一项评估 ABC008 治疗包涵体肌炎疗效和安全性的研究

有源比较器：0.5 mg/kg ABC008

Part A - ABC008 N=12

Part B - ABC008 N= 67

药品：ABC008

Given by subcutaneous injection

有源比较器：2.0 mg/kg ABC008

Part A - ABC008 N=12

Part B - ABC008 N= 67

药品：ABC008

Given by subcutaneous injection

安慰剂比较：Placebo

Part A - Placebo N= 6

Part B - Placebo N= 67

药品：ABC008

Given by subcutaneous injection

Part A: Number of Participants With Treatment Emergent Adverse Events (TEAEs)

An adverse event (AE) was defined as any untoward medical occurrence in any participant participating in a clinical investigation, regardless of the suspected cause. An AE was therefore any unfavorable and unintended sign, symptom, disease, concurrent illness, or clinically significant abnormal laboratory finding that emerged or worsened during the study. A TEAE was defined as an AE that first occurred or worsened after initiation of study drug.

Part A: Number of Participants With TEAEs by Severity

A TEAE was defined as an AE that first occurred or worsened after initiation of study drug and was graded by severity per protocol-specified Common Terminology Criteria for Adverse Events (CTCAE) criteria: Grade 1, Mild (asymptomatic or mild symptoms; clinical or diagnostic observations only; intervention not indicated); Grade 2, Moderate (minimal, local, or noninvasive intervention indicated; limited age-appropriate instrumental activities of daily living (ADL)); Grade 3, Severe or medically significant (medically significant but not immediately life-threatening; hospitalization or prolongation of hospitalization indicated; disabling; or limiting self-care ADL); Grade 4, Life-threatening (threatening consequences; urgent intervention indicated); and Grade 5, Death (death related to an AE).

Part A: Number of Participants With TEAEs Related to Study Drug

An AE was defined as any untoward medical occurrence in any participant participating in a clinical investigation, regardless of the suspected cause. An AE was therefore can be any unfavorable and unintended sign, symptom, disease, concurrent illness, or clinically significant abnormal laboratory finding that emerged or worsened during the study. A TEAE was defined as an AE that first occurred or worsened after initiation of study drug. An AE with missing relationship to study drug was considered as related to study drug.

Part A: Mean Change From Baseline in the Inclusion Body Myositis Functional Rating Scale (IBMFRS) Total Score at Week 76

The IBMFRS was used as an ordinal rating scale to determine participant's assessments of their capabilities. It included 10 measures (swallowing, handwriting, cutting food and handling utensils, fine motor tasks, dressing, hygiene, turning in bed and adjusting covers, changing position from sitting to standing, walking, and climbing stairs) graded on a Likert scale (a psychometric tool) from 0 (being unable to perform) to 4 (normal). The sum of the 10 items provided a value between 0 and 40, with a higher score representing less functional limitation or better functional status. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part B: Number of Participants With TEAEs

An AE was defined as any untoward medical occurrence in any participant participating in a clinical investigation, regardless of the suspected cause. An AE was therefore can be any unfavorable and unintended sign, symptom, disease, concurrent illness, or clinically significant abnormal laboratory finding that emerged or worsened during the study. A TEAE was defined as an AE that first occurred or worsened after initiation of study drug.

Part B: Number of Participants With TEAEs by Severity

A TEAE was defined as an AE that first occurred or worsened after initiation of study drug and was graded by severity per protocol-specified CTCAE criteria: Grade 1, Mild (asymptomatic or mild symptoms; clinical or diagnostic observations only; intervention not indicated); Grade 2, Moderate (minimal, local, or noninvasive intervention indicated; limited age-appropriate instrumental ADL); Grade 3, Severe or medically significant (medically significant but not immediately life-threatening; hospitalization or prolongation of hospitalization indicated; disabling; or limiting self-care ADL); Grade 4, Life-threatening (threatening consequences; urgent intervention indicated); and Grade 5, Death (death related to an AE).

Part B: Number of Participants With TEAEs Related to Study Drug

An AE was defined as any untoward medical occurrence in any participant participating in a clinical investigation, regardless of the suspected cause. An AE was therefore can be any unfavorable and unintended sign, symptom, disease, concurrent illness, or clinically significant abnormal laboratory finding that emerged or worsened during the study. A TEAE was defined as an AE that first occurred or worsened after initiation of study drug. An AE with missing relationship to study drug was considered as related to study drug.

