Clinical trial · Interventional
Pre-Operative Study of PF-4691502 With Letrozole Compared To Letrozole Alone In Patients With Early Breast Cancer
An Open-Label, Randomised Phase 1b/2 Study Of PF-04691502 In Combination With Letrozole Compared With Letrozole Alone In Patients With Estrogen Receptor Positive, Her-2 Negative Early Breast Cancer
- Source
- ClinicalTrials.gov
- Retrieved
- Sep 8, 2026
- Layer
- normalized (units and labels harmonized; values unchanged)
- Run
- ING-CLINICALTRIALS-20260908-000001
Why stopped (as posted): See termination reason in detailed description.
Summary
Brief summary (as posted)
PF-04691502 is an inhibitor of PI3K and mTOR kinase. Published data support the hypothesis that a PI3K/mTOR antagonist in combination with letrozole might mitigate the intrinsic or acquired resistance to hormonal therapy and restore hormone sensitivity in high risk (high Ki-67) patient population of hormone-sensitive breast cancers. In addition, Ki-67, a marker of cellular proliferation, could be used to select those patients who benefit from treatment with a PI3K-pathway inhibitor.
Conditions
Conditions (2)
Free-text conditions as registered, with the CancerIndex entity they were reconciled to and the match type.
| Condition (as posted) | Mapped entity | Match | Confidence |
|---|---|---|---|
| Advanced Breast Cancer (Phase 1b) | Malignant Breast Neoplasm | CURATED_BROADER | 0.78 |
| Early Breast Cancer (Phase 2) | Breast Neoplasm | PROBABILISTIC | 0.70 |
Interventions
Interventions (3)
| Intervention | Type | Mapped drug | Match |
|---|---|---|---|
| Letrozole | Drug | Letrozole | ALIAS |
| PF-04691502 | Drug | — | UNRESOLVED |
| PF-04691502 in combination with Letrozole | Drug | — | UNRESOLVED |
Design
Arms and outcomes
Arms (3)
- type
- EXPERIMENTAL
- label
- A
- interventionNames
- Drug: PF-04691502
- type
- EXPERIMENTAL
- label
- B
- interventionNames
- Drug: PF-04691502 in combination with Letrozole
- type
- ACTIVE_COMPARATOR
- label
- C
- interventionNames
- Drug: Letrozole
Primary outcomes (2)
- measure
- Number of Participants With Treatment-Emergent Adverse Events (AEs) or Serious Adverse Events (SAEs): Phase 1B
Eligibility
Eligibility (as posted)
- Sex
- Female
- Minimum age
- 18 Years
Show eligibility criteria text
Inclusion Criteria: * Phase 1 - Postmenopausal women with diagnosis of breast cancer, metastatic disease or locally advanced disease / Estrogen Receptor positive and HER-2 negative / candidate to receive Letrozole * Phase 2 - Postmenopausal women with newly diagnosed primary breast cancer / Estrogen Receptor positive and HER-2 negative / Ki-67 levels \>10% positive cells * Phase 1 \& 2 - Glucose control, adequate bone marrow, liver, renal, and cardiac function Exclusion Criteria: * Inflammatory carcinoma / Prior therapy with an agent active on PI3K and/or mTOR / Significant gastrointestinal abnormalities, which may impair intake, transit or absorption of the study drugs / Current or anticipated need for food or drugs that are known inhibitors or inducers of CYP3A4
References
Publications (0)
Data not yet available