Bevacizumab

Drug Class:

• Monoclonal antibody — recombinant humanized IgG1 targeting vascular endothelial growth factor A (VEGF-A).
• Angiogenesis inhibitor.

Mechanism of Action:

• Binds VEGF-A → prevents activation of VEGF receptors (VEGFR-1 and VEGFR-2) on endothelial cells.
• Inhibits angiogenesis → reduces tumor blood supply and vascular permeability.
• Starves tumor of oxygen/nutrients and normalizes vasculature to improve chemotherapy delivery.

Oncology Indications:

• Metastatic colorectal cancer (with fluoropyrimidine-based chemo).
• Non-squamous NSCLC (with carboplatin + paclitaxel; avoid in squamous due to bleeding risk).
• Recurrent glioblastoma.
• Cervical cancer (persistent, recurrent, or metastatic).
• Ovarian, fallopian tube, primary peritoneal cancer (first-line, platinum-resistant, platinum-sensitive settings).
• Hepatocellular carcinoma (with atezolizumab).

Adult Dosing Examples:

• 5–15 mg/kg IV every 2–3 weeks depending on indication.
  • mCRC: 5 mg/kg IV q2w (with FOLFOX/FOLFIRI) or 7.5 mg/kg q3w (with CAPOX).
  • NSCLC: 15 mg/kg IV q3w.
  • HCC (with atezolizumab): 15 mg/kg IV q3w.

Pharmacokinetics:

• t½ ~20 days; cleared by proteolytic catabolism (not CYP-dependent).

Key Toxicities / Warnings:

• Hypertension — most common, dose-related.
• Proteinuria — monitor urine protein before and during therapy.
• Bleeding — epistaxis common; serious GI, pulmonary, or CNS hemorrhage possible.
• Thromboembolic events — arterial (stroke, MI) and venous (DVT/PE).
• Impaired wound healing — hold for at least 28 days before/after surgery.
• GI perforation — rare but life-threatening; more common in intra-abdominal tumors.
• Reversible posterior leukoencephalopathy syndrome (RPLS) — rare CNS toxicity.

Monitoring for Pharmacists:

• Blood pressure each cycle.
• Urine protein (dipstick; if ≥2+, confirm with 24-h collection).
• Monitor for bleeding signs and thromboembolic events.
• Assess wound healing status.

Administration Notes:

• IV infusion only — first infusion over 90 min, then 60 min, then 30 min if tolerated.
• Do not administer as an IV push or bolus.
• Can be given before or after chemotherapy depending on protocol — many regimens start with bevacizumab before chemo drugs on infusion day.

Drug Interactions:

• No CYP-mediated interactions.
• Caution with anticoagulants, antiplatelets, and other hypertensive agents.

Clinical Pearls:

• Avoid in squamous NSCLC due to high pulmonary bleeding risk.
• Hold therapy for uncontrolled hypertension, proteinuria >2 g/24h, or significant bleeding.
• In HCC, combination with atezolizumab is first-line standard — requires baseline endoscopy to rule out high-risk varices before starting.

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