Part B: Mean Change From Baseline in the IBMFRS Total Score at Week 76

The IBMFRS was used as an ordinal rating scale to determine participant's assessments of their capabilities. It included 10 measures (swallowing, handwriting, cutting food and handling utensils, fine motor tasks, dressing, hygiene, turning in bed and adjusting covers, changing position from sitting to standing, walking, and climbing stairs) graded on a Likert scale (a psychometric tool) from 0 (being unable to perform) to 4 (normal). The sum of the 10 items provided a value between 0 and 40, with a higher score representing less functional limitation or better functional status. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part C: Time to PD Recovery

Recovery was defined as the return of KLRG1+ cell counts toward baseline levels during the PD follow-up period.

Part A and B: Number of Participants With Treatment-emergent Serious Adverse Events (TESAEs)

A TESAE was defined as a serious AE that first occurred or worsened after initiation of study drug and met seriousness criteria per protocol (including death, life-threatening event, hospitalization or prolongation of hospitalization, persistent or significant disability/incapacity, congenital anomaly, or other medically important event).

Part A and B: Number of Participants With TEAEs With Onset Within 24 Hours From the Start of Any Study Medication Administration

A TEAE was defined as an AE that first occurred or worsened after initiation of study drug, with onset assessed within 24 hours following the dosing.

Part A and B: Number of Participants With TEAEs Leading to Study Discontinuation

A TEAE was defined as an AE that first occurred or worsened after initiation of study drug that led to discontinuation of study.

Part A and B: Change From Baseline in Hematology Parameters - Absolute Neutrophil Count, Basophils, Eosinophils, Leukocytes, Lymphocytes, Monocytes, Neutrophils, and Platelets

Blood samples were collected for the analysis of hematology parameters: Absolute Neutrophil Count, Basophils, Eosinophils, Leukocytes, Lymphocytes, Monocytes, Neutrophils, and Platelets. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Change From Baseline in Hematology Parameter - Erythrocytes

Blood samples were collected for the analysis of hematology parameter Erythrocytes. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Change From Baseline in Hematology Parameters - Hemoglobin and Erythrocyte Mean Corpuscular Hemoglobin Concentration

Blood samples were collected for the analysis of hematology parameters: Hemoglobin and Erythrocyte Mean Corpuscular Hemoglobin Concentration. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Change From Baseline in Hematology Parameter - Erythrocyte Mean Corpuscular Hemoglobin

Blood samples were collected for the analysis of hematology parameters: Hemoglobin and Erythrocyte Mean Corpuscular Hemoglobin. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Change From Baseline in Hematology Parameters - Erythrocyte Mean Corpuscular Volume

Blood samples were collected for the analysis of hematology parameter Erythrocyte Mean Corpuscular Volume. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Change From Baseline in Hematology Parameters - Hematocrit

Blood samples were collected for the analysis of hematology parameter Hematocrit. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Change From Baseline in Blood Chemistry Parameters - Alanine Aminotransferase (ALT), Aldolase, Gamma Glutamyl Transferase (GGT), Lactate Dehydrogenase, Aspartate Aminotransferase (AST)

Blood samples were collected for the analysis of blood chemistry parameters: ALT, Aldolase, AST, GGT and Lactate Dehydrogenase. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Change From Baseline in Blood Chemistry Parameters - Albumin and Protein

Blood samples were collected for the analysis of blood chemistry parameters Albumin and Protein. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Change From Baseline in Blood Chemistry Parameters - Alkaline Phosphatase and Creatine Kinase (CK)

Blood samples were collected for the analysis of blood chemistry parameters Alkaline Phosphatase and CK. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Change From Baseline in Blood Chemistry Parameters - Bicarbonate, Calcium, Chloride, Glucose, Potassium, Sodium and Urea

Blood samples were collected for the analysis of blood chemistry parameters: Bicarbonate, Calcium, Chloride, Glucose, Potassium, and Urea. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Change From Baseline in Blood Chemistry Parameters - Bilirubin, Creatinine and Urate

