosteroids, and or antibiotics. Severe exacerbations require hospitalization.

The mITT population included all participants who were randomized into the study and received any investigational product.

The SGRQ is a health related quality of life questionnaire consisting of 40 items in three domains: symptoms (respiratory symptoms and severity), activity (activities that cause or are limited by breathlessness) and impacts (social functioning and psychological disturbances due to airway disease). Each question's response has a unique empirically derived weight where lowest possible weight is zero and the highest is 100. The total score and domain score are derived from the relevant items and converted to a score of 0 to 100 with a higher score indicating poorer health status.

The mITT population included all participants who were randomized into the study and received any investigational product. Here, 'n' signifies those participants evaluable for this measure at specified time points for each group, respectively.

The SGRQ is a health related quality of life questionnaire consisting of 40 items in three domains: symptoms (respiratory symptoms and severity), activity (activities that cause or are limited by breathlessness) and impacts (social functioning and psychological disturbances due to airway disease). Each question's response has a unique empirically derived weight where lowest possible weight is zero and the highest is 100. The total score and domain score are derived from the relevant items and converted to a score of 0 to 100 with a higher score indicating poorer health status. A 4-point change in total score demonstrates a clinically meaningful change, while an 8-point change and a 12-point change are interpreted as a moderate and large change in health status, respectively.

The mITT population included all participants who were randomized into the study and received any investigational product. Here, 'n' signifies those participants evaluable for this measure at specified time points for each group, respectively.

The BODE index is a multi-dimension COPD grading system that incorporates body-mass index (B), degree of airflow obstruction (O), dyspnea (D), and exercise capacity (E) as measured by the modified medical research council (MMRC) dyspnea scale and the 6-minute walk test. The MMRC dyspnea scale is a 5-point scale that measures the level of dyspnea (trouble breathing) experienced by participants where score range is 0 (none) to 4 (very severe). BODE score is derived into a score range of 0 (healthy) to 10 (severe COPD).

The mITT population included all participants who were randomized into the study and received any investigational product. Here, 'N' signifies those participants evaluable for this measure.

The BODE index is a multi-dimension COPD grading system that incorporates body-mass index (B), degree of airflow obstruction (O), dyspnea (D), and exercise capacity (E) as measured by the modified medical research council (MMRC) dyspnea scale and the 6-minute walk test. The MMRC dyspnea scale is a 5-point scale that measures the level of dyspnea (trouble breathing) experienced by participants where score range is 0 (none) to 4 (very severe). BODE score is derived into a score range of 0 (healthy) to 10 (severe COPD). Negative change score signifies improvement compared to baseline. Number of participants with improvement in BODE score compared to baseline were reported.

The mITT population included all participants who were randomized into the study and received any investigational product. Here, 'N' signifies those participants evaluable for this measure.

An adverse event (AE) was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. A serious adverse event (SAE) was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. Treatment-emergent are events between administration of study drug and up to Week 69 that were absent before treatment or that worsened relative to pre-treatment state. TEAEs reported below included both SAEs and non-serious AEs.

Safety population included all participants who were randomized and received at least one dose of investigational product.

PK population included all participants who were randomized, received at least one dose of investigational product, and had at least one post-dose serum concentration.

Anti-drug antibodies for MEDI8968 were analyzed for participants who received placebo or MEDI8968 as per planned analysis.

Immunogenicity (IM) population included all participants who were randomized, received at least one dose of investigational product, and had at least one post-dose serum sample for IM testing.