Document Type: SAP Official Title: A Phase IIIB, Double-Blind, Multicenter Study to Evaluate the Efficacy and Safety of Alteplase in Patients With Mild Stroke: Rapidly Improving Symptoms and Minor Neurologic Deficits (PRISMS) NCT Number: NCT02072226 Document Date(s): SAP: 17 May 2017 STATISTICAL ANALYSIS PLAN DATE DRAFT: 16 May 2017 IND NUMBER: 3811 PLAN PREPARED BY: PROTOCOL NUMBER: ML29093 / NCT02072226 SPONSOR: Genentech, Inc. STUDY DRUG: Alteplase (RO5532960) TITLE: A PHASE IIIB, DOUBLE-BLIND, MULTICENTER STUDY TO EVALUATE THE EFFICACY AND SAFETY OF ALTEPLASE IN PATIENTS WITH MILD STROKE (RAPIDLY IMPROVING SYMPTOMS AND MINOR NEUROLOGIC DEFICITS (PRISMS) VERSION: 1.0 Confidential Page 1 This is a Genentech, Inc. document that contains confidential information. Nothing herein is to be disclosed without written consent from Genentech, Inc. Statistical Analysis Plan: Alteplase—Genentech USMA 1/ML29093 5/17/2017 Abbreviated Clinical Study Report: Alteplase—Genentech, Inc. 762/aCSR ML29093 TABLE OF CONTENTS Page 1. BACKGROUND ................................................................................................. 5 2. STUDY DESIGN ............................................................................................... 6 2.1 Synopsis ................................................................................................. 6 2.2 Outcome Measures ................................................................................ 6 2.2.1 Primary Efficacy Outcome Measures ........................................ 6 2.2.2 Secondary Efficacy Outcome Measures ................................... 6 2.2.3 Exploratory Efficacy Outcome Measures .................................. 7 2.2.4 Safety Outcome Measures ........................................................ 7 2.3 Determination of Sample Size ................................................................ 8 2.4 Analysis Timing....................................................................................... 9 3. STUDY CONDUCT ........................................................................................... 9 3.1 Randomization Issues ............................................................................ 9 3.2 Data Monitoring .................................................................................... 10 3.2.1 Safety Review Timing ............................................................. 10 4. STATISTICAL METHODS ............................................................................... 11 4.1 Analysis Populations ............................................................................. 11 4.1.1 Intent-to-Treat Population........................................................ 11 4.1.2 Per-Protocol Population .......................................................... 11 4.1.3 Safety Population .................................................................... 12 4.2 Analysis of Study Conduct .................................................................... 12 4.3 Analysis of Treatment Group Comparability ......................................... 12 4.4 Efficacy Analyses.................................................................................. 13 4.4.1 Primary Efficacy Endpoint ....................................................... 14 4.4.2 Secondary Efficacy Endpoints ................................................. 15 4.4.3 Exploratory Efficacy Endpoints ................................................ 17 4.4.4 Subgroup Analyses ................................................................. 19 4.5 Cognitive, Behavioral and Patient Reported Outcome Analyses ............................................................................................... 22 4.5.1 Cognitive Assessments ........................................................... 22 4.5.2 Ambulatory Performance......................................................... 23 4.5.3 Patient Reported Outcomes .................................................... 23 4.6 Safety Analyses .................................................................................... 25 4.6.1 Exposure to Study Medication ................................................. 25 4.6.2 Adverse Events ....................................................................... 26 4.6.3 Neuroimaging .......................................................................... 27 Statistical Analysis Plan: Alteplase—Genentech USMA 2/ML29093 5/17/2017 Abbreviated Clinical Study Report: Alteplase—Genentech, Inc. 763/aCSR ML29093 TABLE OF CONTENTS (cont’d) Page 4.6.4 Laboratory Data ...................................................................... 29 4.6.5 Vital Signs ............................................................................... 