AGI-134: a fully synthetic α-Gal glycolipid that converts tumors into in situ autologous vaccines, induces anti-tumor immunity and is synergistic with an anti-PD-1 antibody in mouse melanoma models.

BACKGROUND: Treatments that generate T cell-mediated immunity to a patient's unique neoantigens are the current holy grail of cancer immunotherapy. In particular, treatments that do not require cumbersome and individualized ex vivo processing or manufacturing processes are especially sought after. Here we report that AGI-134, a glycolipid-like small molecule, can be used for coating tumor cells with the xenoantigen Galα1-3Galß1-4GlcNAc (α-Gal) in situ leading to opsonization with pre-existing natural anti-α-Gal antibodies (in short anti-Gal), which triggers immune cascades resulting in T cell mediated anti-tumor immunity. METHODS: Various immunological effects of coating tumor cells with α-Gal via AGI-134 in vitro were measured by flow cytometry: (1) opsonization with anti-Gal and complement, (2) antibody-dependent cell-mediated cytotoxicity (ADCC) by NK cells, and (3) phagocytosis and antigen cross-presentation by antigen presenting cells (APCs). A viability kit was used to test AGI-134 mediated complement dependent cytotoxicity (CDC) in cancer cells. The anti-tumoral activity of AGI-134 alone or in combination with an anti-programmed death-1 (anti-PD-1) antibody was tested in melanoma models in anti-Gal expressing galactosyltransferase knockout (α1,3GT-/-) mice. CDC and phagocytosis data were analyzed by one-way ANOVA, ADCC results by paired t-test, distal tumor growth by Mantel-Cox test, C5a data by Mann-Whitney test, and single tumor regression by repeated measures analysis. RESULTS: In vitro, α-Gal labelling of tumor cells via AGI-134 incorporation into the cell membrane leads to anti-Gal binding and complement activation. Through the effects of complement and ADCC, tumor cells are lysed and tumor antigen uptake by APCs increased. Antigen associated with lysed cells is cross-presented by CD8α+ dendritic cells leading to activation of antigen-specific CD8+ T cells. In B16-F10 or JB/RH melanoma models in α1,3GT-/- mice, intratumoral AGI-134 administration leads to primary tumor regression and has a robust abscopal effect, i.e., it protects from the development of distal, uninjected lesions. Combinations of AGI-134 and anti-PD-1 antibody shows a synergistic benefit in protection from secondary tumor growth. CONCLUSIONS: We have identified AGI-134 as an immunotherapeutic drug candidate, which could be an excellent combination partner for anti-PD-1 therapy, by facilitating tumor antigen processing and increasing the repertoire of tumor-specific T cells prior to anti-PD-1 treatment.

GENESIS: Phase III trial evaluating BL-8040 + G-CSF to mobilize hematopoietic cells for autologous transplant in myeloma.

Effective hematopoietic cell transplantation relies upon collecting adequate numbers of CD34+ hematopoietic stem cells, typically from peripheral blood. A minimum of ≥2 × 106 CD34+ cells/kg are necessary, while transplants of ≥5-6 × 106 CD34+ cells/kg are associated with improved hematopoietic recovery. Granulocyte colony stimulating factor (G-CSF) remains the gold standard for hematopoietic stem cell mobilization. However, in randomized trials for autologous-hematopoietic cell transplantation in multiple myeloma, approximately 45% of patients remain unable to optimally mobilize with G-CSF alone despite multiple injections and apheresis days. Therefore, reducing mobilization failures remains an unmet need. The study objective is to evaluate the superiority of one dose of BL-8040 plus G-CSF over placebo plus G-CSF to mobilize ≥6.0 × 106 CD34+ cells/kg in up to two apheresis days. ClinicalTrials.gov: NCT03246529.

Single Dose of the CXCR4 Antagonist BL-8040 Induces Rapid Mobilization for the Collection of Human CD34+ Cells in Healthy Volunteers.

Purpose: The potential of the high-affinity CXCR4 antagonist BL-8040 as a monotherapy-mobilizing agent and its derived graft composition and quality were evaluated in a phase I clinical study in healthy volunteers (NCT02073019).Experimental Design: The first part of the study was a randomized, double-blind, placebo-controlled dose escalation phase. The second part of the study was an open-label phase, in which 8 subjects received a single injection of BL-8040 (1 mg/kg) and approximately 4 hours later underwent a standard leukapheresis procedure. The engraftment potential of the purified mobilized CD34+ cells was further evaluated by transplanting the cells into NSG immunodeficient mice.Results: BL-8040 was found safe and well tolerated at all doses tested (0.5-1 mg/kg). The main treatment-related adverse events were mild to moderate. Transient injection site and systemic reactions were mitigated by methylprednisolone, paracetamol, and promethazine pretreatment. In the first part of the study, BL-8040 triggered rapid and substantial mobilization of WBCs and CD34+ cells in all tested doses. Four hours postdose, the count rose to a mean of 8, 37, 31, and 35 cells/µL (placebo, 0.5, 0.75, and 1 mg/kg, respectively). FACS analysis revealed substantial mobilization of immature dendritic, T, B, and NK cells. In the second part, the mean CD34+ cells/kg collected were 11.6 × 106 cells/kg. The graft composition was rich in immune cells.Conclusions: The current data demonstrate that BL-8040 is a safe and effective monotherapy strategy for the collection of large amounts of CD34+ cells and immune cells in a one-day procedure for allogeneic HSPC transplantation. Clin Cancer Res; 23(22); 6790-801. ©2017 AACR.