FDA approves remestemcel-L-rknd for steroid-refractory acute graft versus host disease in pediatric patients
Regulatory approval: On Dec 18, 2024, the FDA approved remestemcel-L-rknd (Ryoncil; Mesoblast), an allogeneic bone marrow–derived mesenchymal stromal cell (MSC) therapy, for steroid-refractory acute graft-versus-host disease (SR-aGVHD) in pediatric patients aged ≥2 months. Approval was supported by the single-arm MSB-GVHD001 study (NCT02336230) in 54 pediatric post-HSCT patients, where Day-28 overall response rate was 70% (95% CI, 56.4–82.0).
FDA approval (Dec 18, 2024)
The FDA approved remestemcel-L-rknd (Ryoncil; Mesoblast, Inc.) for steroid-refractory acute graft-versus-host disease (SR-aGVHD) in pediatric patients aged ≥2 months. Ryoncil is described as the first FDA-approved mesenchymal stromal cell (MSC) therapy.
Evidence base
Efficacy was evaluated in MSB-GVHD001 (NCT02336230), a multicenter, prospective, single-arm trial enrolling 54 pediatric patients with SR-aGVHD after allogeneic hematopoietic stem cell transplantation. Eligible patients had Grade B to D SR-aGVHD, excluding Grade B skin alone (IBMTR Severity Index criteria). SR-aGVHD was defined as aGVHD progressing within 3 days or not improving within 7 consecutive days of methylprednisolone 2 mg/kg/day (or equivalent). Patients who had received second-line aGVHD therapy prior to screening were excluded.
Primary efficacy outcomes were Day-28 overall response rate (ORR) and duration of overall response (CR+PR). Day-28 ORR was 70% (95% CI, 56.4–82.0), including CR 30% (95% CI, 18.0–43.6) and PR 41% (95% CI, 27.6–55.0). Median response duration from Day-28 response was 54 days (range 7–159+).
Safety and dosing (per FDA communication)
Common nonlaboratory adverse reactions (≥20%) included viral infections, bacterial infections, unspecified infection, pyrexia, hemorrhage, edema, abdominal pain, and hypertension. Recommended dosing: 2×10^6 MSC/kg IV, twice weekly for 4 weeks (8 infusions), ≥3 days apart; continuation may be based on Day-28 response.
Remestemcel-L-rknd received fast track, orphan drug, and priority review designations.