efgartigimod alfa: prescribing information – dosing, contraindications, interactions, side effects

Vyvgart is indicated as an add-on to standard therapy for the treatment of adult patients with generalised Myasthenia Gravis (gMG) who are anti-acetylcholine receptor (AChR) antibody positive.

Vyvgart is indicated as
- an add-on to standard therapy for the treatment of adult patients with generalised Myasthenia Gravis (gMG) who are anti-acetylcholine receptor (AChR) antibody positive.
- monotherapy for the treatment of adult patients with progressive or relapsing active chronic inflammatory demyelinating polyneuropathy (CIDP) after prior treatment with corticosteroids or immunoglobulins.

Efgartigimod alfa must be administered by a healthcare professional and under the supervision of a physician experienced in the management of patients with neuromuscular disorders.

Posology

The recommended dose is 10 mg/kg as a 1-hour intravenous infusion to be administered in cycles of once weekly infusions for 4 weeks. Subsequent treatment cycles should be administered according to clinical evaluation. The frequency of treatment cycles may vary by patient (see section 5.1).

In the clinical development program, the earliest time to initiate a subsequent treatment cycle was 7 weeks from the initial infusion of the previous cycle.

In patients weighing 120 kg or more, the recommended dose is 1 200 mg (3 vials) per infusion (see section 6.6).

Missed dose
If a scheduled infusion is not possible, treatment may be administered up to 3 days before or after the scheduled time point. Thereafter, the original dosing schedule should be resumed until the treatment cycle is completed. If a dose needs to be delayed for more than 3 days, the dose should not be administered to ensure two consecutive doses are given with an interval of at least 3 days.

Special populations

Elderly
No dose adjustment is required in patients aged 65 years and older (see section 5.2).

Renal impairment
Limited safety and efficacy data in patients with mild renal impairment is available, no dose adjustment is required for patients with mild renal impairment. There is very limited safety and efficacy data in patients with moderate or severe renal impairment (see section 5.2).

Hepatic impairment
No data in patients with hepatic impairment are available. No dose adjustment is required in patients with hepatic impairment (see section 5.2).

Paediatric population
The safety and efficacy of efgartigimod alfa in paediatric population have not yet been established.
No data are available.

Method of administration

This medicinal product should only be administered via intravenous infusion. Do not administer as an intravenous push or bolus injection. It should be diluted with sodium chloride 9 mg/mL (0.9%) solution for injection prior to administration as described in section 6.6.

This medicinal product should be administered over 1 hour. Appropriate treatment for infusion and hypersensitivity-related reactions should be readily available before administration of efgartigimod alfa. In case of infusion reactions, the infusion should be administered at a slower rate, interrupted or can be discontinued (see section 4.4).

Administration
- Inspect the solution visually for particulate matter prior to administration.
- Infuse the total 125 mL of diluted medicinal product over 1 hour using a 0.2 µm filter.
Administer the full amount of solution, flushing the entire line with sodium chloride 9 mg/mL (0.9%) solution for injection at the end.
- Vyvgart should be administered immediately after dilution and the infusion of diluted solution should be completed within 4 hours of dilution.
- Chemical and physical in-use stability has been demonstrated for 24 hours at 2 °C to 8 °C. From a microbiological point of view, unless the method of dilution precludes the risks of microbial contamination, the product should be used immediately. If not used immediately, in-use storage times and conditions are the responsibility of the user. Do not freeze. Allow the diluted medicinal product to reach room temperature before administration. Complete the infusion within 4 hours of removal from the refrigerator. The diluted medicinal product should not be heated in any other manner than via ambient air.
- Should infusion reactions occur, the infusion should be administered at a slower rate, interrupted or discontinued (see section 4.4).
- Other medicinal products should not be injected into infusion side ports or mixed with Vyvgart.

For instructions on dilution of the medicinal product before administration, see section 6.6.

Treatment must be initiated and supervised by a physician experienced in the management of patients with neuromuscular disorders.

Posology

Generalised myasthenia gravis

The first treatment cycle and first administration of the second treatment cycle must be administered either by or under the supervision of a healthcare professional. Subsequent treatment should be administered by a healthcare professional or may be administered at home by a patient or caregiver after adequate training in the subcutaneous injection technique.

The recommended dose is 1 000 mg to be administered subcutaneously in cycles of once weekly injections for 4 weeks. Subsequent treatment cycles should be administered according to clinical evaluation. The frequency of treatment cycles may vary by patient (see section 5.1).

In the clinical development program, the earliest time to initiate a subsequent treatment cycle was 7 weeks from the initial infusion of the previous cycle.

For patients currently receiving efgartigimod alfa intravenously, the solution for subcutaneous injection may be used as an alternative. It is recommended to switch between formulations at the start of a new treatment cycle. No safety and efficacy data in patients switching formulations during the same cycle is available.

