Relapse rate is defined as the percentage of participants who experience a worsening of functional disability. Worsening of functional disability defined as an increase of >=1 point relative to the pre- subcutaneous (SC) treatment baseline score in 2 consecutive adjusted Inflammatory Neuropathy Cause and Treatment (INCAT) disability score. The INCAT disability score is an effective and responsive tool to assess clinical response to treatment in CIDP. The disability score ranges from 0 to 10 points, where 0 is normal (eg, no upper limb problems and walking not affected) and 10 is severely incapacitated (eg, inability to move either arm for any purposeful movement and restricted to wheelchair, unable to stand and walk a few steps with help).

MITT analysis set included all randomized participants who received any double-blind study medication.

Responder rate is defined as clinically meaningful improvement in functional ability defined as a decrease of >=1 point in the adjusted INCAT disability score at the completion of the intravenous (IV) treatment period [6 months] or at the last study visit of the IV treatment period, relative to the pre-IV treatment baseline score.

E1:Placebo Relapse / E2:GGL/KIOVIG Set included a subset of participants who had a relapse while on placebo in Epoch 1, entered Epoch 2, and were treated with GAMMAGARD LIQUID/KIOVIG in Epoch 2.

Defined as one or more of the following: an increase of >=1 point relative to the pre-subcutaneous (SC) treatment baseline score in 2 consecutive adjusted Inflammatory Neuropathy Cause and Treatment disability scale (INCAT) scores; who experience CIDP worsening (defined as a >=8 kilo Pascal (kPa) decrease in the hand grip strength in the more affected hand); >=4 points decrease in raw Rasch-built Overall Disability Scale (R-ODS) relative to the pre-SC treatment baseline score (at the time of withdrawal from the SC treatment period). Participants are rounded off to nearest single decimal point.

MITT analysis set included all randomized participants who received any double-blind study medication. Overall number of participants analyzed is the number of participants available with data.

Time to relapse is defined as time from the date of the first SC administration of HYQVIA/HyQvia or placebo with rHuPH20 to the date of relapse. Participants who did not relapse were censored at their end of study.

MITT analysis set included all randomized participants who received any double-blind study medication.

The Rasch-Built Overall Disability Scale (R-ODS) is a participant self-reported, linearly-weighted overall disability scale that was specifically designed to capture activity and social participation limitations in participant with immune-mediated peripheral neuropathies including CIDP. The R-ODS is comprised of 24 items for which participants are asked to rate their functioning (i.e, no difficulty, some difficulty, or could not do) related to a variety of everyday tasks at the moment of completion. The centile metric R-ODS score range is 0 to 100. Higher scores indicate better condition. The centile metric R-ODS score was used in the ANCOVA analysis. ANCOVA was used for the analysis.

MITT analysis set included all randomized participants who received any double-blind study medication. Overall number of participants analyzed is the number of participants available with data.

An AE is defined as any untoward medical occurrence in participant administered an Investigational Product (IP) that does not necessarily have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (eg, an abnormal laboratory finding), symptom (eg, rash, pain, discomfort, fever, dizziness, etc.), disease (eg, peritonitis, bacteremia, etc.), or outcome of death temporally associated with the use of an IP, whether or not considered causally related to the IP. A SAE is defined as an untoward medical occurrence that at any dose meets one or more of the following criteria: outcome is fatal/results in death, is life-threatening, requires inpatient hospitalization or results in prolongation of an existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, is a medically important event, thromboembolic events, hemolytic anemia. A nonserious AE is an AE that does not meet the criteria.

Epoch 1 safety analysis set included all participants who received any study treatment.

AE=any untoward medical occurrence in participant administered IP. AE can therefore be any unfavorable and unintended sign (e.g.,abnormal laboratory finding), symptom (e.g.,rash, pain, discomfort, fever, dizziness, etc.), disease (e.g.,peritonitis,bacteremia,etc.), outcome of death temporally associated with use of IP,considered causally related to the IP. SAE=untoward medical occurrence that at any dose meets following criteria: outcome is fatal/results in death, is life-threatening, requires inpatient hospitalization/results in prolongation of an existing hospitalization, results in persistent or significant disability/incapacity, is congenital anomaly/birth defect, is medically important event, thromboembolic events, hemolytic anemia. Non-SAE=AE not meeting this criteria. AE recorded by investigator as possibly/probably related to IP is considered related AE, any AE recorded as unlikely/not related is considered unrelated AE.

