Postural Orthostatic Tachycardia Syndrome
Conditions
Keywords
POTS, Long COVID, Postural Orthostatic Tachycardia Syndrome, efgartigimod
Brief summary
The study aims to investigate the safety, tolerability, efficacy, pharmacodynamics (PD), pharmacokinetics (PK), and immunogenicity of efgartigimod compared to placebo in participants with post-COVID-19 postural orthostatic tachycardia syndrome (POTS) (post-COVID-19 POTS).
Detailed description
The study aims to investigate the safety, tolerability, efficacy, pharmacodynamics (PD), pharmacokinetics (PK), and immunogenicity of efgartigimod compared to placebo in participants with post-COVID-19 postural orthostatic tachycardia syndrome (POTS) (post-COVID-19 POTS). Efgartigimod may be a viable treatment option for individuals diagnosed with post-COVID-19 POTS because it has been shown to reduce IgG levels, including IgG autoantibodies, which may underlie some of the autonomic disease manifestations in these patients.
Interventions
DRUGEfgartigimod
Efgartigimod IV 10 mg/kg infusion qw for 24 weeks. Participants will be randomized to receive efgartigimod IV 10 mg/kg or matching placebo in a 2:1 ratio, respectively
DRUGPlacebo
Receive a matching placebo during weekly infusions during a treatment period of 24 weeks. Participants will be randomized to receive efgartigimod IV 10 mg/kg or matching placebo in a 2:1 ratio, respectively
Sponsors
Iqvia Pty Ltd
argenx
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
TRIPLE (Subject, Caregiver, Investigator)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
1. Reached the age of consent when signing the informed consent form 2. Capable of providing signed informed consent and complying with protocol requirements 3. Diagnosed with new-onset POTS post-COVID-19 established by the following: 1. History of COVID-19 based on a previous positive test result from either laboratory-confirmed COVID-19 test (eg, a PCR test) or non-laboratory-confirmed COVID-19 test (eg, rapid antigen test); this positive result may be either documented or patient-reported 2. Tilt table or orthostatic vital sign measurements during screening consistent with consensus criteria: sustained HR increase of ≥30 bpm within 10 min of standing or head up tilt (≥40 bpm for individuals aged 18 to 19 years) and/or HR reaching \>120 bpm within 10 min; absence of sustained 20 mmHg decrease in systolic blood pressure (SBP) 3. Ongoing symptoms of POTS confirmed by the investigator with at least 3 symptoms in each of the following areas lasting longer than 12 weeks after either diagnosis of COVID-19 or after hospital discharge for COVID-19: i. Vasomotor symptoms: fatigue, orthostatic intolerance, brain fog, exertional dyspnea, difficulty with concentration, venous pooling, and exercise intolerance ii. Sympathetic over-compensation symptoms: palpitation, heat intolerance, nausea with or without vomiting, insomnia, anxiety, lack of appetite, chest pain, and diaphoresis 4. COMPASS 31 ≥35 at screening 5. Agree to use contraceptives consistent with local regulations regarding the methods of contraception for those participating in clinical studies and the following: Male participants: No male contraception is required Female participants of childbearing potential must have a negative serum pregnancy test at screening and a negative urine pregnancy test at baseline before receiving IMP. Contraceptive requirements. 6. Body mass index (BMI) \<35 kg/m2
Exclusion criteria
1. Diagnosis of or receiving treatment for the following conditions before COVID-19: peripheral neuropathy, POTS, myalgic encephalomyelitis encephalitis/chronic fatigue syndrome, Ehlers Danlos syndrome confirmed by genetic testing, autonomic neuropathy, multiple sclerosis, stroke, spinal cord injury, or any known lesions in the central nervous system by imaging or neurological exam 2. History of or currently being treated for clinically significant ongoing cardiac arrythmia, heart failure, myocarditis, pulmonary embolism requiring anticoagulation, pulmonary fibrosis, or critical illness-related polyneuropathy or myopathy 3. Known autoimmune disease that, in the investigator's judgment, would interfere with an accurate assessment of clinical symptoms of post-COVID-19 POTS or puts the participant at undue risk 4. Known HIV disease or common variable immunodeficiency 5. History of malignancy unless considered cured by