AVM Biotechnology (United States)

e14583 Background: Rituximab-cyclophosphamide-doxorubicin-vincristine-prednisone (RCHOP) is the standard of care for most aggressive B-cell lymphomas. RCHOP requires numerous treatment cycles, typically 6, with challenging side effects, including toxicity and long-term secondary malignancies. Trials have demonstrated that 4 cycles of RCHOP was non-inferior to 6 with similar secondary malignancies, however, real world experience has demonstrated that long term outcomes are superior when patients achieve minimal residual disease negative (MRD-) status after the 3rd cycle (1,2). Addition of a novel agent to RCHOP that could reduce the number of cycles to 3 while maintaining response, could overcome the long-term side-effects and allow frail and elderly patients to receive full dose RCHOP in each cycle to improve outcomes. For example, addition of Lenalidomide with RCHOP improved outcomes in ABC-DLBCL patients (3), but leads to therapy related myeloid neoplasm in recent studies (4). AVM0703, an immunomodulatory drug, mobilizes bispecific and i-TCR double-positive NKT cells (AVM_NKT). In the aggressive, immune resistant A20 mouse lymphoma model, neoadjuvant AVM0703 was additive/synergistic, when cyclophosphamide/fludarabine (CyFlu) was dosed 3 + 24 hours later, with no additional toxicities. Therefore, we hypothesized that combining AVM0703 with RCHOP would be an effective and well tolerated treatment of DLBCL. Methods: Tumor-bearing mice were made by sc flank injection of 2x106 murine A20 B-cells in 10-week-old Balb/c mice. When tumor size reached established ~100 mm3, 48 mice (1:1 male: female) were randomized (12 mice each cohort) 1) Placebo 2) 1 cycle RCHOP 3) AVM0703 (18mg/kg HED) 4) AVM0703+1 cycle RCHOP combination treated as described previously (5,6). When Placebo tumors reached ~ 2000 mm3, all mice were sacrificed and tumors, blood, spleen, bone marrow were analyzed for the presence of remnant A20, and immune cell state by flow cytometer. Results: One RCHOP only mouse died from the chemo. There were no deaths in AVM0703+RCHOP group. Tumor remnant live A20 were significantly reduced in all 3 treatment groups compared to Placebo. Interestingly, AVM0703+RCHOP significantly increased the number of MRD- A20 tumors compared to RCHOP alone. Conclusions: Based on this study we plan to determine whether 3 cycles of AVM0703+RCHOP can induce long term CR and if AVM0703 could replace R and reduce long term side effects. 1) Poeschel Lancet 2019. 2) Spurgeon J Natl Canc Inst 2016. 3) Nowakowski JCO 2021. 4) Sperling Blood 2022. 5) Bascuas J Transl Med 2016. 6) Bongard PLoS Pathog 2019. [Table: see text]

