BRAF is a protein kinase that plays a role in regulating genes that are responsible for cell replication and survival. It is estimated that 50% of melanomas contain an abnormal form of BRAF (also called a mutation). This mutated form of BRAF appears to promote overgrowth of these cancer cells. Vemurafenib works by blocking the actions of the abnormal BRAF, inhibiting cell replication and potentially causing cell death.
How to Take Vemurafenib
Vemurafenib is given in a tablet form, with the typical dose being 960 milligrams (made up of 4 240mg tablets) taken twice a day. Vemurafenib tablets should be taken with a glass of water and should not be crushed, broken or chewed. If you miss a dose, you can take the dose up to 4 hours before the next dose. Do not take two doses at once to make up for a missed dose.
Because this medication only works in melanoma that has a mutated form of BRAF, this abnormality must be tested for prior to starting the medication to identify patients appropriate for therapy. In order to test for mutated BRAF, a sample of the tumor is sent to a special laboratory that performs this test.
Possible Side Effects of Vemurafenib
There are a number of things you can do to manage the side effects of Vemurafenib. Talk to your doctor or nurse about these recommendations. They can help you decide what will work best for you. These are some of the most common side effects:
Your skin will be more sensitive to the sun, which can result in severe sunburn or rash. Sun sensitivity can last even after vemurafenib is stopped. Avoid the sun between 10-2pm, when it is strongest. Wear sunscreen (at least SPF 15) and lip balm everyday, wear sunglasses and long sleeves/pants to protect your skin.
Rash and Allergic Reactions
Some patients can develop a reaction to vemurafenib, which can include rash, skin redness, or a serious allergic reaction causing difficulty breathing. If you have any side effects while taking this medication, be sure to inform you oncology team right away.
Nausea and/or Vomiting
Take anti-nausea medications as prescribed. If you continue to have nausea or vomiting, notify your doctor or nurse so they can help you manage this side effect. In addition, dietary changes may help. Avoid things that may worsen the symptoms, such as heavy or greasy/fatty, spicy or acidic foods (lemons, tomatoes, oranges). Try antacids, (e.g. milk of magnesia, calcium tablets such as Tums), saltines, or ginger ale to lessen symptoms. Read the Nausea & Vomiting Tip Sheet for more suggestions.
Call your doctor or nurse if you are unable to keep fluids down for more than 12 hours or if you feel lightheaded or dizzy at any time.
Muscle or Joint Pain/Aches
Your doctor or nurse can recommend medication and other strategies to relive pain. Also view OncoLink's page on pain management.
While on cancer treatment you may need to adjust your schedule to manage fatigue. Plan times to rest during the day and conserve energy for more important activities. Exercise can help combat fatigue; a simple daily walk with a friend can help. Talk to your healthcare team and see OncoLink's section on fatigue for helpful tips on dealing with this side effect.
Loss or Thinning of Scalp and Body Hair (Alopecia)
Your hair may become thin, brittle, or may fall out. This typically begins two to three weeks after treatment starts. This hair loss can be all body hair, including pubic, underarm, legs/arms, eyelashes, and nose hairs. The use of scarves, wigs, hats and hairpieces may help. Hair generally starts to regrow soon after treatment is completed. Remember your hair helps keep you warm in cold weather, so a hat is particularly important in cold weather or to protect you from the sun. Read more on alopecia.
Decrease in Appetite
New Skin Cancer
In clinical trials, some patients developed a new skin cancer (melanoma or squamous cell cancer). You should have skin examinations every 2 months while on therapy and for 6 months after the medication has been stopped. Check your own skin regularly and report any changes to your healthcare provider.
Vemurafenib can cause a heart problem called QT prolongation, which can lead to heart dangerous arrhythmias (irregular rhythms). Your healthcare provider will monitor for this problem with periodic ECGs (electrocardiogram) and lab work to evaluate electrolyte levels.
In clinical trials, several patients developed a condition called uveitis, which is a swelling or irritation of the middle layer of the eye. Symptoms of this condition include blurry vision, "floaters" (dark spots in the field of vision), eye redness or pain and sensitivity to light. If you develop any of these symptoms, notify your healthcare provider right away.