Chronic inflammatory demyelinating polyneuropathy

The first 4 injections must be administered either by or under the supervision of a healthcare professional. Subsequent injections should be administered by a healthcare professional or may be administered at home by a patient or caregiver after adequate training in the subcutaneous injection technique.

The recommended dose is 1 000 mg administered subcutaneously as once-weekly injections.

Treatment is initiated with a weekly dose regimen and may be adjusted to every other week based on clinical evaluation. In case of worsening of symptoms, administration of once-weekly injections should be resumed.

For those patients transitioning from their current CIDP therapies, Vyvgart treatment should preferably be initiated before the clinical effect of these prior therapies starts to decrease.

Clinical response is usually achieved within 3 months of initiation of treatment with efgartigimod alfa subcutaneous. Clinical evaluation should be considered 3 to 6 months after treatment initiation to assess the treatment effect and at regular intervals thereafter.

Missed dose
An interval of at least 3 days should be observed between two consecutive administrations. When administrations cannot be done at the scheduled time point, they should be performed as soon as possible and at least 3 days ahead of the following administration. If there are less than 3 days to the next administration, the missed dose should be skipped and the next dose should be administered at the scheduled time point.

Special populations

Elderly
No dose adjustment is required in patients aged 65 years and older (see section 5.2).

Renal impairment
Limited safety and efficacy data in patients with mild renal impairment is available, no dose adjustment is required for patients with mild renal impairment. There is very limited safety and efficacy data in patients with moderate or severe renal impairment (see section 5.2).

Hepatic impairment
No data in patients with hepatic impairment are available. No dose adjustment is required in patients with hepatic impairment (see section 5.2).

Paediatric population
The safety and efficacy of efgartigimod alfa in paediatric population have not yet been established. No data are available.

Method of administration

This medicinal product should only be administered via subcutaneous injection. Do not administer intravenously.

Vyvgart 1 000 mg solution for injection
After removing the vial from the refrigerator, wait for at least 15 minutes before injecting to allow the solution to reach room temperature. Use aseptic technique when preparing and administering the medicinal product solution. Do not shake the vial.

The solution for injection can be administered using a polypropylene syringe, stainless steel transfer needles and polyvinyl chloride winged infusion set, with a maximum priming volume of 0.4 mL.

• Withdraw the entire content of the efgartigimod alfa solution from the vial using a transfer needle.
• Change the needle on the syringe to the winged infusion set.
• Prior to administration, the volume in the syringe should be adjusted to 5.6 mL.

During the initial administrations of efgartigimod alfa (see section 4.2), appropriate treatment for injection and hypersensitivity-related reactions should be readily available (see section 4.4). The recommended injection sites (abdomen) should be rotated and injections should never be given into moles, scars, or areas where the skin is tender, bruised, red or hard. The volume of 5.6 mL should be injected over 30 to 90 seconds. The injection may be slowed if the patient experiences discomfort.

Vyvgart 1 000 mg solution for injection in pre-filled syringe
After removing the pre-filled syringe from the refrigerator, wait for at least 30 minutes before injecting to allow the solution to reach room temperature. A safety needle, which is not included in the carton, should be connected to the pre-filled syringe. Use aseptic technique when handling the pre-filled syringe and during administration. Do not shake the pre-filled syringe.

During the initial administrations of efgartigimod alfa (see section 4.2), appropriate treatment for injection and hypersensitivity-related reactions should be readily available (see section 4.4). The recommended injection sites (abdomen) should be rotated and injections should never be given into moles, scars, or areas where the skin is tender, bruised, red or hard. The medicinal product should be injected for approximately 20 to 30 seconds. The injection may be slowed if the patient experiences discomfort.

The first self-administration must always be conducted under the supervision of a healthcare professional. After adequate training in subcutaneous injection technique, patients or caregivers may inject the medicinal product at home if a healthcare professional determines that it is appropriate.
Patients or caregivers should be instructed to inject Vyvgart according to the directions provided in the package leaflet.
For comprehensive instructions for the administration of the medicinal product, please refer to the Instructions for Use in the package leaflet.

Hypersensitivity to the active substance or to any of the excipients listed in section 6.1.

Summary of the safety profile

The most frequently observed adverse reactions were upper respiratory tract infections and urinary tract infections (10.7% and 9.5%, respectively).

Tabulated list of adverse reactions

The safety of Vyvgart was evaluated in 167 patients with gMG in the Phase 3 double-blind placebo-controlled clinical study.

Adverse reactions are listed in Table 1 by system organ class and preferred term. Frequency categories are defined as: very common (≥ 1/10), common (≥ 1/100 to < 1/10), uncommon (≥ 1/1 000 to < 1/100). rare (≥ 1/10 000 to < 1/1 000) or not known (cannot be estimated from the available data).
Within each frequency grouping, adverse reactions are presented in order of decreasing seriousness.

