IBRANCE

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IBRANCE

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Medically reviewed

Rosario Oropesa

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of IBRANCE

Quick Facts: IBRANCE (Palbociclib)

Property Description
Active ingredient Palbociclib
Form Hard capsule or tablet (oral dosage form)
Pharmacological class Selective Cyclin-dependent Kinase (CDK) Inhibitor (CDK4/6)
General Use Antineoplastic agent, utilized in systemic cancer therapy
Origin Synthetic small molecule inhibitor

What Type of Medicine is IBRANCE (Palbociclib)?

IBRANCE, containing the active ingredient Palbociclib, is a prescription-only antineoplastic agent classified as a selective Cyclin-dependent Kinase (CDK) inhibitor. It is a kinase inhibitor, which is a type of medicine developed to target specific enzymatic activities. This medicine is defined as a synthetic small molecule inhibitor, a compound structurally derived from piperazine pyridopyrimidine. IBRANCE holds a distinct position as a first-in-class CDK4/6 inhibitor.

Form and Core Composition

The product is formulated for oral administration, available as both a hard capsule and a tablet, representing the common oral dosage form. Palbociclib is the single active ingredient product, although it is utilized as a combination therapy with other endocrine agents. The active pharmaceutical ingredient is formulated with various standard excipients, including lactose monohydrate, necessary to produce the final oral preparation. Palbociclib is administered orally, and its primary function is to halt cell proliferation in specific cancer types.

General Therapeutic Role of CDK4/6 Inhibition

The fundamental therapeutic purpose of IBRANCE is to interfere precisely with the process of unchecked cellular growth through the biological mechanism of selective CDK4/6 inhibition. This action is crucial because CDK4 and CDK6 are key regulators of the cell cycle, and blocking them induces cell cycle arrest. This mechanism is recognized for its ability to promote a state of Growth Pause Induction, which stabilizes the cell’s division process rather than immediately destroying the cell. Therefore, the medicine serves as a specialized component of a combination regimen, aiming to control and slow the overall progression of the underlying condition.

What side effects are possible with IBRANCE?

Possible Side Effects and Safety Information

The regulatory safety profile for IBRANCE (palbociclib) is characterized primarily by adverse reactions affecting the blood and lymphatic system, as documented in official government labeling. Many of these effects are classified as Very Common (ge 1 in 10 patients) by regulatory authorities.


Key Safety Classifications

The most frequently reported adverse reactions include Neutropenia (a decrease in a type of white blood cell), Leukopenia, Anemia, Thrombocytopenia, Infections, Fatigue, Nausea, and Stomatitis (mouth inflammation). Time-related safety data notes that the median time to the first episode of neutropenia is approximately 15 days, with Grade ge 3 episodes typically lasting about seven days.

Adverse effects are documented across several System-Organ Classes, including the Gastrointestinal, Skin and Subcutaneous Tissue, and Eye Disorders systems.


Serious Adverse Reactions

The official label highlights the potential for several serious adverse reactions. These include Febrile Neutropenia (fever with low white blood cell count), Venous Thromboembolism (blood clots), and the risk of severe, life-threatening, or fatal Interstitial Lung Disease (ILD) / Pneumonitis.


Population-Specific Safety Notes

The prescribing information includes specific safety constraints for certain patient groups. Individuals with severe hepatic impairment (Child-Pugh Class C) require a reduced dose due to expected increased exposure. Furthermore, the label notes that the concomitant use of strong CYP3A inhibitors or inducers must be managed due to potential safety consequences. The medicine is contraindicated in patients with known hypersensitivity to palbociclib.

Overdose and Emergency Response

Overdose Map: Overdose and when to seek help — Official Regulatory Information for IBRANCE (Palbociclib)

Feature Description (Strictly derived from official regulatory labeling)
Documented overdose presentations Overdose is expected to cause an exaggeration of the established pharmacological action, resulting primarily in severe hematologic toxicities (Neutropenia, Leukopenia, Anemia, and Thrombocytopenia).
Physiological systems affected (as stated in label) The primary system affected by overdose is the hematologic system, specifically bone marrow function.
Dose-related or exposure-related factors (if applicable) Acute overdose exposure may lead to the most severe clinical expressions of the drug's dose-limiting toxicities.
Population-specific overdose notes (if applicable) No specific differential overdose considerations are documented for distinct populations in the overdose setting.
Emergency-response statements (as written in official documents) Seek immediate medical attention or call emergency medical services upon suspected overdose. Contacting a poison control helpline is an official action described in regulatory consumer information.
When immediate medical help is required (label-derived phrasing only) Urgent medical help is required immediately upon recognizing any sign or suspicion of an overdose.

