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Palbociclib + Letrozole
Palbociclib is a CDK4/6 inhibitor that blocks the cell cycle, while Letrozole is an aromatase inhibitor that reduces estrogen levels.
Palbociclib is a CDK4/6 inhibitor that blocks the cell cycle, while Letrozole is an aromatase inhibitor that reduces estrogen levels. Used for Hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced or metastatic breast cancer.
At a glance
| Generic name | Palbociclib + Letrozole |
|---|---|
| Sponsor | Pfizer |
| Drug class | CDK4/6 inhibitor and aromatase inhibitor |
| Target | CDK4/6 and aromatase |
| Modality | Small molecule |
| Therapeutic area | Oncology |
| Phase | Phase 3 |
Mechanism of action
Palbociclib works by inhibiting the cyclin-dependent kinases 4 and 6 (CDK4/6), which are involved in cell cycle progression. This leads to cell cycle arrest and apoptosis in cancer cells. Letrozole, on the other hand, inhibits the enzyme aromatase, which is responsible for converting androgens to estrogens. By reducing estrogen levels, Letrozole can help slow the growth of hormone receptor-positive breast cancer cells.
Approved indications
- Hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2-) advanced or metastatic breast cancer
Common side effects
- Fatigue
- Nausea
- Diarrhea
- Vomiting
- Leukopenia
- Neutropenia
- Thrombocytopenia
- Anemia
Key clinical trials
- BGB-43395 Plus Letrozole Versus CDK4/6i Plus Letrozole for Patients With Advanced or Metastatic HR+/HER2- Breast Cancer Who Have Not Received Prior Treatment for Advanced or Metastatic Disease (PHASE3)
- A Study of Tersolisib (LY4064809/STX-478) With Other Anti-Cancer Treatments in Participants With Advanced Breast Cancer With a Genetic Change (PIK3CA) (PHASE3)
- Neoadjuvant Endocrine Therapy, Palbociclib, Avelumab in Estrogen Receptor Positive Breast Cancer (PHASE2)
- A Study Evaluating the Efficacy and Safety of Multiple Treatment Combinations in Patients With Metastatic or Locally Advanced Breast Cancer (PHASE1, PHASE2)
- Saruparib (AZD5305) Plus Camizestrant Compared With CDK4/6 Inhibitor Plus Endocrine Therapy or Plus Camizestrant in HR-Positive, HER2-Negative (IHC 0, 1+, 2+/ ISH Non-amplified), BRCA1, BRCA2, or PALB2m Advanced Breast Cancer (PHASE3)
- To Evaluate the Safety, Tolerability, and Pharmacokinetics of Inavolisib Single Agent in Participants With Solid Tumors and in Combination With Endocrine and Targeted Therapies in Participants With Breast Cancer (PHASE1)
- A Study Evaluating the Efficacy and Safety of Biomarker-Driven Therapies in Patients With Persistent or Recurrent Rare Epithelial Ovarian Tumors (PHASE2)
- First-in-Human Study of STX-478 as Monotherapy and in Combination With Other Antineoplastic Agents in Participants With Advanced Solid Tumors (PHASE1, PHASE2)
Primary sources
Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.
| Source | Used for |
|---|---|
| ClinicalTrials.gov | Trial enrolment, design, endpoints, results |
Competitive intelligence
For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:
- Palbociclib + Letrozole CI brief — competitive landscape report
- Palbociclib + Letrozole updates RSS · CI watch RSS
- Pfizer portfolio CI