Table 1. Adverse reactions
System organ class
Adverse reaction
Frequency category
Infections and infestations*
Upper respiratory tract infections
Very common
Urinary tract infections
Common
Bronchitis
Common
Immune system disorders
Anaphylactic reaction a
Not known

System organ class
Adverse reaction
Frequency category
Gastrointestinal disorders
Nausea a
Common
Musculoskeletal and connective tissue disorders
Myalgia
Common
Injury, poisoning and procedural complications*
Procedural headache
Common
* See paragraph “Description of selected adverse reactions” a From spontaneous post-marketing reporting

Description of selected adverse reactions

Infections

The most frequently reported adverse reactions were infections, and the most reported infections were upper respiratory tract infections (10.7% [n = 9] of patients treated with efgartigimod alfa and 4.8% [n = 4] of patients treated with placebo) and urinary tract infections (9.5% [n = 8] of patients treated with efgartigimod alfa and 4.8% [n = 4] of patients treated with placebo). These infections were mild to moderate in severity in patients who received efgartigimod alfa (≤ Grade 2 according to the Common Terminology Criteria for Adverse Events). Overall, treatment emergent infections were reported in 46.4% (n = 39) of patients treated with efgartigimod alfa and 37.3% (n = 31) of patients treated with placebo. The median time from treatment initiation to emergence of infections was 6 weeks. Incidence of infections did not increase with subsequent treatment cycles. Treatment discontinuation or temporary interruption of treatment due to an infection occurred in less than 2% of patients.

Procedural headache

Procedural headache was reported in 4.8% of the patients treated with efgartigimod alfa and 1.2% of patients treated with placebo. Procedural headache was reported when a headache was judged to be temporally related to the intravenous infusion of efgartigimod alfa. All were mild or moderate except one event which was reported as severe (Grade 3).

All other adverse reactions were mild or moderate with the exception of one case of myalgia (Grade 3).

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorisation of the medicinal product is important.
It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the national reporting system listed in Appendix V.

Summary of the safety profile

The most frequently observed adverse reactions were injection site reactions (33%), upper respiratory tract infections (10.7%) and urinary tract infections (9.5%).

The overall safety profile of Vyvgart subcutaneous for both cyclic and continuous dose regimens was consistent with the known safety profile of the intravenous formulation.

Tabulated list of adverse reactions

Adverse reactions described in this section were identified in clinical trials and from post-marketing reports. These reactions are presented by system organ class and preferred term. Frequency categories are defined as: very common (≥ 1/10), common (≥ 1/100 to < 1/10), uncommon (≥ 1/1 000 to < 1/100), rare (≥ 1/10 000 to < 1/1 000) or not known (cannot be estimated from the available data).
Within each frequency grouping, adverse reactions are presented in order of decreasing seriousness.

Table 1. Adverse reactions
System organ class
Adverse reaction
Frequency category
Infections and infestations*
Upper respiratory tract infections
Very common
Urinary tract infections
Common
Bronchitis
Common
Immune system disorders
Anaphylactic reaction a
Not known
Gastrointestinal disorders
Nausea b
Common
Musculoskeletal and connective tissue disorders
Myalgia
Common
General disorders and administration site conditions*
Injection site reactions c, d
Very common
Injury, poisoning and procedural complications*
Procedural headache e
Common
* See paragraph “Description of selected adverse reactions” a From spontaneous post-marketing reporting with intravenous route of administration

b From spontaneous post-marketing reporting.
c Subcutaneous administration only.
d (e.g. injection site rash, injection site erythema, injection site pruritus, injection site pain) e Intravenous administration only.

Description of selected adverse reactions

Injection site reactions

In the pooled dataset from two clinical studies in gMG with efgartigimod alfa subcutaneous (n = 168), all injection site reactions were mild to moderate in severity and did not lead to treatment discontinuation. 44.0% (n = 74)) of patients experienced an injection site reaction. Injection site reactions occurred within 24 hours after administration in 78.4% (58/74) of patients and resolved without treatment in 85.1% (63/74) of the patients. The incidence of injection site reactions was the highest in the first treatment cycle, reported in 36.3% (61/168) of patients during the first treatment cycle and decreased to 20.1% (30/149), 15.4% (18/117) and 12.5% (10/80) of patients with the second, third and fourth treatment cycle. In a pooled dataset from 2 clinical studies in patients with CIDP who received continuous administration of efgartigimod alfa subcutaneous the incidence of injection site reactions was 26% (61/235). Analysis by 3-month intervals showed that the percentage of participants with injection-site reactions was highest in the first 3 months of treatment (73 [22.2%] participants) and decreased in subsequent 3-month intervals (range: 0 to 17 [6.8%] participants).

