Gamifant (emapalumab or emapalumab-lzsg) is the first medication approved for the treatment of a potentially severe inflammatory problem called primary hemophagocytic lymphohistiocytosis (HLH). It's given as an infusion through the veins (intravenously or IV) every 3 to 4 days by a healthcare provider.
Gamifant (emapalumab) is a type of monoclonal antibody called an interferon gamma (IFNγ) blocking antibody. It works to lower inflammation by blocking a protein in the immune system called interferon gamma. This helps to improve inflammatory symptoms of primary HLH.
The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Contact your healthcare provider immediately if you experience any of the following.
Side effects that you should report to your care team as soon as possible:
Side effects that usually do not require medical attention (report these to your care team if they continue or are bothersome):
Primary HLH is a rare, genetic problem that causes your immune system to be overly active, leading to inflammation. This causes several symptoms including fever, infection, rash, liver problems, seizures and other brain problems, lung problems, and blood cell problems. Primary HLH can progress quickly and be a life-threatening problem if not treated promptly. In studies, about half of the people with primary HLH weren't eligible for a stem cell transplant because of poor response to other HLH treatments. Gamifant (emapalumab) helps lower the activity of your immune system to help decrease symptoms. It can improve your condition and raise your chances of being able to get a stem cell transplant.
In clinical studies looking at how well the medication works, 63% of people with primary HLH had an improvement in their symptoms and lab values (e.g., blood cell and protein levels) after 8 weeks of Gamifant (emapalumab) treatment. Also, 70% of people taking Gamifant (emapalumab) were stable enough to receive a stem cell transplant.
There isn't a specific amount of time that you'll need to take Gamifant (emapalumab). Since primary HLH is a genetic problem, you'll likely need to continue taking the medication as long as you're not having side effects, like infections and fever, it's helping your condition, and until you can receive a stem cell transplant. Discuss with your provider about how long you need to take Gamifant (emapalumab).
Yes. Your provider will give you certain medications before each dose of Gamifant (emapalumab) to prevent infections. These medications include an antiviral (e.g., acyclovir (Zovirax), valacyclovir (Valtrex)) for shingles prevention, an antibiotic (e.g., Bactrim (sulfamethoxazole / trimethoprim)) for Pneumocystis pneumonia prevention, and an antifungal (e.g., fluconazole (Diflucan)) for fungal infection prevention. Since Gamifant (emapalumab) lowers your immune system activity and your body's ability to fight off infections, it's important to take these medications because you're more likely to develop infections during treatment with Gamifant (emapalumab). You'll also need to take dexamethasone (a corticosteroid) once per day during Gamifant (emapalumab) treatment to help lower inflammation further. Speak with your provider if you have any concerns about taking these additional medications during treatment with Gamifant (emapalumab).
If you're pregnant, thinking of getting pregnant, or breastfeeding, make sure to talk to your provider about the risks and benefits of using Gamifant (emapalumab). There haven't been any human studies done to know with certainty the safety of Gamifant (emapalumab) during pregnancy or breastfeeding. In animal studies, babies born to mothers exposed to Gamifant (emapalumab) during pregnancy weren't harmed. Additionally, there is only a little bit of evidence that shows levels of other monoclonal antibody medications like Gamifant (emapalumab) are low in breast milk. To be safe, discuss with your provider about whether it's possible to take Gamifant (emapalumab) while pregnant or breastfeeding.
Gamifant (emapalumab) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Gamifant (emapalumab) can affect your body's ability to fight off infections. This can raise your risk of serious or life-threatening bacterial, viral, or fungal infections. Before starting Gamifant (emapalumab), you'll need to get tested for tuberculosis (TB) and get treatment if you test positive (meaning you have a confirmed TB infection). Then, during treatment, your provider will give you anti-infective medications before each Gamifant (emapalumab) dose to help lower your risk for infections. While taking Gamifant (emapalumab), go to the hospital immediately if you develop symptoms of an infection, like fever, cough, difficulty breathing, diarrhea, weakness, sweating, or chills. You'll need to get tested for an infection. You might have to stop taking Gamifant (emapalumab) so your body can fight the infection. Tell your provider about your medical conditions and medications so they can make sure Gamifant (emapalumab) is safe for you.
You can still receive most vaccines, including the flu shot, while taking Gamifant (emapalumab). However, you shouldn't receive live vaccines while taking this medication and for at least 4 weeks after your last dose. This is because it's not known if they're safe for you while you're taking Gamifant (emapalumab). Examples of live vaccines include the FluMist Quadrivalent (live attenuated influenza vaccine), which is given through a nasal spray, and MMR (measles, mumps, and rubella vaccine). You should be brought up to date with all vaccines before starting Gamifant (emapalumab). Be sure to let your provider know you're taking Gamifant (emapalumab) before you receive any vaccines.
The typical dose is based on your body weight and is infused into the veins over 1 hour every 3 to 4 days. Your provider will adjust the dose based on how well it's helping your symptoms, your lab values, or if you're having side effects.