Document Classification

Section Type: RESULTS

Text: In cohort 1 (n = 66), median progression-free survival was 5. 7 months (2. 6-10. 5) for the letrozole group and 26. 1 months (11. 2-not estimable) for the palbociclib plus letrozole group (HR 0. 299, 0. 156-0. 572 ; one-sided p < 0. 0001) ; in cohort 2 (n = 99), median progression-free survival was 11. 1 months (7. 1-16. 4) for the letrozole group and 18. 1 months (13. 1-27. 5) for the palbociclib plus letrozole group (HR 0. 508, 0. 303-0. 853 ; one-sided p = 0. 0046).