Infections

In the gMG ARGX-113-1704 placebo-controlled study with efgartigimod alfa intravenous, the most frequently reported adverse reactions were infections, and the most reported infections were upper respiratory tract infections, (10.7% [n = 9] of patients treated with efgartigimod alfa intravenous and 4.8% [n = 4] of patients treated with placebo) and urinary tract infections (9.5% [n = 8] of patients treated with efgartigimod alfa intravenous and 4.8% [n = 4] of patients treated with placebo). These infections were mild to moderate in severity in patients who received efgartigimod alfa intravenous (≤ Grade 2 according to the Common Terminology Criteria for Adverse Events). Overall, treatment emergent infections were reported in 46.4% (n = 39) of patients treated with efgartigimod alfa intravenous and 37.3% (n = 31) of patients treated with placebo. The median time from treatment initiation to emergence of infections was 6 weeks. Incidence of infections did not increase with subsequent treatment cycles. Treatment discontinuation or temporary interruption of treatment due to an infection occurred in less than 2% of patients. In the placebo-controlled part of the ARGX-113-1802 study in patients with CIDP, continuous administration of efgartigimod alfa subcutaneous was not associated with any increase in the incidence of infections (31.5% [35/111] in the efgartigimod alfa subcutaneous group and 33.6% [37/110] in the placebo group) (see section 5.1).

Procedural headache

Procedural headache was reported in 4.8% of the patients treated with efgartigimod alfa intravenous and 1.2% of patients treated with placebo. Procedural headache was reported when a headache was judged to be temporally related to the intravenous infusion of efgartigimod alfa. All were mild or moderate except one event which was reported as severe (Grade 3).

All other adverse reactions were mild or moderate with the exception of one case of myalgia (Grade 3).

Reporting of suspected adverse reactions

Reporting suspected adverse reactions after authorisation of the medicinal product is important.
It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the national reporting system listed in Appendix V.

Traceability

In order to improve the traceability of biological medicinal products, the name and the batch number of the administered product should be clearly recorded.

Myasthenia Gravis Foundation of America (MGFA) Class V patients

Treatment with efgartigimod alfa in patients with MGFA Class V (i.e. myasthenic crisis), defined as intubation with or without mechanical ventilation except in the setting of routine postoperative care, has not been studied. The sequence of therapy initiation between established therapies for MG crisis and efgartigimod alfa, and their potential interactions, should be considered (see section 4.5).

Infections

As efgartigimod alfa causes transient reduction in IgG levels the risk of infections may increase (see sections 4.8 and 5.1). The most common infections observed in clinical trials were upper respiratory tract infections and urinary tract infections (see section 4.8). Patients should be monitored for clinical signs and symptoms of infections during treatment with Vyvgart. In patients with an active infection, the benefit-risk of maintaining or withholding treatment with efgartigimod alfa should be considered until the infection has resolved. If serious infections occur, delaying treatment with efgartigimod alfa should be considered until the infection has resolved.

Infusion reactions and hypersensitivity reactions

Infusion reactions such as rash or pruritus may occur. In the clinical trial, infusion reactions were mild to moderate and did not lead to treatment discontinuation. Patients should be monitored during administration and for 1 hour thereafter for clinical signs and symptoms of infusion reactions. Should a reaction occur and based on the severity of the reaction the infusion should be administered at a slower rate, interrupted or discontinued and appropriate supportive measures should be instituted.
Once resolved, administration may be cautiously resumed, based on clinical evaluation.
Cases of anaphylactic reaction have been reported in the post-marketing setting. If an anaphylactic reaction is suspected, administration of Vyvgart should be immediately discontinued and appropriate medical treatment initiated. Patients should be informed of the signs and symptoms of hypersensitivity and anaphylactic reactions and advised to contact their healthcare provider immediately should they occur.

Immunisations

All vaccines should be administered according to immunisation guidelines.

The safety of immunisation with live or live-attenuated vaccines and the response to immunisation with these vaccines during treatment with efgartigimod alfa are unknown. For patients that are being treated with efgartigimod alfa, vaccination with live or live-attenuated vaccines is generally not recommended. If vaccination with live or live-attenuated vaccines is required, these vaccines should be administered at least 4 weeks before treatment and at least 2 weeks after the last dose of efgartigimod alfa.
Other vaccines may be administered as needed at any time during treatment with efgartigimod alfa.

Immunogenicity

In the double-blind placebo-controlled study, pre-existing antibodies that bind to efgartigimod alfa were detected in 25/165 (15%) patients with gMG. Treatment-induced antibodies to efgartigimod alfa were detected in 17/83 (21%) patients. In 3 of these 17 patients, treatment-induced anti-drug antibodies (ADAs) persisted until the end of the study. Neutralising antibodies were detected in 6/83 (7%) of patients treated with Vyvgart, including the 3 patients with persisting treatment-induced ADAs. Retreatment did not cause an increase in incidence or titres of efgartigimod alfa antibodies.

There was no apparent impact of antibodies to efgartigimod alfa on clinical efficacy or safety, nor on pharmacokinetics and pharmacodynamic parameters.

Immunosuppressant and anticholinesterase therapies

When non-steroidal immunosuppressants, corticosteroids and anticholinesterase therapies are decreased or discontinued, patients should be monitored closely for signs of disease exacerbation.