Overdose classifications (high-level)

Classification Aspect Regulatory Statement
Severity classification (as defined in official documents) Overdose can lead to life-threatening complications, such as Febrile Neutropenia, an escalation of severe hematologic toxicity.
Regulatory basis (EMA / FDA / etc.) The overdose description and management are founded upon official regulatory prescribing information (e.g., FDA, EMA).
Overdose-context constraints (as defined in official documents) No specific antidote is known for Palbociclib overdose, constraining management to supportive measures.

Resulting overdose structure

Official overdose statements:

  • The major clinical manifestation expected is severe bone marrow suppression, including Grade 4 Neutropenia.
  • Management consists of general supportive care and monitoring of the patient's vital functions.
  • Close and continuous hematologic monitoring, specifically frequent complete blood counts, is required.

Connection to the overall overdose profile (3 sentences): Regulatory documents define the IBRANCE overdose profile through the prediction of severe hematologic consequences, which are an exaggerated form of the drug's primary dose-limiting toxicity. This anticipated clinical manifestation, coupled with the official declaration that no specific antidote is known, structures the emergency-seeking condition. Regulators consequently mandate that patients seek immediate medical attention for the prompt initiation of general supportive care and intensive hematologic monitoring.

Therapeutic Uses of IBRANCE

What IBRANCE treats: Main Uses and Benefits

IBRANCE (palbociclib) is considered relevant in the therapeutic context of treating a specific type of advanced cancer. The medicine is commonly used for Hormone Receptor (HR)-positive, HER2-negative advanced or metastatic breast cancer in adult patients.

Therapeutic Scope and Benefit

IBRANCE is applied across therapeutic domains where additional symptomatic support is needed to support the management of tumor growth. It is commonly used to help with conditions presenting with systemic or localized discomfort driven by the uncontrolled multiplication of specific cancer cells. A key benefit is that this medicine may assist with delaying the progression of the disease, which contributes to maintaining a sense of stability when symptoms are more noticeable.

This medicine is relevant in contexts involving heightened systemic burden, specifically when used as the initial endocrine-based therapy for advanced disease or when the cancer has progressed following prior hormonal treatment. This approach contributes to easing the overall symptom load and may assist with providing symptomatic relief that helps patients cope more steadily.


Quick Fact: Symptom Management in Advanced Cancer
Primary Indication HR-positive, HER2-negative advanced or metastatic breast cancer.
Use Context Applied as an initial endocrine-based therapy or following disease progression.
Key Benefit May assist with easing the overall symptom burden by supporting the management of disease progression.

Eligibility and Restrictions for Use

Eligibility for IBRANCE (Palbociclib)

IBRANCE is officially indicated for adult patients with Hormone Receptor (HR)-positive, HER2-negative advanced or metastatic breast cancer. This includes both men and women. The official eligibility criteria define who must not use the medicine and under what conditions use is restricted.


Populations Excluded from Use

Classification Exclusion Criteria (Regulatory Basis)
Contraindicated Patients with a known hypersensitivity to palbociclib or any of the product's excipients.
Pregnancy/Lactation Contraindicated in pregnancy (can cause fetal harm); not recommended while breastfeeding.
Age Restriction Safety and efficacy have not been established in children and adolescents under 18 years of age; use is not recommended in this population.

Conditional and Restricted Use

Certain pre-existing conditions or treatment-related events mandate regulatory restrictions on use:

  • Severe Hepatic Impairment (Child-Pugh Class C) requires a mandated dose reduction to 75 mg once daily.
  • Organ Function: No dose adjustment is required for patients with mild, moderate, or severe renal impairment (creatinine clearance ge 15 mL/min) or for those with mild or moderate hepatic impairment.
  • Severe Complication: The medicine must be permanently discontinued if the patient develops severe Interstitial Lung Disease (ILD) or pneumonitis.

What should I know about interactions with other medicines?

IBRANCE (palbociclib) is primarily processed in the body by the CYP3A enzyme system, making it susceptible to interactions with other medicines and products that affect this pathway.

