Efgartigimod alfa-fcab

Acknowledgment
This article consists of drug labeling information developed under U.S. FDA guidance and excerpted from DailyMed. It was not reviewed by the MedLink Neurology Editorial Board. For the latest FDA-approved information about this drug, visit Drugs@FDA.com.

Highlights

Indications and usage
Efgartigimod alfa-fcab (Vyvgart®) injection is a neonatal Fc receptor blocker indicated for the treatment of generalized myasthenia gravis in adult patients who are anti-acetylcholine receptor antibody-positive.
Dosage and administration
	• Evaluate the need to administer age-appropriate vaccines according to immunization guidelines before initiation of a new treatment cycle with efgartigimod alfa-fcab.
	• The recommended dosage is 10 mg/kg administered as an intravenous infusion over one hour once weekly for 4 weeks. In patients weighing 120 kg or more, the recommended dose is 1200 mg per infusion.
	• Administer subsequent treatment cycles based on clinical evaluation; safety of initiating subsequent cycles sooner than 50 days from the start of the previous treatment cycle has not been established.
	• Must be diluted with 0.9% sodium chloride injection, USP before administration.
	• Administer as an intravenous infusion over one hour via a 0.2 micron in-line filter.
Dosage forms and strengths
• Injection: 400 mg in 20 mL (20 mg/mL) single-dose vial.
Notes:
	• Efgartigimod alfa-fcab was first approved by the U.S. FDA in 2021.
	• Dosage and administration, contraindications, and warnings and precautions have been changed since the original approval.
	• This article discusses Vyvgart®; for information about efgartigimod alfa and hyaluronidase-qvfc (Vyvgart Hytrulo®), see separate DAILYMED drug label information.

Contraindications
	• Efgartigimod alfa-fcab is contraindicated in patients with serious hypersensitivity to efgartigimod alfa-fcab products or any of the excipients of efgartigimod alfa-fcab injection.
Warnings and precautions
	• Infections. Delay administration of efgartigimod alfa-fcab to patients with an active infection. Monitor for signs and symptoms of infection in patients treated with efgartigimod alfa-fcab. If serious infection occurs, administer appropriate treatment and consider withholding efgartigimod alfa-fcab until the infection has resolved.
	• Hypersensitivity reactions. Anaphylaxis, hypotension leading to syncope, angioedema, dyspnea, and rash have occurred. If a hypersensitivity reaction occurs, the healthcare professional should institute appropriate measures if needed, or the patient should seek medical attention.
	• Infusion or injection-related reactions. If a severe infusion-related reaction occurs, discontinue the infusion and initiate appropriate therapy; consider the risks and benefits of readministering. If a mild to moderate infusion-related reaction occurs, the patient may be rechallenged with close clinical observation, slower infusion rates, and pre-medications.
Adverse reactions
• Most common adverse reactions ( 10% or more) in patients treated with efgartigimod alfa-fcab are respiratory tract infections, headache, and urinary tract infections.
To report SUSPECTED ADVERSE REACTIONS, contact argenx at 1-833-argx411 or FDA at 1-800-FDA-1088 www.fda.gov/medwatch.
Drug interactions
	• Closely monitor for reduced effectiveness of medications that bind to the human neonatal Fc receptor. When concomitant long-term use of such medications is essential for patient care, consider discontinuing efgartigimod alfa-fcab and using alternative therapies.
	• See patient counseling information and FDA-approved patient labeling.

Indications

Efgartigimod alfa-fcab is indicated for the treatment of generalized myasthenia gravis in adult patients who are anti-acetylcholine receptor antibody-positive.

Dosage and administration

Recommended vaccination

Evaluate the need to administer age-appropriate vaccines according to immunization guidelines before initiation of a new treatment cycle with efgartigimod alfa-fcab. Because efgartigimod alfa-fcab causes a transient reduction in IgG levels, vaccination with live vaccines is not recommended during treatment with efgartigimod alfa-fcab.

Recommended dose and dose schedules

Dilute efgartigimod alfa-fcab before administration. Administer via intravenous infusion only.

The recommended dosage of efgartigimod alfa-fcab is 10 mg/kg administered as an intravenous infusion over 1 hour once weekly for 4 weeks. For patients weighing 120 kg or more, the recommended dose is 1200 mg (three vials) per infusion.

