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AboutDosing & MonitoringDosing & MonitoringDosing and administrationMonitoringRecommended dose modificationsIBRANCE tablets and capsulesClinical Trial DataClinical Trial DataIBR + AI Efficacy & SafetyIBR + AI Additional AnalysesIBR + Fulvestrant Efficacy & SafetyIBR + Fulvestrant Additional AnalysesAdditional DataAdditional DataRCTs and RWESelect data and publicationsLabelLinkLinkLinkLinkLabelLinkLinkLinkLinkVideosPatient SupportPatient SupportPerspectives for your patientsResources for your patientsCoverage and accessMaterials
Prescribing Information for CapsulesPrescribing Information for Tablets Indications Patient Site
AboutLearn how IBRANCE has helped evolve the treatment landscape of HR+/HER2- mBC over the last decade 10 years since initial IBRANCE FDA approval

On February 3, 2015, IBRANCE received its initial FDA approval,* making an important impact on the treatment landscape of HR+/HER2- mBC as the first-in-class CDK4/6 inhibitor.

 Download brochure LoadingIn-practice experience

Experience with IBRANCE combination therapy in HR+/HER2- mBC since its FDA approval in 2015*:

 ReferencesIBRANCE was initially approved in combination with letrozole for the treatment of postmenopausal women with ER+/HER2- advanced breast cancer as initial endocrine-based therapy for their metastatic disease.1Data on file.Evaluated in a broad range of HR+/HER2- mBC patientsReferencesPALOMA-2 was a 2:1 randomized, double-blind, Phase 3 trial of postmenopausal women with ER+/HER2- mBC with no prior treatment in the metastatic setting (N=666). IBRANCE 125 mg PO once daily was taken 3 weeks on, 1 week off + letrozole 2.5 mg PO once daily vs placebo + letrozole.4PALOMA-3 was a 2:1 randomized, double-blind, Phase 3 trial of women with HR+/HER2- mBC who progressed on or after endocrine therapy in the adjuvant or metastatic setting (N=521). IBRANCE 125 mg PO once daily was taken 3 weeks on, 1 week off + fulvestrant 500 mg IM on Days 1, 15, 29, and monthly thereafter vs placebo + fulvestrant.5Mechanism of actionFirst-in-class IBRANCE delivers dual inhibition with endocrine therapy by selectively inhibiting CDK4/6 downstream of ER in HR+/HER2- mBC1

Both CDK4 and CDK6 are key regulators of cell division6,7

  • Inhibition of CDK4/6 helps control cell growth by inducing G1 arrest and reducing cell-cycle progression6,7
  • It is important to inhibit both CDK4 and CDK6 for effective suppression of tumor activity6,7

CDK4/6 is also active in healthy cells8

  • Inhibiting CDK4/6 in healthy cells can result in side effects, some of which may be serious8
  • Human bone marrow mononuclear cells treated with palbociclib in the presence or absence of an antiestrogen in vitro did not become senescent and resumed proliferation following palbociclib withdrawal. This evidence suggests IBRANCE may not have cytotoxic effects on bone marrow cells8
AI=aromatase inhibitor; CDK4/6=cyclin-dependent kinases 4 and 6; DFI=disease-free interval; ER=estrogen receptor; ER+=estrogen receptor-positive; ET=endocrine therapy; FDA=Food and Drug Administration; HR+=hormone receptor-positive; HER2-=human epidermal growth factor receptor 2-negative; IM=intramuscular; mBC=metastatic breast cancer; PO=by mouth.References:IBRANCE capsules [prescribing information]. New York, NY. Pfizer Inc.; February 2015; February 2016; March 2017; September 2019; December 2022; April 2025.IBRANCE tablets [prescribing information]. New York, NY. Pfizer Inc.; November 2019; April 2025.Data on file. Pfizer, New York, NY.Finn RS, Martin M, Rugo HS, et al. Palbociclib and letrozole in advanced breast cancer. N Engl J Med. 2016;375(20):1925-1936.Turner NC, Ro J, André F, et al; PALOMA3 Study Group. Palbociclib in hormone-receptor–positive advanced breast cancer. N Engl J Med. 2015;373(3):209-219.Fry DW, Harvey PJ, Keller PR, et al. Specific inhibition of cyclin-dependent kinase 4/6 by PD 0332991 and associated antitumor activity in human tumor xenografts. Mol Cancer Ther. 2004;3(11):1427-1438.Chen P, Lee NV, Hu W, et al. Spectrum and degree of CDK drug interactions predicts clinical performance. Mol Cancer Ther. 2016;15(10):2273-2281.Finn RS, Crown JP, Lang I, et al. The cyclin-dependent kinase 4/6 inhibitor palbociclib in combination with letrozole versus letrozole alone as first-line treatment of oestrogen receptor-positive, HER2-negative, advanced breast cancer (PALOMA-1/TRIO-18): a randomised phase 2 study. Lancet Oncol. 2015;16(1):25-35. A resource for your patients  Connects patients and caregivers with an IBRANCE Patient or Caregiver Ambassador for private one-on-one phone conversations. Learn more Loading A resource for your patients Delivers insights, facts, and resources to help patients throughout treatment. Learn more Loading

