Sorafenib is an oral medication used in targeted cancer therapy. It is a type of drug known as a kinase inhibitor, which interferes with signaling pathways that promote cancer cell growth. Commonly recognized by its brand name, Nexavar, this medication has become a treatment option for specific types of advanced cancers.
How Sorafenib Works
Sorafenib functions as a multi-kinase inhibitor, blocking several different enzymes involved in cancer growth. Its mechanism involves a dual-action approach. First, it targets kinases located on the surface of and inside tumor cells, such as RAF, c-KIT, and FLT-3. By blocking these, it interrupts signaling pathways, like the RAF/MEK/ERK pathway, that instruct cancer cells to multiply, thereby slowing down tumor proliferation.
The medication also works to inhibit angiogenesis, the process of forming new blood vessels. Tumors require a dedicated blood supply to obtain the oxygen and nutrients necessary for their expansion. Sorafenib obstructs the activity of vascular endothelial growth factor receptors (VEGFR) and platelet-derived growth factor receptors (PDGFR) in the tumor’s vasculature. This action curtails the tumor’s ability to develop its blood supply, limiting its growth and survival.
Medical Uses for Sorafenib
Regulatory agencies have approved sorafenib for the treatment of several specific types of cancer. Its use is for hepatocellular carcinoma (HCC), the most common form of primary liver cancer, particularly for cases where the tumor cannot be surgically removed. Patients with advanced renal cell carcinoma (RCC), a type of kidney cancer, may also be prescribed sorafenib. Another indication is for differentiated thyroid carcinoma (DTC) that is progressive and no longer responds to radioactive iodine treatment.
Common Side Effects and Adverse Reactions
Patients taking sorafenib may experience a range of side effects. Among the most frequently reported is hand-foot skin reaction (HFSR), also called palmar-plantar erythrodysesthesia, which is characterized by redness, swelling, and discomfort on the palms of the hands and soles of the feet. Other common side effects include:
- Diarrhea
- Fatigue
- Rash
- Hair loss (alopecia)
- High blood pressure (hypertension)
Sorafenib can also cause more serious adverse reactions that require immediate medical attention. An increased risk of bleeding is a notable concern, and any significant bleeding event may necessitate stopping the treatment. Cardiac complications, including heart ischemia or infarction, have been observed in some patients. Additionally, the medication can lead to severe hypertension or liver problems.
Administration and Monitoring
Sorafenib is administered as an oral tablet, typically taken twice daily. For optimal absorption, tablets should be taken without food or with a low- to moderate-fat meal. If a high-fat meal is consumed, the medication should be taken at least one hour before or two hours after eating. The tablets should be swallowed whole with a glass of water.
Continuous medical supervision is part of the treatment with sorafenib. Regular monitoring is necessary to track the body’s response to the drug and manage any side effects. This includes frequent blood pressure checks, as hypertension is a common side effect. Blood tests are also performed to assess liver function, electrolyte levels, and blood cell counts. A doctor may adjust the dosage or temporarily interrupt treatment to manage adverse reactions.