Loading
Palbociclib was the first CDK4/6 inhibitor (2015), and in 2026 became the first approved as maintenance in HER2-positive, hormone-positive breast cancer.
Palbociclib is a reversible CDK4/6 inhibitor that halts the cell cycle at G1, given as 125 mg daily for 21 days of a 28-day cycle with an aromatase inhibitor or fulvestrant. It was the first CDK4/6 inhibitor, approved in 2015 for HR-positive, HER2-negative advanced breast cancer on PALOMA-2 and PALOMA-3, which improved progression-free but not overall survival; the adjuvant trials PALLAS and PENELOPE-B were negative. In PATINA (SABCS 2024; approved Q2 2026) adding palbociclib to anti-HER2 plus endocrine maintenance in HR-positive, HER2-positive metastatic disease extended progression-free survival by about 15 months. Pfizer markets it; neutropenia (80%) is frequent but rarely febrile. Why it lacks the survival benefit seen with ribociclib and abemaciclib is debated. For a newcomer: the drug that opened the CDK4/6 class, now finding a new home in HER2-positive disease.
Reversible CDK4/6 inhibitor. Connects to CDK4/6.
1.Oral drug is absorbed and reaches the tumour
Background: ADC sequencing, Antigen escape (antigen loss, lineage switch), BCG-unresponsive, Castration-resistant prostate cancer (CRPC), Circulating tumour DNA (ctDNA). Also on OnCo: Resistance: how tumours escape each drug class · Lines of therapy.
Source: US prescribing information (DailyMed). Doses are for orientation; the current label governs.
Oral, self-administered, so it is a Part D drug: covered through a stand-alone Part D plan or Medicare Advantage drug benefit, usually on the specialty tier with 25 to 33% coinsurance until the annual cap ($2,000 in 2025, $2,100 in 2026). Ibrance was selected for Medicare price negotiation in January 2025; the negotiated price takes effect 1 January 2027.
Covered for FDA-labelled and NCCN-listed uses, but almost always behind prior authorisation confirming diagnosis, biomarker and line of therapy; dispensed through a specialty pharmacy. Some PBMs designate a preferred CDK4/6 inhibitor and require it first.
Part D out-of-pocket capped at $2,000 (2025) / $2,100 (2026). Medicare patients cannot use manufacturer co-pay cards; charity funds (PAN, HealthWell, CancerCare) and the Extra Help subsidy are the routes.
Sources: Medicare.gov: Drug coverage (Part D) · Medicare.gov: Costs for Medicare drug coverage (annual out-of-pocket cap) · CMS: Medicare Drug Price Negotiation Program. Not medical or financial advice; verify with your plan.
Sources: NICE TA495 · SMC advice: palbociclib. Funding decisions are indication-specific and change monthly; verify with NICE and your treating team.
In combination with letrozole for postmenopausal women with ER-positive, HER2-negative advanced breast cancer as initial endocrine-based therapy for metastatic disease
Accelerated approval with letrozole: first CDK4/6 inhibitor (PALOMA-1) source
With fulvestrant after endocrine therapy (PALOMA-3) source
In combination with letrozole for postmenopausal women with ER-positive, HER2-negative advanced breast cancer as initial endocrine-based therapy for metastatic disease
Full approval (PALOMA-2) source
Men with HR+/HER2- breast cancer source
Maintenance in HR+/HER2+ advanced breast cancer with anti-HER2 and endocrine therapy (PATINA) source
Gedatolisib with fulvestrant, with or without palbociclib, HR+/HER2- advanced breast cancer (VIKTORIA-1) source
| Region | Year | Indication |
|---|---|---|
| US | 2015 | HR+/HER2- advanced breast cancer with endocrine therapy |
| US | 2026 | HR+/HER2+ advanced breast cancer maintenance with anti-HER2 and endocrine therapy |
| Adverse event | Any grade | Grade 3+ |
|---|---|---|
| Neutropenia | 80% | 66% |
| Infections | 60% | 7% |
| Leukopenia | 39% | 25% |
| Fatigue | 37% | 2% |
| Nausea | 35% | 1% |
| Alopecia | 33% | - |
| Stomatitis | 30% | 1% |
| Diarrhoea | 26% | 1% |
| Anaemia | 24% | 6% |
| Rash | 18% | 1% |
PALOMA-2 with letrozole. Rates read from the US prescribing information. Blank cells mean the figure was not sourced, not that it is zero.