Administer subsequent treatment cycles based on clinical evaluation. The safety of initiating subsequent cycles sooner than 50 days from the start of the previous treatment cycle has not been established.

If a scheduled infusion is missed, efgartigimod alfa-fcab may be administered up to 3 days after the scheduled time. Thereafter, resume the original dosing schedule until the treatment cycle is completed.

Preparation and administration instructions

Before administration, efgartigimod alfa-fcab single-dose vials require dilution in 0.9% sodium chloride injection, USP, to achieve a total of 125 mL.

Check that the efgartigimod alfa-fcab solution is clear to slightly opalescent and colorless to slightly yellow. Parenteral drug products should be inspected visually for particulate matter and discoloration before administration, whenever the solution and container permit. Do not use if opaque particles, discoloration, or other foreign particles are present.

Use aseptic technique when preparing the efgartigimod alfa-fcab diluted solution for intravenous infusion. Each vial is for a single dose only.

Discard any unused portion.

Preparation
	• Calculate the dose (mg), total drug volume (mL) of efgartigimod alfa-fcab solution required, and the number of vials needed based on the recommended dose according to the patient's body weight. Each vial contains a total of 400 mg of efgartigimod alfa-fcab injecion at a concentration of 20 mg per mL.
	• Gently withdraw the calculated dose of efgartigimod alfa-fcab from the vials with a sterile syringe and needle. Discard any unused portion of the vials.
	• Dilute the withdrawn efgartigimod alfa-fcab with 0.9% sodium chloride injection, USP to make a total volume of 125 mL for intravenous infusion.
	• Gently invert the infusion bag containing the diluted efgartigimod alfa-fcab without shaking to ensure thorough mixing of the product and the diluent.
	• The diluted solution can be administered using polyethylene (PE), polyvinyl chloride (PVC), ethylene vinyl acetate (EVA), or ethylene/polypropylene copolymer bags (polyolefin bags), and with PE, PVC, EVA, or polyurethane/polypropylene infusion lines.
Storage conditions of the diluted solution
	Efgartigimod alfa-fcab does not contain preservatives. Administer immediately after dilution and complete the infusion within 4 hours of dilution.
	If immediate use is not possible, the diluted solution may be stored refrigerated at 2°C to 8°C (36°F to 46°F) for up to 8 hours. Do not freeze. Protect from light. Allow the diluted drug to reach room temperature before administration. Complete the infusion within 4 hours of removal from the refrigerator. Do not heat the diluted drug in any manner other than via ambient air.
Administration
	• Efgartigimod alfa-fcab should be administered via intravenous infusion by a healthcare professional.
	• Visually inspect efgartigimod alfa-fcab diluted solution for particles or discoloration before administration. Do not use if it is discolored or if opaque or foreign particles are seen.
	• Infuse the total 125 mL of diluted solution intravenously over one hour via a 0.2 micron in-line filter.
	• After administration of efgartigimod alfa-fcab, flush the entire line with 0.9% sodium chloride injection, USP.
	• Monitor patients during administration and for 1 hour thereafter for clinical signs and symptoms of hypersensitivity reactions. If a hypersensitivity reaction occurs during administration, discontinue administration of efgartigimod alfa-fcab and institute appropriate supportive measures.
	• Other medications should not be injected into infusion side ports or mixed with efgartigimod alfa-fcab injection.

Dosage forms and strengths

Injection. 400 mg/20 mL (20 mg/mL) as a colorless to slightly yellow, clear to slightly opalescent solution, in a single-dose vial.

Contraindications

Efgartigimod alfa-fcab is contraindicated in patients with a serious hypersensitivity to efgartigimod alfa-fcab products or any of the excipients of efgartigimod alfa-fcab injection. Reactions have included anaphylaxis and hypotension leading to syncope.

Warnings and precautions

Infections

Efgartigimod alfa-fcab may increase the risk of infection. The most common infections observed in Study 1 were urinary tract infection (10% of patients treated with efgartigimod alfa-fcab compared to 5% of placebo-treated patients) and respiratory tract infections (33% of patients treated with efgartigimod alfa-fcab compared to 29% of placebo-treated patients). A higher frequency of patients who received efgartigimod alfa-fcab injection compared to placebo were observed to have below normal levels for white blood cell counts (12% versus 5%, respectively), lymphocyte counts (28% versus 19%, respectively), and neutrophil counts (13% versus 6%, respectively). Most infections and hematologic abnormalities were mild to moderate in severity. Delay efgartigimod alfa-fcab administration in patients with an active infection until the infection is resolved. During treatment with efgartigimod alfa-fcab, monitor for clinical signs and symptoms of infections. If serious infection occurs, administer appropriate treatment and consider withholding efgartigimod alfa-fcab until the infection has resolved.

