Palboxen is a targeted cancer therapy containing Palbociclib, a selective cyclin-dependent kinase (CDK) 4/6 inhibitor. It is indicated for the treatment of hormone receptor (HR)-positive, HER2-negative advanced or metastatic breast cancer in combination with endocrine therapies. By inhibiting CDK4/6, Palboxen blocks cellular proliferation, leading to cell cycle arrest in the G1 phase. When combined with anti-estrogen therapy, it enhances tumor growth suppression and promotes sustained cell senescence, offering improved clinical outcomes for patients with ER-positive breast cancer.

Palboxen is designed for oral administration and provides a convenient dosing schedule that integrates into standard breast cancer treatment regimens. Its mechanism allows for targeted action on cancer cells while minimizing effects on normal tissues.

রেজিস্টার্ড চিকিৎসকের পরামর্শ অনুযায়ী ঔষধ সেবন করুন

Therapeutic Class

Protein kinase inhibitor

Pharmacology

Palbociclib works by inhibiting CDK4 and CDK6, key regulators of the cell cycle. In ER-positive breast cancer cells:

• Blocks progression from G1 to S phase, reducing cell proliferation

• Decreases phosphorylation of retinoblastoma (RB) protein

• Reduces E2F transcription factor signaling

• Enhances growth arrest and promotes cellular senescence

Preclinical studies show that combining Palbociclib with anti-estrogen therapy (e.g., letrozole or fulvestrant) produces greater inhibition of tumor growth than either agent alone. This dual approach provides effective disease control for patients with advanced HR-positive breast cancer.

Indications

Palboxen is indicated for the treatment of:

• Hormone receptor (HR)-positive, HER2-negative advanced or metastatic breast cancer

• Use in combination with:

  • Aromatase inhibitors as initial endocrine therapy in postmenopausal women

  • Fulvestrant for patients with disease progression following endocrine therapy

Dosage and Administration

• Recommended dose: 125 mg orally once daily for 21 consecutive days, followed by 7 days off (28-day cycle)

• Administration: Take with food at approximately the same time each day

• Dose adjustments:

  • If toxicity occurs, dose may be reduced; discontinue if dose reduction below 75 mg/day is required

  • Monitor blood counts regularly; adjust dose for neutropenia or other adverse effects

Use in children: Not indicated

Interactions

• CYP3A inhibitors (e.g., ketoconazole, clarithromycin) increase Palboxen exposure; dose reduction may be necessary

• CYP3A inducers (e.g., rifampin, phenytoin) decrease Palboxen exposure; avoid concomitant use

• Can increase plasma levels of CYP3A substrates with narrow therapeutic indices (e.g., cyclosporine, tacrolimus)

  রেজিস্টার্ড চিকিৎসকের পরামর্শ অনুযায়ী ঔষধ সেবন করুন

Side Effects

Common adverse effects include:

• Hematologic: Neutropenia, leukopenia, thrombocytopenia, anemia

• Gastrointestinal: Nausea, vomiting, diarrhea

• Hepatic: Increased AST and ALT

• Others: Fatigue, hair loss, rash, dry skin, mouth inflammation, fever

Serious warnings: Febrile neutropenia, interstitial lung disease (ILD)/pneumonitis

Pregnancy and Lactation

• Can cause fetal harm; advise effective contraception during treatment and for at least 3 weeks after the last dose

• Not recommended during pregnancy or breastfeeding

Precautions & Warnings

• Monitor for neutropenia and pulmonary symptoms

• Discontinue permanently in severe ILD/pneumonitis

• Avoid grapefruit and grapefruit juice

Overdose

No specific antidote. Supportive care and monitoring are recommended.

Storage Conditions

Store below 30°C, away from light and moisture. Keep out of reach of children.