adequate treatment with no evidence of recurrence for ≥3 years before the first administration of IMP. Adequately-treated participants with the following cancers may be included at any time: 1. Basal cell or squamous cell skin cancer 2. Carcinoma in situ of the cervix 3. Carcinoma in situ of the breast 4. Incidental histological finding of prostate cancer (TNM stage T1a or T1b) 6. Clinically significant uncontrolled active or chronic bacterial, viral, or fungal infection or positive SARS-CoV-2 PCR test at screening 7. Positive serum test at screening for an active infection with any of the following: 1. Hepatitis B virus (HBV) that is indicative of an acute or chronic infection, unless associated with a negative HB surface antigen (HBsAg) or negative HBV DNA test 2. Hepatitis C virus (HCV) based on HCV antibody assay unless a negative RNA test is available 3. HIV 8. A medical condition that could confound the results of the study or put the participant at undue risk in the investigator's judgment 9. Clinically significant disease, recent major surgery (within 3 months of screening), or intends to have surgery during the study; or any other condition that in the opinion of the investigator could confound the results of the study or put the participant at undue risk 10. Total IgG \<4 g/L at screening 11. Received within 12 weeks or 5 half-lives (whichever is longer) before screening an investigational product 12. Received within 12 weeks before screening either intravenous immunoglobulin (Ig) IV or SC or plasmapheresis/plasma exchange (PLEX) 13. Received a live or live-attenuated vaccine less than 4 weeks before screening 14. Known hypersensitivity to IMP or 1 of its excipients 15. Previously participated in an efgartigimod clinical study and received at least 1 dose of IMP 16. Currently participating in another interventional clinical study 17. History (within 12 months of screening) of or current alcohol, drug, or medication abuse 18. Pregnant or lactating or intends to become pregnant during the study 19. Unwilling to remain on a stable regimen of medications during the study 20. Unwilling to avoid initiation of new physical rehabilitation or other physician-prescribed exercise programs during the 24-week treatment period
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change From Baseline to Week 24 in the COMPASS 31 (2-week Recall Version) | Baseline (Day 1) and Week 24 | Composite Autonomic Symptom Score (COMPASS) 31 modified version (2-week recall) is a self-rated questionnaire to evaluate the severity and distribution of autonomic symptoms in various autonomic nerve disorders. It consists of 31 questions in 6 weighted domains (orthostatic intolerance, vasomotor, secretomotor, gastrointestinal {GI}-mixed upper and diarrhea, bladder, and pupillomotor). A weighted total score of 0 (mild) to 100 (severe) was determined by adding a maximum raw score for each domain. Higher scores indicated a more severe degree of autonomic symptoms. |
| Change From Baseline to Week 24 in the MaPS | Baseline (Day 1) and Week 24 | The Malmö POTS Symptom Score (MaPS) score is a dedicated POTS symptom scoring questionnaire. The score consists of 12 questions that assess symptom burden related (tachycardia, palpitations, dizziness, presyncope) and unrelated to orthostatic intolerance (GI symptoms, insomnia, concentration difficulties). Participants graded their symptoms for the past 7 days using a visual analog scale ranging from 0 (no symptoms) to 10 (worst possible). The total score was calculated by summing up the items/individual items and range was 0 to 120 points, with higher scores indicating more severe symptoms. |
| Number of Participants With TEAEs and TESAEs | From the first dose of study drug (Day 1) up to 60 days post last dose of study drug, up to 236 days | An adverse event (AE) was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study drug, whether or not considered related to the study drug. A serious adverse event (SAE) was any untoward medical occurrence that at any dose resulted in death, was life threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect or any other medically important event. Treatment-emergent adverse events (TEAEs) were defined as AEs with onset on or after the first administration of study drug up to and including 60 days after the last study drug administration. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change From Baseline to Week 24 in the PROMIS Cognitive Function Short Form 6a | Baseline (Day 1) and Week 24 | PROMIS Cognitive Function Short Form 6a assesses the frequency of cognitive difficulties experienced in the past 7 days. The questionnaire comprises 6 questions on subjective cognitive difficulties regarding a participant's concentration, memory, language, mental acuity, and perceived changes in cognitive functioning. The participant marks their response on a 5-point Likert scale (1: never and 5: very often). Scores ranged from 6 to 30; higher scores indicated worse perceived cognitive functioning and were converted to a T-score with a mean of 50 and standard deviation of 10. An increase in T-score (positive change from baseline) indicated better cognitive function. |
| Percent Change From Baseline in Total IgG Levels at Week 24 | Baseline (Day 1) and Week 24 | Blood samples for immunoglobulin G (IgG) analysis were collected at specified time points. Total IgG concentrations were quantified using validated methods at a central laboratory. |
| Percentage of Participants With Improved PGI-S at Week 24 | Baseline (Day 1) and Week 24 | The Patient Global Impression-Severity (PGI-S) is a participant-rated, single-item scale to assess the severity of a health condition. The scale was used to assess the severity of symptoms over the past week (1-week recall) and overall experience of symptoms over the past 2 weeks (2-week recall). Both were rated on a 4-point type Likert scale, with scores ranging from 1 (none), 2 (mild), 3 (moderate), and 4 (severe). Higher scores indicate greater symptom severity. An improved PGI-S was defined by a change from baseline of -3, -2 and -1. |
| Number of Participants With ADAs Against Efgartigimod | Up to Week 24 | Blood samples were collected at specified timepoints to assess anti-drug antibodies (ADAs) against efgartigimod. ADA incidence reported here was defined as total number of participants with treatment-induced and treatment-boosted ADA. Treatment-induced ADA was defined as a baseline negative sample and at least 1 positive post-baseline sample. Treatment-boosted ADA was defined as a baseline positive sample and the titer value increased 4-fold or more compared to baseline. |
| Serum Concentration of Efgartigimod | Pre-dose and post-dose at Baseline (Day 1), Weeks 1, 4, 12 and at Week 24 | Serum samples were collected at specified timepoints to determine the concentration of efgartigimod. |
| Percentage of Participants With Improved in PGI-C at Week 24 | Baseline (Day 1) and Week 24 | The Patient Global Impression-Change (PGIC) is a single-item scale to capture the participant's perception of a change in their overall symptom severity. Overall change in symptoms was rated on a 7-point Likert scale, with scores ranging from 1 (much better), 2 (somewhat better), 3 (a little better), 4 (no change), 5 (a little worse), 6 (somewhat worse), and 7 (much worse). Higher PGI-C scores signify worse outcome. An improved PGI-C was defined by a change from baseline of 1, 2 and 3. |
| Change From Baseline to Week 24 in the PROMIS Fatigue Short Form 8a | Baseline (Day 1) and Week 24 | The Patient-Reported Outcomes Measurement Information System (PROMIS) Fatigue Short Form 8a assesses the impact and perceived fatigue during the last 7 days. This validated 8-question scale has 5 response options, with scores ranging from 1 (not at all) to 5 (very much). Total scores ranged from 8 to 40; higher scores indicated higher fatigue levels and were converted to a T-score with a mean of 50 and standard deviation of 10. A decrease in T-score (negative change from baseline) indicated improvement in fatigue. |
Countries
United States
Participant flow
Recruitment details
This phase 2, randomized, double-blind study was conducted at 11 sites in the United States from 23-Sep-22 to 18-Apr-24 in participants with post-coronavirus disease 2019 (COVID-19) postural orthostatic tachycardia syndrome (POTS).
Pre-assignment details
The study consisted of a screening period (approximately 4 weeks), a treatment period (24 weeks) and a follow-up period (approximately 8 weeks for participants who did not roll over to the open label extension study ARGX-113-2105 \[NCT05918978). A total of 53 participants were randomized in a 2:1 ratio to receive either efgartigimod or matching placebo, respectively.