Excipients with known effect

Sodium
This medicinal product contains 33.2 mg sodium per vial, equivalent to 1.7% of the WHO recommended maximum daily intake of 2 g sodium for an adult. This medicinal product will be further prepared for administration with sodium-containing solution (see section 6.6) and this should be considered in relation to the total sodium intake to the patient from all sources per day.

Polysorbates
This medicinal product contains 8.2 mg of polysorbate 80 in each vial which is equivalent to 0.4 mg/mL. Polysorbates may cause allergic reactions.

Traceability

In order to improve the traceability of biological medicinal products, the name and the batch number of the administered product should be clearly recorded.

Myasthenia Gravis Foundation of America (MGFA) Class V patients

Treatment with efgartigimod alfa in patients with MGFA Class V (i.e. myasthenic crisis), defined as intubation with or without mechanical ventilation except in the setting of routine postoperative care, has not been studied. The sequence of therapy initiation between established therapies for MG crisis and efgartigimod alfa, and their potential interactions, should be considered (see section 4.5).

Infections

As efgartigimod alfa causes transient reduction in IgG levels the risk of infections may increase (see sections 4.8 and 5.1). The most common infections observed in clinical trials were upper respiratory tract infections and urinary tract infections (see section 4.8). Patients should be monitored for clinical signs and symptoms of infections during treatment with Vyvgart. In patients with an active infection, the benefit-risk of maintaining or withholding treatment with efgartigimod alfa should be considered until the infection has resolved. If serious infections occur, delaying treatment with efgartigimod alfa should be considered until the infection has resolved.

Injection reactions and hypersensitivity reactions

Injection reactions such as rash or pruritus were reported in the clinical trials (see section 4.8). These were mild to moderate. Cases of anaphylactic reaction have been reported with efgartigimod alfa intravenous in the post-marketing setting. The first administrations of Vyvgart must be performed under the supervision of a healthcare professional (see section 4.2). Patients should be monitored for 30 minutes after administration for clinical signs and symptoms of injection reactions. Should a reaction occur and based on the severity of the reaction, appropriate supportive measures should be initiated. Subsequent injections may be cautiously administered, based on clinical evaluation.
If an anaphylactic reaction is suspected, administration of Vyvgart should be immediately discontinued and appropriate medical treatment initiated. Patients should be informed of the signs and symptoms of hypersensitivity and anaphylactic reactions and advised to contact their healthcare professional immediately should they occur.

Immunisations

All vaccines should be administered according to immunisation guidelines.

The safety of immunisation with live or live-attenuated vaccines and the response to immunisation with these vaccines during treatment with efgartigimod alfa are unknown. For patients that are being treated with efgartigimod alfa, vaccination with live or live-attenuated vaccines is generally not recommended. If vaccination with live or live-attenuated vaccines is required, these vaccines should be administered at least 4 weeks before treatment and at least 2 weeks after the last dose of efgartigimod alfa.
Other vaccines may be administered as needed at any time during treatment with efgartigimod alfa.

Immunogenicity

In the active-controlled study ARGX-113-2001, pre-existing antibodies that bind to efgartigimod alfa were detected in 12/110 (11%) patients with gMG. Anti-efgartigimod alfa antibodies were detected in 19/55 (35%) patients treated with efgartigimod alfa subcutaneous compared to 11/55 (20%) patients treated with the intravenous formulation. Neutralising antibodies were detected in 2 (4%) patients treated with efgartigimod alfa subcutaneous and 2 (4%) patients treated with efgartigimod alfa intravenous.

In study ARGX-113-1802, pre-existing antibodies that bind to efgartigimod alfa were detected in 13/317 (4.1%) patients with CIDP. Anti-efgartigimod alfa antibodies were detected in 20/317 (6.3%) of patients treated in the open-label part of the study (Stage A), and in 2/111 (1.8%) of patients treated in the placebo-controlled part (Stage B). Neutralising antibodies were detected in 1 (0.3%) patient in the open-label part of the study only (see section 5.1).

The impact of antibodies to efgartigimod alfa on clinical efficacy or safety, pharmacokinetics and pharmacodynamic cannot be assessed given the low incidence of neutralizing antibodies.

Immunosuppressant and anticholinesterase therapies

When non-steroidal immunosuppressants, corticosteroids and anticholinesterase therapies are decreased or discontinued, patients should be monitored closely for signs of disease exacerbation.

Excipients with known effect

Sodium
This medicinal product contains less than 1 mmol sodium (23 mg) per vial/pre-filled syringe, that is to say essentially ‘sodium-free’.

Polysorbates
Vyvgart 1 000 mg solution for injection
This medicinal product contains 2.7 mg of polysorbate 80 in each vial which is equivalent to 0.4 mg/mL. Polysorbates may cause allergic reactions.

Vyvgart 1 000 mg solution for injection in pre-filled syringe
This medicinal product contains 2.1 mg of polysorbate 80 in each syringe which is equivalent to 0.4 mg/mL. Polysorbates may cause allergic reactions.