Epoch 1 safety analysis set included all participants who received any study treatment.

An AR plus suspected AR is any AE that meets any of the following criteria: an AE considered by either the investigator and/or the sponsor to be possibly or probably related to IP administration, or that begins during infusion of IP or within 72 h following the end of IP infusion, or AE for which causality assessment is missing or indeterminate. A SAE is defined as an untoward medical occurrence that at any dose meets one or more of the following criteria: outcome is fatal/results in death, is life-threatening, requires inpatient hospitalization or results in prolongation of an existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, is a medically important event, thromboembolic events, hemolytic anemia. A nonserious AE is an AE that does not meet the criteria.

Epoch 1 safety analysis set included all participants who received any study treatment.

AE: any untoward medical occurrence in participant administered an IP that does not necessarily have a causal relationship with the treatment. AE can therefore be any unfavorable and unintended sign (eg, an abnormal laboratory finding), symptom (eg, rash, pain, discomfort, fever, dizziness, etc.), disease (eg, peritonitis, bacteremia, etc.), or outcome of death temporally associated with the use of an IP, whether or not considered causally related to the IP. SAE: an untoward medical occurrence that at any dose meets one or more of the following criteria: outcome is fatal/results in death, is life-threatening, requires inpatient hospitalization or results in prolongation of an existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, is a medically important event, thromboembolic events, hemolytic anemia. A nonserious AE is an AE that does not meet the criteria. Participants can have more than one adverse event.

Epoch 1 safety analysis set included all participants who received any study treatment. Participants can have more than one adverse event.

AE: any untoward medical occurrence in participant administered IP. AE can therefore be any unfavorable and unintended sign (e.g., abnormal laboratory finding), symptom (e.g., rash, pain, discomfort, fever, dizziness, etc.), disease (e.g., peritonitis, bacteremia, etc.), outcome of death temporally associated with use of IP, whether or not considered causally related to the IP. SAE: untoward medical occurrence that at any dose meets following criteria: outcome is fatal/results in death, is life-threatening, requires inpatient hospitalization/results in prolongation of an existing hospitalization, results in persistent or significant disability/incapacity, is congenital anomaly/birth defect, is medically important event, (e.g., thromboembolic events, hemolytic anemia). Non-SAE:AE not meeting this criteria. AE recorded by investigator as possibly/probably related to IP is considered related AE, any AE recorded as unlikely/not related is considered unrelated AE.

Epoch 1 safety analysis set included all participants who received any study treatment. Participants can have more than one causally related adverse event.

AEs occurring during an infusion or within 72 hours after completion of an infusion. An AE is defined as any untoward medical occurrence in participant administered an Investigational Product (IP) that does not necessarily have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (eg, an abnormal laboratory finding), symptom (eg, rash, pain, discomfort, fever, dizziness, etc.), disease (eg, peritonitis, bacteremia, etc.), or outcome of death temporally associated with the use of an IP, whether or not considered causally related to the IP. Participants can have more than one temporally associated with infusion adverse event.

Epoch 1 safety analysis set included all participants who received any study treatment. Participants can have more than one temporally associated with infusion adverse event.

AR plus suspected AR: any AE that meets any of the criteria: AE considered by either investigator and/or the sponsor to be possibly or probably related to IP administration, or that begins during infusion of IP or within 72 h following end of IP infusion, or AE for which causality assessment is missing or indeterminate. SAE: untoward medical occurrence that at any dose meets one or more of following criteria: outcome is fatal/results in death, is life-threatening, requires inpatient hospitalization or results in prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, is a medically important event, thromboembolic events, hemolytic anemia. Nonserious AE is AE that does not meet the criteria. Infusion per event = number of events / total number of infusions administered (started) to participants in analysis set. Participants can have more than one AR/suspected AR associated with infusion.