Participants by arm
| Arm | Count |
|---|---|
| Efgartigimod Participants received efgartigimod 10 mg/kg via IV infusion once weekly from Day 1 up to 24 weeks. | 36 |
| Placebo Participants received placebo matched to efgartigimod via IV infusion once weekly from Day 1 up to 24 weeks. | 17 |
| Total | 53 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 |
|---|---|---|---|
| Overall Study | Adverse Event | 1 | 0 |
| Overall Study | Other | 1 | 1 |
| Overall Study | Physician Decision | 2 | 0 |
| Overall Study | Withdrawal by Subject | 1 | 0 |
Baseline characteristics
| Characteristic | Placebo | Total | Efgartigimod |
|---|---|---|---|
| Age, Continuous | 36.8 years STANDARD_DEVIATION 11.99 | 37.9 years STANDARD_DEVIATION 12.47 | 38.4 years STANDARD_DEVIATION 12.82 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 3 Participants | 6 Participants | 3 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 13 Participants | 46 Participants | 33 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 1 Participants | 1 Participants | 0 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants | 1 Participants | 1 Participants |
| Race (NIH/OMB) Black or African American | 0 Participants | 1 Participants | 1 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 1 Participants | 1 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 17 Participants | 50 Participants | 33 Participants |
| Sex: Female, Male Female | 15 Participants | 45 Participants | 30 Participants |
| Sex: Female, Male Male | 2 Participants | 8 Participants | 6 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 36 | 0 / 17 |
| other Total, other adverse events | 31 / 36 | 14 / 17 |
| serious Total, serious adverse events | 0 / 36 | 0 / 17 |
Outcome results
Primary
Change From Baseline to Week 24 in the COMPASS 31 (2-week Recall Version)
Composite Autonomic Symptom Score (COMPASS) 31 modified version (2-week recall) is a self-rated questionnaire to evaluate the severity and distribution of autonomic symptoms in various autonomic nerve disorders. It consists of 31 questions in 6 weighted domains (orthostatic intolerance, vasomotor, secretomotor, gastrointestinal {GI}-mixed upper and diarrhea, bladder, and pupillomotor). A weighted total score of 0 (mild) to 100 (severe) was determined by adding a maximum raw score for each domain. Higher scores indicated a more severe degree of autonomic symptoms.
Time frame: Baseline (Day 1) and Week 24
Population: The FAS included all randomized participants who received at least 1 dose of study drug. Only those participants with data collected at Baseline and Week 24 are reported.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Efgartigimod | Change From Baseline to Week 24 in the COMPASS 31 (2-week Recall Version) | -14.369 score on a scale | Standard Deviation 15.2541 |
| Placebo | Change From Baseline to Week 24 in the COMPASS 31 (2-week Recall Version) | -15.957 score on a scale | Standard Deviation 17.2963 |
Primary
Change From Baseline to Week 24 in the MaPS
The Malmö POTS Symptom Score (MaPS) score is a dedicated POTS symptom scoring questionnaire. The score consists of 12 questions that assess symptom burden related (tachycardia, palpitations, dizziness, presyncope) and unrelated to orthostatic intolerance (GI symptoms, insomnia, concentration difficulties). Participants graded their symptoms for the past 7 days using a visual analog scale ranging from 0 (no symptoms) to 10 (worst possible). The total score was calculated by summing up the items/individual items and range was 0 to 120 points, with higher scores indicating more severe symptoms.
Time frame: Baseline (Day 1) and Week 24
Population: The FAS included all randomized participants who received at least 1 dose of study drug. Only those participants with data collected at Baseline and Week 24 are reported.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Efgartigimod | Change From Baseline to Week 24 in the MaPS | -23.5 score on a scale | Standard Deviation 25.87 |
| Placebo | Change From Baseline to Week 24 in the MaPS | -19.8 score on a scale | Standard Deviation 27.75 |
Primary
Number of Participants With TEAEs and TESAEs
An adverse event (AE) was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study drug, whether or not considered related to the study drug. A serious adverse event (SAE) was any untoward medical occurrence that at any dose resulted in death, was life threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect or any other medically important event. Treatment-emergent adverse events (TEAEs) were defined as AEs with onset on or after the first administration of study drug up to and including 60 days after the last study drug administration.
