PFS assessed by BICR was defined as the time from the date of randomization to the date of the first documentation of objective progression of disease (PD) per RECIST v1.1, or death due to any cause, whichever occurred first. PD as per RECIST v1.1 was defined as at least a 20% increase in the sum of diameters of target measurable lesions above nadir (smallest sum observed considering baseline and all assessments prior to the timepoint under evaluation), with a minimum absolute increase of 5 millimeters (mm) relative to nadir or unequivocal progression of existing non-target lesions or the presence of new lesions. PFS was censored on the date of last adequate disease assessment for those who did not have a PFS event, discontinued the study treatment due to withdrawal of consent prior to an event, started a new anticancer therapy prior to an event, had an event after a gap of 2 or more missing disease assessments, or lost to follow-up. Kaplan-Meier method was used.

PFS assessed by BICR was defined as the time from the date of randomization to the date of the first documentation of objective PD per RECIST v1.1, or death due to any cause, whichever occurred first. PD as per RECIST v1.1 was defined as at least a 20% increase in the sum of diameters of target measurable lesions above nadir (smallest sum observed considering baseline and all assessments prior to the timepoint under evaluation), with a minimum absolute increase of 5 mm relative to nadir or unequivocal progression of existing non-target lesions or the presence of new lesions. PFS was censored on the date of last adequate disease assessment for those who did not have a PFS event, discontinued the study treatment due to withdrawal of consent prior to an event, started a new anticancer therapy prior to an event, had an event after a gap of 2 or more missing disease assessments, or lost to follow-up. Kaplan-Meier method was used.

Dose Limiting Toxicities rate for ARV-471 in combination with Ribociclib, estimated based on data from DLT-evaluable participants during the DLT observation period (Cycle 1 \[28 days\]).

Objective response (OR) refers to confirmed complete response (CR) or partial response (PR) according to Response Evaluation Criteria in Solid Tumor (RECIST) version 1.1. as determined by investigator assessment.

Exposure (AUCtau) of ribociclib with and without co-administration of ARV-471

Concentration (Cmax) of ribociclib with and without co-administration of ARV-471

Maximum plasma concentration

Area under the concentration-time profile from time zero to time tau (τ), the dosing interval, where tau = 24 hours (QD dosing)

Maximum Observed Plasma Concentration (Cmax)

Area under the concentration curve from time 0 to end of dosing interval (AUCtau), where dosing interval was 24 hours.

Cmax was defined as maximum observed plasma concentration. Cmax for total dabigatran was observed directly from data.

AUCinf was defined as area under the concentration-time curve from time 0 extrapolated to infinity. AUCinf was calculated by AUClast + (Clast/kel), where Clast was the predicted plasma concentration at the last quantifiable time point from the log-linear regression analysis and kel was the terminal phase rate constant calculated by a linear regression of the log-linear concentration time curve; AUClast was defined as area under the plasma concentration-time profile from time 0 to the time of the last quantifiable concentration.

Cmax was defined as maximum plasma concentration. Cmax of rosuvastatin was observed directly from data.

AUClast was defined as area under the plasma concentration-time profile from time 0 to the time of the last quantifiable concentration. AUClast of rosuvastatin was determined using Linear/Log trapezoidal method.