Alpelisib

Alpelisib (Piqray) is a targeted therapy approved by the U.S. Food and Drug Administration to treat people with locally advanced or metastatic, hormone receptor-positive breast cancer that has tested positive for a mutation on the PIK3CA gene.

Alpelisib is a PI3K (phosphatidylinositol-3 kinase) inhibitor, a type of medicine that works by blocking a pathway in cancer cells, called PI3K, that may cause breast cancers to stop responding to hormonal therapies. It is given with the hormonal therapy fulvestrant (Faslodex).

Alpelisib was approved by the FDA in May 2019 and is the first PI3K inhibitor approved to treat breast cancer.

How alpelisib works

A mutation on the PIK3CA gene can cause the PI3K pathway in breast cancer cells to become too active. Researchers believe this path causes some breast cancer to stop responding to hormonal therapy. Alpelisib is a PI3K inhibitor, meaning it blocks this pathway and works with hormonal therapy to keep the cancer from growing.

Who gets alpelisib

Alpelisib is approved for people with advanced or metastatic, hormone receptor-positive, HER2-negative breast cancer that has grown during or after treatment with hormonal therapy. The tumor must also test positive for a mutation on the PIK3CA gene. This mutation is present in the tumors of about 40% of people with this diagnosis. Along with alpelisib, the FDA approved a biomarker test, the therascreenPIK3CA RGQ PCR Kit, to test for this mutation.

How alpelisib is given

Alpelisib is a pill. The standard dose is 300 milligrams (mg) by mouth daily (two 150 mg tablets each day). It is given along with fulvestrant. Fulvestrant is given in your doctor’s office as two 250 mg injections (for a total of 500 mg). Fulvestrant injections are given on day 1 and day 15 in the first month. After that, the injections are given only once a month.

Side effects and things to remember

High blood sugar is a notable side effect of alpelisib. In the SOLAR-1 trial, it was the most common reason people stopped treatment with alpelisib. High blood sugar can be managed with diabetes medicines, changes in diet, changes to the dose of alpelisib, and taking a break from alpelisib. 

Whether or not you have diabetes, let your doctors know if you experience: 

• Extreme thirst 
• Dry mouth 
• Changes in amount of urination 
• Unexpected weight loss 
• A fruity odor to your breath 
• Dry, flushed, or red skin 
• Blurred vision  
• Fatigue 

These can all be signs of elevated blood sugar levels. 

Other common side effects were: 

• Diarrhea 
• Nausea 
• Mouth sores 
• Rash 
• Fatigue 

Less common but serious side effects can include severe rash, lung inflammation, and allergic reactions. Let your doctor know if you have had any serious skin reactions or breathing issues related to medicines you’ve taken in the past.

Tell your doctor if you are pregnant or planning to become pregnant. Alpelisib may be dangerous to an unborn baby, so it is recommended that you not take this medicine while pregnant and not get pregnant for at least a week after you have stopped treatment.

Alpelisib drug and supplement interactions

Alpelisib interacts with certain medicines and supplements that affect a liver enzyme called CYP3A4. These medicines may change how alpelisib works.  

Let your care team know about all the medicines and supplements you take, including the ones listed below. 

Medicines and supplements that decrease alpelisib levels:

• Rifampin, an antibiotic for tuberculosis, meningitis, and other infections 
• Carbamazepine, a medicine that reduces the risk of seizures; carbamazepine is also sometimes used to treat bipolar disorder 
• Phenobarbital, a sedative used to prevent seizures 
• Phenytoin, a medicine used to control seizures 

The supplement St. John’s wort also decreases alpelisib levels. 

Medicines that increase alpelisib levels:

• Erythromycin, a common antibiotic 
• Itraconazole, an antifungal medicine that treats serious yeast or fungal infections in the body 
• Ketoconazole, an antifungal medicine   
• Clarithromycin, a common antibiotic used for skin and respiratory infections 

Other alpelisib interactions

Alpelisib can also change the levels of a blood thinner called warfarin. If you take warfarin, let your care team know. People taking alpelisib and warfarin need to be monitored closely. 

It’s also important to avoid grapefruit and grapefruit juice while taking alpelisib. Grapefruit can change the way alpelisib works. 

Paying for alpelisib

Novartis, the makers of alpelisib, offers the Novartis Oncology Universal Co-pay Program to help people with private insurance cover copays and other out-of-pocket costs for alpelisib. 

Besides treatment, costs after a breast cancer diagnosis can include traveling to and from appointments, taking time off work, and paying for childcare. Learn more about resources and support for covering the cost of breast cancer on our Financial matters pages.