Time frame: From the first dose of study drug (Day 1) up to 60 days post last dose of study drug, up to 236 days
Population: The safety analysis set (SAF) included all randomized participants who received at least 1 dose of study drug.
| Arm | Measure | Group | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|---|
| Efgartigimod | Number of Participants With TEAEs and TESAEs | TEAEs | 31 Participants |
| Efgartigimod | Number of Participants With TEAEs and TESAEs | TESAEs | 0 Participants |
| Placebo | Number of Participants With TEAEs and TESAEs | TEAEs | 14 Participants |
| Placebo | Number of Participants With TEAEs and TESAEs | TESAEs | 0 Participants |
Secondary
Change From Baseline to Week 24 in the PROMIS Cognitive Function Short Form 6a
PROMIS Cognitive Function Short Form 6a assesses the frequency of cognitive difficulties experienced in the past 7 days. The questionnaire comprises 6 questions on subjective cognitive difficulties regarding a participant's concentration, memory, language, mental acuity, and perceived changes in cognitive functioning. The participant marks their response on a 5-point Likert scale (1: never and 5: very often). Scores ranged from 6 to 30; higher scores indicated worse perceived cognitive functioning and were converted to a T-score with a mean of 50 and standard deviation of 10. An increase in T-score (positive change from baseline) indicated better cognitive function.
Time frame: Baseline (Day 1) and Week 24
Population: The FAS included all randomized participants who received at least 1 dose of study drug. Only those participants with data collected at Baseline and Week 24 are reported.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Efgartigimod | Change From Baseline to Week 24 in the PROMIS Cognitive Function Short Form 6a | 3.9 T-score | Standard Deviation 9.58 |
| Placebo | Change From Baseline to Week 24 in the PROMIS Cognitive Function Short Form 6a | 6.7 T-score | Standard Deviation 9.74 |
Secondary
Change From Baseline to Week 24 in the PROMIS Fatigue Short Form 8a
The Patient-Reported Outcomes Measurement Information System (PROMIS) Fatigue Short Form 8a assesses the impact and perceived fatigue during the last 7 days. This validated 8-question scale has 5 response options, with scores ranging from 1 (not at all) to 5 (very much). Total scores ranged from 8 to 40; higher scores indicated higher fatigue levels and were converted to a T-score with a mean of 50 and standard deviation of 10. A decrease in T-score (negative change from baseline) indicated improvement in fatigue.
Time frame: Baseline (Day 1) and Week 24
Population: The FAS included all randomized participants who received at least 1 dose of study drug. Only those participants with data collected at Baseline and Week 24 are reported.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Efgartigimod | Change From Baseline to Week 24 in the PROMIS Fatigue Short Form 8a | -9.5 T-score | Standard Deviation 8.77 |
| Placebo | Change From Baseline to Week 24 in the PROMIS Fatigue Short Form 8a | -7.0 T-score | Standard Deviation 9.4 |
Secondary
Number of Participants With ADAs Against Efgartigimod
Blood samples were collected at specified timepoints to assess anti-drug antibodies (ADAs) against efgartigimod. ADA incidence reported here was defined as total number of participants with treatment-induced and treatment-boosted ADA. Treatment-induced ADA was defined as a baseline negative sample and at least 1 positive post-baseline sample. Treatment-boosted ADA was defined as a baseline positive sample and the titer value increased 4-fold or more compared to baseline.
Time frame: Up to Week 24
Population: The SAF included all randomized participants who received at least 1 dose of study drug.
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| Efgartigimod | Number of Participants With ADAs Against Efgartigimod | 5 Participants |
| Placebo | Number of Participants With ADAs Against Efgartigimod | 1 Participants |
Secondary
Percentage of Participants With Improved in PGI-C at Week 24
The Patient Global Impression-Change (PGIC) is a single-item scale to capture the participant's perception of a change in their overall symptom severity. Overall change in symptoms was rated on a 7-point Likert scale, with scores ranging from 1 (much better), 2 (somewhat better), 3 (a little better), 4 (no change), 5 (a little worse), 6 (somewhat worse), and 7 (much worse). Higher PGI-C scores signify worse outcome. An improved PGI-C was defined by a change from baseline of 1, 2 and 3.