Medicines and Products to Avoid

  • Strong CYP3A Inhibitors: Medicines that strongly inhibit the CYP3A enzyme can significantly increase the level of IBRANCE in the bloodstream, raising the risk of side effects. Common examples include certain antifungals (like ketoconazole and itraconazole) and some HIV/AIDS medications (like ritonavir). Coadministration is generally avoided, or the IBRANCE dose may need a mandatory reduction.
  • Strong CYP3A Inducers: Medicines that strongly induce or speed up the CYP3A enzyme can greatly decrease the level of IBRANCE in the bloodstream, potentially reducing its effectiveness. These include certain anti-seizure medicines (like phenytoin and carbamazepine) and the antibiotic rifampin. Coadministration with strong inducers must be avoided.
  • Herbal and Food Interactions: Consumption of St. John's Wort is prohibited due to its strong CYP3A-inducing effect. Grapefruit and grapefruit juice should also be avoided as they can increase IBRANCE levels in the body.

Potential for Interactions with Other Medicines

IBRANCE itself is considered a time-dependent inhibitor of CYP3A in the gut. This means it can increase the concentration of other medicines that are sensitive substrates of the CYP3A enzyme and have a narrow therapeutic range, such as certain opioids (fentanyl, alfentanil) and immunosuppressants (cyclosporine, tacrolimus). The dose of these coadministered medicines may require adjustment to prevent toxicity.

Co-therapy Requirement

When IBRANCE is combined with an aromatase inhibitor or fulvestrant in pre- or perimenopausal women, treatment with a LHRH (luteinizing hormone-releasing hormone) agonist is also necessary.

Mechanism of Action

Selective Blockade of the Cell Cycle Engine

IBRANCE (palbociclib) functions as a highly selective inhibitor targeting the enzymatic activity of Cyclin-dependent Kinase 4 ( CDK4) and CDK6. These enzymes are critical regulators that determine whether a cell proceeds through the division cycle. Palbociclib achieves a functional blockade by competing for the ATP binding pocket of these kinases, thereby preventing their normal enzymatic function. This targeted action modulates the physiological process of cellular multiplication by interfering with enzymatic signaling.


Inducing G1 Phase Arrest via Rb Protein Regulation

The inhibition of CDK4/6 ensures that the Retinoblastoma ( Rb) protein remains in its hypophosphorylated state. The hypophosphorylated Rb protein acts as a repressor, binding to and inactivating the E2 F transcription factor. This molecular cascade prevents the necessary transcription of DNA synthesis genes, resulting in the establishment of G1 phase Cell Cycle Arrest, which suppresses the progression of cellular proliferation.


Mechanistic Synergy with Endocrine Signaling Blockade

Palbociclib is utilized alongside agents that suppress the Estrogen Receptor ( ER) pathway. This dual-pronged strategy creates a synergistic effect, combining internal proliferation inhibition (CDK4/6 blockade) with external growth and survival signal suppression ( ER pathway modulation). This complementary action combines two distinct regulatory steps to control cellular activity.

Dosage and Administration Information

How to Use IBRANCE (Palbociclib)

IBRANCE is administered exclusively via the oral route, utilizing the hard capsule or film-coated tablet dosage form. Its use is governed by a defined intermittent cyclic dosing schedule, and it is used as a combination therapy with approved hormonal agents.

Standard Dosing Protocol and Timing

The standard regimen requires a 28-day treatment cycle. The principal dosing pattern is taking the medicine once daily at the recommended starting dose of 125 mg for 21 consecutive days. This intake period is followed by a 7-day period without treatment to complete the cycle. Treatment continues over subsequent cycles for the duration of the long-term management plan.

To maintain consistent drug levels, the dose is typically taken at approximately the same time each day.

Administration Condition Capsule Formulation Tablet Formulation
Timing Relative to Food Must be taken with food May be taken with or without food
Physical Handling Must be swallowed whole (do not crush, chew, or open) Must be swallowed whole (do not crush, chew, or open)

Official Rules for Procedural Errors

If a dose is missed or if vomiting occurs after taking the medicine, an additional dose is not taken that day. The regular prescribed schedule is resumed with the next planned dose at the usual time.

Dose Modification Principles

The daily dose may be modified downward to 100 mg and then to 75 mg per day based on clinical circumstances. For patients with severe hepatic impairment (Child-Pugh class C), the recommended starting dose is initially reduced to 75 mg once daily.

Recent Clinical Evidence

Research Evidence / Overview of Studies for IBRANCE

Evidence for Use as Initial Endocrine-Based Therapy

The primary research base for IBRANCE, when was studied for use as the first endocrine-based therapy for advanced or metastatic Hormone Receptor (HR)-positive, HER2-negative breast cancer, rests on large-scale, international Randomized Controlled Trials (RCTs). The key outcomes monitored in these studies were time periods such as Progression-Free Survival (PFS), which is the time until disease progression is observed, and Overall Survival (OS). Findings from these foundational trials described patterns of a longer time period without disease progression being recorded for the combination treatment group.

However, certain aspects remain uncertain. The long-term follow-up for Overall Survival (OS) in the principal first-line RCT did not establish a statistically significant difference between the two study groups. Research has not established that the combination treatment extends the time patients live compared to the control arm. Interpretation of this evidence is limited because patients in the control group often had the opportunity to receive similar medicines outside the trial setting later on.


Evidence for Use Following Prior Endocrine Therapy

Research also explored the use of IBRANCE in patients whose cancer had progressed after receiving a prior hormone therapy. For this clinical situation, the main evidence is derived from another pivotal Phase 3 RCT. This research examined outcomes related to PFS and OS in a population that included both premenopausal and postmenopausal women, as well as men. The studies consistently described patterns of a longer time without documented disease progression (PFS) for the combination treatment group.

An exploratory analysis of the long-term data also indicated a numerically longer overall survival (OS) measurement in the combination group. Data are limited for patients whose disease progressed rapidly after their initial hormone treatment. The certainty of this long-term finding remains an area of research because the study design permitted the control group to access the active medicine after their progression.

Frequently Asked Questions (FAQ)

Common questions about IBRANCE (FAQ)


Q: What is the main job of IBRANCE in cancer treatment?

A: IBRANCE is classified as a kinase inhibitor, which means it blocks the action of specific proteins, CDK4 and CDK6, that drive cancer cell multiplication. This mechanism helps to slow or control the proliferation of cancer cells. The drug is always utilized as part of a combination regimen with hormonal therapy.


Q: Is IBRANCE a type of chemotherapy?

A: IBRANCE is not classified as traditional chemotherapy. It is a form of targeted therapy or biological therapy that works by blocking specific molecular pathways inside the cancer cell (CDK4/6 inhibitor). This selective mechanism differs from the broad-spectrum action of chemotherapy.


Q: How is IBRANCE different from traditional hormonal treatments?

A: IBRANCE is a CDK4/6 inhibitor that works inside the cell to prevent division. Traditional hormonal treatments work externally by suppressing or blocking the hormones, like estrogen, that signal the cancer cells to grow. The combination creates a dual-mechanism effect that modulates cancer growth at two distinct regulatory points.


Q: Does IBRANCE cure cancer or just slow it down?

A: IBRANCE is indicated for advanced or metastatic breast cancer. Its therapeutic function is to control and slow the overall progression of cancer cells. Treatment is continued only for as long as the patient is deriving clinical benefit and any side effects are manageable.


Q: Why do doctors check blood counts so often when taking IBRANCE?

A: Official documents state that blood counts, including the complete blood count (CBC), are monitored before starting therapy, at the beginning of each cycle, and periodically during treatment. This is because IBRANCE commonly causes a decrease in white blood cells (neutropenia). Low white blood cell counts are associated with an increased risk of infection.


Q: Can IBRANCE cause hair thinning or hair loss?

A: Yes, regulatory documents list alopecia (hair loss or thinning) as a very common adverse reaction observed in clinical studies for IBRANCE.


Q: Does IBRANCE affect the liver?

A: IBRANCE is processed through the liver, and regulatory documents stipulate a dose reduction for patients with severe hepatic impairment (Child-Pugh Class C). Clinical trial data also reported cases of increased liver enzymes (AST/ALT) as adverse reactions, indicating potential effects on the liver function.


Q: How soon after starting IBRANCE do side effects usually appear?

A: The onset of side effects varies for each person. Time-related safety data for neutropenia, the most frequently reported side effect, indicates that the median time to the first episode of Grade 3 or higher neutropenia is approximately 15 days after starting the medicine.


Q: Can IBRANCE be taken with vitamins or herbal supplements?

A: Official product information states that the herbal supplement St. John's Wort must be avoided because it can decrease IBRANCE levels in the body. IBRANCE is a CYP3A enzyme substrate, making it sensitive to interactions with other products that affect this enzyme pathway. Official documents emphasize the importance of communicating all supplements being taken to the healthcare provider.


Q: What is the typical duration of IBRANCE treatment?

A: There is no fixed duration for IBRANCE treatment. Official guidelines state that therapy should be continued for as long as the patient is benefitting from it. Treatment continuation is determined by ongoing clinical assessment of benefit and side effect management.


Q: How will I know if IBRANCE is working for me?

A: In clinical studies, effectiveness was measured by the time patients lived without their disease getting worse (Progression-Free Survival). The patient's condition is monitored using clinical assessments and imaging to determine if clinical benefit is being derived from the combination therapy.


