Nirogacestat (Ogsiveo™)

Author: Karen Arnold-Korzeniowski, MSN RN and Allyson Distel, MPH
Content Contributor: Desiree Croteau, PharmD, BCOP
Last Reviewed: December 26, 2023

Pronounce: NYE-roe-GAY-se-stat

Classification: Gamma Secretase Inhibitor

About: Nirogacestat (Ogsiveo™)

This medication is a gamma secretase inhibitor. It blocks activation of the Notch receptor which is found on some cells. By blocking these receptors, tumor growth is slowed or stopped.

How to Take Nirogacestat

Nirogacestat is a tablet taken by mouth with or without food. It is often taken twice a day. The tablet should not be broken, crushed, or chewed. If you are having trouble swallowing the tablets, ask your provider how else they can be taken. If you miss a dose or vomit after taking it, do not take another dose. Take your next dose as scheduled.

It is important to make sure you are taking the correct amount of medication every time. Before every dose, check that what you are taking matches what you have been prescribed.

The blood levels of this medication can be affected by certain foods and medications, so they should be avoided. These may include: grapefruit, grapefruit juice, Seville oranges, starfruit, ketoconazole, rifampin, itraconazole, clarithromycin, erythromycin, fluconazole, efavirenz, and midazolam, among others. Be sure to tell your healthcare provider about all medications and supplements you take.

To manage heartburn, you can take antacids such as Tums (calcium-carbonate) and Rolaids (Calcium Carbonate and Magnesium Hydroxide) but you should take these medications 2 hours before or 2 hours after taking your nirogacestat. You should not take proton pump inhibitors such as Prilosec (omeprazole), Nexium (esomeprozole), Protonix (pantoprazole) or H2 blockers, such as Pepcid (famotidine) while taking this medication.

Storage and Handling

Store your medication in the original, labeled container at room temperature and in a dry location (unless otherwise directed by your healthcare provider or pharmacist). This medication should not be stored in a pillbox. Keep containers out of reach of children and pets.

If a caregiver prepares your dose for you, they should consider wearing gloves or pour the pills directly from their container into the cap, a small cup, or directly into your hand. They should avoid touching the pills. They should always wash their hands before and after giving you the medication. Pregnant or nursing women should not prepare the dose for you. Ask your oncology team where to return any unused medication for disposal. Do not flush it down the toilet or throw it in the trash.

Where do I get this medication?

Certain medications are only available through specialty pharmacies. If you need to get this medication through a specialty pharmacy, your provider will help you start this process. Where you can fill your prescriptions may also be influenced by your prescription drug coverage. Ask your healthcare provider or pharmacist for assistance in identifying where you can get this medication.

Insurance Information

This medication may be covered under your prescription drug plan. Patient assistance may be available to qualifying individuals depending upon prescription drug coverage. Co-pay cards, which reduce the patient co-pay responsibility for eligible commercially (non-government sponsored) insured patients, may also be available. Your care team can help you find these resources if they are available.

Possible Side Effects

There are a number of things you can do to manage the side effects of nirogacestat. Talk to your care team about these recommendations. They can help you decide what will work best for you. These are some of the most common or important side effects:


Your oncology care team can recommend medications to relieve diarrhea. Also, try eating low-fiber, bland foods, such as white rice and boiled or baked chicken. Avoid raw fruits, vegetables, whole grain breads, cereals, and seeds. Soluble fiber is found in some foods and absorbs fluid, which can help relieve diarrhea. Foods high in soluble fiber include: applesauce, bananas (ripe), canned fruit, orange sections, boiled potatoes, white rice, products made with white flour, oatmeal, cream of rice, cream of wheat, and farina. Drink 8-10 glasses of non-alcoholic, un-caffeinated fluid a day to prevent dehydration. Call your team right away if supportive measures like medications and changes in your diet are not managing your diarrhea.