e14545 Background: Glucocorticoids (GC) are a common component of blood cancer regimens, at doses 40 mg or lower due to concerns of pancreatitis and hepatotoxicity (Walasik-Szemplińska et al. Thyroid Research (2019) 12:13; Ataallah et al. Cureus. 2020 Jul; 12(7)) and neuropsychiatric effects. AVM Biotechnology has developed a high concentration, high volume, preservative-free, patent pending formulation of dexamethasone (Dex) (AVM0703), allowing administration up to 21 mg/kg (1470 mg for 70 kg) in one-hour IV infusion. Prophylactic use of physiologic hydrocortisone reduces the risk of GC neuropsychiatric side-effects (Warris, L. T. et al. J. Clin. Oncol. (2016) 34:2287; Meijer & de Kloet Endocrinology (2017) 158:448). At supra-pharmacologic doses (>6 mg/kg) AVM0703 mobilizes endogenous bispecific gamma delta invariant TCR+ Natural Killer T-like cells (AVM-NKT) (PCT/US21/19773), via a non-GC receptor, that rapidly home to cancer in tumor models and are directly related to tumor killing. GCs have been reported to induce biological responses independent of GCRs: corticosterone has been shown to bind a G-protein coupled receptor that does not bind either Dex or aldosterone (Mitre-Aguilar, et. Al International Journal of Clinical and Experimental Pathology (2015) 8:1; Powell, C. E., et. Al. Endocrine (1999) 10: 271) and the non-GCR mineralocorticoid receptor has high affinity for prednisone but not Dex. Methods: a) Mouse splenocytes or human whole blood were incubated with Dex from 1nM to 1mM. Apoptosis was measured for human whole blood by CBCs and for mouse splenocytes by flow cytometry 4 to 6 hours later. RU486 was used to block expected transmembrane (tm)GCR activity. b) Naïve, tumor bearing and humanized mice were dosed with AVM0703 at human equivalent doses (HED) >18 mg/kg. Depending on the disease state of the mice, novel AVM-NKT were observed in the blood between 3 and 96 hours later, determined by flow cytometry. Results: a) Apoptosis via the tmGCR was observed at expected concentrations between 10nM and 100uM and was blocked by the GCR antagonist RU486. At concentrations above 250uM, which correspond to in vivo peak blood levels from acute 7mg/kg and greater, no Dex-induced apoptosis was observed. b) Acute supra-pharmacologic AVM0703 induced the appearance of CD3+, CD56+, gdTCR+, invariant TCR+ bi-specific Natural Killer T-like cells, that in a cancer setting also expressed activation markers like CD16 and NKp44. Intriguingly, the AVM-NKT also express B220 in certain settings, and CD3+ B220+ DP has been indicative of IL-2 or IL-12 lymphoma killing (Masztalerz, A, et. Al. Anticancer Res (2004) 24(5A):2633). Conclusions: CBC’s and clinical chemistries from enrolling clinical trial confirmed the in vitro non-GCR findings.

e14011 Background: Chimeric antigen receptor T-cell (CAR-T) therapy is a relatively novel regimen for the treatment of acute lymphoblastic leukemia that has already shown promising results. Two FDA-approved CAR-T therapies, Kymriah and Yescarta have an 80% success rate in sending patients into remission. However, both of these treatments require preconditioning (PC) with chemotherapy to ensure CarT expansion and engraftment. Chemotherapy severely compromises patient’s immune-system, a further economic burden up to $70K per patient due to hospitalization, and fuels side effects of CAR-T therapy such as cytokine release syndrome (CRS) and neuroedema, driven by the release of IL-6 and GM-CSF respectively. Also, up to one third of cancer patients are too frail to tolerate chemotherapy and do not qualify for potentially life-saving therapies. A single acute dose of AVM0703 induces lymphodepletion equivalent to chemotherapy, and transiently eliminates the sites in the spleen where therapeutic cells accumulate without inducing toxicities associated with chemotherapy. Methods: Mice with subcutaneously implanted melanoma were preconditioned with AVM0703 prior to treatment with a mouse Pmel CAR-T therapy. Tumor growth was tracked and spleens were analyzed after dissection for binding of labeled CAR-T cells. In a separate study, four human patients were dosed with low doses of AVM0703 and the levels of released cytokines in the blood were quantified. Results: The mice demonstrated reduced T-cell sequestration in the spleen as noted by a reduction of fluorescently labeled cells. AVM0703 alone significantly delayed tumor growth, and as PC before Pmel T-cells, dramatically improved CAR-T-driven delay of tumor growth. In humans, a significant increase in beneficial IL-2 and IL-15 was observed, as well as a lack of released IL-6. In addition, existing literature demonstrate that AVM0703 reduces the release of GM-CSF. Conclusions: AVM0703 shows efficacy as preconditioning agent in a mouse solid tumor model of melanoma, reduces the binding of CAR-T cells in the spleen, and stimulates the release of beneficial cytokines. AVM0703 could be a non-toxic, effective preconditioning agent for patients receiving CAR-T therapy.