Examination of necrosis in tumors treated with AVM0703 compared to chemotherapy.

Abstract

e20029 Background: AVM0703 should be the first choice for no-option cancer patients. AVM0703 is a fast-acting formulation that lympho-ablates while sparing HSCs, MSCs, platelets, and RBCs. Its transient and manageable side effects reduce the need for additional maintenance treatments while improving quality of life. AVM0703 induces a novel NKT that induces tumor-killing activity without causing GvHD or CRS. AVM0703 is a versatile formulation that can be safely redosed or given in combination with known chemotherapeutics. It is predicted to be safe for previously neglected patient populations. Methods: Mice were monitored over the course of 13 weeks or endpoint criteria. Body weights and tumor measurements were taken 3x per week. Both group and individual growth was tracked. Tumors were dissected from the right flank on takedown and fixed for 24 hours in 4% paraformaldehyde, then stored in 70% ethanol. For analysis, tumors were sent to HistoTox Labs, embedded in paraffin blocks, then sliced and stained for H&E. In a separate study, mice with subcutaneous A20 were treated with increasing concentrations of AVM0703 and allowed to go to endpoint. Tumors were dissected and stained for H&E, CD3, NKp46, and AC3. Finally, tumor bearing mice were treated with high doses of AVM0703 48 hours before takedown. Tumors were dissected and sent to HistoTox for embedding, slicing and staining for H&E, NKp46, CD3, CD49b, AC3, CD31, B220, Ly6G, Sca-1, and PSR. Results: Mice treated with repeat doses of AVM0703 did not display significant loss of body weight or worsening of condition, which was observed in mice treated with chemotherapy. All combination mice displayed significantly higher tumor necrosis and resorption compared to all other treatment groups. Significant necrosis was observed in tumors in as little as 48 hours post dosing. At endpoint, apoptosis was slightly increased at all doses compared to placebo. CD3 and CD49b were decreased in doses above 18 mg/kg, indicating activation of NKT cells in comparison to placebo and low dose AVM0703. There was also an increase in NKp46 staining along the border of large necrotic regions within the tumor. While necrosis was prevalent within the tumor, there was only a slight increase in apoptosis staining. Conclusions: AVM0703 can be repeatedly dosed without significant signs of toxicity. A single dose after 48 hours displays large regions of necrosis within the tumor, indicating that AVM0703 is a fast-acting formulation. AVM0703 is able to replace a dose of Cy/Flu in mice with similar efficacy and increased tumor killing in comparison to Cy/Flu alone with less toxicity.