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The safety and efficacy of this agent(s), or use in this setting, has not been established or is subject to confirmation. For an agent(s) whose safety and efficacy has not been established or confirmed, future regulatory approval or commercial availability is not guaranteed.
Atirmociclib (PF-07220060) is an investigational compound. Its safety and efficacy have not been established.
Active enrolling
United States, Australia, Belgium, Italy, Korea, Republic of, Poland, Slovakia, Spain, Sweden, Taiwan
for more information at clinicaltrials.gov
EXPERIMENTAL: Arm A/Experimental/PF-07220060 plus letrozole
PF-07220060 given as tablet by mouth twice a day for 14 days. Letrozole given as tablet by mouth once a day for 14 days.
DRUG: PF-07220060
PF-07220060 given as tablet by mouth twice a day for 14 days.
DRUG: letrozole
Letrozole given as tablet by mouth once a day for 14 days
ACTIVE_COMPARATOR: Arm B/Control/letrozole
Letrozole given by mouth once a day for 14 days.
DRUG: letrozole
Letrozole given as tablet by mouth once a day for 14 days
Rate of Ki-67
Centrally assessed biopsy
Day 14
Incidence of Adverse Events (AEs)
Baseline, Day 14, and Day 28 post last treatment follow-up visit
Incidence of Serious AEs
Baseline, Day 14, and Day 28 post last treatment follow-up visit
Incidence of AEs leading to Discontinuation
Baseline, Day 14, and Day 28 post last treatment follow-up visit
Ctrough and peri-biopsy plasma concentrations of PF-07220060
Ctrough was defined as pre-dose serum concentration during multiple dosing and observed directly from data.
Pre-dose within 30 minutes and post-dose within 1 hour before or after biopsy
Circulating tumor DNA (ctDNA) measurements
Evaluate response on treatment
Baseline and Day 14
Percentage of Ki-67
All participants will have Ki-67 staining from the biopsy sample on Day 14 and Screening if not previously available
Screening and Day 14
118
Sponsor: Pfizer
Collaborator: None
For more information, call or email the Pfizer Clinical Trial Contact Center:
When calling, please reference this study number: