Stem Cell Transplantation:
Allogeneic stem cell transplantation is the only curative option for many patients suffering from hematological malignancies. Although providing cure for many patients, stem cell transplantation may be accompanied by severe treatment-related side-effects, including acute Graft-versus- Host Disease (GvHD).
GVHD occurs when immune cells present in the stem cell transplant attack healthy tissue of the graft recipient. There is an acute and a chronic form. The acute form may proceed mild (grade I), but can also be severe giving rise to damage to tissues and organs, particularly of the skin, the intestine and the liver (grade II to IV). Acute GVHD is treated using immunosuppressive agents. Patients are given corticosteroids (such as prednisone) in high doses, often in combination with other immunosuppressive drugs. Half of the patients treated with corticosteroids respond well to the treatment, however in the other half of the patients the GvHD response to corticosteroids is inadequate or absent, so-called steroid-refractory GVHD. Steroid-refractory acute GvHD has a high mortality rate (70% on average) and surviving patients often develop chronic GvHD, which severely reduces quality of life. Therefore, there is an urgent need for new and better treatment modalities. Several studies have indicated that third-party mesenchymal stromal cells (MSC) might be an effective therapy for steroid-refractory GvHD.
MSC are cells that support normal blood-forming stem cells. They also have a putative immune-suppressive and tissue repair-promoting effect. MSC can be obtained from the bone marrow and after propagation in the laboratory can be administered to patients by intravenous therapy. Pilot studies using MSC have yielded encouraging results suggesting that this treatment may induce responses in the majority of patients with acute GvHD with organ involvement. We therefore initiated a phase III randomized placebo-controlled double-blind multicenter study in patients with steroid-refractory acute GvHD. Such a study is very important in determining whether the new MSC treatment is truly effective for this patient group. Furthermore it is also a prerequisite to get the new treatment registered and reimbursed by health insurance companies.