Immunization. Evaluate the need to administer age-appropriate vaccines according to immunization guidelines before initiation of a new treatment cycle with efgartigimod alfa-fcab. The safety of immunization with live vaccines and the immune response to vaccination during treatment with efgartigimod alfa-fcab are unknown. Because efgartigimod alfa-fcab causes a reduction in IgG levels, vaccination with live vaccines is not recommended during treatment with efgartigimod alfa-fcab.

Hypersensitivity reactions

In clinical trials, hypersensitivity reactions, including rash, angioedema, and dyspnea, were observed in efgartigimod alfa-fcab-treated patients. Hypersensitivity reactions were mild or moderate, occurred within 1 hour to 3 weeks of administration, and did not lead to treatment discontinuation.

Anaphylaxis and hypotension leading to syncope have been reported in postmarketing experience with efgartigimod alfa-fcab. Anaphylaxis and hypotension occurred during or within an hour of administration and led to infusion discontinuation and, in some cases, to permanent treatment discontinuation.

Monitor patients during administration and for 1 hour thereafter for clinical signs and symptoms of hypersensitivity reactions. If a hypersensitivity reaction occurs, the healthcare professional should institute appropriate measures if needed, or the patient should seek medical attention. Efgartigimod alfa-fcab is contraindicated in patients with a history of serious hypersensitivity to efgartigimod alfa-fcab products or to any of the excipients of efgartigimod alfa-fcab.

Infusion or injection-related reactions

Infusion-related reactions have been reported with efgartigimod alfa-fcab injection in postmarketing experience. The most frequent symptoms and signs were hypertension, chills, shivering, and thoracic, abdominal, and back pain. Infusion-related reactions occurred during or within an hour of administration and led to infusion discontinuation. If a severe infusion-related reaction occurs during administration, discontinue efgartigimod alfa-fcab infusion and initiate appropriate therapy. Consider the risks and benefits of readministering efgartigimod alfa-fcab following a severe infusion-related reaction. If a mild to moderate infusion-related reaction occurs, patients may be rechallenged with close clinical observation, slower infusion rates, and pre-medications.

Adverse reactions

The following clinically significant adverse reactions are described elsewhere in the labeling:

• Infections
• Hypersensitivity reactions
• Infusion-related reactions

Clinical trials experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

In clinical studies, the safety of efgartigimod alfa-fcab has been evaluated in 246 patients who received at least one dose of efgartigimod alfa-fcab, including 57 patients exposed to at least seven treatment cycles and eight patients exposed to at least 10 treatment cycles.

In a placebo-controlled study (Study 1) in patients with efgartigimod alfa-fcab, 84 patients received efgartigimod alfa-fcab 10 mg/kg. Of these 84 patients, approximately 75% were female, 82% were White, 11% were Asian, and 8% were of Hispanic or Latino ethnicity. The mean age at study entry was 46 years (range 19 to 78).

The minimum time between treatment cycles, specified by the study protocol, was 50 days. On average, patients treated with efgartigimod alfa-fcab received two cycles in Study 1. The mean and median times to the second treatment cycle were 94 days and 72 days from the initial infusion of the first treatment cycle, respectively.

Adverse reactions reported in at least 5% of patients treated with efgartigimod alfa-fcab and more frequently than placebo are summarized in Table 1. The most common adverse reactions (reported in at least 10% of patients treated with efgartigimod alfa-fcab) were respiratory tract infection, headache, and urinary tract infection.

Table 1. Adverse Reactions in at least 5% of Patients Treated with Efgartigimod Alfa and More Frequently than in Placebo-Treated Patients in Study 1 (Safety Population)

Adverse reaction	EFG IV (N=84)	Placebo (N=83)
Respiratory tract infection	33%	29%
Headache*	32%	29%
Urinary tract infection	10%	5%
Paraesthesia†	7%	5%
Myalgia	6%	1%
* Headache includes migraine and procedural headache. † Paresthesia includes oral hypoesthesia, hypoesthesia, and hyperesthesia.