Read for the class this product belongs to (cdk4/6 inhibitors) unless the answer names the product. Population figures from the cohorts named, not a prediction for one person. Blank where no source gives a recovery figure.
| Country | Reimbursement | List price | Assistance |
|---|---|---|---|
| United States | Medicare Part D; generic entry expected 2027 in the US | not disclosed | pfizeroncologytogether.com |
| United Kingdom | NICE: recommended with aromatase inhibitor (TA495) and fulvestrant (TA619) | not disclosed | - |
List prices are manufacturer or Medicare figures where publicly disclosed; net prices after rebates are usually lower. Reimbursement changes; check the payer.
Country and place are remembered in this browser only. A postcode is sent to OpenStreetMap's Nominatim service to find coordinates when you press the button; nothing else leaves your device.
Query for this drug: (TITLE:"Palbociclib" OR ABSTRACT:"Palbociclib" OR TITLE:"Ibrance" OR ABSTRACT:"Ibrance") AND (cancer OR tumor OR tumour OR oncology OR carcinoma OR lymphoma OR leukemia OR leukaemia OR myeloma OR sarcoma OR melanoma OR glioma). Results are unfiltered search hits about Palbociclib, not a curated reading list.
Shares A Phase Ib/II Study to Evaluate Multiple Combination Therapies of FWD1802 in Patients With ER+/HER2- BC, A First-in-human Dose Escalation and Expansion Study to Evaluate the Safety, and Tolerability of AZD8421 Alone or in Combination in Participants With , Study of PF-07220060 With Letrozole in Adults With HR-positive HER2-negative Breast Cancer Who Have Not Received Anticancer Treatment for Advanced/Metastatic Disease, A Study to Evaluate Efficacy and Safety of Giredestrant Compared With Fulvestrant (Plus a CDK4/6 Inhibitor), in Participants With ER-Positive, HER2-Negative Advanced Breast Cancer Resistant to Adjuvant Endocrine Therapy (pionERA Breast Cancer).
Shares A Phase Ib/II Study to Evaluate Multiple Combination Therapies of FWD1802 in Patients With ER+/HER2- BC, A First-in-human Dose Escalation and Expansion Study to Evaluate the Safety, and Tolerability of AZD8421 Alone or in Combination in Participants With , Study of PF-07220060 With Letrozole in Adults With HR-positive HER2-negative Breast Cancer Who Have Not Received Anticancer Treatment for Advanced/Metastatic Disease, A Study to Evaluate Efficacy and Safety of Giredestrant Compared With Fulvestrant (Plus a CDK4/6 Inhibitor), in Participants With ER-Positive, HER2-Negative Advanced Breast Cancer Resistant to Adjuvant Endocrine Therapy (pionERA Breast Cancer).
Shares SNV4818 in Participants With Advanced Solid Tumors, DNA-guided Second Line Adjuvant Therapy for High Residual Risk, Estrogen Receptor Positive, HER-2 Negative Breast Cancer (DARE), PF-07104091 as a Single Agent and in Combination Therapy, Study for Participants Continuing From Pfizer-sponsored Palbociclib (a Study Medicine) Studies.
Shares PF-07104091 as a Single Agent and in Combination Therapy, Study of AVZO-021 in Patients With Advanced Solid Tumors, PALOMA-2, PATINA.
Shares Study of PF-07220060 With Letrozole in Adults With HR-positive HER2-negative Breast Cancer Who Have Not Received Anticancer Treatment for Advanced/Metastatic Disease, CDK4-selective inhibitors as the new first-line backbone, Study of PF-07248144 in Advanced or Metastatic Solid Tumors, The cell-cycle engine (cyclins & CDKs).
Shares persevERA, A Comparative Study of AZD9833 Plus Palbociclib Versus Anastrozole Plus Palbociclib in Patients With ER-Positive HER2 Negative Breast Cancer Who Have Not Received Any Systemic Treatment for Advanced Disease, Vepdegestrant (ARV-471/PF-07850327) + Palbociclib vs Letrozole + Palbociclib in ER(+)/HER2(-) Advanced Breast Cancer, A Study to Evaluate Efficacy and Safety of Giredestrant Compared With Fulvestrant (Plus a CDK4/6 Inhibitor), in Participants With ER-Positive, HER2-Negative Advanced Breast Cancer Resistant to Adjuvant Endocrine Therapy (pionERA Breast Cancer).
Shares Massimo Cristofanilli, Komal Jhaveri, Seock-Ah Im, ER status (oestrogen receptor by IHC).
Shares Gedatolisib Plus Fulvestrant With or Without Palbociclib vs Standard-of-Care for the Treatment of Patients With Advanced or Metastatic HR+/HER2- Breast Cancer (VIKTORIA-1), Open-Label Umbrella Study To Evaluate Safety And Efficacy Of Elacestrant In Various Combination In Participants With Metastatic Breast Cancer, Sherry Lansing, ER status (oestrogen receptor by IHC).