Pirfenidone

FVC is a standard pulmonary function test. FVC is defined as the volume of air that can forcibly be blown out after full inspiration in the upright position, measured in liters. Baseline FVC will be the average of the highest FVC measurement recorded at the Screening and Day 1. The FVC at Week 26 will be the average of the highest FVC measurement recorded on two separate days at Week 26.

Predicted FVC is based on sex, age, and height of a person. Percent predicted FVC (in %) = \[(observed FVC)/(predicted FVC)\]\*100.

An adverse event defined as any unfavorable, harmful, or pathologic change in a research participant administered a pharmaceutical study treatment as indicated by physical signs, symptoms, and/or clinically significant laboratory abnormalities that occurred during the treatment and the post-treatment period, regardless of suspected cause.

Mean Change in Percent Predicted Forced Vital Capacity (FVC) as measured from baseline to week 72.

Mean Change in Percent Predicted Forced Vital Capacity (FVC) as measured from baseline to week 72. It is calculated as the simple difference between baseline Percent Predicted FVC measurements and week 72 Percent Predicted FVC measurements.

Rate of decline in FVC was measured in mL by daily handheld spirometer. The analyses were repeated due to an additional independent review of the home spirometry data.

Disease Progression defined as relative decline in 6-minute walking distance (6MWD) from baseline (defined as \>25% from baseline or 15-25% from baseline associated with worsening oxygen saturation, worsening Borg score, or increased oxygen requirements), respiratory-related non-elective hospitalizations, or all-cause mortality.

Annualized rates of decrease (slope throughout time from baseline to Week 52) for percent predicted FVC was assessed and reported. FVC is a standard pulmonary function test. FVC is defined as the volume of air that can forcibly be blown out after full inspiration in the upright position, measured in liters. Predicted FVC is based on sex, age, and height of a person. Percent predicted FVC (in %) = \[(observed FVC)/(predicted FVC)\]\*100.

Percentage of participants who had treatment-emergent AEs, defined as newly occurring or worsening after first dose. Relatedness to (study drug) was assessed by the investigator (Yes/No). Participants with multiple occurrences of an AE within a category were counted once within the category.

An 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 first dose of study drug and up to 28 days after last dose that were absent before treatment or that worsened relative to pretreatment state.

Percentage of participants with dose reductions in N-Acetylcysteine and placebo cohorts during the 24-week treatment period.

Percentage of participants with early treatment discontinuations in N-Acetylcysteine and placebo cohorts during the 24-week treatment period.

An adverse event (AE) is defined as any untoward medical occurrence in a participant who is administered a study treatment regardless of whether or not the event has a causal relationship with the treatment. An AE, therefore, could be any unfavorable or unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the study treatment, whether or not related to the treatment.

An AE was any untoward medical occurrence attributed to study drug in a participant who received study drug. An 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. AEs were classified as severe (Grade 3) in following cases: marked limitation in activity; some assistance usually required; medical intervention/ therapy required, hospitalization possible. Treatment-emergent AEs were those occurring on or after the first dosing day and up to 28 days after discontinuation of study treatment, and those occurring before treatment that worsened after the first study dose. AE included serious as well as non-serious AEs.

An adverse event is any untoward medical occurrence in a participant who receive study drug without regard to possibility of causal relationship. A serious adverse event is an adverse event 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.

An adverse event is any untoward medical occurrence in a participant who receive study drug without regard to possibility of causal relationship. Relatedness to the study drug will be assessed by the investigator.

An adverse event is any untoward medical occurrence in a participant who receive study drug without regard to possibility of causal relationship.

Vital signs and laboratory parameters will be evaluated, and percentage of participants with any clinically meaningful abnormalities as assessed by Investigator will be reported. Laboratory abnormalities of National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) Grade greater than (\>) 3 will be considered clinical meaningful.