Grant Award Details

Development of OSSM-007, cryopreserved interferon-gamma primed allogeneic MSCs, for treatment of steroid refractory acute graft versus host disease
Grant Number: 
Project Objective: 
  • The objectives of this project are to 1) carry out three pilot-scale manufacturing runs of OSSM-007 [cryopreserved interferon-gamma primed MSC] to demonstrate manufacturing consistency and product safety; 2) collect stability data with OSSM-007 stored in the final container-closure system; 3) conduct a compatibility study of OSSM-007 with preparation and delivery devices; 4) develop a potency assay for OSSM-007 to add to the final release criteria; 5) validate the predictiveness of the potency assays in an allogeneic mouse model of aGVHD; and 6) refine the clinical dosing regimen and determine the biodistribution of OSSM-007 in an aGVHD mouse model; 7) carry out multiple outreach and engagement activities to prepare for enrolling a diverse population in a future clinical trial.
Disease Focus: 
Immune Disease
Human Stem Cell Use: 
Adult Stem Cell
Award Value: 

Grant Application Details

Application Title: 
  • Development of OSSM-007, cryopreserved interferon-gamma primed allogeneic MSCs, for treatment of steroid refractory acute graft versus host disease
Public Abstract: 

Therapeutic Candidate or Device

OSSM007: cryopreserved, interferon-gamma-primed bone marrow mesenchymal stem cells (BM-MSC)


acute Graft versus host disease (aGVHD) resulting from hematopoietic cell transplantation

Therapeutic Mechanism

Immunomodulation of host-reactive T cells to induce operational tolerance of donor HSC-derived lymphocytes through direct cell-to-cell contact and secreted paracrine factors. Interferon-gamma priming of MSCs enhances therapeutic effects through establishing the cells in a immunosuppressive state prior to treatment. Primed cells are able to quickly activate regulatory T cells as well as direct suppress host-reactive T cell activity.

Unmet Medical Need

Systemic steroid therapy is the standard first-line treatment for aGVHD; however, the disease becomes refractory to systemic steroid therapy in 35–50% of patients. Mortality rates for patients who fail to respond to first-line steroid therapy are 80% due to very limited alternative treatments.

Project Objective

Commence Phase 1 clinical trial

Major Proposed Activities

  • Address clinical hold CMC issues, including OSSM-007 manufacturing reproducibility and stability of product
  • Develop a matrix of predictive potency assays and demonstrate utility in a mouse aGVHD model
  • Refine the clinical dosing regimen by conducting a dose escalation study in a humanized mouse model of aGVHD
Statement of Benefit to California: 

Steroid-refractory acute Graft-versus-host-disease (SR-aGVHD) is a severe health concern given the 80% mortality rate associated with the disease. There are no effective treatments currently available, thus, SR-aGVHD patients face a very poor prognosis. Development of OSSM-007 has to the potential to extend the lifespans of this patient population by reducing disease severity and, potentially, reversing the course of the disease.