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INDICATIONS IBRANCE® (palbociclib) 125 mg capsules and tablets are indicated for the treatment of adult patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced or metastatic breast cancer (mBC) in combination with:
 
  • an aromatase inhibitor as initial endocrine-based therapy, or
  • fulvestrant in patients with disease progression following endocrine therapy.
IMPORTANT SAFETY INFORMATIONNeutropenia was the most frequently reported adverse reaction in PALOMA-2 (80%) and PALOMA-3 (83%). In PALOMA-2, Grade 3 (56%) or 4 (10%) decreased neutrophil counts were reported in patients receiving IBRANCE plus letrozole. In PALOMA-3, Grade 3 (55%) or Grade 4 (11%) decreased neutrophil counts were reported in patients receiving IBRANCE plus fulvestrant. Febrile neutropenia has been reported in 1.8% of patients exposed to IBRANCE across PALOMA-2 and PALOMA-3. One death due to neutropenic sepsis was observed in PALOMA-3. Inform patients to promptly report any fever. 
Monitor complete blood count prior to starting IBRANCE, at the beginning of each cycle, on Day 15 of first 2 cycles and as clinically indicated. Dose interruption, dose reduction, or delay in starting treatment cycles is recommended for patients who develop Grade 3 or 4 neutropenia. 

Severe, life-threatening, or fatal interstitial lung disease (ILD) and/or pneumonitis can occur in patients treated with CDK4/6 inhibitors, including IBRANCE when taken in combination with endocrine therapy. Across clinical trials (PALOMA-1, PALOMA-2, PALOMA-3), 1% of IBRANCE-treated patients had ILD/pneumonitis of any grade, 0.1% had Grade 3 or 4, and no fatal cases were reported. Additional cases of ILD/pneumonitis have been observed in the post-marketing setting, with fatalities reported. 

Monitor patients for pulmonary symptoms indicative of ILD/pneumonitis (e.g., hypoxia, cough, dyspnea). In patients who have new or worsening respiratory symptoms and are suspected to have developed pneumonitis, interrupt IBRANCE immediately and evaluate the patient. Permanently discontinue IBRANCE in patients with severe ILD or pneumonitis. 

Based on the mechanism of action, IBRANCE can cause fetal harm. Advise females of reproductive potential to use effective contraception during IBRANCE treatment and for at least 3 weeks after the last dose. IBRANCE may impair fertility in males and has the potential to cause genotoxicity. Advise male patients to consider sperm preservation before taking IBRANCE. Advise male patients with female partners of reproductive potential to use effective contraception during IBRANCE treatment and for 3 months after the last dose. Advise females to inform their healthcare provider of a known or suspected pregnancy. Advise women not to breastfeed during IBRANCE treatment and for 3 weeks after the last dose because of the potential for serious adverse reactions in nursing infants. 

