BIIB104

The MCCB is a cognitive battery that assesses 7 domains recommended by the MATRICS initiative (i.e., Working Memory, Verbal Learning, Speed of Processing, Attention/Vigilance, Visual Learning, Social Cognition, and Reasoning and Problem Solving). MCCB was administered via laptop computer and paper-and-pencil assessments. T-scores for the individual tests were calculated according to the developer's recommended scoring algorithms. MCCB composite T scores are between 40 and 60 (normal range). Higher scores indicate better cognitive functioning. The working memory domain score of the MCCB is reported in this outcome measure.

Cmax steady state for PF-04958242 0.25 mg group and PF-04958242 0.475 mg group at Day 14 were presented.

Tmax steady state for PF-04958242 0.25 mg group and PF-04958242 0.475 mg group at Day 14 were presented.

AUCτ steady state for PF-04958242 0.25 mg group and PF-04958242 0.475 mg group at Day 14 were presented.

Clearance of a drug is a measure of the rate at which a drug is metabolized or eliminated by normal biological processes. Clearance obtained after oral dose (apparent oral clearance) is influenced by the fraction of the dose absorbed. Clearance was estimated from population pharmacokinetic modeling. Drug clearance is a quantitative measure of the rate at which a drug substance is removed from the blood. CL/F steady state for PF-04958242 0.25 mg group and PF-04958242 0.475 mg group at Day 14 were presented.

Volume of distribution is defined as the theoretical volume in which the total amount of drug would need to be uniformly distributed to produce the desired plasma concentration of a drug. Apparent volume of distribution after oral dose (Vz/F) is influenced by the fraction absorbed. Vz/F steady state for PF-04958242 0.25 mg group and PF-04958242 0.475 mg group at Day 14 were presented.

Terminal half-life is the time measured for the plasma concentration to decrease by one half. t1/2 steady state for PF-04958242 0.25 mg group and PF-04958242 0.475 mg group at Day 14 were presented.

Accumulation ratio was calculated as, Rac obtained from Area Under the Concentration Time Curve (AUC) from time 0-t (Day X) divided by AUC from time 0-t (Day 1). Rac steady state for PF-04958242 0.25 mg group and PF-04958242 0.475 mg group at Day 14 (ie. X = 14) were presented.

Accumulation ratio based on Cmax was calculated as: Rac,Cmax = Cmax at steady state (ss) divided by Cmax at first dose. Rac, Cmax steady state for PF-04958242 0.25 mg group and PF-04958242 0.475 mg group at Day 14 were presented.

PTR was calculated as Cmax divided by Cmin (that is defined as lowest concentration observed during the dosing interval). PTR steady state for PF-04958242 0.25 mg group and PF-04958242 0.475 mg group at Day 14 were presented.

The following laboratory parameters were reported: hematology (hemoglobin, hematocrit, red blood cell \[RBC\] count, mean corpuscular volume \[MCV\], mean corpuscular hemoglobin \[MCH\], mean corpuscular hemoglobin concentration \[MCHC\], platelet count, white blood cell \[WBC\] count, total neutrophils, eosinophils, monocytes, basophils, lymphocytes); blood chemistry (blood urea nitrogen \[BUN\], creatinine, glucose, calcium, sodium, potassium, chloride, total bicarbonate, aspartate aminotransferase \[AST\], alanine aminotransferase \[ALT\], total bilirubin, alkaline phosphatase, phosphorus, cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL), bicarbonate, uric acid, albumin, and total protein); urinalysis (color, appearance, specific gravity, pH, glucose, protein, blood, ketones, nitrites, leukocyte esterase, and microscopy); others (follicle stimulating hormone \[FSH\], and urine drug screening).

Vital signs assessment included pulse rate and blood pressure. Criteria for vital sign values meeting potential clinical concern included: supine/sitting pulse rate less than (\<) 40 or greater than (\>) 120 beats per minute (bpm), standing pulse rate \<40 or \>140 bpm; systolic blood pressure (SBP) greater than or equal to (\>=) 30 millimeters of mercury (mm Hg) change from baseline in same posture or SBP \<90 mm Hg, diastolic blood pressure (DBP) \>=20 mm Hg change from baseline in same posture or DBP \<50 mm Hg. IFB = increase from baseline; DFB = decrease from baseline.

Electrocardiogram (ECG) parameters included beginning of the P wave until the beginning of the QRS complex (PR) interval, time from ECG Q wave to the end of the S wave corresponding to ventricle depolarization (QRS) interval, and QTc using Fridericia's formula (QTcF). Criteria for ECG changes meeting potential clinical concern included: PR interval \>=300 milliseconds (msec) or \>=25% increase when baseline is \>200 msec and \>=50% increase when baseline is less than or equal to (=\<)200 msec; QRS interval \>=140 msec or \>=50% increase from baseline (IFB); and and QTcF \>=450 to \<480, 480 to \<500 and \>=500 msec. The number of participants with potentially clinically significant ECG findings at any visit were reported.

The extended neurological examination, performed by a board certified neurologist, included observation for cerebellar (intention) tremor and for non-cerebellar tremors (eg, resting or positional), finger, nose, heel, shin, Romberg, tandem walking, positional and gaze evoked nystagmus, reflexes, muscle strength, cranial nerves, sensory function of upper and lower extremities. The brief neurological examination included an assessment of motor and sensory function, cranial nerves, reflexes, non-cerebellar tremor (eg, resting or positional) and cerebellar function. The assessment of cerebellar function were complemented by the Scale for Assessment and Rating of Ataxia (SARA).

A full physical examination included head, ears, eyes, nose, mouth, skin, heart and lung examinations, lymph nodes, gastrointestinal, musculoskeletal, and neurological systems. The brief physical examination focused on general appearance, the respiratory and cardiovascular systems, as well as towards participant reported symptoms.

An AE was any untoward medical occurrence in a participant who received study drug. 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 pre-treatment state. AEs included both SAEs and non-SAEs.

The C-SSRS (mapped to Columbia Classification Algorithm of Suicide Assessment \[C-CASA\]) is an interview-based rating scale to systematically assess suicidal ideation and suicidal behavior. C-SSRS assessed whether participant experienced the following: completed suicide (1), suicide attempt (2) (response of "Yes" on "actual attempt"), preparatory acts toward imminent suicidal behavior (3)("Yes" on "preparatory acts or behavior"), suicidal ideation (4) ("Yes" on "wish to be dead", "non-specific active suicidal thoughts", "active suicidal ideation with methods without intent to act or some intent to act, without specific plan or with specific plan and intent), any suicidal behavior or ideation, self-injurious behavior (7)("Yes" on "Has participant engaged in non-suicidal self-injurious behavior").