Phase I Clinical Trial to Assess Safety of Synthetic Preimplantation Factor (PIF-1) in Patients With Steroid-Resistant Acute Graft-Versus-Host Disease (GVHD) After Allogeneic Hematopoietic Stem-Cell Transplantation

Allogeneic BMT is a well-established treatment modality for malignant and non-malignant hematological diseases. Mature donor T cells within the stem-cell graft are the main mediators of the beneficial immune effects, but they are also responsible for the induction of GVHD, which becomes the major cause of morbidity and mortality post-transplant. Acute GVHD occurs within a 100-day period post-transplant and generally is manifested by dermatitis, enteritis, and hepatitis. The treatment of GVHD continues to be a challenge. To eliminate undesirable host-derived hematopoietic elements before BMT, patients are traditionally treated with myeloablative conditioning regimens involving high-dose chemotherapy and total-body irradiation. Standard GVHD prophylaxis and therapy comprise drugs that cause generalized immune suppression and place patients in danger of opportunistic infections and tumor relapse. For acute GVHD prevention, cyclosporine is often used; however, it is frequently necessary to administer long-term high-dose steroids as well.

An acute GVHD patient's lack of response to steroids is associated with poor prognosis. The ideal prophylaxis treatment for BMT patients would be one that prevented the graft from attacking the host, and that modulated the host's immune response so that it would accept the transplant, while maintaining its ability to protect the body against opportunistic hostile agents.

Pregnancy is an immune paradox: it allows maternal (host) acceptance of a semi-allograft (embryo), while it does not cause graft-versus-host or host-versus-graft reactions against the host/mother, or immune suppression. Therefore, the pregnant immunological status is compatible with the desired immune profile in patients undergoing BMT. By replicating the immune profile present in pregnancy in BMT patients, we may be able to reduce the occurrence of GVHD-related morbidity and mortality rates.

Preimplantation factor (PIF-1) is a novel, embryo-secreted peptide whose synthetic version matches the native peptide's properties. PIF-1 appears to play an important role in mediating the maternal response to pregnancy in mammals. In preclinical studies, PIF-1 has been found to be effective in preclinical BMT-GVHD models, without apparent toxicity.