Nirogacestat (Ogsiveo) for Desmoid Tumors: The 6 Essential Facts on This Twice-Daily Tablet

Did you know that not all tumors are cancerous? Noncancerous tumors - also known as benign tumors - don't spread to other parts of the body. But they can still cause problems. Even though they generally stay in one place, they can grow and become painful. And if they press on nearby organs, such as your gut or blood vessels, it can turn into a serious issue.

Desmoid tumors are benign tumors that grow in connective tissue - the tissue that holds your organs in place and connects your muscles, ligaments, and bones. They typically show up in the belly but can also appear in your arms or legs.

Historically, surgery was the main treatment option for desmoid tumors. But people often weren't happy with how their bodies looked and functioned after surgery. Without any approved treatments available, oncologists turned toward nonspecific treatments, such as chemotherapy and radiation. But these can cause many side effects of their own.

Nirogacestat (Ogsiveo) is a new oral medication approved for the treatment of desmoid tumors. Since it's the first medication of its kind, let's explore six essential facts about the first FDA-approved medication for desmoid tumors.

1. Nirogacestat's mechanism of action: Here's how nirogacestat works

Scientists aren't exactly sure why desmoid tumors happen. But they have some good guesses. It's thought that having high amounts of a protein called Notch increases the growth of desmoid tumors. Gamma secretase is another protein that acts like a switch to increase Notch production.

Nirogacestat is a gamma secretase inhibitor, meaning it blocks gamma secretase activity. By doing this, it shuts off a pathway that leads to desmoid tumor growth. This helps slow the tumor's growth over time.

2. Nirogacestat is typically taken twice a day, but doses can vary

Nirogacestat is available as 50 mg, 100 mg, and 150 mg oral tablets. The typical nirogacestat dosage is 150 mg twice a day.

However, if you're struggling with side effects, your oncologist may ask you to take a lower dose. If this is the case, the next-lowest dosage is 100 mg twice a day. In a clinical study, roughly 4 in 10 people needed to decrease their dose due to a side effect.

Don't change your dose or stop nirogacestat without talking to your oncology team. These healthcare professionals may be able to help you manage certain side effects without having to change your dose.

3. Nirogacestat is a preferred medication for progressing desmoid tumors

Nirogacestat is the first medication approved for desmoid tumors.

In the study that led to its approval, nirogacestat increased the amount of time people lived without experiencing any growth of their desmoid tumor. After 2 years, about three-quarters of people were likely to have no tumor growth, compared with less than half of people who received a placebo (a pill with no medication).

In the same study, nirogacestat partially or fully shrank desmoid tumors in about 40% of people - compared with only 8% of those who received a placebo. Nirogacestat also decreased recipients' pain and improved their quality of life.

Because it has good supporting evidence, your oncologist may prefer to prescribe nirogacestat over other treatments if your tumor starts to grow.

4. Nirogacestat side effects are possible

Like any medication, nirogacestat has the potential to cause side effects. Most tend to be rather mild and can be managed with the help of your oncology team.

Common nirogacestat side effects include:

• Diarrhea

• Nausea and vomiting

• Fatigue

• Rash (including acne-like rash)

• Mouth sores

• Headache

• Stomach pain

• Cough

• Hair loss or thinning

• Infection

• Shortness of breath

• Low blood levels of phosphate or potassium

• Increased liver enzymes

• Ovarian failure

Some of these side effects warrant dose reductions or the need to permanently stop taking nirogacestat. These include:

• Diarrhea

• Mouth sores

• Skin toxicities, such as rash, bumps under the skin, and inflammation of hair follicles

• Low phosphate levels

• Increased liver enzymes

• Ovarian failure

Let's dive a little deeper into a few of these side effects that might benefit from a little extra attention.

Diarrhea

Diarrhea is the most common nirogacestat side effect, occurring in more than 80% of people who take it. In most people, diarrhea resolves with reducing their dose, stopping nirogacestat for a period of time, or taking antidiarrheal medication such as loperamide (Imodium A-D).