Epoch 1 safety analysis set included all participants who received any study treatment. Participants can have more than one AR/suspected AR associated with infusion.

A treatment-emergent adverse event (TEAE) is defined as any event not present prior to the initiation of the treatments or any event already present that worsens in either intensity or frequency following exposure to the treatments. Participants can have more than one TEAE associated with infusion.

Epoch 1 safety analysis set included all participants who received any study treatment. Participants can have more than one TEAE associated with infusion.

AE=any untoward medical occurrence in participant administered an IP that does not have causal relationship with treatment. AE can be any unfavorable and unintended sign (e.g., abnormal laboratory finding), symptom (e.g., rash, pain, discomfort, fever, dizziness, etc.), disease (e.g., peritonitis, bacteremia, etc.), or outcome of death temporally associated with the use of an IP, whether or not considered causally related to the IP. Adverse reaction/suspected adverse reaction=AE that is considered by the investigator to be possibly or probably related to IP administration, or for which the causality is indeterminate or missing, or that begins during infusion of IP or within 72 hours following the end of IP infusion. Treatment-emergent adverse events (TEAEs) are defined as adverse events that occurred during or after administration of the first dose of IP. Infusion site adverse events and injection site adverse events refer to the same type of adverse events.

Epoch 1 safety analysis set included all participants who received any study treatment.

Epoch 1 safety analysis set included all participants who received any study treatment.

An AE is defined as any untoward medical occurrence in participant administered an IP that does not necessarily have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (eg, an abnormal laboratory finding), symptom (eg, rash, pain, discomfort, fever, dizziness, etc.), disease (eg, peritonitis, bacteremia, etc.), or outcome of death temporally associated with the use of an IP, whether or not considered causally related to the IP. Data for number of events per infusion is assessed at the group level as follows: Per infusion = number of events / total number of infusions administered (started) to participants in the analysis set.

Epoch 1 safety analysis set included all participants who received any study treatment.

An AE is defined as any untoward medical occurrence in participant administered an IP that does not necessarily have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (eg, an abnormal laboratory finding), symptom (eg, rash, pain, discomfort, fever, dizziness, etc.), disease (eg, peritonitis, bacteremia, etc.), or outcome of death temporally associated with the use of an IP, whether or not considered causally related to the IP. Data is reported for number of events per participant which is assessed at the group level as follows: AE per participant = number of AEs/ total number of participants in the safety analysis set.

Epoch 1 safety analysis set included all participants who received any study treatment.

An AE is defined as any untoward medical occurrence in participant administered an IP that does not necessarily have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (eg, an abnormal laboratory finding), symptom (eg, rash, pain, discomfort, fever, dizziness, etc.), disease (eg, peritonitis, bacteremia, etc.), or outcome of death temporally associated with the use of an IP, whether or not considered causally related to the IP. Data for number of events per 1000 participant-years is assessed as follows: Per 1000 participant-years = 1000 x (number of events / total number of days of exposure, i.e., the sum of duration of treatment for all participants in the safety analysis set, divided by 365.25)

Epoch 1 safety analysis set included all participants who received any study treatment.

An AE is defined as any untoward medical occurrence in participant administered an IP that does not necessarily have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (eg, an abnormal laboratory finding), symptom (eg, rash, pain, discomfort, fever, dizziness, etc.), disease (eg, peritonitis, bacteremia, etc.), or outcome of death temporally associated with the use of an IP, whether or not considered causally related to the IP. An AE that is recorded by the investigator as possibly related or probably related to IP was considered a related AE, and any AE recorded as unlikely related or not related was considered unrelated AE. Data for number of events per infusion is assessed at the group level as follows: Per infusion = number of events / total number of infusions administered (started) to participants in the analysis set.

Epoch 1 safety analysis set included all participants who received any study treatment.

An AE is defined as any untoward medical occurrence in participant administered an IP that does not necessarily have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (eg, an abnormal laboratory finding), symptom (eg, rash, pain, discomfort, fever, dizziness, etc.), disease (eg, peritonitis, bacteremia, etc.), or outcome of death temporally associated with the use of an IP, whether or not considered causally related to the IP. An AE that is recorded by the investigator as possibly related or probably related to IP was considered a related AE, and any AE recorded as unlikely related or not related was considered unrelated AE. Data is reported for number of events per participant which is assessed at the group level as follows: AE per participant = number of AEs/ total number of participants in the safety analysis set.

