A Study to Evaluate the Safety and Tolerability of Oral Ixazomib in Scleroderma-related Lung Disease Patients

Inclusion Criteria: * Male and female patients, age ≥18 years at time of signing informed written consent * Confirmed diagnosis of diffuse cutaneous systemic sclerosis/scleroderma * Disease duration not longer than 60 months defined as the time from the first non-Raynaud phenomenon manifestation * Scleroderma skin thickness score (modified Rodnan skin score) between 15 and 45 * Evidence of scleroderma-related lung involvement on chest CT scan completed within the preceding 3 months or at screening study visit * Pulmonary function testing demonstrating FVC ≥45% predicted and DLCO ≥40% predicted at screening study visit * Resting transthoracic echocardiogram within the preceding 6 months or at screening study visit without evidence of pulmonary artery hypertension * Stable mycophenolate dose during the preceding 3 months for those who are taking mycophenolate. Mycophenolate use is not an eligibility requirement to participate; but those participants already using mycophenolate at screening study visit will continue taking the medication throughout the entire study. * Willingness to undergo supervised withdrawal during the first 90 days of the study of any other medication besides mycophenolate used specifically as treatment of scleroderma-related interstitial lung disease with confirmed stable pulmonary status. * Willingness to undergo supervised withdrawal during the first 90 days of the study of any other prohibited medications with confirmed stable status. * Able to underst…