Q: Is IBRANCE used for early-stage breast cancer?

A: The official indication for IBRANCE is for the treatment of advanced or metastatic breast cancer. It is not indicated or approved for use in early-stage breast cancer.


Q: How often are people checked for lung problems related to IBRANCE?

A: The official label highlights the risk of severe Interstitial Lung Disease (ILD) / pneumonitis and advises healthcare professionals to monitor patients regularly for any pulmonary symptoms. The drug discontinuation is stipulated if ILD or pneumonitis is suspected.


Q: If I get diarrhea from IBRANCE, what should I do about my dose?

A: Dose modifications are recommended for severe non-blood-related side effects, such as Grade 3 or higher diarrhea, that do not resolve with medical treatment. The medicine may be temporarily withheld or interrupted according to clinical guidelines. If symptoms resolve, the dose may be resumed, often at a lower level.


Q: What is the percentage of people who see a benefit from IBRANCE in studies?

A: Clinical trials found that patients taking IBRANCE in combination therapy experienced a significantly longer median time without their disease progressing (Progression-Free Survival or PFS). For instance, one foundational trial showed a PFS of 24.8 months for the combination therapy group versus 14.5 months for the control group.


Q: Does IBRANCE have a box warning from the FDA?

A: IBRANCE does not carry the formal FDA Black Box Warning for all indications. However, the regulatory agency has issued specific warnings for the class of drugs regarding the risk of severe, life-threatening, or fatal Interstitial Lung Disease (ILD) and pneumonitis.


Q: What if I have an allergic reaction to IBRANCE?

A: IBRANCE is officially contraindicated (should not be used) in patients with a known history of hypersensitivity (allergic reaction) to palbociclib or any components of the product. This means the drug poses a known risk for these individuals.


Q: Can IBRANCE treatment be stopped and restarted later?

A: Treatment may be temporarily interrupted or stopped to manage certain side effects, following clinical protocols. Based on official guidelines for dose modification, the medicine can typically be resumed once the side effects have resolved to an acceptable level. Permanent discontinuation is required for severe complications.


Q: What does HR-positive, HER2-negative mean in the context of IBRANCE?

A: This describes the specific tumor profile IBRANCE is approved to treat. HR-positive means the cancer cells have hormone receptors that can be used to control growth. HER2-negative means the cancer cells do not overproduce the HER2 protein. IBRANCE is indicated for this specific status.


Q: Why is it important to use effective birth control while on IBRANCE?

A: Official labeling states that IBRANCE can cause fetal harm when used during pregnancy. For this reason, females of reproductive potential are stipulated to use effective contraception during treatment and for at least 3 weeks after the last dose. Male patients are also stipulated to use effective contraception.


Q: Does IBRANCE affect fertility in men or women?

A: Based on findings from animal studies, IBRANCE may impair fertility in males and has the potential to cause genotoxicity. Male patients are advised to discuss sperm preservation options with their physician prior to treatment.


Q: What tests are done before starting IBRANCE?

A: Regulatory requirements stipulate the monitoring of the patient's complete blood count (CBC) prior to initiating IBRANCE therapy. Additionally, women of reproductive potential must have a pregnancy test before starting the medicine.


Q: Where can I find the official package insert for IBRANCE?

A: The official product information, such as the full Patient Package Insert, is a regulatory document. The document is available by request through their pharmacist or physician.


Q: How is the safety of IBRANCE monitored after it is released to the public?

A: The safety of IBRANCE is monitored through post-marketing surveillance. Healthcare professionals and patients can help track safety issues, as the FDA MedWatch program is available for patients and professionals to report adverse events involving the medicine.

How should IBRANCE be stored and disposed of?

Storage and Handling Requirements

IBRANCE (palbociclib) must be stored at Controlled Room Temperature, defined as 20°C to 25°C (68°F to 77°F), with permitted brief temperature variations between 15°C and 30°C. To maintain product integrity, the medicine must be stored in its original container or blister pack and protected from both direct light and excessive moisture. It is essential that IBRANCE remains out of the sight and reach of children and pets at all times.

Disposal of Unused Medicine

Unused or expired IBRANCE should not be discarded in household trash or flushed down the toilet, as instructed by official regulatory guidance. Instead, disposal must occur through formal pharmaceutical waste programs. Patients should utilize drug take-back programs or authorized collection sites, typically available through a pharmacy or oncology team, to ensure proper handling and disposal of the specialized medication.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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