Clinical Trials




A Phase II Randomized, Double-Blind, Parallel Cohort Study of Neoadjuvant Letrozole + GDC-0032 versus Letrozole + Placebo in Post-Menopausal Women with ER+/HER2- Primary Breast Cancer

Primary Objective

Co-Primary Objectives
To evaluate the efficacy of combining GDC-0032 with letrozole in women with ER+/HER2- early breast cancer, in terms of the co-primary endpoints of Tumor overall response rate (ORR), assessed by RECIST criteria by breast MRI; Pathological complete response in breast and axilla (total pCR).
Key Secondary Objectives
1. To compare the efficacy of neoadjuvant treatment with letrozole plus GDC-0032 with letrozole plus placebo in terms of: Residual cancer burden (RCB); Preoperative endocrine prognostic index (PEPI) score; Decrease of Ki67 from baseline to surgery, from W3 to surgery, and from W3 to W5 (in those patients who consent for W5 biopsy); ORR by physical examination, breast US and volumetric criteria by breast MRI.
2. To assess the decrease in Ki67 after 2 weeks on letrozole in the overall population, and according to PIK3CA mutational status.
3. To evaluate the safety and tolerability of the experimental regimen during treatment and up to 30 days after its discontinuation.
4. To compare the rate of breast conserving surgery (BCS).


Parallel, 2-arm, randomized, double-blind, multicenter, pre-operative study to evaluate the effect of combining GDC-0032 to standard neoadjuvant aromatase inhibitor therapy with letrozole in postmenopausal women with ER+/HER2- untreated, stage I-III operable breast cancer.

Sample size: 331

LACOG Study Coordinator: Gustavo Werutsky

Status: Recruiting.

Sponsor: Genentech




Phone: 55 51 3384 5334