Some patients may develop a rash, scaly skin, or red itchy bumps. Use an alcohol-free moisturizer on your skin and lips; avoid moisturizers with perfumes or scents. Your oncology care team can recommend a topical medication if itching is bothersome. If your skin does crack or bleed, be sure to keep the area clean to avoid infection. Be sure to notify your oncology care team of any rash that develops, as this can be a reaction. They can give you more tips on caring for your skin.

Nausea and/or Vomiting

Talk to your oncology care team so they can prescribe medications to help you manage nausea and vomiting. 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 saltines, or ginger ale to lessen symptoms.

Call your oncology care team if you are unable to keep fluids down for more than 12 hours or if you feel lightheaded or dizzy at any time.


Fatigue is very common during treatment and is an overwhelming feeling of exhaustion that is not usually relieved by rest. While on treatment, and for a period after, 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 for helpful tips on dealing with this side effect.

Electrolyte Abnormalities

This medication can affect the normal levels of electrolytes (potassium and phosphate) in your body. Your levels will be monitored using blood tests. If your levels become too low, your care team may prescribe specific electrolytes to be given by IV or taken by mouth. Do not take any supplements without first consulting with your care team.

Kidney Problems

This medication can cause a decrease in kidney function or damage to the kidney which can cause an elevated level of glucose and protein in your urine. For this reason, your healthcare team will monitor your kidney function with blood tests and urine tests. Notify your provider if you notice any blood in your urine, decrease in urination, or darkening of the urine.

Mouth Ulcers (Mucositis)

Certain treatments can cause sores or soreness in your mouth and/or throat. Notify your oncology care team if your mouth, tongue, inside of your cheek, or throat becomes white, ulcerated, or painful. Performing regular mouth care can help prevent or manage mouth sores. If mouth sores become painful, your doctor or nurse can recommend a pain reliever.

  • Brush with a soft-bristle toothbrush or cotton swab twice a day.
  • Avoid mouthwashes that contain alcohol. A baking soda and/or salt with warm water mouth rinse (2 level teaspoons of baking soda or 1 level teaspoon of salt in an eight-ounce glass of warm water) is recommended 4 times daily.
  • If your mouth becomes dry, eat moist foods, drink plenty of fluids (6-8 glasses), and suck on sugarless hard candy.
  • Avoid smoking and chewing tobacco, drinking alcoholic beverages, and citrus juices.

Liver Toxicity

This medication can cause liver toxicity, which your oncology care team may monitor for using blood tests called liver function tests. Notify your healthcare provider if you notice yellowing of the skin or eyes, your urine appears dark or brown, or you have pain in your abdomen, as these can be signs of liver toxicity.


This medication can cause headaches. Your healthcare provider can recommend medications and other strategies to help relieve pain.

Less common but important side effects can include:

  • New Non-Melanoma Skin Cancer: A secondary cancer develops as a result of treatment for another illness. This is quite rare, but you should be aware of the risk. There is a very low risk of developing non-melanoma skin cancer during treatment with this medication. Because this medication has been associated with the development of skin cancers, it is important to practice sun safety. Avoid the sun between 10-2pm, when it is strongest. Wear sunscreen (at least SPF 15) everyday; wear sunglasses, a hat, and long sleeves/pants to protect your skin and seek out shade whenever possible. You will be checked for skin cancer before starting your treatment and during treatment. Check your own skin regularly and report any new growths, sores, or bumps that bleed or do not heal, or notice any changes in moles to your oncology care team.

Sexual & Reproductive Concerns

This medication may affect your reproductive system and fertility. Talk with your provider about any concerns you might have if you wish to have children in the future.

Exposure of an unborn child to this medication could cause birth defects, so you should not become pregnant or father a child while on this medication. For women and men, effective birth control is necessary during treatment and for at least 1 week after treatment, even if your menstrual cycle stops or if you believe you are not producing sperm. You should not breastfeed while receiving this medication and for 1 week after the last dose.