Clinical data on ATIR presented.

ATIR initial Clinical Data suggests;  Feasible Strategy for Mismatched Stem Cell Transplantation

Keystone, February 08, 2007 - Kiadis Pharma has announced Phase I/II data suggesting that its investigational product  ATIR enables immune reconstitution with a reduced the risk of acute graft-versus-host disease among blood cancer patients who received donor lymphocyte infusions (DLI) following mismatched stem cell transplantation. Data were presented during the CIBMTR 2007 Tandem Meeting.

This product, ATIR,  can help blood cancer patients to achieve sustained remission after stem cell transplantation by restoring their immune system, which helps protect them against both infection and cancer relapse. However, donor cells known as “alloreactive T cells” can attack the tissues and organs of the patient (host), leading to a serious condition called acute graft-versus-host disease (GvHD). ATIR is designed to remove these harmful T cells from the donor graft while leaving T cells that help fight infection and cancer.

Denis-Claude Roy, M.D., Oncologist/Hematologist from the Stem Cell Transplantation Unit at the Maisonneuve-Rosemont Hospital in Montreal, Quebec, reported data on nine high-risk blood cancer patients who received stem cells transplanted from a “mismatched” donor (haploidentical transplantation) followed by a DLI in which activated alloreactive T cells were selectively removed with  the Kiadis Pharma’s product ATIR. No patient developed acute GvHD.

In this dose-escalation study, whose primary endpoints are the safety (incidence and severity of acute GvHD) and efficacy (immune reconstitution, infection, relapse and survival), nine patients with haploidentical stem cell donors received DLI add-back of up to 3.2 x 10⁵ T cells per kilogram to date. No patient developed acute GvHD. Four patients are alive at a median time of 10 (4-19) months post transplant.

ATIR, is based on the proprietary Theralux™ technology platform and designed to selectively eliminate activated alloreactive T cells responsible for acute GvHD, while sparing the T cell repertoire needed for immune reconstitution. If successful, this product could allow patients to undergo blood stem cell transplantation even if they cannot find matched donors. Additionally, this therapy could make matched blood stem cell transplantation much safer as would less immune suppression would be required. The success of this approach would solve a long-standing problem and represent a shift in the way blood cancers are treated.