A Study of TAK-771 in Japanese Participants With Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP) and Multifocal Motor Neuropathy (MMN)

TEAEs were defined as adverse events that occurred during or after administration of the first dose of investigational product (IP). TEAEs caused in Epoch 1 were defined as AEs that occurred on or after the start of study drug administration, and before the first dose of IP in Epoch 2 (6 months). TEAEs caused in Epoch 2 (6 months) were defined as AEs that began during or after administration of the first dose of IP in Epoch 2 (6 months).

SAEs were defined as any untoward clinical manifestation of signs, symptoms, outcomes (related to IP or not) at any dose: resulted in death, was life-threatening, required inpatient/prolongation of hospitalization, resulted in persistent/significant disability/incapacity, congenital abnormality/birth defect, or any other important medical event.

Related SAES and TEAEs: that followed a reasonable temporal sequence from administration of a drug (including the course after withdrawal of the drug), or for which possible involvement of the drug cannot be ruled out, although factors other than the drug, such as underlying diseases, complications, concomitant medications and concurrent treatments, may also be responsible.

Adverse reactions plus suspected ARs were defined as TEAEs that were considered by the investigator to be related to IP administration, or for which the causality was indeterminate or missing, or that began during infusion of IP or within 72 hours following the end of IP infusion.

Infusion associated SAEs and/or TEAEs were defined as SAEs and/or TEAEs considered to be "infusion-related reactions" by investigators.

Related SAES and TEAEs: that followed a reasonable temporal sequence from administration of a drug (including the course after withdrawal of the drug), or for which possible involvement of the drug cannot be ruled out, although factors other than the drug, such as underlying diseases, complications, concomitant medications and concurrent treatments, may also be responsible. SAEs and TEAEs associated with infusions were the events considered to be "infusion-related reactions" by investigators.

TEAEs were defined as adverse events that occurred during or after administration of the first dose of IP. TEAEs caused in Epoch 1 were defined as AEs that occurred on or after the start of study drug administration, and before the first dose of IP in Epoch 2 (6 months). TEAEs caused in Epoch 2 (6 months) were defined as AEs that began during or after administration of the first dose of IP in Epoch 2 (6 months). TEAEs temporally associated with infusions defined as AEs occurring during or within 72 hours after completion of an infusion.

Adverse reactions plus suspected ARs were defined as TEAEs that were considered by the investigator to be related to IP administration, or for which the causality was indeterminate or missing, or that began during infusion of IP or within 72 hours following the end of IP infusion. AEs temporally associated with infusions are defined as AEs occurring during or within 72 hours after completion of an infusion.

Any TEAEs other than local TEAEs were considered a systemic TEAE. Infusion associated TEAEs were defined as TEAE considered to be "infusion-related reactions" by investigators.

Any reaction with the medical dictionary for regulatory activities (MedDRA) high-level group term (HLGT) of "Administration site reactions" were considered a local infusion site reaction (local TEAE). In addition, any TEAE with Injection Site Reaction Flag = "Yes" was considered a local TEAE. Infusion associated reaction were defined as event considered to be "infusion-related reactions" by investigators.

Number of infusions for which the infusion rate was reduced and/or the infusion was interrupted or stopped due to intolerability and/or AEs were reported.

Plasma samples for the detection of anti-rHuPH20 binding and neutralizing antibodies were collected. Participants were monitored for the formation of anti-rHuPH20 antibodies using validated anti-rHuPH20 antibody detection assay (also known as the Screening and Confirmatory Binding Assay). Positive antibodies were defined as participants who had anti rHuPH20 antibody titer greater than or equal to (>=) 1:160 at least one time during treatment.

Clinical Worsening of CIDP was defined as a >=8 kPa decrease in hand grip strength in the more affected hand OR >=4 points decrease in Rasch Built Overall Disability Scale (R-ODS) relative to the pre-SC treatment baseline score at 2 consecutive time points. Hand grip strength was measured using the Martin vigorimeter by quantifying air pressure. The R-ODS was a participant self-reported, linearly-weighted overall disability scale that was specifically designed to capture activity and social participation limitations in participants with immune-mediated peripheral neuropathies including CIDP. R-ODS was comprised of 24 items that rate participant's functioning related to a variety of everyday tasks at moment of completion on a scale of 0 to 2 (where 0 indicates it is not possible for the respondent to perform the task and 2 means that task can be performed without difficulty). Total scores range from 0 to 48 and higher scores indicate greater ability to perform daily and social tasks.

Time to relapse was defined as time from the date of the first SC administration of TAK-771 in Epoch 1 or 2 to the date of relapse.

The R-ODS was a participant self-reported, linearly-weighted overall disability scale that was specifically designed to capture activity and social participation limitations in participants with immune-mediated peripheral neuropathies including CIDP. R-ODS was comprised of 24 items that rate participant's functioning related to a variety of everyday tasks at moment of completion on a scale of 0 to 2 (where 0 indicates it is not possible for the respondent to perform the task and 2 means that task can be performed without difficulty). Total scores range from 0 to 48 and higher scores indicate greater ability to perform daily and social tasks.

The Martin Vigorimeter was used to assess grip strength in both hands. The instrument consisted of a compressible rubber ball that was connected to a manometer. When the rubber ball was squeezed, the force of compression was measured in kPa ranging from 0 to 160 kPa. Average of grip strength was defined as an average of the two maximum values: maximum of the 3 measurements in the more affected hand and the maximum of the 3 measurements in the less affected hand.

The MRC sum score served as a measure of muscle strength. The following muscles on each side of the body were examined and the strength of each muscle was rated according to the MRC scale: deltoids, biceps, wrist extensors, iliopsoas, quadriceps, and anterior tibialis. The MRC scale ranged from 0 to 5, where: 0 = no visible contraction; 1 = visible contraction without movement of the limb; 2 = movement of the limb but not against gravity; 3 = movement against gravity over (almost) the full range; 4 = movement against gravity and resistance; and 5 = normal. All scores from both left and right side of the body were summed to obtain the total MRC sum score. The total MRC sum score ranged from 0 (paralysis) to 60 (normal strength) with higher score indication normal strength.

GNDS was a questionnaire which consisted of 12 separate categories (4 to 8 questions per category). The categories included: cognition, mood, vision, speech, swallowing, upper limb function, lower limb function, bladder function, bowel function, sexual function, fatigue, and others. In the current study, only 2 categories; upper limb function and the lower limb function was used for assessment of the disability of participants with MMN. The severity of each subscale (including upper limb and lower limb) was graded from 0 (normal function) to 5 (total loss of function) based according to severity and impact on the individual. The total GNDS score was the sum of the 12 separate scores ranging between 0 and 60 with higher scores indicating loss of function.