Inavolisib (Itovebi): What to Expect, Side Effects, and More
If you’ve been diagnosed with locally advanced or metastatic hormone receptor-positive, HER2-negative breast cancer with a PIK3CA mutation that has grown or come back during or after hormonal therapy treatment for early-stage disease, your doctor may prescribe inavolisib (brand name: Itovebi) in combination with Faslodex (chemical name: fulvestrant) and Ibrance (chemical name: palbociclib).
Locally advanced breast cancer is cancer that has spread to tissue near the breast. Metastatic breast cancer is cancer that has spread to parts of the body away from the breast.
Inavolisib is a PI3K inhibitor, a targeted therapy that disrupts the ability of cancer cells to get the energy they need to divide and grow.
See inavolisib prescribing information.
PI3K inhibitors block the PI3K pathway. The PI3K pathway helps all cells — both healthy and cancer cells — get the energy they need. When this pathway is over-activated because of a mutation in the PIK3CA gene, cancer cells can grow unchecked. When the PI3K pathway is blocked, it makes it hard for cancer cells to grow.
Different mutations in the PIK3CA gene make different forms of the PI3 protein, called isoforms by researchers. There are several isoforms of PI3; one of them is the alpha isoform. Inavolisib specifically targets the alpha isoform.
Piqray (chemical name: alpelisib) and Truqap (chemical name: capivasertib) are other targeted therapies used to treat some breast cancers with a PIK3CA mutation.
Inavolisib is prescribed with Faslodex and Ibrance.
Inavolisib and Ibrance are pills taken by mouth. Each Faslodex treatment is made up of two injections, one into each butt cheek. Each injection takes about one to two minutes.
If you’re prescribed inavolisib, you’ll take inavolisib and Ibrance on a 28-day cycle: for 21 days, you take both medicines and then for seven days don’t take Ibrance. You take inavolisib every day. You receive Faslodex on day one and day 15 of the first treatment cycle and then on day one of the rest of the treatment cycles.
People who are pregnant or planning to get pregnant should not take inavolisib. Inavolisib can harm the developing fetus. If there’s any chance you could become pregnant while taking inavolisib, you must use birth control during treatment and for at least one week after your last dose.
Men taking inavolisib with female partners who could become pregnant should use effective birth control while taking inavolisib and for at least one week after the last dose.
Also, women who are breastfeeding or plan to breastfeed shouldn’t take inavolisib. Together, you and your doctor will decide if you should take inavolisib or breastfeed.
Like almost all breast cancer medicines, inavolisib can cause side effects, some of them severe.
High blood sugar or glucose, also called hyperglycemia, is a serious side effect of inavolisib. High blood sugar, which is common in people with diabetes, happens when the body has too little insulin or can’t use insulin properly. If left untreated, it can cause nerve damage, eye disease, and kidney damage.
Before starting inavolisib, your doctor should test your fasting blood sugar level. These blood tests will be repeated at least monthly while you’re taking inavolisib. If you have any symptoms of high blood sugar — such as being excessively thirsty, urinating more often than usual, or being hungrier than usual but losing weight — tell your doctor right away.
Mouth sores, or stomatitis, can be another serious side effect of inavolisib. Severe mouth sores can be painful and can affect how you eat, drink, chew, swallow, and talk. Mouth sores also can make you more susceptible to an oral yeast infection. If you start to develop mouth or throat sores, tell your doctor right away; there are prescription steroid mouthwashes that can help.
Inavolisib also may cause severe diarrhea, which can lead to dehydration. For many people, it starts in the first two weeks of treatment. Tell your doctor right away if you have any signs of diarrhea.
Other common side effects of inavolisib are:
anemia (low red blood cell counts)
low potassium or calcium levels
Since inavolisib is taken with Faslodex and Ibrance, you also may have side effects caused by those medicines. Common side effects of Faslodex are hot flashes and pain at the site of the injections. Less common side effects include nausea and vomiting. Common side effects of Ibrance are anemia, fatigue, low white blood cell counts, and nausea.
The cost of inavolisib may vary. The price you’ll pay depends on the drug manufacturer, your health insurance provider and plan, where you live, and the pharmacy you use.
If your doctor prescribes inavolisib and you have problems paying for it or getting it covered by insurance, Genentech Patient Support Services may be able to help. The Genentech Patient Foundation helps people without insurance or who have financial concerns. If you need help understanding your health insurance coverage for inavolisib, you can call Genentech Access Solutions at 877-436-3683.
Learn more about financial assistance and medicine cost-lowering tips.
— Last updated on November 30, 2024 at 6:34 PM