No interaction studies have been performed.

Efgartigimod alfa may decrease concentrations of compounds that bind to the human neonatal Fc Receptor (FcRn), i.e., immunoglobulin products, monoclonal antibodies, or antibody derivatives containing the human Fc domain of the IgG subclass. If possible, it is recommended to postpone initiation of treatment with these products to 2 weeks after the last dose of any given treatment cycle of Vyvgart. As a precaution, patients receiving Vyvgart while on treatment with these products should be closely monitored for the intended efficacy response of those products.

Plasma exchange, immunoadsorption, and plasmapheresis may reduce circulating levels of efgartigimod alfa.

All vaccines should be administered according to immunisation guidelines.
The potential interaction with vaccines was studied in a nonclinical model using Keyhole limpet hemocyanin (KLH) as the antigen. The weekly administration of 100 mg/kg to monkeys did not impact the immune response to KLH immunisation.
For patients that are being treated with efgartigimod alfa, vaccination with live or live-attenuated vaccines is generally not recommended. If vaccination with live or live-attenuated vaccines is required, these vaccines should be administered at least 4 weeks before treatment and at least 2 weeks after the last dose of a treatment cycle efgartigimod alfa (see section 4.4).

No interaction studies have been performed.

Efgartigimod alfa may decrease concentrations of compounds that bind to the human neonatal Fc Receptor (FcRn), i.e., immunoglobulin products, monoclonal antibodies, or antibody derivatives containing the human Fc domain of the IgG subclass. If possible, it is recommended to postpone the initiation of treatment with these products to 2 weeks after the last dose of Vyvgart. As a precaution, patients receiving Vyvgart while on treatment with these products should be closely monitored for the intended efficacy response of those products.

Plasma exchange, immunoadsorption, and plasmapheresis may reduce circulating levels of efgartigimod alfa.

All vaccines should be administered according to immunisation guidelines.
The potential interaction with vaccines was studied in a nonclinical model using Keyhole limpet hemocyanin (KLH) as the antigen. The weekly administration of 100 mg/kg to monkeys did not impact the immune response to KLH immunisation.
For patients that are being treated with efgartigimod alfa, vaccination with live or live-attenuated vaccines is generally not recommended. If vaccination with live or live-attenuated vaccines is required, these vaccines should be administered at least 4 weeks before treatment and at least 2 weeks after the last dose of efgartigimod alfa (see section 4.4).

Pregnancy

There is no available data on the use of efgartigimod alfa during pregnancy. Antibodies including therapeutic monoclonal antibodies are known to be actively transported across the placenta (after 30 weeks of gestation) by binding to the FcRn.

Efgartigimod alfa may be transmitted from the mother to the developing foetus. As efgartigimod alfa is expected to reduce maternal antibody levels, and is also expected to inhibit the transfer of maternal antibodies to the foetus, reduction in passive protection to the newborn is anticipated. Therefore, risks and benefits of administering live/live-attenuated vaccines to infants exposed to efgartigimod alfa in utero should be considered (see section 4.4).

Treatment of pregnant women with Vyvgart should only be considered if the clinical benefit outweighs the risks.

Breast-feeding

There is no information regarding the presence of efgartigimod alfa in human milk, the effects on the breastfed child or the effects on milk production. Animal studies on the transfer of efgartigimod alfa into milk have not been conducted, and therefore, excretion into maternal milk cannot be excluded.
Maternal IgG is known to be present in human milk. Treatment of lactating women with efgartigimod alfa should only be considered if the clinical benefit outweighs the risks.

Fertility

There is no available data on the effect of efgartigimod alfa on fertility in humans. Animal studies showed no impact of efgartigimod alfa on male and female fertility parameters (see section 5.3).

Pregnancy

There is no available data on the use of efgartigimod alfa during pregnancy. Antibodies including therapeutic monoclonal antibodies are known to be actively transported across the placenta (after 30 weeks of gestation) by binding to FcRn.

Efgartigimod alfa may be transmitted from the mother to the developing foetus. As efgartigimod alfa is expected to reduce maternal antibody levels, and is also expected to inhibit the transfer of maternal

antibodies to the foetus, reduction in passive protection to the newborn is anticipated. Therefore, risks and benefits of administering live/live-attenuated vaccines to infants exposed to efgartigimod alfa in utero should be considered (see section 4.4).

Treatment of pregnant women with Vyvgart should only be considered if the clinical benefit outweighs the risks.

Breast-feeding

There is no information regarding the presence of efgartigimod alfa in human milk, the effects on the breastfed child or the effects on milk production. Animal studies on the transfer of efgartigimod alfa into milk have not been conducted, and therefore, excretion into maternal milk cannot be excluded.
Maternal IgG is known to be present in human milk. Treatment of lactating women with efgartigimod alfa should only be considered if the clinical benefit outweighs the risks.