Postmarketing experience

The following adverse reactions have been identified during postapproval use of efgartigimod alfa-fcab injection. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Immune system disorders. Hypersensitivity reactions, including anaphylaxis and hypotension, and infusion-related reactions.

Immunogenicity

As with all therapeutic proteins, there is potential for immunogenicity. The detection of antibody formation is highly dependent on the sensitivity and specificity of the assay. Additionally, the observed incidence of antibody (including neutralizing antibody) positivity in an assay may be influenced by several factors, including assay methodology, sample handling, timing of sample collection, concomitant medications, and underlying disease. For these reasons, comparison of the incidence of antibodies to efgartigimod alfa-fcab in the studies described below with the incidence of antibodies in other studies or to other products may be misleading.

In up to 26 weeks of treatment in Study 1, 20% (17 or 83) of patients developed antibodies to efgartigimod alfa-fcab. Seven percent of patients (6 of 83) developed neutralizing antibodies.

Because few patients tested positive for anti-efgartigimod alfa-fcab antibodies and neutralizing antibodies, the available data are too limited to make definitive conclusions regarding immunogenicity and the effect on pharmacokinetics, safety, or efficacy of efgartigimod alfa-fcab.

Drug interactions

Effect of efgartigimod alfa-fcab on other drugs

Concomitant use of efgartigimod alfa-fcab with medications that bind to the human neonatal Fc receptor (FcRn) (eg, immunoglobulin products, monoclonal antibodies, or antibody derivatives containing the human Fc domain of the IgG subclass) may lower systemic exposures and reduce the effectiveness of such medications. Closely monitor for reduced efficacy of medications that bind to the human neonatal Fc receptor. When concomitant long-term use of such medications is essential for patient care, consider discontinuing efgartigimod alfa-fcab and using alternative therapies.

Use in specific populations

Pregnancy

Pregnancy exposure registry. There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to efgartigimod alfa-fcab during pregnancy. Healthcare providers and patients may call 1-855-272-6524 or go to www.Vyvgartpregnancy.com to enroll in or to obtain information about the registry.

Risk summary. There are no available data on the use of efgartigimod alfa-fcab during pregnancy. There is no evidence of adverse developmental outcomes following the administration of efgartigimod alfa-fcab at up to 100 mg/kg/day in rats and rabbits (see Data).

The background rate of major birth defects and miscarriage in the indicated population is unknown. In the U.S. general population, the estimated background rate of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.

Clinical considerations.

Fetal or neonatal adverse reactions. Monoclonal antibodies are increasingly transported across the placenta as pregnancy progresses, with the largest amount transferred during the third trimester. Therefore, efgartigimod alfa-fcab may be transmitted from the mother to the developing fetus.

As efgartigimod alfa-fcab is expected to reduce maternal IgG antibody levels, a reduction in passive protection to the newborn is anticipated. Risk and benefits should be considered before administering live vaccines to infants exposed to efgartigimod alfa-fcab in utero.

Data.

Animal data. Intravenous administration of efgartigimod alfa-fcab (0, 30, or 100 mg/kg/day) to pregnant rats and rabbits throughout organogenesis resulted in no adverse effects on embryofetal development in either species. The doses tested are three and 10 times the recommended human dose of 10 mg/kg, on a body weight (mg/kg) basis.

Intravenous administration of efgartigimod alfa-fcab (0, 30, or 100 mg/kg/day) to rats throughout gestation and lactation resulted in no adverse effects on pre- or postnatal development. The doses tested are three and 10 times the recommended human dose of 10 mg/kg, on a body weight (mg/kg) basis.

Lactation

Risk summary. There is no information regarding the presence of efgartigimod alfa-fcab in human milk, the effects on the breastfed infant, or the effects on milk production. Maternal IgG is known to be present in human milk.

The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for efgartigimod alfa-fcab and any potential adverse effects on the breastfed infant from efgartigimod alfa-fcab or from the underlying maternal condition.

Pediatric use

Safety and effectiveness in pediatric patients have not been established.

Geriatric use

Clinical studies of efgartigimod alfa-fcab did not include sufficient numbers of patients aged 65 and older to determine whether they respond differently from younger adult patients.