The most common adverse reactions (≥10%) of any grade reported in PALOMA-2 for IBRANCE plus letrozole vs placebo plus letrozole were neutropenia (80% vs 6%), infections (60% vs 42%), leukopenia (39% vs 2%), fatigue (37% vs 28%), nausea (35% vs 26%), alopecia (33% vs 16%), stomatitis (30% vs 14%), diarrhea (26% vs 19%), anemia (24% vs 9%), rash (18% vs 12%), asthenia (17% vs 12%), thrombocytopenia (16% vs 1%), vomiting (16% vs 17%), decreased appetite (15% vs 9%), dry skin (12% vs 6%), pyrexia (12% vs 9%), and dysgeusia (10% vs 5%).

The most frequently reported Grade ≥3 adverse reactions (≥5%) in PALOMA-2 for IBRANCE plus letrozole vs placebo plus letrozole were neutropenia (66% vs 2%), leukopenia (25% vs 0%), infections (7% vs 3%), and anemia (5% vs 2%). 

Lab abnormalities of any grade occurring in PALOMA-2 for IBRANCE plus letrozole vs placebo plus letrozole were decreased WBC (97% vs 25%), increased blood creatinine (96% vs 91%), decreased neutrophils (95% vs 20%), decreased hemoglobin (78% vs 42%), decreased platelets (63% vs 14%), increased aspartate aminotransferase (52% vs 34%), and increased alanine aminotransferase (43% vs 30%). 

The most common adverse reactions (≥10%) of any grade reported in PALOMA-3 for IBRANCE plus fulvestrant vs placebo plus fulvestrant were neutropenia (83% vs 4%), leukopenia (53% vs 5%), infections (47% vs 31%), fatigue (41% vs 29%), nausea (34% vs 28%), anemia (30% vs 13%), stomatitis (28% vs 13%), diarrhea (24% vs 19%), thrombocytopenia (23% vs 0%), vomiting (19% vs 15%), alopecia (18% vs 6%), rash (17% vs 6%), decreased appetite (16% vs 8%), and pyrexia (13% vs 5%). 

The most frequently reported Grade ≥3 adverse reactions (≥5%) in PALOMA-3 for IBRANCE plus fulvestrant vs placebo plus fulvestrant were neutropenia (66% vs 1%) and leukopenia (31% vs 2%). 

Lab abnormalities of any grade occurring in PALOMA-3 for IBRANCE plus fulvestrant vs placebo plus fulvestrant were decreased WBC (99% vs 26%), decreased neutrophils (96% vs 14%), increased blood creatinine (95% vs 82%), decreased hemoglobin (78% vs 40%), decreased platelets (62% vs 10%), increased aspartate aminotransferase (43% vs 48%), and increased alanine aminotransferase (36% vs 34%). 

Other Clinical Trials Experience: venous thromboembolism has been reported as an adverse reaction following administration of IBRANCE. 

Avoid concurrent use of strong CYP3A inhibitors. If patients must be administered a strong CYP3A inhibitor, reduce the IBRANCE dose to 75 mg. If the strong inhibitor is discontinued, increase the IBRANCE dose (after 3-5 half-lives of the inhibitor) to the dose used prior to the initiation of the strong CYP3A inhibitor. Grapefruit or grapefruit juice may increase plasma concentrations of IBRANCE and should be avoided. Avoid concomitant use of strong CYP3A inducers. The dose of sensitive CYP3A substrates with a narrow therapeutic index may need to be reduced as IBRANCE may increase their exposure. 

For patients with severe hepatic impairment (Child-Pugh class C), the recommended dose of IBRANCE is 75 mg. The pharmacokinetics of IBRANCE have not been studied in patients requiring hemodialysis. 
 
Please see full Prescribing Information for IBRANCE capsules and tablets.
INDICATIONSIBRANCE® (palbociclib) 125 mg capsules and tablets are indicated for the treatment of adult patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-) advanced or metastatic breast cancer (mBC) in combination with: 
  • an aromatase inhibitor as initial endocrine-based therapy, or 
  • fulvestrant in patients with disease progression following endocrine therapy.
Please see full Prescribing Information for IBRANCE capsules and tablets.