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Palbociclib is a kinase inhibitor indicated: - for the treatment of adult patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer in combination with: o an aromatase inhibitor as initial endocrine-based therapy; or o fulvestrant in patients with disease progression following endocrine therapy. - in combination with inavolisib and fulvestrant for the treatment of adult patients with endocrine-resistant, PIK3CA -mutated, HR-positive, HER2-negative, locally advanced or metastatic breast cancer, as detected by an FDA‑authorized test, following recurrence on or after completing adjuvant endocrine therapy. - in combination with trastuzumab, with or without pertuzumab, and endocrine therapy for the maintenance treatment of adult patients with HR-positive, HER2‑positive locally advanced or metastatic breast cancer following induction treatment. HER2-Negative Metastatic Breast Cancer Palbociclib is indicated for the treatment of adult patients with hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced or metastatic breast cancer in combination with: - an aromatase inhibitor as initial endocrine-based therapy; or - fulvestrant in patients with disease progression following endocrine therapy. Palbociclib is indicated in combination with inavolisib and fulvestrant for the treatment of adult patients with endocrine-resistant, PIK3CA -mutated, HR-positive, HER2-negative, locally advanced or metastatic breast cancer, as detected by an FDA- authorized test, following recurrence on or after completing adjuvant endocrine therapy. HER2-Positive Metastatic Breast Cancer Palbociclib is indicated in combination with trastuzumab, with or without pertuzumab, and endocrine therapy for the maintenance treatment of adult patients with HR-positive, HER2-positive locally advanced or metastatic breast cancer following induction treatment.

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Source: US FDA prescribing information, via openFDA. Provided for general information only — it is not a substitute for your doctor's or pharmacist's advice. Always follow your prescriber's instructions.

• Neutropenia: Monitor complete blood count prior to start of Palbociclib therapy and at the beginning of each cycle, as well as on Day 15 of the first 2 cycles, and as clinically indicated. - Interstitial Lung Disease (ILD)/Pneumonitis: Severe and fatal cases of ILD/pneumonitis have been reported. Monitor for pulmonary symptoms of ILD/pneumonitis. Interrupt Palbociclib immediately in patients with suspected ILD/pneumonitis. Permanently discontinue Palbociclib if severe ILD/pneumonitis occurs. - Embryo-Fetal Toxicity: Palbociclib can cause fetal harm. Advise patients of potential risk to a fetus and to use effective contraception. Neutropenia was the most frequently reported adverse reaction in PALOMA-2 with an incidence of 80% and PALOMA-3 with an incidence of 83%. A Grade ≥3 decrease in neutrophil counts was reported in 66% of patients receiving Palbociclib plus letrozole in PALOMA-2 and 66% of patients receiving Palbociclib plus fulvestrant in PALOMA-3. In PALOMA-2 and PALOMA-3, the median time to first episode of any grade neutropenia was 15 days and the median duration of Grade ≥3 neutropenia was 7 days. Neutropenia was the most frequently reported adverse reaction in PATINA with an incidence of 78%. Grade ≥3 neutropenia was reported in 61% of patients receiving Palbociclib in combination with trastuzumab, with or without pertuzumab, and endocrine therapy. Based on laboratory findings, 93% had a decrease in neutrophil counts including 47% with Grade 3 and 3.1% with Grade 4. The median time to first episode of any grade neutropenia was 22 days and the median duration of Grade ≥3 neutropenia events was 9 days. Monitor complete blood counts prior to starting Palbociclib therapy and at the beginning of each cycle, as well as on Day 15 of the 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. Febrile neutropenia has been reported in 1.8% of patients exposed to Palbociclib across PALOMA-2 and PALOMA-3. One death due to neutropenic sepsis was observed in PALOMA-3. Febrile neutropenia has been reported in 0.8% of patients exposed to Palbociclib in the PATINA study. Physicians should inform patients to promptly report any episodes of fever. Interstitial Lung Disease (ILD)/Pneumonitis Severe, life-threatening, or fatal interstitial lung disease (ILD) and/or pneumonitis can occur in patients treated with cyclin-dependent kinase 4/6 (CDK4/6) inhibitors, including Palbociclib when taken in combination with endocrine therapy. Across clinical trials (PALOMA-1, PALOMA-2, PALOMA-3), 1% of Palbociclib-treated patients had ILD/pneumonitis of any grade, 0.1% had Grade 3 or 4 and no fatal cases were reported. Abridged from the full prescribing information.

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Source: US FDA prescribing information, via openFDA. Provided for general information only — it is not a substitute for your doctor's or pharmacist's advice. Always follow your prescriber's instructions.

The following clinically significant adverse reactions are described elsewhere in the labeling: - Neutropenia - ILD/Pneumonitis Most common adverse reactions (incidence ≥20%) in combination with either letrozole or fulvestrant, including laboratory abnormalities, were white blood cell count decreased, neutrophils decreased, blood creatinine increased, hemoglobin decreased, platelets decreased, infections, aspartate aminotransferase increased, alanine aminotransferase increased, fatigue, nausea, stomatitis, diarrhea, and alopecia. The most common adverse reactions (incidence ≥20%) in combination with inavolisib and fulvestrant, including laboratory abnormalities, were neutrophils decreased, hemoglobin decreased, fasting glucose increased, platelets decreased, lymphocytes decreased, stomatitis, diarrhea, calcium decreased, fatigue, potassium decreased, creatinine increased, alanine aminotransferase (ALT) increased, nausea, sodium decreased, magnesium decreased, rash, decreased appetite, COVID-19 infection, and headache. The most common adverse reactions (incidence ≥20%) in combination with trastuzumab, with or without pertuzumab, and endocrine therapy, including laboratory abnormalities, were white blood cell decreased, neutrophil count decreased, creatinine increased, hemoglobin decreased, diarrhea, infections, platelet count decreased, stomatitis, aspartate aminotransferase increased, decreased calcium, alanine aminotransferase increased, decreased potassium, fatigue, alkaline phosphatase increased, nausea, asthenia, headache, rash, pruritus, and muscle spasms.. Clinical Studies Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. PALOMA-2: Palbociclib plus Letrozole Patients with estrogen receptor (ER)-positive, HER2-negative advanced or metastatic breast cancer for initial endocrine-based therapy The safety of Palbociclib plus letrozole was evaluated in a randomized, double-blind trial (PALOMA-2) in 666 patients with ER-positive, HER2-negative advanced breast cancer. The median duration of treatment for Palbociclib plus letrozole was 19.8 months while the median duration of treatment for placebo plus letrozole arm was 13.8 months. Dose reductions due to an adverse reaction of any grade occurred in 36% of patients receiving Palbociclib plus letrozole. No dose reduction was allowed for letrozole in PALOMA-2. Abridged from the full prescribing information.

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Source: US FDA prescribing information, via openFDA. Provided for general information only — it is not a substitute for your doctor's or pharmacist's advice. Always follow your prescriber's instructions.