Skin reactions

Nirogacestat can cause a variety of skin reactions. A discolored, bumpy rash is the most common.

Still, you should call your oncology team right away if you notice any type of rash while taking nirogacestat. This could be a sign of an allergic reaction. If there's no concern for an allergy, your oncology team may give you medications including topical corticosteroids or antibiotics.

Nirogacestat can also rarely cause new skin cancers. Your oncology team should check your skin regularly before and during treatment.

Ovarian failure

If you're planning to become pregnant, you may want to talk to your oncology team about whether nirogacestat is right for you. And you shouldn't take it at all if you are already pregnant.

It's estimated that up to 3 out of 4 women of child-bearing age who take nirogacestat experience ovarian problems, including loss of their period, early menopause, or ovarian failure. These symptoms can be reversible in some people, but they also have the potential to cause permanent fertility issues.

5. Be mindful of nirogacestat interactions, too

Nirogacestat doesn't play well with all medications. Here's a rundown of potential medications that can affect nirogacestat.

CYP3A4 inhibitors and inducers

Many medications are broken down (metabolized) by a protein in the body called CYP3A4. Nirogacestat is one of these medications. However, other medications can slow the function of CYP3A4 ("inhibition") or speed it up ("induction"). This can result in unwanted nirogacestat side effects or decreased effectiveness, respectively.

It's best to avoid taking nirogacestat with other medications that affect CYP3A4. This is hard to figure out on your own, so your pharmacist can let you know if any of your medications have the potential to interact in this way.

Good to know: Grapefruit, Seville oranges (found in marmalade), and starfruit can also slow CYP3A4. It's best to avoid these foods while taking nirogacestat.

Acid reducers

Nirogacestat needs stomach acid for proper absorption. Medications that decrease stomach acid can lessen nirogacestat's effectiveness by inhibiting its absorption.

Proton pump inhibitors (PPIs) such as omeprazole (Prilosec) and H2 blockers such as famotidine (Pepcid) last much longer in the body than short-acting antacids such as calcium carbonate (Tums). It's best to avoid using these types of acid-lowering medications with nirogacestat.

If acid reducers can't be avoided, stick to short-acting antacids. Just make sure to separate doses by taking nirogacestat at least 2 hours before or after the antacid.

CYP3A4 and CYP2C19 substrates

Nirogacestat can impact how other medications are metabolized. For example, it can enhance the side effects of medications that are metabolized by CYP3A4. It may also impact the effectiveness of medications that rely on a similar protein called CYP2C19.

Taking nirogacestat with these types of medications should be avoided when possible.

6. There are other treatment options for desmoid tumors, too

Although it's exciting that desmoid tumors finally have an approved medication, nirogacestat might not be for everyone. Your oncology team will take into account the location of your tumor, how fast it's growing, and the potential side effects of each treatment option.

In some cases, you might not even need treatment. If your tumor is growing very slowly (or not at all) and isn't causing pain, your oncology team may just watch it for a while. Desmoid tumors can also shrink on their own, so observation may be the best option if your tumor isn't causing problems.

If you're experiencing pain or other symptoms or your tumor is actively growing, it's probably time for treatment. Other options for desmoid tumors include:

• Chemotherapy, such as liposomal doxorubicin (Doxil)

• Targeted therapy, including tyrosine kinase inhibitors such as sorafenib (Nexavar)

• Surgery

• Radiation

• Ablation (extreme heat or cold)

• Nonsteroidal anti-inflammatory drugs (NSAIDs)

How to save on nirogacestat

There are ways to save on nirogacestat, which is only available as a brand-name medication. GoodRx can help you navigate between copay savings cards and patient assistance programs to save money on your prescription.

• Save with a copay savings card: If you have commercial insurance, you may be eligible to pay as little as $0 for Ogsiveo using a savings card from the manufacturer.

• Save with patient assistance programs: If you're uninsured or underinsured, you may be eligible for nirogacestat's patient assistance program, which offers the medication free of charge.