Time frame: Baseline (Day 1) and Week 24
Population: The FAS included all randomized participants who received at least 1 dose of study drug. Only participants with data available for week 24 are included.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Efgartigimod | Percentage of Participants With Improved in PGI-C at Week 24 | 65.4 percentage of participants |
| Placebo | Percentage of Participants With Improved in PGI-C at Week 24 | 53.3 percentage of participants |
Secondary
Percentage of Participants With Improved PGI-S at Week 24
The Patient Global Impression-Severity (PGI-S) is a participant-rated, single-item scale to assess the severity of a health condition. The scale was used to assess the severity of symptoms over the past week (1-week recall) and overall experience of symptoms over the past 2 weeks (2-week recall). Both were rated on a 4-point type Likert scale, with scores ranging from 1 (none), 2 (mild), 3 (moderate), and 4 (severe). Higher scores indicate greater symptom severity. An improved PGI-S was defined by a change from baseline of -3, -2 and -1.
Time frame: Baseline (Day 1) and Week 24
Population: The FAS included all randomized participants who received at least 1 dose of study drug. Only participants with available data at week 24 are included.
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Efgartigimod | Percentage of Participants With Improved PGI-S at Week 24 | 1-week recall | 45.5 percentage of participants |
| Efgartigimod | Percentage of Participants With Improved PGI-S at Week 24 | 2-week recall | 54.5 percentage of participants |
| Placebo | Percentage of Participants With Improved PGI-S at Week 24 | 1-week recall | 53.3 percentage of participants |
| Placebo | Percentage of Participants With Improved PGI-S at Week 24 | 2-week recall | 33.3 percentage of participants |
Secondary
Percent Change From Baseline in Total IgG Levels at Week 24
Blood samples for immunoglobulin G (IgG) analysis were collected at specified time points. Total IgG concentrations were quantified using validated methods at a central laboratory.
Time frame: Baseline (Day 1) and Week 24
Population: The SAF included all randomized participants who received at least 1 dose of study drug. Only those participants with data collected at Baseline and Week 24 are reported.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Efgartigimod | Percent Change From Baseline in Total IgG Levels at Week 24 | -69.341 percent change | Standard Deviation 6.0637 |
| Placebo | Percent Change From Baseline in Total IgG Levels at Week 24 | 5.868 percent change | Standard Deviation 13.1379 |
Secondary
Serum Concentration of Efgartigimod
Serum samples were collected at specified timepoints to determine the concentration of efgartigimod.
Time frame: Pre-dose and post-dose at Baseline (Day 1), Weeks 1, 4, 12 and at Week 24
Population: The pharmacokinetic (PK) analysis set included all randomized participants who received at least 1 dose of efgartigimod and had at least 1 measured concentration of efgartigimod at a scheduled PK time point after start of dosing without protocol violations or events with potential to affect the PK concentration. Only those participants with data collected at specified timepoints are reported.
| Arm | Measure | Group | Value (MEAN) | Dispersion |
|---|---|---|---|---|
| Efgartigimod | Serum Concentration of Efgartigimod | Baseline, pre-dose | NA nanogram (ng)/mL | — |
| Efgartigimod | Serum Concentration of Efgartigimod | Baseline, post-dose | 260536 nanogram (ng)/mL | Standard Deviation 235110 |
| Efgartigimod | Serum Concentration of Efgartigimod | Week 1, pre-dose | 10711 nanogram (ng)/mL | Standard Deviation 3580 |
| Efgartigimod | Serum Concentration of Efgartigimod | Week 1, post-dose | 235100 nanogram (ng)/mL | Standard Deviation 68316 |
| Efgartigimod | Serum Concentration of Efgartigimod | Week 4, pre-dose | 12612 nanogram (ng)/mL | Standard Deviation 5631 |
| Efgartigimod | Serum Concentration of Efgartigimod | Week 4, post-dose | 230308 nanogram (ng)/mL | Standard Deviation 54329 |
| Efgartigimod | Serum Concentration of Efgartigimod | Week 12, pre-dose | 18966 nanogram (ng)/mL | Standard Deviation 39993 |
| Efgartigimod | Serum Concentration of Efgartigimod | Week 12, post-dose | 216760 nanogram (ng)/mL | Standard Deviation 56621 |
| Efgartigimod | Serum Concentration of Efgartigimod | Week 24 | 10450 nanogram (ng)/mL | Standard Deviation 3894 |