Epoch 1 safety analysis set included all participants who received any study treatment.

An AE is defined as any untoward medical occurrence in participant administered an IP that does not necessarily have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (eg, an abnormal laboratory finding), symptom (eg, rash, pain, discomfort, fever, dizziness, etc.), disease (eg, peritonitis, bacteremia, etc.), or outcome of death temporally associated with the use of an IP, whether or not considered causally related to the IP. An AE that is recorded by the investigator as possibly related or probably related to IP was considered a related AE, and any AE recorded as unlikely related or not related was considered unrelated AE.

Epoch 1 safety analysis set included all participants who received any study treatment.

An AR plus suspected AR is any AE that meets any of the following criteria: an AE considered by either the investigator and/or the sponsor to be possibly or probably related to IP administration, or that begins during infusion of IP or within 72 h following the end of IP infusion, or AE for which causality assessment is missing or indeterminate. Data for number of events per infusion is assessed at the group level as follows: Per infusion = number of events / total number of infusions administered (started) to participants in the analysis set.

Epoch 1 safety analysis set included all participants who received any study treatment.

An AR plus suspected AR is any AE that meets any of the following criteria: an AE considered by either the investigator and/or the sponsor to be possibly or probably related to IP administration, or that begins during infusion of IP or within 72 h following the end of IP infusion, or AE for which causality assessment is missing or indeterminate. Data is reported for number of events per participant which is assessed at the group level as follows: AE per participant = number of AEs/ total number of participants in the safety analysis set.

Epoch 1 safety analysis set included all participants who received any study treatment.

An AR plus suspected AR is any AE that meets any of the following criteria: an AE considered by either the investigator and/or the sponsor to be possibly or probably related to IP administration, or that begins during infusion of IP or within 72 h following the end of IP infusion, or AE for which causality assessment is missing or indeterminate. Data for number of events per 1000 participant-years is assessed as follows: Per 1000 participant-years = 1000 x (number of events / total number of days of exposure, i.e., the sum of duration of treatment for all participants in the safety analysis set, divided by 365.25)

Epoch 1 safety analysis set included all participants who received any study treatment.

Number of participants who developed binding and/or neutralizing antibodies to rHuPH20 in Epoch 1 were reported. High-binding antibodies is defined as number of participants who had at least one anti-rHuPH20 antibody titer ≥1:160 during treatment.

Epoch 1 safety analysis set included all participants who received any study treatment.

Number of participants experiencing any treatment-emergent serious and/or non-serious adverse events regardless of causality in Epoch 2 was reported.

Epoch 2 safety analysis set included all participants who had a relapse in Epoch 1, entered Epoch 2, and received IGIV treatment with either GGL/KIOVIG or GAMUNEX-C.

AE: any untoward medical occurrence in participant administered IP. AE can therefore be any unfavorable and unintended sign (e.g., abnormal laboratory finding), symptom (e.g., rash, pain, discomfort, fever, dizziness, etc.), disease (e.g., peritonitis, bacteremia, etc.), outcome of death temporally associated with use of IP, whether or not considered causally related to the IP. SAE: untoward medical occurrence that at any dose meets following criteria: outcome is fatal/results in death, is life-threatening, requires inpatient hospitalization/results in prolongation of an existing hospitalization, results in persistent or significant disability/incapacity, is congenital anomaly/birth defect, is medically important event, (e.g., thromboembolic events, hemolytic anemia). Non-SAE:AE not meeting this criteria. AE recorded by investigator as possibly/probably related to IP is considered related AE, any AE recorded as unlikely/not related is considered unrelated AE.

Epoch 2 safety analysis set included all participants who had a relapse in Epoch 1, entered Epoch 2, and received IGIV treatment with either GGL/KIOVIG or GAMUNEX-C.

An adverse reaction/suspected adverse reaction is defined as an Adverse Event that is considered by the investigator to be possibly or probably related to IP administration, or for which the causality is indeterminate or missing, or that begins during infusion of IP or within 72 hours following the end of IP infusion.

