A Study of MT-0551 in Patients With Systemic Sclerosis

Phase 3 Study of MT-0551 in Patients With Systemic Sclerosis (Placebo-Controlled Double-Blind Study)

The study will verify the superiority of MT-0551 to placebo at 26 weeks after treatment initiation in systemic sclerosis (SSc) patients using the modified Rodnan Total Skin thickness Score (mRTSS) as a measure of skin thickening. The safety and pharmacokinetics will also be investigated.

Study Overview

• Status: Active, not recruiting
• Conditions: Systemic Sclerosis
• Intervention / Treatment: Drug: Inebilizumab; Drug: Placebo

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Phase 3

Contacts and Locations

Study Locations

• Japan
  • Fukui
    • Yoshida-gun, Fukui, Japan, 910-1193
      • University of Fukui Hospital
  • Ishikawa-ken
    • Kanazawa, Ishikawa-ken, Japan, 920-8641
      • Kanazawa University Hospital
  • Kanagawa
    • Kawasaki-shi, Kanagawa, Japan, 216-8511
      • St. Marianna University Hospital
  • Tokyo
    • Bunkyo-ku, Tokyo, Japan, 113-8655
      • The University of Tokyo Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

Additional screening criteria check may apply for qualification:

1. ACR/European League Against Rheumatism (EULAR) criteria (2013) systemic sclerosis (SSc) diagnostic criteria satisfied.
2. Skin thickening score based on the mRTSS between 10 and 22 inclusive.

Exclusion Criteria:

Additional screening criteria check may apply for qualification:

1. Pulmonary hypertension associated with SSc.
2. Presence of a serious, SSc-related concurrent illness other than interstitial pneumonia.
3. Finding of inadequate respiratory reserve capacity.
4. Past history of rituximab, blinatumomab, obinutuzumab, or ofatumumab.
5. Presence of a clinically significant active infection requiring antimicrobial therapy.
6. A past history of cancer.
7. Past history of a recurrent, clinically significant infection.
8. Past history of severe allergy or anaphylactic reaction to a biologic drug product.
9. Treatment with live vaccine within a certain period (inactivated vaccine is acceptable).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: MT-0551 group; Participants will receive intravenous (IV) inebilizumab on Day 1 and Day 15 of randomized controlled period (RCP). The participants who entered open label period (OLP) will receive IV inebilizumab on Day 1 and IV placebo on Day 15 of OLP and will be followed by IV inebilizumab every 26 weeks.	Drug: Inebilizumab; Participants will receive IV inebilizumab.; Other Names: MT-0551; Drug: Placebo; Participants will receive IV placebo matched to inebilizumab.
Placebo Comparator: Placebo group; Participants will receive IV placebo on Day 1 and Day 15 of the RCP. The participants who entered OLP will receive IV inebilizumab on both Day 1 and Day 15 in OLP and will be followed by IV inebilizumab every 26 weeks.	Drug: Inebilizumab; Participants will receive IV inebilizumab.; Other Names: MT-0551; Drug: Placebo; Participants will receive IV placebo matched to inebilizumab.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Change from baseline in the mRTSS up to the end of the long-term extension period	baseline, RCP 4, 12, 26, OLP 4,12, 26, the long-term extension period 26, 52, 78, 104 weeks

Secondary Outcome Measures

Outcome Measure	Time Frame
Pulmonary function tests: Change from baseline in the percent predicted forced vital capacity (%FVC) and percent predicted diffusing capacity of the lung carbon monoxide (%DLco)	Baseline to at least 52 weeks or early termination
Pulmonary function tests: Percentage change from baseline in the %FVC and %DLco	Baseline to at least 52 weeks or early termination
Change from baseline in the mRTSS	Baseline to at least 52 weeks or early termination
Composite response index in diffuse cutaneous systemic sclerosis	Week 26 to at least 52 weeks or early termination

Collaborators and Investigators

• Sponsor: Tanabe Pharma Corporation
• Investigators: Study Director: General Manager, Tanabe Pharma Corporation

Study record dates

Study Major Dates

• Study Start (Actual): July 20, 2022
• Primary Completion (Actual): July 31, 2025
• Study Completion (Estimated): August 1, 2026

Study Registration Dates

• First Submitted: January 6, 2022
• First Submitted That Met QC Criteria: January 6, 2022
• First Posted (Actual): January 20, 2022

Study Record Updates

• Last Update Posted (Actual): December 8, 2025
• Last Update Submitted That Met QC Criteria: December 4, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Connective Tissue Diseases; Skin Diseases; Skin and Connective Tissue Diseases; Scleroderma, Systemic; Substandard Drugs; Pharmaceutical Preparations; inebilizumab
• Other Study ID Numbers: MT-0551-A-301

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes