Bevacizumab

Bevacizumab is a recombinant humanized monoclonal antibody (IgG1) directed against vascular endothelial growth factor A (VEGF-A). By neutralizing circulating VEGF-A, it blocks one of the principal drivers of tumor angiogenesis.

Mechanism of Action

VEGF-A is a key signaling protein in tumor angiogenesis: tumors secrete VEGF-A to stimulate new blood vessel growth, which supplies oxygen and nutrients to growing tumors and increases vascular permeability.

Bevacizumab binds all biologically active isoforms of VEGF-A and prevents engagement with its receptors VEGFR-1 and VEGFR-2, as well as neuropilin co-receptors (NRP-1 and NRP-2). The downstream effects include:

• Inhibition of new tumor blood vessel formation (antiangiogenesis).
• Normalization of existing tumor vasculature, pruning abnormal and leaky vessels.
• Reduced vascular permeability and lower interstitial pressure within tumors.
• Limited oxygen and nutrient supply to tumor tissue.
• Improved delivery and efficacy of co-administered chemotherapy through vascular normalization.

Pharmacokinetics

• Half-life: approximately 20 days (range 11–50 days), enabling every-2-week or every-3-week dosing schedules.
• Steady state: reached after approximately 84–100 days of regular dosing.
• Distribution: largely confined to plasma and the vascular space; volume of distribution approximately 3.29 L in males and 2.39 L in females.
• Protein binding: bevacizumab binds and neutralizes >97% of circulating VEGF.
• Clearance: approximately 0.207 L/day; clearance increases by ~30% in patients weighing >114 kg and decreases by ~30% in those weighing <49 kg. Males clear bevacizumab approximately 26% faster than females.
• Elimination: cleared via general protein catabolism, pinocytosis, reticuloendothelial system (RES) sequestration, and target-mediated drug disposition. Not metabolized by hepatic enzymes and not renally excreted intact.
• Linearity: pharmacokinetics are linear and dose-proportional within the therapeutic range.

Bevacizumab has demonstrated clinically meaningful benefit across multiple solid tumors, almost always in combination with chemotherapy or other targeted agents. Improvements in progression-free survival have been consistent across indications; overall survival benefits have been shown in selected settings (notably first-line metastatic colorectal cancer, advanced ovarian cancer, and recurrent cervical cancer). Approved regimens, lines of therapy, and labelling vary by region.

Approved oncology indications (regional variation applies):

• Metastatic colorectal cancer — first- and second-line, combined with fluoropyrimidine-based chemotherapy.
• Non-squamous non-small cell lung cancer (NSCLC) — first-line, with platinum-based chemotherapy.
• Recurrent glioblastoma — typically as monotherapy.
• Advanced renal cell carcinoma — first-line, in combination with interferon alfa.
• Epithelial ovarian, fallopian tube, and primary peritoneal cancer — first-line, recurrent platinum-sensitive and platinum-resistant disease, including maintenance.
• Persistent, recurrent, or metastatic cervical cancer — combined with chemotherapy.
• Hepatocellular carcinoma — first-line, in combination with atezolizumab (in regions where this regimen is approved).
• HER2-negative metastatic breast cancer — combined with paclitaxel (region-dependent; not approved in all jurisdictions).

Off-label / other uses (region-dependent): ophthalmic conditions including neovascular age-related macular degeneration, diabetic macular edema, and retinal vein occlusion (intravitreal use).

Absolute:

• Hypersensitivity to bevacizumab or to any of its excipients.
• Hypersensitivity to Chinese hamster ovary (CHO) cell products or other recombinant human or humanized antibodies.
• Squamous-cell histology in NSCLC — due to risk of severe pulmonary hemorrhage.

Relative / special precautions:

• Untreated CNS metastases.
• Recent hemoptysis (≥2.5 mL of bright red blood).
• Active or recent significant bleeding.
• Recent major surgery (within 28 days) or non-healing surgical wounds.
• Severe, uncontrolled hypertension.
• Pregnancy and breastfeeding.

Very common (>10%): hypertension (the most frequent adverse event, up to ~42%), fatigue, asthenia, diarrhea, abdominal pain, nausea, decreased appetite, proteinuria, epistaxis, headache, dyspnea, stomatitis.

