A Phase I Study Shows that Recombinant Human Interleukin-7 (CYT107) Promotes T-cell Recovery Following T-cell Depleted Allogeneic Hematopoietic Stem Cell Transplantation

Cytheris SA, a clinical stage biopharmaceutical company focused on research and development of new therapies for immune modulation, today announced interim results from a Phase I clinical trial of its investigational drug candidate, recombinant human interleukin-7 (CYT107), in the treatment of post-transplant patients with T-cell depleted (TCD) bone marrow or peripheral blood stem cell transplants. Preliminary assessment of the immunological effects of CYT107 in eight evaluable patients demonstrates a median increase in CD4 T-cells exhibiting a naïve or central memory phenotype of 69 per cent over baseline, and a median increase in CD8 T-cells exhibiting a naïve or effector memory phenotype of 94 per cent over baseline.
 
The study is being conducted at Memorial Sloan-Kettering Cancer Center (MSKCC) in New York City, where Marcel R.M. van den Brink, M.D., Ph.D., Head, Division of Hematologic Oncology, and Miguel-Angel Perales, M.D., Director, Adult Bone Marrow Transplantation Fellowship Program, serve as Principal Investigator and co-Principal Investigator, respectively.  
 
The interim results, ‘Recombinant Human Interleukin-7 (CYT107) Enhances CD4 and CD8 T-cell Recovery Following T-cell Depleted Allogeneic Hematopoietic Stem Cell Transplant In Patients with Myeloid Malignancies (Abstract 674)’, were presented by Dr. Perales in an oral session entitled ‘Clinical Care - Acute and Chronic GVHD, Infectious Complications and Immune Reconstitution of Transplantation II’ at the 52nd annual meeting of the American Society of Hematology (ASH) held in Orlando, Florida.

“Delayed and deficient reconstitution of T-cell populations together with consequent development of opportunistic infections remains a common cause of transplant failure and constitutes a major obstacle to the success of a hematopoietic stem cell allograft,” said Dr. Perales. “The interim study results reported here suggest that the administration of CYT107, which is known to stimulate thymopoiesis and peripheral T-cell survival/expansion with minimal toxicity, may represent a new and promising therapeutic pathway leading to enhancement of post-transplant immune recovery in recipients of a T-cell depleted allo-HSCT without causing graft-versus-host disease.”

Currently, there are a limited number of interventions available to promote immune reconstitution post-transplant. The therapeutic efficacy of hematopoietic stem cell transplantation (HSCT) is contingent not only on the eradication of malignancy, but also on the quality and rate of immunologic reconstitution. Despite more precise human leukocyte antigen (HLA) typing, effective methods to prevent graft rejection and/or reduce the incidence and severity of acute GVHD, infection remains a common cause of transplant failure in patients receiving an allograft from a matched sibling or a matched unrelated donor.
 
“These results in post-transplant patients are entirely consistent with similar effects observed in our HIV studies, where immunocompromised patients treated with CYT107 show a greatly expanded T-cell repertoire that is both functional and long-lasting,” said Michel Morre, DVM, president and chief executive officer of Cytheris. “As in the study reviewed here, this development and expansion of CD4 and CD8 T-cells appears to result in an immune system recovery which may be associated with a lower incidence of opportunistic infections and a longer life expectancy, a clinical benefit that we hope to demonstrate in future large-scale randomized clinical studies.”