Treg Enhancing Drug Programs
Our lead product, RGI-2001, is a liposomal formulation of an alpha-galactosylceramide (alpha-GalCer) analog. alpha-GalCer is a ligand for CD1d expressed on antigen presenting cells and invariant NKT cells. It was discovered that a liposomal alpha-GalCer promotes tolerogenic immune cascade, resulting in the activation and expansion of Tregs.
In animal studies, RGI-2001 demonstrated to prolong the survival of mice with MHC-fully mismatched bone marrow transplantation without compromising graft-versus-leukemia (GvL) effect or immune responses to third-party antigens.
RGI-2001 has been evaluated for prevention of Graft-versus-Host Disease (GvHD) in patients undergoing HLA-matched allogeneic hematopoietic stem cell transplantation (HSCT) for the treatment of hematological malignancies. A Phase 2b study (NCT04014790) has completed the enrollment of 49 patients: RGI-2001 was well tolerated and demonstrated preliminary signs of efficacy.
In addition, RGI-2001 is under evaluation in a haploidentical HSCT setting in an investigator sponsored pilot study currently ongoing at Massachusetts General Hospital (NCT04473911).
Treg Suppressing Antibody Programs
Our lead antibody therapeutic, RGI-AB04, is a human antibody targeting a molecule expressed on Treg cells, designed to kill Treg cells via the ADCC mechanism. The expression of this molecule is restricted to activated Treg cells, and not expressed in other T cells or resting Tregs. This unique feature allows AB04 to selectively eliminate activated Tregs in the tumor microenvironment and enhance T cells to fight against tumor cells. As AB04 will not eliminate resting Tregs which are important to maintain self-tolerance, the risk of AB04 to induce immune related adverse events will be low.
RGI-AB01 is an antibody designed to suppress Treg function, by inhibiting the activity of a key mediator for immune suppression.