A Study to Evaluate the Efficacy and Safety of Intravenous Prasinezumab in Participants With Early Parkinson's Disease

Time to confirmed motor progression event was the first time point of a worsening event defined as either >= 5 points increase in MDS-UPDRS Part III score (assessed in "OFF" medication state) from baseline sustained over 2 consecutive assessments or a change in medication after first occurrence of >= 5 points increase in MDS-UPDRS Part III score from baseline & before follow-up assessment. MDS-UPDRS Part III is a clinician rater scale that assessed the motor signs of PD. The scale is composed of 18 clinical domains or tasks, which yield 33 distinct scores or ratings. For each distinct rating, a numeric score is assigned between 0-4, where 0 = Normal, 1 = Slight, 2 = Mild, 3 = Moderate, and 4 = Severe. The total MDS-UPDRS Part III score (ranging from 0 to 132) is calculated by summing these 33 individual ratings, with higher scores indicating severe impairment.

Time to worsening of the motor function was defined as ≥3 points increase in MDS-UPDRS Part II score from baseline in the presence of a confirmed motor progression event. For the confirmed motor progression event the definition is as per primary endpoint definition. MDS-UPDRS Part II assesses motor experiences of daily living & contained 13 questions answered by participant. For each question a numeric score is assigned between 0-4, 0 = Normal, 1=Slight, 2=Mild, 3=Moderate, 4=Severe. Score range: 0 to 52 with higher score=severe impairment.

The PGI is a measure commonly used in PD clinical trials to provide a concise assessment of overall health state. The change component (PGI-C) was intended to measure health state changes as reported by the participant on a 7-point scale (1=Very much improved to 7=Very much worse). The meaningfulness of the change was assessed and reported by the participant.

The CGI was a measure commonly used in PD clinical trials to provide a concise assessment of overall health state. The change component (CGI-C) was intended to measure health state changes as reported by the clinician on a 7-point scale (1=Very much improved to 7=Very much worse).

MDS-UPDRS Part IV assessed motor complications of symptomatic treatment, dyskinesias, and motor fluctuations. The rater completed this assessment only for participants on L-Dopa treatment.

MDS-UPDRS Part III is a clinician rater scale that assessed the motor signs of PD. The scale is composed of 18 clinical domains or tasks, which yield 33 distinct scores or ratings. For each distinct rating, a numeric score is assigned between 0-4, where 0 = Normal, 1 = Slight, 2 = Mild, 3 = Moderate, and 4 = Severe. The total MDS-UPDRS Part III score (ranging from 0 to 132) is calculated by summing these 33 individual ratings, with higher scores indicating severe impairment.

MDS-UPDRS Part III is a clinician rater scale that assessed the motor signs of PD. The scale is composed of 18 clinical domains or tasks, which yield 33 distinct scores or ratings. For each distinct rating, a numeric score is assigned between 0-4, where 0 = Normal, 1 = Slight, 2 = Mild, 3 = Moderate, and 4 = Severe. For bradykinesia, subscore ranges from 0 to 52, while rigidity subscore ranges from 0 to 20, with higher scores indicating greater impairment. Change in bradykinesia and rigidity was assessed in "OFF" medication state. Adjusted mean is reported here.

An AE was any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (including abnormal laboratory values or abnormal clinical test results), symptoms, or disease temporally associated with the use of a pharmaceutical product, whether or not considered related to the pharmaceutical product. SAE is any significant hazard, contraindication, or side effect that is fatal or life-threatening, requires hospitalization or prolongation of an existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, is medically significant or requires intervention. Number of participants with atleast 1 AE and SAE are reported here.

An AE was any untoward medical occurrence in participant administered a pharmaceutical product & which does not necessarily have to have a causal relationship with treatment. It can therefore be any unfavorable and unintended sign (including abnormal laboratory values/ abnormal clinical test results), symptoms/disease temporally associated with use of pharmaceutical product, whether/not considered related to product. AESIs included potential drug-induced liver injury that include an elevated alanine transaminase (ALT) & aspartate aminotransferase (AST) in combination with either an elevated bilirubin/clinical jaundice defined by Hy's law and suspected transmission of an infectious agent by study drug.

An AE was any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (including abnormal laboratory values or abnormal clinical test results), symptoms, or disease temporally associated with the use of a pharmaceutical product, whether or not considered related to the pharmaceutical product.

IRRs were defined as any signs and symptoms (AEs) occurring during infusion and/or within 24 hours administration after the end of infusion and were considered related to study treatment by the investigator. Symptoms include flushing, rash, respiratory difficulty, hypotension, tachycardia.

C-SSRS=assessment tool used to assess lifetime suicidality of participant (at baseline) as well as any new instances of suicidality (C-SSRS since last visit). Structured interview prompts recollection of suicidal ideation, including intensity of ideation, behavior, and attempts with actual/potential lethality. Categories have binary responses (yes/no) and include Wish to be Dead; Non-specific Active Suicidal Thoughts; Active Suicidal Ideation with Any Methods (Not Plan) without Intent to Act; Active Suicidal Ideation with Some Intent to Act, without Specific Plan; Active Suicidal Ideation with Specific Plan and Intent, Preparatory Acts and Behavior; Aborted Attempt; Interrupted Attempt; Actual Attempt (non-fatal); Completed Suicide. Suicidal ideation/behavior is indicated by a "yes" answer to any of the listed categories. Score of 0 is assigned if no suicide risk is present. Score of 1 or higher= suicidal ideation or behavior. Categories with non-zero values are only reported here.

An AE was any untoward medical occurrence in a participant administered a pharmaceutical product and which does not necessarily have to have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (including abnormal laboratory values or abnormal clinical test results), symptoms, or disease temporally associated with the use of a pharmaceutical product, whether or not considered related to the pharmaceutical product. SAE is any significant hazard, contraindication, or side effect that is fatal or life-threatening, requires hospitalization or prolongation of an existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, is medically significant or requires intervention.

An AE was any untoward medical occurrence in participant administered a pharmaceutical product & which does not necessarily have to have a causal relationship with treatment. It can therefore be any unfavorable and unintended sign (including abnormal laboratory values/ abnormal clinical test results), symptoms/disease temporally associated with use of pharmaceutical product, whether/not considered related to product. AESIs included potential drug-induced liver injury that include an elevated ALT & AST in combination with either an elevated bilirubin/clinical jaundice defined by Hy's law and suspected transmission of an infectious agent by study drug.

IRRs were defined as any signs and symptoms (AEs) occurring during infusion and/or within 24 hours administration after the end of infusion and were considered related to study treatment by the investigator. Symptoms include flushing, rash, respiratory difficulty, hypotension, tachycardia.

C-SSRS=assessment tool used to assess lifetime suicidality of participant (at baseline) as well as any new instances of suicidality (C-SSRS since last visit). Structured interview prompts recollection of suicidal ideation, including intensity of ideation, behavior, and attempts with actual/potential lethality. Categories have binary responses (yes/no) and include Wish to be Dead; Non-specific Active Suicidal Thoughts; Active Suicidal Ideation with Any Methods (Not Plan) without Intent to Act; Active Suicidal Ideation with Some Intent to Act, without Specific Plan; Active Suicidal Ideation with Specific Plan and Intent, Preparatory Acts and Behavior; Aborted Attempt; Interrupted Attempt; Actual Attempt (non-fatal); Completed Suicide. Suicidal ideation/behavior is indicated by a "yes" answer to any of the listed categories. Score of 0 is assigned if no suicide risk is present. Score of 1 or higher= suicidal ideation or behavior.