Common (1–10%): venous and arterial thromboembolism, minor hemorrhage (gum bleeding, rectal bleeding), leukopenia and neutropenia, weight loss, dysgeusia, increased lacrimation, dry skin and other skin toxicity.

Serious adverse events (lower frequency but clinically important):

• Cardiovascular: severe hypertension; arterial thromboembolic events (stroke, myocardial infarction, transient ischemic attack, angina) in approximately 2–5%; venous thromboembolism (deep vein thrombosis, pulmonary embolism) in approximately 5–15%; congestive heart failure, particularly with concurrent or prior anthracycline exposure.
• Hemorrhagic: severe bleeding in 1–5% — most commonly gastrointestinal, pulmonary, or central nervous system. Pulmonary hemorrhage risk is markedly increased in squamous-cell NSCLC.
• Gastrointestinal: gastrointestinal perforation (0.3–3%), fistula formation, anastomotic leak.
• Wound healing: impaired wound healing, wound dehiscence, non-healing wounds and ulcers.
• Renal: proteinuria (up to ~40%, usually mild and asymptomatic); nephrotic syndrome (rare); thrombotic microangiopathy (rare).
• Neurological: posterior reversible encephalopathy syndrome (PRES), also referred to as reversible posterior leukoencephalopathy syndrome (RPLS) — rare, typically reversible after discontinuation.
• Reproductive: ovarian failure in premenopausal women.
• Other: osteonecrosis of the jaw (rare; risk increased with concomitant bisphosphonates); infusion reactions (uncommon and usually mild).

• Hepatic enzymes: bevacizumab does not undergo hepatic metabolism and has no clinically relevant cytochrome P450 interactions.
• Anthracyclines (e.g., doxorubicin): increased risk of congestive heart failure.
• Sunitinib: increased risk of microangiopathic hemolytic anemia when combined.
• Bisphosphonates: possibly increased risk of osteonecrosis of the jaw.
• Live vaccines: avoid during treatment due to immunomodulatory effects.

Hypertension

Hypertension is the most common adverse effect. Blood pressure should be monitored regularly throughout treatment and managed with standard antihypertensive therapy (target generally <140/90 mmHg). Severe or uncontrolled hypertension may require dose interruption.

Proteinuria

Monitor urinary protein periodically. Quantify (24-hour urine or protein/creatinine ratio) when dipstick proteinuria reaches 2+ or higher. Treatment is typically interrupted for protein excretion ≥2 g/24h and discontinued if nephrotic syndrome develops.

Wound Healing and Surgery

VEGF inhibition impairs wound healing. Bevacizumab should be discontinued for an interval before elective surgery (commonly at least 28 days, longer for major surgery) and not resumed until wounds are fully healed.

Hemorrhage Risk

Risk of severe pulmonary hemorrhage is markedly elevated in squamous-cell NSCLC, where bevacizumab is contraindicated. Recent hemoptysis is also a contraindication.

Pregnancy and Fertility

Bevacizumab causes fetal harm based on its mechanism of action and animal data. Effective contraception is required during treatment and for at least 6 months after the last dose. The drug may impair female fertility, including premature ovarian failure in premenopausal women. Breastfeeding should be discontinued and not resumed for at least 6 months after the last dose.

Special Populations

• Pediatric use: limited data; some evidence of increased toxicity in children — restricted to specialist oncology centers.
• Elderly (>65 years): increased risk of arterial thromboembolic events; efficacy is comparable.
• Renal or hepatic impairment: no specific pharmacokinetic-driven adjustments are required, but close clinical monitoring is recommended.

• Originator: Genentech / Roche (marketed as Avastin).
• First approval: FDA approved in 2004 for first-line metastatic colorectal cancer; EMA approval followed in 2005. Indications have since expanded across multiple solid tumors.
• Biosimilars: bevacizumab was among the first biologic oncology agents with multiple approved biosimilars. Notable biosimilars include Mvasi (FDA-approved 2017, EMA-approved 2018) and Zirabev (FDA-approved 2019, EMA-approved 2019). Additional biosimilars are approved in further regions.