Epoch 2 safety analysis set included all participants who had a relapse in Epoch 1, entered Epoch 2, and received IGIV treatment with either GGL/KIOVIG or GAMUNEX-C.

A SAE is defined as an untoward medical occurrence that at any dose meets one or more of the following criteria: outcome is fatal/results in death, is life-threatening, requires inpatient hospitalization or results in prolongation of an existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, is a medically important event, thromboembolic events, hemolytic anemia. A nonserious AE is an AE that does not meet the criteria. An AR plus suspected AR is any AE that meets any of the following criteria: an AE considered by either the investigator and/or the sponsor to be possibly or probably related to IP administration, or that begins during infusion of IP or within 72 h following the end of IP infusion, or AE for which causality assessment is missing or indeterminate. Participants can have more than one adverse event.

Epoch 2 safety analysis set included all participants who had a relapse in Epoch 1, entered Epoch 2, and received IGIV treatment with either GGL/KIOVIG or GAMUNEX-C. Participants can have more than one adverse event.

AE: any untoward medical occurrence in participant administered IP. AE can therefore be any unfavorable and unintended sign (e.g., abnormal laboratory finding), symptom (e.g., rash, pain, discomfort, fever, dizziness, etc.), disease (e.g., peritonitis, bacteremia, etc.), outcome of death temporally associated with use of IP, whether or not considered causally related to the IP. SAE: untoward medical occurrence that at any dose meets following criteria: outcome is fatal/results in death, is life-threatening, requires inpatient hospitalization/results in prolongation of an existing hospitalization, results in persistent or significant disability/incapacity, is congenital anomaly/birth defect, is medically important event, (e.g., thromboembolic events, hemolytic anemia). Non-SAE:AE not meeting this criteria. AE recorded by investigator as possibly/probably related to IP is considered related AE, any AE recorded as unlikely/not related is considered unrelated AE.

Epoch 2 safety analysis set included all participants who had a relapse in Epoch 1, entered Epoch 2, and received IGIV treatment with either GGL/KIOVIG or GAMUNEX-C. Participants can have more than one adverse event.

AEs occurring during an infusion or within 72 hours after completion of an infusion. An AE is defined as any untoward medical occurrence in participant administered an IP that does not necessarily have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (eg, an abnormal laboratory finding), symptom (eg, rash, pain, discomfort, fever, dizziness, etc.), disease (eg, peritonitis, bacteremia, etc.), or outcome of death temporally associated with the use of an IP, whether or not considered causally related to the IP. Participants can have more than one adverse event.

Epoch 2 safety analysis set included all participants who had a relapse in Epoch 1, entered Epoch 2, and received IGIV treatment with either GGL/KIOVIG or GAMUNEX-C. Participants can have more than one adverse event.

A SAE is defined as an untoward medical occurrence that at any dose meets one or more of the following criteria: outcome is fatal/results in death, is life-threatening, requires inpatient hospitalization or results in prolongation of an existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, is a medically important event, thromboembolic events, hemolytic anemia. A nonserious AE is an AE that does not meet the criteria. An AR plus suspected AR is any AE that meets any of the following criteria: an AE considered by either the investigator and/or the sponsor to be possibly or probably related to IP administration, or that begins during infusion of IP or within 72 h following the end of IP infusion, or AE for which causality assessment is missing or indeterminate. Participants can have more than one AR/SAR.

Epoch 2 safety analysis set included all participants who had a relapse in Epoch 1, entered Epoch 2, and received IGIV treatment with either GGL/KIOVIG or GAMUNEX-C. Participants can have more than one AR/SAR.

A treatment-emergent adverse event (TEAE) is defined as any event not present prior to the initiation of the treatments or any event already present that worsens in either intensity or frequency following exposure to the treatments. Participants can have more than one treatment-emergent systemic AEs.

Epoch 2 safety analysis set included all participants who had a relapse in Epoch 1, entered Epoch 2, and received IGIV treatment with either GGL/KIOVIG or GAMUNEX-C. Participants can have more than one treatment-emergent systemic AEs.

