Safety Follow-up of Treatment With Remestemcel-L in Pediatric Participants Who Have Failed to Respond to Steroid Treatment for Acute GVHD

This is a safety follow-up study through 180 days of remestemcel-L treatment in participants who took part in MSB-GVHD001. This study will also explore duration of response over time. Participants who took part in in MSB-GVHD001 and received at least one dose of remestemcel-L as outlined in that protocol will be evaluated at baseline (Day 100) and at Days 120, 140, 160 and 180 for safety endpoints. Participants who took part in Protocol MSB-GVHD001 and received the first 8 doses of remestemcel-L as outlined in that protocol will be evaluated at baseline (Day 100) and at Days 120, 140, 160 and 180 after initial remestemcel-L infusion for evidence of duration of response over time.