30 4.6.6 Mortality................................................................................... 30 4.6.7 Previous and Concomitant Medications .................................. 30 4.7 Handling of Dropouts, Missing/Incomplete Data, or Outliers ................................................................................................. 30 4.8 Interim Analyses and/or Safety Reviews .............................................. 31 5. REFERENCES ................................................................................................ 31 TABLES AND FIGURES Table 1 Estimated Power for the Final Sample Size (N=313) ................................... 9 Table 2 Summary of Efficacy Analyses .................................................................. 21 Table 3 Cognitive Assessments ............................................................................. 22 Table 4 Intermediate Variables for the Next Allocation Probability ......................... 44 Table 5 Decisions Based on Site and Overall Imbalance ....................................... 44 Table 6 Baseline Characteristics to be Evaluated for Imbalance ............................ 50 Figure 1 Study Flowchart ....................................................................................... 42 Figure 2 Study Randomization Schema ................................................................. 45 Statistical Analysis Plan: Alteplase—Genentech USMA 3/ML29093 5/17/2017 Abbreviated Clinical Study Report: Alteplase—Genentech, Inc. 764/aCSR ML29093 TABLE OF CONTENTS (cont’d) Page APPENDICES Appendix A Protocol Synopsis Appendix B Schedule of Assessment and Study Flow Chart Appendix C Randomization Scheme Appendix D Statistical Methods Requiring Input Appendix E Documentation of Additional Analyses Performed after Database Lock Appendix F Data Handling Rules Appendix G Programming Codes for Statistical Analysis Statistical Analysis Plan: Alteplase—Genentech USMA 4/ML29093 5/17/2017 Abbreviated Clinical Study Report: Alteplase—Genentech, Inc. 765/aCSR ML29093 1. BACKGROUND Stroke is the fourth leading cause of death and a leading cause of disability in the United States (U.S.). More than half of all ischemic stroke patients have mild strokes at initial presentation in population-based studies (3; 10). Alteplase is the only approved therapeutic agent for the treatment of AIS (acute ischemic stroke) and is widely accepted as the standard of care for eligible patients (4; 6). The currently approved Activase® (alteplase) U.S. Package Insert (USPI) contains wording that recommends against use of alteplase in patients with “minor neurological deficit or with rapidly improving stroke symptoms” due to the fact this patient population has not been evaluated. Furthermore, the current American Heart Association/American Stroke Association Council Guidelines include “minor and rapidly improving stroke symptoms (clearing spontaneously)” as a relative exclusion criterion for alteplase (6). This is largely due to the aforementioned label wording not recommending treatment of patients with minor neurological deficit or with rapidly improving stroke symptoms (RISS), the lack of a consistent and consensus definition of who constitutes this patient population, and the absence of definitive evidence of alteplase efficacy in this setting (TREAT Task Force 2013). Therefore, this trial is designed to evaluate the efficacy and safety of alteplase in confirmed AIS patients with minor neurological deficit or with RISS, which will be referred to collectively as “mild stroke”. For further background information see Section 1 of the protocol. The original plan was for approximately 948 patients with mild stroke to be enrolled and randomized in a 1:1 ratio to two treatment groups. However the study enrollment was prematurely terminated due to recruitment below target in December 2016 (at approximately 1/3 of original planned enrollment of 948) and the analysis will be performed using available data from patients randomized prior to study termination. This Statistical Analysis Plan (SAP) describes the statistical methods to be used for the clinical study report of study ML29093. This version of the SAP has been developed using version 3 of the study protocol dated 08 Jan 2015. The SAP will be finalized by and approved by Genentech, Inc. before database lock and unblinding. Statistical Analysis Plan: Alteplase—Genentech USMA 5/ML29093 5/17/2017 Abbreviated Clinical Study Report: Alteplase—Genentech, Inc. 766/aCSR ML29093 2. STUDY DESIGN This is a double-blind, multicenter, randomized, Phase IIIb study to evaluate the efficacy and safety of IV alteplase in AIS patients with mild strokes that do not appear to be clearly disabling. The trial will consist of a screening assessment and randomization,