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palbociclib plus letrozole (palbociclib-plus-letrozole)
palbociclib plus letrozole (generic name: palbociclib-plus-letrozole) is a palbociclib plus letrozole drug developed by Pfizer Inc.. It is currently in preclinical development.
palbociclib plus letrozole
Palbociclib is a small molecule inhibitor of the cytochrome P450 19A1 enzyme, which is involved in the production of estrogen. Palbociclib is often used in combination with letrozole, an aromatase inhibitor, to treat hormone receptor-positive breast cancer.
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Baseline preclinical → approval rate
+5.0pp
Industry-wide preclinical drugs reach approval ~5% of the time (BIO/Informa 2023 industry benchmark across all therapeutic areas). -
Big-pharma sponsor
+3.0pp
Pfizer Inc. is a top-20 pharma sponsor — historical approval rates run ~3pp above average due to scale, regulatory experience, and trial-design quality.
| Regulator | Country | Likely year | Lag vs FDA |
|---|---|---|---|
| FDA | US | 2036–2040 | — |
| EMA | EU | 2037–2041 | +0.7 yr |
| MHRA | GB | 2037–2041 | +0.7 yr |
| Health Canada | CA | 2037–2042 | +0.9 yr |
| TGA | AU | 2037–2042 | +1.2 yr |
| PMDA | JP | 2037–2042 | +1.5 yr |
| NMPA | CN | 2038–2043 | +2.3 yr |
| MFDS | KR | 2037–2042 | +1.4 yr |
| CDSCO | IN | 2037–2043 | +1.8 yr |
| ANVISA | BR | 2038–2043 | +2.3 yr |
Hover any row for the lag rationale. Lag estimates are reduced when the drug has FDA Breakthrough or EMA PRIME designation (sponsors file globally in parallel).
Estimate based on the BIO/Informa industry phase transition rates plus per-drug modifiers for therapeutic area, sponsor type, FDA designations, mechanism, and trial design. Per-jurisdiction lags from Tufts CSDD international approval studies. Not investment, clinical or regulatory advice. Methodology: /methodology#likelihood.
At a glance
| Generic name | palbociclib-plus-letrozole |
|---|---|
| Sponsor | Pfizer Inc. |
| Drug class | palbociclib plus letrozole |
| Therapeutic area | Oncology |
| Phase | preclinical |
Mechanism of action
Breast cancer cells that are hormone receptor-positive depend on estrogen to grow and survive. Letrozole works by blocking the enzyme aromatase, which converts other hormones into estrogen in the body. By reducing circulating estrogen levels, letrozole deprives these cancer cells of a critical growth signal, slowing their progression. Palbociclib takes a complementary approach by targeting the machinery inside cancer cells that controls division. Cancer cells progress through their growth cycle using proteins called CDK4 and CDK6. Palbociclib acts as a brake on these proteins, preventing cells from advancing to the next phase of division. This creates a dual blockade: even if cancer cells aren't completely starved of estrogen, they're locked in a resting state and unable to multiply. Together, palbociclib and letrozole work synergistically—one cuts off growth signals from outside the cell while the other prevents the internal machinery from responding. This combination approach has proven more effective than hormone therapy alone, particularly in women whose cancers have progressed despite prior treatments.
Approved indications
Pipeline indications
- Breast Cancer — preclinical
Common side effects
Key clinical trials
- A Study Evaluating the Efficacy and Safety of Multiple Treatment Combinations in Patients With Metas (Phase 1/2)
- Neoadjuvant Letrozole and Palbociclib in Patients With Stage II-IIIB Breast Cancer, HR+, HER2 - (Phase 2)
- Biological and Clinical Effects of Palbociclib With Ovarian Suppression and Letrozole in the Neoadju (Phase 2)
- Palbociclib Pharmacokinetics Study In Postmenopausal Chinese Women With ER (+), HER2 (-) Advanced Br (Phase 1)
- A Study of Tersolisib (LY4064809/STX-478) With Other Anti-Cancer Treatments in Participants With Adv (Phase 3)
- Palbociclib for HR Positive / HER2-negative Isolated Locoregional Recurrence of Breast Cancer (Phase 3)
- To Reduce the Use of Chemotherapy in Postmenopausal Patients With ER-positive and HER2-positive Brea (Phase 2)
- Study of PF-07220060 With Letrozole in Adults With HR-positive HER2-negative Breast Cancer Who Have (Phase 3)
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 plus letrozole CI brief — competitive landscape report
- palbociclib plus letrozole updates RSS · CI watch RSS
- Pfizer Inc. portfolio CI
Frequently asked questions about palbociclib plus letrozole
What is palbociclib plus letrozole?
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Related
- Drug class: All palbociclib plus letrozole drugs
- Manufacturer: Pfizer Inc. — full pipeline
- Therapeutic area: All drugs in Oncology
Primary sources · FDA · ClinicalTrials.gov · EMA · SEC EDGAR · ChEMBL · Wikidata · full sourcing