Renal impairment

No dose adjustment of efgartigimod alfa-fcab is needed for patients with mild renal impairment. There are insufficient data to evaluate the impact of moderate renal impairment (eGFR 30-59 mL/min/1.73 m2) and severe renal impairment (eGFR <30 mL/min/1.73 m2) on the pharmacokinetic parameters of efgartigimod alfa-fcab.

Clinical pharmacology

Mechanism of action

Efgartigimod alfa-fcab is a human IgG1 antibody fragment that binds to the neonatal Fc receptor (FcRn), resulting in the reduction of circulating IgG.

Pharmacodynamics

In Study 1, the pharmacological effect of efgartigimod alfa-fcab was assessed by measuring the decrease in serum IgG levels and AChR autoantibody levels. In patients testing positive for AChR antibodies and who were treated with efgartigimod alfa-fcab, there was a reduction in total IgG levels relative to baseline. A decrease in AChR autoantibody levels followed a similar pattern.

Pharmacokinetics

Efgartigimod alfa-fcab exhibits linear pharmacokinetics, and following single doses of efgartigimod alfa-fcab, exposures increase proportionally up to 50 mg/kg (five times the recommended dosage).

Distribution. The volume of distribution is 15 to 20L.

Metabolism and elimination. Efgartigimod alfa-fcab is expected to be degraded by proteolytic enzymes into small peptides and amino acids. The terminal half-life is 80 to 120 hours (3 to 5 days). After a single intravenous dose of 10 mg/kg efgartigimod alfa-fcab in healthy subjects, less than 0.1% of the administered dose was recovered in urine.

Specific populations.

Age, sex, and race. A population pharmacokinetics analysis assessing the effects of age, sex, and race did not suggest any clinically significant impact of these covariates on efgartigimod alfa-fcab exposures.

Patients with renal impairment. No dedicated pharmacokinetic study has been performed in patients with renal impairment.

A population PK analysis of data from the efgartigimod alfa-fcab clinical studies indicated that patients with mild renal impairment (eGFR 60-89 mL/min/1.72m²) had a 22% increase in exposure relative to the exposure in patients with normal renal function.

Patients with hepatic impairment. No dedicated pharmacokinetic study has been performed in patients with hepatic impairment. Hepatic impairment is not expected to affect the pharmacokinetics of efgartigimod alfa-fcab.

Drug interaction studies. Clinical drug interaction studies have not been performed with efgartigimod alfa-fcab.

P450 enzymes. Efgartigimod alfa-fcab is not metabolized by cytochrome P450 enzymes; therefore, interactions with concomitant medications that are substrates, inducers, or inhibitors of cytochrome P450 enzymes are unlikely.

Drug interactions with other drugs or biological products. Efgartigimod alfa-fcab may decrease concentrations of compounds that bind to the human FcRn.

Nonclinical toxicology

Carcinogenesis, mutagenesis, impairment of fertility

Carcinogenesis and mutagenesis. No studies have been conducted to assess the carcinogenic potential of efgartigimod alfa-fcab.

No studies have been conducted to assess the genotoxic potential of efgartigimod alfa-fcab.

Impairment of fertility. Intravenous administration of efgartigimod alfa-fcab (0, 30, or 100 mg/kg/day) to male and female rats before and during mating and continuing in females through gestation day 7 resulted in no adverse effects on fertility. The doses tested are three and 10 times the recommended human dose of 10 mg/kg, on a body weight (mg/kg) basis.

Cinical studies

The efficacy of efgartigimod alfa-fcab for treating generalized myasthenia gravis in adults who are AChR antibody-positive was established in a 26-week, multicenter, randomized, double-blind, placebo-controlled trial (Study 1; NCT03669588).

Study 1 enrolled patients who met the following criteria at screening:

	• Myasthenia Gravis Foundation of America (MGFA) clinical classification classes II to IV
	• Myasthenia Gravis-Activities of Daily Living (MG-ADL) total score of 5 or greater
	• On stable dose of myasthenia gravis therapy before screening, which included acetylcholinesterase inhibitors, steroids, or nonsteroidal immunosuppressive therapies, either in combination or alone
	• IgG levels of at least 6 g/L

A total of 167 patients were enrolled in Study 1 and were randomized to receive either efgartigimod alfa-fcab injection 10 mg/kg (1200 mg for those weighing 120 kg or more) (n=84) or placebo (n=83). Baseline characteristics were similar between treatment groups. Patients had a median age of 46 years at screening (range: 19 to 81 years) and a median time since diagnosis of 7 years. Seventy-one percent were female, and 84% were White. Median MG-ADL total score was 9, and median Quantitative Myasthenia Gravis (QMG) total score was 16. Most patients (n=65 for efgartigimod alfa-fcab; n=64 for placebo) were positive for AChR antibodies.

