alpelisib at a glance
Medicine class
PI3K-alpha inhibitor and targeted anticancer treatment
Biomarker required
A validated test must confirm a PIK3CA mutation in tumour tissue or plasma.
Administration
Take immediately after food and swallow the tablets whole.
Important monitoring
Blood glucose requires close monitoring, particularly soon after treatment starts.
What is alpelisib used for?
The selected UK product is licensed only in combination with fulvestrant for:
Postmenopausal women and men with PIK3CA-mutated, hormone receptor-positive, HER2-negative locally advanced or metastatic breast cancer after progression following endocrine-based therapy.
How does alpelisib work?
Alpelisib selectively inhibits PI3K-alpha, a signalling protein that can be overactive when PIK3CA is mutated. Blocking this pathway reduces signals that help cancer cells grow and survive; fulvestrant also blocks oestrogen-receptor signalling.
alpelisib preparations and strengths
Tablet
Route: Oral
Strengths: 50 mg, 150 mg, 200 mg
How to take alpelisib
Follow the oncology team's prescription and the blister-card instructions.
Take the tablets immediately after food, at approximately the same time each day.
Swallow tablets whole; do not chew, crush or split them.
Do not take tablets that are broken, cracked or otherwise damaged.
If you vomit after taking alpelisib, do not repeat it; wait until the next scheduled administration.
alpelisib side effects
Common or expected effects
- Raised blood glucose
- Diarrhoea, nausea, vomiting or abdominal discomfort
- Rash, itching or dry skin
- Tiredness
- Reduced appetite or weight loss
- Mouth soreness or ulcers
- Headache or altered taste
- Hair thinning
- Changes in blood counts, kidney markers, liver enzymes or electrolytes
Get urgent medical advice
- Severe hyperglycaemia, ketoacidosis or hyperosmolar illness
- Severe allergic reaction or angioedema
- Severe blistering or peeling skin reactions, including SJS or DRESS
- Pneumonitis with new or worsening respiratory symptoms
- Severe diarrhoea, dehydration, colitis or acute kidney injury
- Pancreatitis
- Osteonecrosis of the jaw
- Uveitis with eye pain, redness, light sensitivity or visual change
alpelisib in pregnancy
Alpelisib is not recommended during pregnancy and may harm a developing baby. Pregnancy status should be checked where relevant, and effective contraception is required during treatment and for at least one week afterwards; male patients with partners who could become pregnant should use condoms over the same period. Discuss pregnancy, contraception and fertility with the specialist team before treatment.
alpelisib while breastfeeding
Breastfeeding is not recommended during alpelisib treatment or for at least one week afterwards because serious effects in a breastfed infant cannot be excluded.
alpelisib interactions
The oncology team should review prescription, non-prescription and herbal products before treatment.
Strong CYP3A4 inducers, including rifampicin, carbamazepine, phenytoin, apalutamide, enzalutamide, mitotane and St John’s wort
These can substantially reduce alpelisib exposure and should generally be avoided in favour of an alternative.
BCRP inhibitors, including eltrombopag, lapatinib and pantoprazole
These may increase alpelisib exposure, so monitor for toxicity.
Proton-pump inhibitors, H2-receptor antagonists and antacids
Acid-reducing treatments may be co-administered provided alpelisib is taken immediately after food.
Common questions about alpelisib
Answers are fully visible for fast scanning and source review.
Why is alpelisib used with fulvestrant?
The two treatments block different growth signals: alpelisib targets PI3K-alpha, while fulvestrant targets the oestrogen receptor.
Why do I need a PIK3CA test before alpelisib?
Its licensed use requires a confirmed PIK3CA mutation, which identifies cancers driven by the pathway alpelisib targets.
Why can alpelisib raise blood sugar?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.