Blood samples were collected for the analysis of blood chemistry parameters: Bilirubin, Creatinine, and Urate. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Change From Baseline in Urinalysis Parameter - pH

Urine samples were collected for the analysis of Urinalysis parameter: pH. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Change From Baseline in Urinalysis Parameter- Specific Gravity

Urine samples were collected for the analysis of Urinalysis parameters- specific gravity. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Change From Baseline in Complement Parameters - C3 and C4

Blood samples were collected for the analysis of complement parameters included C3 and C4. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Change From Baseline in Complement Parameters - Hemolytic Complement Filtration (CH50)

Blood samples were collected for the analysis of complement parameter- hemolytic complement filtration (CH50). Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Change From Baseline in C Reactive Protein (CRP)

Blood samples were collected for the analysis of blood chemistry parameter- CRP. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Number of Participants With Clinically Significant Changes in Vital Signs

Vital signs were planned to be measured after 5 minutes of rest and taken in the same position throughout the study. Vital signs included blood pressure, pulse, temperature, and respiration rate. Clinically significant changes in vital signs were defined according to protocol-specified criteria for abnormal values (or clinically significant worsening from baseline) as determined by the Investigator.

Part A and B: Change From Baseline in Electrocardiogram (ECG) Mean Heart Rate

Triplicate 12-lead ECG was recorded with the participant in a supine position for at least 5 minutes. Changes in ECG parameters were defined according to protocol-specified criteria for change from baseline values as determined by the Investigator. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-baseline visits minus the Baseline.

Part A and B: Change From Baseline in ECG Parameters: PR Interval, QRS Duration, QT Interval and Interval Corrected Using Fridericia's Formula (QTcF) Interval

Triplicate 12-lead ECG was recorded with the participant in a supine position for at least 5 minutes. Changes in ECG parameters were defined according to protocol-specified criteria for change from baseline values as determined by the Investigator. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Number of Participants With Treatment-emergent Adverse Events of Special Interest (AESI)

An AE was defined as any untoward medical occurrence in any participant partaking in a clinical investigation, regardless of the suspected cause. An AE was therefore can be any unfavorable and unintended sign, symptom, disease, concurrent illness, or clinically significant abnormal laboratory finding that emerged or worsened during the study. AESIs included injection site reactions, systemic injection reactions (e.g., hypersensitivity, systemic inflammatory response), and infection.

Part A and B: Mean Change From Baseline in the Manual Muscle Testing - 12 (MMT-12) Score at Week 76

Manual Muscle Testing - 12 assessed the muscle strength across the muscle groups that included neck flexion and both right and left shoulder abduction, elbow flexion, elbow extension, wrist extension, wrist flexion, flexor pollicis longus, hip flexors, hip abduction, hip extension, knee extension, and ankle dorsiflexion. Scores were calculated by summing the outcomes, with the Investigator providing the score, on a scale of 0 (no contraction) to 5 (normal strength), which is then converted by a standard procedure to a Kendall score equivalent on a scale of 0 to 10. Individual scores are summed to generate a total score ranging from 0 to 60. A higher score reflects better muscle strength. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Mean Change From Baseline in the Hand Grip Strength Score by Dynamometry at Week 76

Grip strength was assessed using a handheld dynamometer which provided a precise measurement of the force that a muscle can exert and reflects muscle strength of the hand. Positive values indicated increased grip strength and negative values indicated decreased grip strength. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Mean Change From Baseline in the Quadriceps Strength Score by Dynamometry at Week 76

Quadriceps strength was measured using a dynamometer which provided the applied force of leg extension and reflects muscle strength of the dominant leg. Positive values indicated increased strength and negative values indicated decreased strength. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.

Part A and B: Mean Change From Baseline in Modified Timed Up and Go Test (mTUG) at Week 76

The mTUG assessed functional mobility by measuring the time required for a participant to rise from a standard armchair, walk 3 meters, turn around, walk back to the chair, and sit down (assistive devices permitted after standing, but no support from a caregiver, or a wall). Negative values indicated faster performance and positive values indicated slower performance. Baseline value was defined as the last non-missing valid value prior to first administration of study treatment (on Day 1). Change from Baseline was calculated as the data collected at post-randomization visits minus the Baseline.