A Study of Abiraterone Acetate Plus Prednisone With or Without Abemaciclib (LY2835219) in Participants With Prostate Cancer

The rPFS time is measured from the date of randomization to the earliest date of investigator determined radiographic disease progression (by objective radiographic disease assessment per response evaluation criteria in solid tumors (RECIST) version 1.1 for soft tissue AND/OR radionuclide bone scan using prostate cancer working group 3 -PCWG3 criteria for bone) or death from any cause, whichever occurs first.

The PSA progression is defined as a greater than or equal to (>=) 25 percentage (%) increase and an absolute increase of >=2 nanogram/milliliter (ng/mL) above the nadir (or baseline value if baseline is the smallest on study), which is confirmed by a second value obtained 3 or more weeks later.

rPFS is defined as the time from the date of randomization to the earliest date of radiographic disease progression determined by blinded independent central review (BICR) or death from any cause, whichever occurs first.

ORR is a summary measure of best overall response (BOR) as defined by RECIST 1.1 for soft tissue per investigator assessment. BOR is derived from time point responses. All time point responses observed while on study treatment and during the short-term follow-up period (but before the initiation of post-discontinuation systemic anticancer therapy) will be included in the derivation.

Each patient's BOR will be categorized as complete response (CR), partial response (PR), stable disease (SD), progressive disease (PD), or not evaluable (NE). A BOR of CR or PR will require confirmation, but sensitivity analyses of response-based endpoints may be performed where confirmation of a BOR of CR or PR is not required.

The DoR time is defined only for responders (participants with a soft tissue BOR of CR or PR) in the measurable disease population. It is measured from the date of first evidence of soft tissue CR or PR to the earliest date of investigator determined radiographic disease progression or death from any cause, whichever is earlier.

The OS time is measured from the date of randomization to the date of death from any cause. If the participant was alive or lost to follow-up at the time of data analysis, OS data were censored on the last date the participant was known to be alive.

Time to symptomatic progression is defined as the time from randomization to any of the following (whichever occurs earlier):

• Symptomatic Skeletal Event (SSE), defined as symptomatic fracture, surgery or radiation to bone, or spinal cord compression.
• Pain progression or worsening of disease-related symptoms requiring initiation of a new systemic anti-cancer therapy.
• Development of clinically significant symptoms due to loco-regional tumor progression requiring surgical intervention or radiation therapy.

PK: Mean steady state exposure of abemaciclib.

PK: Mean steady state exposure of abemaciclib metabolite LSN2839567.

PK: Mean steady state exposure of abemaciclib metabolite LSN3106726.

PK: Mean Steady State Exposure of Abiraterone Acetate.

Time to Worst Pain Progression defined as the time from randomization to any of the following (whichever occurs earlier): For participants without opioid use at baseline (World Health Organization-Analgesic Ladder-WHO-AL ≤ 2):- Worst pain progression (an increase of 2 points from baseline on the Worst Pain Numeric Rating Scale (NRS) item on 2 consecutive evaluations), Initiation of weak or strong opioids (WHO-AL ≥ 3); For participants with weak or strong opioid use at baseline (WHO-AL ≥ 3): Worst pain progression (an increase of 2 points from baseline on the Worst Pain NRS item on 2 consecutive evaluations) without concurrent decreased opioid use (a decrease in WHO-AL of 1 or more) -Increased opioid use (an increase in WHO-AL of 1 or more).