EncompaSSc: Evaluation of MTX-474 in Participants With Diffuse Cutaneous Systemic Sclerosis (dcSSc)

Participants with dcSSc who meet the study's inclusion and exclusion criteria will be randomly assigned in a 3:2 ratio to receive MTX-474 or a matching placebo by intravenous (IV) infusion. Concomitant use of one of the approved dcSSc therapies (immunosuppressive therapy, systemic glucocorticoids or other antifibrotic agents) is permitted under certain criteria. Participants randomized to the MTX-474 arm of the study will receive an IV infusion every 4 weeks, beginning at Day 0 and ending at Week 20. The End of Treatment Visit will occur at Week 24, and a Safety Follow-Up Visit will occur at Week 28, 8 weeks after the final infusion. mRSS assessments will occur at Screening, Baseline, and at all subsequent treatment visits up to and including Week 24. Spirometry will be performed at screening and Weeks 12. HRCT will be performed at screening and week 24. DLCO will be performed at Screening. Skin biopsies will be performed at Baseline and Week 12. Participants will have blood drawn for safety assessment and to assess Ephrin receptor levels at Screening, Baseline and every 4 weeks until Week 28. Blood will be drawn for serum PK analyses relative to the first and last doses of MTX-474.