Fertility

There is no available data on the effect of efgartigimod alfa on fertility in humans. Animal studies showed no impact of efgartigimod alfa on male and female fertility parameters (see section 5.3).

Vyvgart has no or negligible influence on the ability to drive and use machines.

There are no known specific signs and symptoms of overdose with efgartigimod alfa. In the event of an overdose the adverse events that may occur are not expected to be different from those that may be observed at the recommended dose. Patients should be monitored for adverse reactions, and appropriate symptomatic and supportive treatment initiated. There is no specific antidote for overdose with efgartigimod alfa.

5.
PHARMACOLOGICAL PROPERTIES

Pharmacotherapeutic group: Immunosuppressants, neonatal fragment crystallizable receptor (FcRn) inhibitors, ATC code: L04AL01

Mechanism of action

Efgartigimod alfa is a human IgG1 antibody fragment engineered for increased affinity to the neonatal Fc Receptor (FcRn). Efgartigimod alfa binds to FcRn, resulting in a reduction in the levels of circulating IgG including pathogenic IgG autoantibodies. Efgartigimod alfa does not affect the levels of other immunoglobulins (IgA, IgD, IgE or IgM), and does not reduce those of albumin.

IgG autoantibodies are the underlying cause of the pathogenesis of MG. They impair neuromuscular transmission by binding to acetylcholine receptors (AChR), muscle-specific tyrosine kinase (MuSK) or low-density lipoprotein receptor-related protein 4 (LRP4).

Pharmacodynamic effects

In a double-blind placebo-controlled study in gMG patients, efgartigimod alfa decreased serum IgG levels and AChR autoantibody levels at the recommended dose and schedule (see section 4.2).
Maximum mean percentage decrease in total IgG levels compared to baseline reached 61% one week after the last infusion of the initial treatment cycle and returned to baseline levels 9 weeks after the last infusion. Similar effects were also observed for all subtypes of IgG. Decrease in AChR autoantibody levels followed a similar time course with maximum mean percentage decrease of 58% one week after the last infusion and return to baseline levels 7 weeks after the last infusion. Similar changes were observed during the second cycle of the study.

Clinical efficacy and safety

Efficacy of efgartigimod alfa for the treatment of adults with generalised Myasthenia Gravis (gMG) was studied in a 26-week, multicentre randomised double-blind placebo-controlled trial (ARGX-113-1704).

In this study, patients had to meet the following main criteria at screening:
- Myasthenia Gravis Foundation of America (MGFA) clinical classification class II, III or IV;
- Patients with either positive or negative serologic tests for antibodies to AChR;
- MG-Activities of Daily Living (MG-ADL) total score of ≥ 5;
- On stable doses of MG therapy prior to screening, that included acetylcholinesterase (AChE) inhibitors, steroids or non-steroidal immunosuppressive therapy (NSIST), either in combination or alone [NSISTs included but were not limited to azathioprine, methotrexate, cyclosporine, tacrolimus, mycophenolate mofetil, and cyclophosphamide];
- IgG levels of at least 6 g/L.

Patients with MGFA Class V gMG; patients with documented lack of clinical response to PLEX;
patients treated with PLEX, IVIg one month and monoclonal antibodies six months prior to starting treatment; and patients with active (acute or chronic) hepatitis B infection, hepatitis C seropositivity, and diagnosis of AIDS, were excluded from the trials.

Pharmacotherapeutic group: Immunosuppressants, neonatal fragment crystallizable receptor (FcRn) inhibitors, ATC code: L04AL01

Mechanism of action

Efgartigimod alfa is a human IgG1 antibody fragment engineered for increased affinity to the neonatal Fc Receptor (FcRn). Efgartigimod alfa binds to FcRn, resulting in a reduction in the levels of circulating IgG including pathogenic IgG autoantibodies. Efgartigimod alfa does not affect the levels of other immunoglobulins (IgA, IgD, IgE or IgM), and does not reduce those of albumin.

IgG autoantibodies are the underlying cause of the pathogenesis of IgG mediated autoimmune diseases.

In MG these impair neuromuscular transmission by binding to acetylcholine receptors (AChR), muscle-specific tyrosine kinase (MuSK) or low density lipoprotein receptor-related protein 4 (LRP4).

In CIDP, several lines of evidence point to the key role of IgG autoantibodies in the pathogenesis of this disease. This includes the demonstration of autoreactive IgG antibodies against components of myelinated nerves, passive transfer of CIDP symptoms to animal models using sera or IgG’s from patients with CIDP, and the therapeutic effect of plasma exchange and immunoadsorption for treating patients with CIDP.

