Rotator cuff tear is one of the most common shoulder diseases and conservative treatment is commonly used for tears involving ≤50% of tendon thickness. Since conventional conservative treatments are not fundamental to repair tendon tissue, there is a growing need of new therapy to improve structural outcome. This study assesses the safety and efficacy of allogeneic fibroblasts on partial-thickness rotator cuff tear. The primary outcome is change in Constant Score (CS) at 24 weeks after TPX-115 injection. Secondary outcomes include changes from baseline in CS, Visual Analogue Score (VAS) pain score, American Shoulder and Elbow Surgeons (ASES) score, Quick Disabilities of the Arm, Shoulder and Hand (Quick-DASH), Simple Shoulder Test (SST), and functional evaluations including Range of Motion (ROM) at 4, 12, 24 and 52 weeks after administration and structural evaluation using MRI at 24 and 52 weeks after injection.