AE=any untoward medical occurrence in participant administered an IP that does not have causal relationship with treatment. AE can be any unfavorable and unintended sign (e.g., abnormal laboratory finding), symptom (e.g., rash, pain, discomfort, fever, dizziness, etc.), disease (e.g., peritonitis, bacteremia, etc.), or outcome of death temporally associated with the use of an IP, whether or not considered causally related to the IP. Adverse reaction/suspected adverse reaction=AE that is considered by the investigator to be possibly or probably related to IP administration, or for which the causality is indeterminate or missing, or that begins during infusion of IP or within 72 hours following the end of IP infusion. TEAEs are defined as adverse events that occurred during or after administration of the first dose of IP. Infusion site adverse events and injection site adverse events refer to the same type of adverse events.

Epoch 2 safety analysis set included all participants who had a relapse in Epoch 1, entered Epoch 2, and received IGIV treatment with either GGL/KIOVIG or GAMUNEX-C.

An AE is defined as any untoward medical occurrence in participant administered an IP that does not necessarily have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (eg, an abnormal laboratory finding), symptom (eg, rash, pain, discomfort, fever, dizziness, etc.), disease (eg, peritonitis, bacteremia, etc.), or outcome of death temporally associated with the use of an IP, whether or not considered causally related to the IP.

Epoch 2 IGIV Analysis Set included participants who relapsed in Epoch 1 and received at least one dose of IGIV treatment (GGL/KIOVIG or GAMMUNEX-C).

An AE is defined as any untoward medical occurrence in participant administered an IP that does not necessarily have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (eg, an abnormal laboratory finding), symptom (eg, rash, pain, discomfort, fever, dizziness, etc.), disease (eg, peritonitis, bacteremia, etc.), or outcome of death temporally associated with the use of an IP, whether or not considered causally related to the IP. Data for number of events per infusion is assessed at the group level as follows: Per infusion = number of events / total number of infusions administered (started) to participants in the analysis set

Epoch 2 safety analysis set included all participants who had a relapse in Epoch 1, entered Epoch 2, and received IGIV treatment with either GGL/KIOVIG or GAMUNEX-C.

An AE is defined as any untoward medical occurrence in participant administered an IP that does not necessarily have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (eg, an abnormal laboratory finding), symptom (eg, rash, pain, discomfort, fever, dizziness, etc.), disease (eg, peritonitis, bacteremia, etc.), or outcome of death temporally associated with the use of an IP, whether or not considered causally related to the IP. Data is reported for number of events per participant which is assessed at the group level as follows: AE per participant = number of AEs/ total number of participants in the safety analysis set.

Epoch 2 safety analysis set included all participants who had a relapse in Epoch 1, entered Epoch 2, and received IGIV treatment with either GGL/KIOVIG or GAMUNEX-C.

An AE is defined as any untoward medical occurrence in participant administered an IP that does not necessarily have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (eg, an abnormal laboratory finding), symptom (eg, rash, pain, discomfort, fever, dizziness, etc.), disease (eg, peritonitis, bacteremia, etc.), or outcome of death temporally associated with the use of an IP, whether or not considered causally related to the IP.

Epoch 2 safety analysis set included all participants who had a relapse in Epoch 1, entered Epoch 2, and received IGIV treatment with either GGL/KIOVIG or GAMUNEX-C.

An AE is defined as any untoward medical occurrence in participant administered an IP that does not necessarily have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (eg, an abnormal laboratory finding), symptom (eg, rash, pain, discomfort, fever, dizziness, etc.), disease (eg, peritonitis, bacteremia, etc.), or outcome of death temporally associated with the use of an IP, whether or not considered causally related to the IP. An AE that is recorded by the investigator as possibly related or probably related to IP was considered a related AE, and any AE recorded as unlikely related or not related was considered unrelated AE. Data for number of events per infusion is assessed at the group level as follows: Per infusion = number of events / total number of infusions administered (started) to participants in the analysis set

Epoch 2 safety analysis set included all participants who had a relapse in Epoch 1, entered Epoch 2, and received IGIV treatment with either GGL/KIOVIG or GAMUNEX-C.

