Indication

Palbociclib is indicated for the treatment of hormone receptor (HR)-positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer. It is used in combination with an aromatase inhibitor as the initial endocrine-based therapy in postmenopausal women, or with fulvestrant in women with disease progression following endocrine therapy.

Pharmacology

Palbonix (Palbociclib) functions as a reversible and selective inhibitor targeting cyclin-dependent kinase (CDK) 4 and 6. By hindering the activity of CDK 4 and 6, Palbociclib disrupts the progression of the cell cycle from the G1 phase to the S phase. This inhibition impedes cellular proliferation, particularly targeting breast cancer cells that are hormone receptor-positive.

Doses and Administration

For HR-positive, HER2-negative locally advanced or metastatic breast carcinoma, the recommended adult dose is 125 mg once daily for 21 days, followed by 7 days off, repeated every 28 days until disease progression or unacceptable toxicity. Dosage adjustments may be necessary based on individual safety and tolerability, with the option for dose reductions or interruptions.Palbociclib does not require dose adjustment in patients with mild, moderate, or severe renal impairment (CrCl >15 mL/min). However, its use has not been studied in patients undergoing hemodialysis.Palbociclib, available as a hard capsule, should be taken orally with food at the same time each day. The capsules must be swallowed whole and should not be chewed, crushed, or opened. Patients are advised to avoid consuming grapefruit products while on this medication.

Interaction

Palbonix (Palbociclib) has the potential to interact with other medications, particularly strong CYP3A inhibitors and inducers, which can impact its plasma concentration and effectiveness. Patients should inform their healthcare provider about all prescribed and over-the-counter medications, supplements, and herbal products before initiating Palbonix therapy.

Side Effects

Common adverse reactions associated with palbociclib include nausea, vomiting, loss of appetite, diarrhea, tiredness, weakness, hair loss, mouth sores, and numbness/tingling of arms or legs.

Precaution and warnings

Clinical trials have reported neutropenia and febrile neutropenia as potential adverse effects. Regular monitoring of complete blood count (CBC) is recommended before initiating treatment and throughout the treatment cycle. Dose adjustments or interruptions may be necessary for patients experiencing grade 3 or 4 neutropenia.

Overdose Effects

In instances of Palbonix overdose, symptomatic and supportive treatment should be initiated. There is no specific antidote available. Patients should be carefully monitored for adverse reactions, and appropriate medical intervention should be administered as required.