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PD-0332991 (pd-0332991)
PD-0332991, 125mg, 3 cycles
PD-0332991 (palbociclib) is a cyclin-dependent kinase 4/6 (CDK4/6) inhibitor approved for hormone receptor-positive, HER2-negative advanced breast cancer in combination with endocrine therapy. Its key clinical differentiator is the ability to restore sensitivity to hormone therapy in patients with endocrine-resistant disease, improving progression-free survival when combined with aromatase inhibitors or fulvestrant.
At a glance
| Generic name | pd-0332991 |
|---|---|
| Sponsor | Pfizer Inc. |
| Drug class | PD-0332991, 125mg, 3 cycles |
| Target | Phosphatidylinositol 5-phosphate 4-kinase type-2 alpha, Phosphatidylinositol 5-phosphate 4-kinase type-2 gamma, Serine/threonine-protein kinase TAO2 |
| Therapeutic area | Oncology |
| Phase | discontinued |
Mechanism of action
PD-0332991 works by targeting two closely related proteins called CDK4 and CDK6, which act as molecular 'accelerators' that push cancer cells through their division cycle. In many breast cancers, these proteins become overactive, allowing cells to divide rapidly. By blocking these proteins, the drug essentially hits the brakes on cell division, causing cancer cells to pause and preventing them from multiplying. What makes PD-0332991 particularly useful is that it restores cancer cells' sensitivity to hormone-blocking drugs. Some breast cancers develop resistance to hormone therapy because they find alternative pathways to keep dividing. By blocking CDK4/6, PD-0332991 cuts off these escape routes, making hormone-blocking medications effective again. This combination approach has significantly improved how long patients survive without their cancer worsening. The drug specifically targets breast cancer cells that depend on estrogen for growth. It's given as a pill taken daily in combination with other endocrine treatments, allowing doctors to use hormonal therapy more effectively in patients whose cancers had stopped responding to it alone.
Approved indications
- Hormone receptor positive malignant neoplasm of breast
- Human epidermal growth factor 2 negative carcinoma of breast
Pipeline indications
- Advanced Hepatocellular Carcinoma — discontinued
Common side effects
Key clinical trials
- A Study Evaluating the Efficacy and Safety of Multiple Treatment Combinations in Patients With Metas (discontinued)
- TREATMENT AND MONITORING PATTERNS AND CLINICAL OUTCOMES IN PATIENTS RECEIVING PALBOCICLIB COMBINATIO (discontinued)
- Treatment Patterns and Clinical Outcomes Among Patients Receiving Palbociclib Combinations for Hormo (discontinued)
- Neoadjuvant Letrozole and Palbociclib in Patients With Stage II-IIIB Breast Cancer, HR+, HER2 - (discontinued)
- Palbociclib and Dexamethasone in Treating Participants With Relapsed or Refractory B-Cell Acute Lymp (discontinued)
- A Study of Palbociclib in Addition to Standard Endocrine Treatment in Hormone Receptor Positive Her2 (discontinued)
- Biological and Clinical Effects of Palbociclib With Ovarian Suppression and Letrozole in the Neoadju (discontinued)
- Proton Pump Inhibitor (PPI, Rabeprazole) Effect On Tablet Formulation Of Palbociclib (discontinued)
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:
- PD-0332991 CI brief — competitive landscape report
- PD-0332991 updates RSS · CI watch RSS
- Pfizer Inc. portfolio CI