Time from first dose of study treatment to first event of VTE was evaluated using hazard ratio as the measure of treatment effect, estimated from Cox proportional hazards regression model. The analysis was based on pooled data from studies JAJA (NCT03915964) and JAJD (NCT04086745) and was stratified by study, with treatment group and randomization stratification factors (VTE history, age/Body Mass Index (BMI) combination, prior inadequate response or intolerance to a TNF inhibitor, and geographic region) as explanatory variables.

All participants from the pooled analysis set. As per the planned analysis, for the Baricitinib 2/4 mg arm, all events from the Baricitinib 2 mg or 4 mg arms were attributed to it, with no censoring applied after initiation of rescue treatment or any non-permitted RA treatments.

Time from first dose of study treatment to first event of VTE was evaluated using hazard ratio as the measure of treatment effect, estimated from Cox proportional hazards regression model. The analysis was based on pooled data from studies JAJA (NCT03915964) and JAJD (NCT04086745) and was stratified by study, with treatment group and randomization stratification factors (VTE history, age/Body Mass Index (BMI) combination, prior inadequate response or intolerance to a TNF inhibitor, and geographic region) as explanatory variables.

All participants from the pooled analysis set. As per the planned analysis, for the baricitinib 2 mg and 4 mg arms, events occurring after initiation of rescue treatment or any non-permitted RA treatments were censored.

Time from first dose of study treatment to first ATE was evaluated using hazard ratio as the measure of treatment effect, estimated from Cox proportional hazards regression model. The analysis was based on pooled data from studies JAJA (NCT03915964) and JAJD (NCT04086745) and was stratified by study, with treatment group and randomization stratification factors (VTE history, age/BMI combination, prior inadequate response or intolerance to a TNF inhibitor, and geographic region) as explanatory variables.

All participants from the pooled analysis set. As per the planned analysis, for the baricitinib 2 mg and 4 mg arms, events occurring after initiation of rescue treatment or any non-permitted RA treatments were censored. For the baricitinib 2/4 mg arm, all events from the baricitinib 2 mg or 4 mg arms were attributed to it, with no censoring applied after initiation of rescue treatment or any non-permitted RA treatments.

Time from first dose of study treatment to first MACE was evaluated using hazard ratio as the measure of treatment effect, estimated from Cox proportional hazards regression model. The analysis was based on pooled data from studies JAJA (NCT03915964) and JAJD (NCT04086745) and was stratified by study, with treatment group and randomization stratification factors (VTE history, age/BMI combination, prior inadequate response or intolerance to a TNF inhibitor, and geographic region) as explanatory variables.

All participants from the pooled analysis set. As per the planned analysis, for the baricitinib 2 mg and 4 mg arms, events occurring after initiation of rescue treatment or any non-permitted RA treatments were censored. For the baricitinib 2/4 mg arm, all events from the baricitinib 2 mg or 4 mg arms were attributed to it, with no censoring applied after initiation of rescue treatment or any non-permitted RA treatments.

Time from first dose of study treatment to first malignancy (excluding NMSC) was evaluated using hazard ratio as the measure of treatment effect, estimated from Cox proportional hazards regression model. The analysis was based on pooled data from studies JAJA (NCT03915964) and JAJD (NCT04086745) and was stratified by study, with treatment group and randomization stratification factors (VTE history, age/BMI combination, prior inadequate response or intolerance to a TNF inhibitor, and geographic region) as explanatory variables.

All participants from the pooled analysis set. As per the planned analysis, for the baricitinib 2 mg and 4 mg arms, events occurring after initiation of rescue treatment or any non-permitted RA treatments were censored. For the baricitinib 2/4 mg arm, all events from the baricitinib 2 mg or 4 mg arms were attributed to it, with no censoring applied after initiation of rescue treatment or any non-permitted RA treatments.

Time from first dose of study treatment to first opportunistic infection was evaluated using hazard ratio as the measure of treatment effect, estimated from Cox proportional hazards regression model. The analysis was based on pooled data from studies JAJA (NCT03915964) and JAJD (NCT04086745) and was stratified by study, with treatment group and randomization stratification factors (VTE history, age/BMI combination, prior inadequate response or intolerance to a TNF inhibitor, and geographic region) as explanatory variables.

All participants from the pooled analysis set. As per the planned analysis, for the baricitinib 2 mg and 4 mg arms, events occurring after initiation of rescue treatment or any non-permitted RA treatments were censored. For the baricitinib 2/4 mg arm, all events from the baricitinib 2 mg or 4 mg arms were attributed to it, with no censoring applied after initiation of rescue treatment or any non-permitted RA treatments.

Time from first dose of study treatment to first serious infection was evaluated using hazard ratio as the measure of treatment effect, estimated from Cox proportional hazards regression model. The analysis was based on pooled data from studies JAJA (NCT03915964) and JAJD (NCT04086745) and was stratified by study, with treatment group and randomization stratification factors (VTE history, age/BMI combination, prior inadequate response or intolerance to a TNF inhibitor, and geographic region) as explanatory variables.

All participants from the pooled analysis set. As per the planned analysis, for the baricitinib 2 mg and 4 mg arms, events occurring after initiation of rescue treatment or any non-permitted RA treatments were censored. For the baricitinib 2/4 mg arm, all events from the baricitinib 2 mg or 4 mg arms were attributed to it, with no censoring applied after initiation of rescue treatment or any non-permitted RA treatments.

Duration of exposure was calculated as:

• Baricitinib 2mg exposure = date of last baricitinib 2mg treatment - date of first baricitinib 2mg dose + 1. For participants who were rescued from baricitinib 2 mg to 4 mg, their drug exposure after rescue was censored and not counted as exposure to baricitinib 2mg.
• Baricitinib 4mg exposure = date of last baricitinib 4mg treatment - date of first baricitinib 4mg dose + 1.
• TNF inhibitor exposure = date of last TNFi (adalimumab or etanercept) - date of first TNFi dose (adalimumab or etanercept) + 1, regardless of treatment cycling from adalimumab to etanercept or vice versa.
• Total baricitinib exposure (2/4 mg) = date of last baricitinib (2mg or 4mg) treatment - date of first baricitinib (2mg or 4mg) dose + 1, regardless of rescue from baricitinib 2mg to baricitinib 4mg.

Patient-years is calculated as sum of duration of exposure in days for all patients in dosing regimen divided by 365.25.

All participants from the safety analysis set.