An AE is defined as any untoward medical occurrence in participant administered an IP that does not necessarily have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (eg, an abnormal laboratory finding), symptom (eg, rash, pain, discomfort, fever, dizziness, etc.), disease (eg, peritonitis, bacteremia, etc.), or outcome of death temporally associated with the use of an IP, whether or not considered causally related to the IP. An AE that is recorded by the investigator as possibly related or probably related to IP was considered a related AE, and any AE recorded as unlikely related or not related was considered unrelated AE. Data is reported for number of events per participant which is assessed at the group level as follows: AE per participant = number of AEs/ total number of participants in the safety analysis set.

Epoch 2 safety analysis set included all participants who had a relapse in Epoch 1, entered Epoch 2, and received IGIV treatment with either GGL/KIOVIG or GAMUNEX-C.

An AE is defined as any untoward medical occurrence in participant administered an IP that does not necessarily have a causal relationship with the treatment. An AE can therefore be any unfavorable and unintended sign (eg, an abnormal laboratory finding), symptom (eg, rash, pain, discomfort, fever, dizziness, etc.), disease (eg, peritonitis, bacteremia, etc.), or outcome of death temporally associated with the use of an IP, whether or not considered causally related to the IP. An AE that is recorded by the investigator as possibly related or probably related to IP was considered a related AE, and any AE recorded as unlikely related or not related was considered unrelated AE.

Epoch 2 safety analysis set included all participants who had a relapse in Epoch 1, entered Epoch 2, and received IGIV treatment with either GGL/KIOVIG or GAMUNEX-C.

An AR plus suspected AR is any AE that meets any of the following criteria: an AE considered by either the investigator and/or the sponsor to be possibly or probably related to IP administration, or that begins during infusion of IP or within 72 h following the end of IP infusion, or AE for which causality assessment is missing or indeterminate. Data for number of events per infusion is assessed at the group level as follows: Per infusion = number of events / total number of infusions administered (started) to participants in the analysis set.

Epoch 2 safety analysis set included all participants who had a relapse in Epoch 1, entered Epoch 2, and received IGIV treatment with either GGL/KIOVIG or GAMUNEX-C.

An AR plus suspected AR is any AE that meets any of the following criteria: an AE considered by either the investigator and/or the sponsor to be possibly or probably related to IP administration, or that begins during infusion of IP or within 72 h following the end of IP infusion, or AE for which causality assessment is missing or indeterminate. Data is reported for number of events per participant which is assessed at the group level as follows: AE per participant = number of AEs/ total number of participants in the safety analysis set.

Epoch 2 safety analysis set included all participants who had a relapse in Epoch 1, entered Epoch 2, and received IGIV treatment with either GGL/KIOVIG or GAMUNEX-C.

An AR plus suspected AR is any AE that meets any of the following criteria: an AE considered by either the investigator and/or the sponsor to be possibly or probably related to IP administration, or that begins during infusion of IP or within 72 h following the end of IP infusion, or AE for which causality assessment is missing or indeterminate. Data for number of events per 1000 participant-years is assessed as follows: Per 1000 participant-years = 1000 x (number of events / total number of days of exposure, i.e., the sum of duration of treatment for all participants in the safety analysis set, divided by 365.25)

Epoch 2 safety analysis set included all participants who had a relapse in Epoch 1, entered Epoch 2, and received IGIV treatment with either GGL/KIOVIG or GAMUNEX-C.

Defined as one or more of the following: a decrease of >=1 point in the adjusted Inflammatory Neuropathy Cause and Treatment disability scale (INCAT) score at 2 consecutive time points; who experience CIDP improvement (defined as ≥8 kilo Pascal (kPa) increase in hand grip strength in the more affected hand; >=4 points increase in Rasch-built Overall Disability Scale (R-ODS)) at the completion of the intravenous (IV) treatment period [6 months] or at the last study visit of the IV treatment period, relative to the pre-IV treatment baseline score.

Epoch 2 IGIV Analysis Set included participants who relapsed in Epoch 1 and received at least one dose of IGIV treatment (GGL/KIOVIG or GAMMUNEX-C)