Use of Bone Marrow Stem Cells (MesenCell) for the Treatment of Patients With Chronic Graft-versus-host Disease

Number of participants experiencing unexpected adverse events or adverse events considered probably or definitely attributable to MesenCell infusion within 30 days after the last dose. Adverse events will be classified according to the Common Terminology Criteria for Adverse Events (CTCAE) version 6.0 (2025). Grade 3 or higher events will be considered for toxicity assessment.

Percentage of participants with partial or complete overall response, according to the 2014 National Institutes of Health (NIH) Consensus Development Project response criteria for chronic graft-versus-host disease.

Change from baseline in overall severity according to the 2014 National Institutes of Health (NIH) Consensus Development Project criteria. Overall severity is classified as mild, moderate, or severe based on the number of organs involved and the severity scores assigned to each affected organ. Mild disease is defined as involvement of 1 or 2 organs, with no organ scoring more than 1, and a lung score of 0. Moderate disease is defined as involvement of 3 or more organs with no organ scoring more than 1, or at least 1 non-lung organ with a score of 2, or a lung score of 1. Severe disease is defined as at least 1 organ with a score of 3 or a lung score of 2 or 3.

Change from baseline in organ-specific response scores for the skin, mouth, eyes, gastrointestinal tract, liver, lungs, joints and fascia, and genital tract. Each organ is scored on an ordinal scale from 0 to 3 according to predefined clinical or laboratory criteria specific to the affected organ. A score of 0 indicates no signs or symptoms, while a score of 3 indicates severe involvement. Higher scores indicate greater disease severity and a worse outcome.

Time from the first MesenCell infusion to death from any cause. Survival will be estimated at 6 and 12 months and as median overall survival during the follow-up period. Participants who remain alive will be censored at the last contact.

Time from the first MesenCell infusion to the first occurrence of treatment failure, defined as relapse of the underlying disease, progression or reactivation of chronic graft-versus-host disease, or death from any cause. Relapse of the underlying disease will be assessed primarily by complete blood count, with bone marrow aspirate performed when relapse is suspected based on blood count findings. Reactivation of chronic graft-versus-host disease will be assessed at each medical visit according to the NIH organ scoring criteria. Participants without treatment failure will be censored at the last contact. Failure-free survival will be estimated at 6 and 12 months.

Percentage of participants who have a reduction in corticosteroid dose compared with baseline during the follow-up period. Corticosteroid dose will be assessed using medical records, prescription data, and clinical follow-up.

Percentage of participants who discontinue systemic immunosuppressive therapy during the follow-up period. Immunosuppressive therapy use and discontinuation will be determined from medical records, prescription data, and clinical follow-up.

Time from the first MesenCell infusion to the first documentation of the best overall response according to the 2014 National Institutes of Health (NIH) Consensus Development Project response criteria for chronic graft-versus-host disease.