Avastin (Bevacizumab): Uses, Mechanism, Side Effects, and Key Considerations

Avastin (bevacizumab) is a recombinant humanized monoclonal antibody that inhibits vascular endothelial growth factor (VEGF-A), blocking angiogenesis (new blood vessel formation). It is used in combination with chemotherapy for several advanced/metastatic cancers.

FDA-Approved Indications (U.S.)

• Metastatic colorectal cancer (with 5-FU-based chemo)
• Non-squamous non-small cell lung cancer (with carboplatin/paclitaxel)
• Metastatic renal cell carcinoma (with interferon-alfa)
• Recurrent glioblastoma (as single agent)
• Persistent/recurrent/metastatic cervical cancer (with chemo ± immunotherapy)
• Epithelial ovarian/fallopian tube/primary peritoneal cancer (with chemo, then maintenance)
• Hepatocellular carcinoma (with atezolizumab) — accelerated approval

Note: Breast cancer indication was withdrawn in 2011 due to risk/benefit concerns.

Mechanism of Action

By binding VEGF-A, bevacizumab prevents VEGF receptor activation on endothelial cells, inhibiting tumor neovascularization. This "normalizes" tumor vasculature transiently, improving chemotherapy delivery, and starves the tumor of oxygen/nutrients.

Administration

• IV infusion every 2–3 weeks.
• First infusion over 90 minutes; subsequent over 60/30 minutes if tolerated.

Common Side Effects (≥10%)

• Hypertension (very common — monitor and treat)
• Fatigue, nausea, diarrhea, decreased appetite
• Headache, epistaxis, proteinuria
• Taste changes, dry skin, stomatitis

Serious Risks (Boxed Warnings)

• GI perforation (fistula, abscess)
• Impaired wound healing — hold 28 days pre/post surgery
• Hemorrhage (including fatal pulmonary/ CNS bleeding)
• Arterial/venous thromboembolism
• Posterior reversible encephalopathy syndrome (PRES)
• Nephrotic syndrome
• Osteonecrosis of the jaw

Monitoring

BP at each visit; urine protein (dipstick then 24-hr if positive); CBC, LFTs, electrolytes; assess for neurological symptoms.

Discuss risks/benefits thoroughly with your oncology team.