At baseline, over 80% of patients in each group received AChE inhibitors, over 70% in each treatment group received steroids, and approximately 60% in each treatment group received nonsteroidal immunosuppressive therapies at stable doses.

Patients were treated with efgartigimod alfa-fcab at the recommended dosage regimen.

The efficacy of efgartigimod alfa-fcab was measured using the Myasthenia Gravis-Specific Activities of Daily Living scale (MG-ADL), which assesses the impact of efgartigimod alfa-fcab on daily functions of eight signs or symptoms that are typically affected in efgartigimod alfa-fcab. Each item is assessed on a 4-point scale where a score of 0 represents normal function and a score of 3 represents loss of ability to perform that function. A total score ranges from 0 to 24, with the higher scores indicating more impairment. In this study, an MG-ADL responder was defined as a patient with a 2-point or greater reduction in the total MG-ADL score compared to the treatment cycle baseline for at least 4 consecutive weeks, with the first reduction occurring no later than 1 week after the last infusion of the cycle.

The primary efficacy endpoint was the comparison of the percentage of MG-ADL responders during the first treatment cycle between treatment groups in the AChR-Ab positive population. A statistically significant difference favoring efgartigimod alfa-fcab was observed in the MG-ADL responder rate during the first treatment cycle (67.7% in the efgartigimod alfa-fcab-treated group vs. 29.7% in the placebo-treated group [p <0.0001]).

The efficacy of efgartigimod alfa-fcab was also measured using the Quantitative Myasthenia Gravis (QMG) total score, which is a 13-item categorical grading system that assesses muscle weakness. Each item is assessed on a 4-point scale where a score of 0 represents no weakness and a score of 3 represents severe weakness. A total possible score ranges from 0 to 39, where higher scores indicate more severe impairment. In this study, a QMG responder was defined as a patient who had a 3-point or greater reduction in the total QMG score compared to the treatment cycle baseline for at least 4 consecutive weeks, with the first reduction occurring no later than 1 week after the last infusion of the cycle.

The secondary endpoint was the comparison of the percentage of QMG responders during the first treatment cycle between both treatment groups in the AChR-Ab-positive patients. A statistically significant difference favoring efgartigimod alfa-fcab was observed in the QMG responder rate during the first treatment cycle (63.1% in the efgartigimod alfa-fcab-treated group vs. 14.1% in the placebo-treated group [p <0.0001]).

For details of Study 1 results, see the Clinical Studies section of the DAILYMED drug label information.

How supplied/storage and handling

Efgartigimod alfa-fcab is a preservative-free, sterile, colorless to slightly yellow, clear to slightly opalescent solution supplied as 400 mg/20 mL (20 mg/mL) in one single-dose vial per carton (NDC 73475-3041-5).

Store efgartigimod alfa-fcab vials refrigerated at 2°C to 8°C (36°F to 46°F) in the original carton to protect from light until time of use. Do not freeze. Do not shake.

Refer to Dosage and administration section for information on stability and storage of the diluted solutions of efgartigimod alfa-fcab.

Patient counseling information

Infections. Instruct patients to communicate any history of infections to their healthcare provider and to contact their healthcare provider if they develop any symptoms of infection. Advise patients to complete age-appropriate vaccinations according to immunization guidelines before initiation of a new treatment cycle with efgartigimod alfa-fcab. Administration of live vaccines is not recommended during treatment with efgartigimod alfa-fcab.

Hypersensitivity reactions. Inform patients that hypersensitivity reactions, including angioedema and anaphylaxis, have occurred in patients who were treated with efgartigimod alfa-fcab. Inform patients about the signs and symptoms of these reactions, and advise patients to contact their healthcare provider immediately if these occur.

Infusion-related reactions. Advise patients of the potential risk of infusion-related reactions, which can include hypertension, chills, shivering, and chest, abdominal, and back pain.

Pregnancy registry. There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to efgartigimod alfa-fcab during pregnancy; information can be found at www.vyvgartpregnancy.com/home.html. Encourage participation and advise patients about how they may enroll in the registry.

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