Common Side Effects of Cabometyx
Cabometyx (cabozantinib), used for advanced kidney, liver, and thyroid cancers, causes side effects in most patients. The most frequent, affecting over 25% of users, include diarrhea (up to 81%), fatigue (up to 64%), nausea (up to 50%), decreased appetite (up to 48%), hypertension (up to 45%), palmar-plantar erythrodysesthesia (redness, pain, swelling on hands/feet, up to 42%), vomiting (up to 32%), weight loss (up to 30%), dysphonia (hoarse voice, up to 30%), and constipation (up to 25%). These often start within weeks and may require dose adjustments.[1][2]
Serious Side Effects Patients Report
Severe risks include perforations or fistulas in the stomach/intestines (2-3% incidence), bleeding (3-5%), blood clots (3-5%), liver damage (elevated enzymes in 10-15%), heart problems like failure or arrhythmias (2-5%), and reversible posterior leukoencephalopathy syndrome (brain swelling, rare). Hypertension can lead to stroke or heart attack if uncontrolled. Fatal events like hemorrhage or thrombosis occur in under 1% but prompt immediate medical attention.[1][2][3]
Side Effects by Cancer Type
In kidney cancer trials, hypertension and diarrhea topped lists (74% and 74%). Liver cancer studies showed more hand-foot syndrome (53%) and fatigue (45%). Thyroid trials had higher rates of stomatitis (mouth sores, 40%) and hypothyroidism (26%). Combinations with immunotherapy like Opdivo increase risks like immune-related issues (colitis, pneumonitis).[2][3]
How Long Do Side Effects Last and What Helps?
Most resolve after stopping or reducing the dose (100mg daily standard). Diarrhea and hand-foot issues improve with loperamide or creams; hypertension needs blood pressure meds. Fatigue and appetite loss persist months for some. Patients often manage with hydration, topical treatments, and monitoring—doctors advise weekly checks early on.[1][3]
Why Do These Side Effects Happen?
Cabozantinib blocks blood vessel growth signals (VEGFR, MET, RET), starving tumors but also harming healthy vessels and tissues, causing hypertension, bleeding, and skin issues. Liver enzyme spikes stem from its metabolism there.[2]
Patient Concerns and When to Call a Doctor
Users frequently mention debilitating fatigue, mouth pain, and rash online. Seek help for severe diarrhea (>4 episodes/day), blood in stool/urine, chest pain, vision changes, confusion, or seizures. Pregnancy risks are high (fetal harm); use contraception.[1][3]
[1] Cabometyx Prescribing Information, Exelixis, https://cabometyx.com/
[2] FDA Label for Cabometyx, https://www.accessdata.fda.gov/drugsatfda_docs/label/2023/208115s029lbl.pdf
[3] Drugs.com Side Effects Database, https://www.drugs.com/sfx/cabometyx-side-effects.html