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Gamifant® (emapalumab-lzsg) is an interferon gamma (IFNγ)–blocking antibody indicated for the treatment of adult and pediatric (newborn and older) patients with primary hemophagocytic lymphohistiocytosis (HLH) with refractory, recurrent, or progressive disease or intolerance with conventional HLH therapy.


Gamifant® (emapalumab-lzsg) is an interferon gamma (IFNγ)–blocking antibody indicated for the treatment of adult and pediatric (newborn and older) patients with primary hemophagocytic lymphohistiocytosis (HLH) with refractory, recurrent, or progressive disease or intolerance with conventional HLH therapy.

Important Safety Information


Before initiating Gamifant, patients should be evaluated for infection, including latent tuberculosis (TB). Prophylaxis for TB should be administered to patients who are at risk for TB or known to have a positive purified protein derivative (PPD) test result or positive IFNγ release assay.

During Gamifant treatment, patients should be monitored for TB, adenovirus, Epstein-Barr virus (EBV), and cytomegalovirus (CMV) every 2 weeks and as clinically indicated.

Patients should be administered prophylaxis for herpes zoster, Pneumocystis jirovecii, and fungal infections prior to Gamifant administration.

Increased Risk of Infection With Use of Live Vaccines

Do not administer live or live attenuated vaccines to patients receiving Gamifant and for at least 4 weeks after the last dose of Gamifant. The safety of immunization with live vaccines during or following Gamifant therapy has not been studied.

Infusion-Related Reactions

Infusion-related reactions, including drug eruption, pyrexia, rash, erythema, and hyperhidrosis, were reported with Gamifant treatment in 27% of patients. In one-third of these patients, the infusion-related reaction occurred during the first infusion.

Adverse Reactions

In the pivotal trial, the most commonly reported adverse reactions (≥10%) for Gamifant included infection (56%), hypertension (41%), infusion-related reactions (27%), pyrexia (24%), hypokalemia (15%), constipation (15%), rash (12%), abdominal pain (12%), CMV infection (12%), diarrhea (12%), lymphocytosis (12%), cough (12%), irritability (12%), tachycardia (12%), and tachypnea (12%).

Additional selected adverse reactions (all grades) that were reported in less than 10% of patients treated with Gamifant included vomiting, acute kidney injury, asthenia, bradycardia, dyspnea, gastrointestinal hemorrhage, epistaxis, and peripheral edema.

Click here for full Prescribing Information for Gamifant.

You may also contact Sobi at or 866-773-5274.


  1. Sepulveda F, de Saint Basile G. Hemophagocytic syndrome: primary forms and predisposing conditions. Curr Opin Immunol. 2017; 49:20-26.
  2. Jordan MB, Allen CE, Weitzman S, Filipovich AH, McClain KL. How I treat hemophagocytic lymphohistiocytosis. Blood. 2011;118(15):4041-4052. doi:
  3. Lehmberg K, Nichols KE, Henter J-I, et al. Consensus recommendations for the diagnosis and management of hemophagocytic lymphohistiocytosis associated with malignancies. Haematologica. 2015:100(8):997-1004.
  4. Marsh RA, Haddad E. How I treat primary haemophagocytic lymphohistiocytosis. Br J Haematol. 2018;182(2):185-199. doi: 10.1111/bjh.15274.
  5. Gamifant [prescribing information]. Stockholm, Sweden: Swedish Orphan Biovitrum AB.
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Resources for You and Your Patients

Help guide your patients and their caregivers along the treatment journey with these tools and resources.

  • Primary HLH treatment
  • Financial assistance programs*
  • Health insurance options
  • Reimbursement

*For eligible patients.

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Call 833-597-6530 for assistance

*For eligible patients.

GAMIFANT® (emapalumab-lzsg)

Full Prescribing Information


Dosing and Administration Guide


Product Monograph


Clinical Overview


How Gamifant Works


Gamifant Brochure


Hypothetical Patient CASE STUDY


Pivotal Trial Brochure



IFNγ in Primary HLH



Product Information


Patient Enrollment Form


Patient Consent Form


Summary of Relevant Codes


Guide to Requesting Medical Exception


Letter of Medical Necessity


Medical vs Pharmacy Benefits Brochure


Tips for Completing a Benefits Investigation


Guide to Prior Authorization Submission


Find helpful educational materials to share with your patients about primary HLH and the treatment journey by clicking the button below.


Advocacy Groups

The mission of The Matthew and Andrew Akin Foundation is to inform, inspire, and invest in families affected by hemophagocytic lymphohistiocytosis.

Founded by the mother of an HLH survivor, the goal of this program is to support and connect others struggling with the disease. In addition to hosting an active Facebook support group, HLH Support holds events like the Marsh Family Annual Toy Drive to raise money for HLH.

Hannah, the HLH survivor who inspired the program, also sells handmade blue Swarovski crystal bracelets to spread awareness and fund HLH research.

Histiocytosis Association provides educational materials, peer/physician networking opportunities, and a physician directory for treatment/second opinions. The organization also offers staff to assist families with awareness, advocacy, and programs to raise funds for research.

Liam’s Lighthouse Foundation (LLF) is a nonprofit, tax exempt organization established to increase awareness of HLH and other histiocytic disorders. The organization focuses on bringing the families affected together, offering support through a variety of programs, and raising much-needed funds for continued research and education at leading medical institutions.

Founded in 1980, the Immune Deficiency Foundation (IDF) is a national nonprofit patient organization dedicated to improving the diagnosis, treatment, and quality of life of persons with primary immunodeficiency (PI) diseases through advocacy, education, and research. IDF provides accurate and timely information and valuable resources for patients and families living with PI, including HLH.

Transplant Resources

BMT InfoNet is an organization for bone marrow, stem cell, and cord blood transplant patients. It empowers patients and caregivers with knowledge through its website, video learning library, patient books, and symposiums. BMT InfoNet also provides personal guidance and a one-on-one peer support program.

Over the past 30 years, Be The Match®, operated by the National Marrow Donor Program® (NMDP), has managed the largest and most diverse marrow registry in the world. Their team works every day to save lives through transplant.
Doctor playing with young patient beside Sobi "rare strength" logo

A rare dedication

At Sobi, we focus on ultra-rare diseases, which can affect just hundreds or even dozens of patients. These patients have many critical unmet needs, yet are frequently overlooked by the healthcare industry.

We are dedicated to providing access to innovative treatments that make a significant difference in the lives of individuals with ultra-rare diseases.

We work closely with patients, caregivers, and advocacy organizations to understand and address the challenges they face throughout their journey, from infancy to adulthood. And we keep innovating to meet their evolving needs, serving as a trusted partner for life.