Pharmacodynamic effects

Intravenous formulation

In the ARGX-113-1704 double-blind placebo-controlled study in gMG patients, efgartigimod alfa 10 mg/kg administered once weekly for 4 weeks decreased serum IgG levels and AChR autoantibody (AChR-Ab) levels. Maximum mean percentage decrease in total IgG levels compared to baseline reached 61% one week after the last infusion of the initial treatment cycle and returned to baseline levels 9 weeks after the last infusion. Similar effects were also observed for all subtypes of IgG.
Decrease in AChR-Ab levels followed a similar time course with maximum mean percentage decrease of 58% one week after the last infusion and return to baseline levels 7 weeks after the last infusion.
Similar changes were observed during the second cycle of the study.

Subcutaneous formulation

In the ARGX-113-2001 study, decreases in AChR-Ab levels followed a comparable time course as total IgG levels and were similar between the efgartigimod alfa subcutaneous and intravenous groups.
Maximum mean percentage decreases in AChR-Ab levels of 62.2% and 59.6% were observed one week after the last administration in the efgartigimod alfa subcutaneous and intravenous groups, respectively. For both the efgartigimod alfa subcutaneous and intravenous groups, decrease in total

IgG and AChR-Ab levels were associated with a clinical response, as measured by the change from baseline in MG-ADL total score (see figure 1).

Figure 1.
Relationship between total IgG and AChR-Ab and MG-ADL total score in
AChR-Ab seropositive population treated with efgartigimod alfa subcutaneous (1A) and efgartigimod alfa intravenous (1B) (study ARGX-113-2001)

Distribution

Based upon population PK data analysis in healthy subjects and patients the volume of distribution is 18 L.

Biotransformation

Efgartigimod alfa is expected to be degraded by proteolytic enzymes into small peptides and amino acids.

Elimination

The terminal half-life is 80 to 120 hours (3 to 5 days). Based upon population PK data analysis, the clearance is 0.128 L/h. The molecular weight of efgartigimod alfa is approximately 54 kDa, which is at the boundary of molecules that are renally filtered.

Linearity/non-linearity

The pharmacokinetics profile of efgartigimod alfa is linear, independent of dose or time, with negligible accumulation. The geometric mean accumulation ratio based on observed peak concentrations was 1.12.

Special populations

Age, gender, race and bodyweight
The pharmacokinetics of efgartigimod alfa were not affected by age (19-78 years), gender and race.

A population pharmacokinetic analysis showed that the effect of bodyweight on efgartigimod alfa exposure was limited at a dose of 10 mg/kg in patients up to 120 kg as well as in patients of 120 kg and above who received a capped dose of 1 200 mg/infusion. There was no effect of bodyweight on the extent of IgG reduction. In the double-blind placebo-controlled study, 5 (3%) patients were over 120 kg. The median bodyweight of patients on efgartigimod alfa in the study was 76.5 kg (min 49;
max 229).

Renal impairment
No dedicated pharmacokinetic studies have been performed in patients with renal impairment.

The effect of renal function marker estimated glomerular filtration rate [eGFR] as a covariate in a population pharmacokinetic analysis showed a reduced clearance resulting in a limited increase in exposure in patients with mild renal impairment (eGFR 60-89 mL/min/1.73 m2). No specific dose adjustment is recommended in patients with mild renal impairment.

Absorption

Based upon population PK data analysis, the estimated bioavailability with efgartigimod alfa 1 000 mg subcutaneous is 77%.

The mean Ctrough after 4 once weekly administrations with efgartigimod alfa 1 000 mg subcutaneous and efgartigimod alfa 10 mg/kg intravenous were 22.0 µg/mL (37% CV) and 14.9 µg/mL (43% CV), respectively. The AUC0-168h of efgartigimod alfa after administration of one treatment cycle with 1 000 mg subcutaneous and 10 mg/kg intravenous were comparable.

In patients receiving continuous subcutaneous administration of efgartigimod alfa 1 000 mg once weekly, mean Ctrough ranged from 14.9 to 20.1 µg/mL.

Distribution

Based upon population PK data analysis in healthy subjects and patients the volume of distribution is 18 L.

Probability of No Adjusted INCAT Deterioration

Biotransformation

Efgartigimod alfa is expected to be degraded by proteolytic enzymes into small peptides and amino acids.

Elimination

The terminal half-life is 80 to 120 hours (3 to 5 days). Based upon population PK data analysis, the clearance is 0.128 L/h. The molecular weight of efgartigimod alfa is approximately 54 kDa, which is at the boundary of molecules that are renally filtered.

Linearity/non-linearity

The pharmacokinetics profile of efgartigimod alfa is linear, independent of dose or time, with minimal accumulation.

Special populations

Age, gender, race and bodyweight
The pharmacokinetics of efgartigimod alfa were not affected by age (19-84 years), gender, race and bodyweight.

Renal impairment
No dedicated pharmacokinetic studies have been performed in patients with renal impairment.

The effect of renal function marker estimated glomerular filtration rate [eGFR] as a covariate in a population pharmacokinetic analysis showed an increase in exposure (11% to 21%) in patients with mild renal impairment (eGFR 60-89 mL/min/1.73 m2). No specific dose adjustment is recommended in patients with mild renal impairment.