Background CD19-specific chimeric antigen receptor (CAR) T cell therapy has achieved high efficacy in acute lymphoblastic leukemia patients. However, the treatment of acute myeloid leukemia (AML) has remained a particular challenge due to the heterogeneity of AML bearing cells, which renders single antigen targeting CAR T cell therapy ineffective. CLL1 and CD33 are often used as targets for AML CAR T cell therapy. CLL1 is associated with leukemia stem cells and disease relapse, and CD33 is expressed on the bulk AML disease. Previously, we demonstrated the profound anti-tumor activity of CLL1-CD33 compound CAR (cCAR) T cells. Here we present the efficacy of cCAR in preclinical study and update the success in level 1 dose escalation clinical trial on relapsed/refractory AML patients. Methods We engineered a cCAR comprising of an anti-CLL1 CAR linked to an anti- CD33 CAR via a self-cleaving P2A peptide and expressing both functional CAR molecules on the surface of a T-cell cell. We tested the anti-leukemic activities of CLL1-CD33 cCAR using multiple AML cell lines, primary human AML samples, human leukemia cell line (REH cells) expressing either CLL1 or CD33, and multiple mouse models. An alemtuzumab safety switch has also been established to ensure the elimination of CAR T cells following tumor eradication. Children and adults with relapsed/refractory AML were enrolled in our phase 1 dose escalation trial with primary objective to evaluate the safety of cCAR and secondary objective to assess the efficacy of cCAR anti-tumor activity. Results Co-culture assays results showed that cCAR displayed profound tumor killing effects in AML cell lines, primary patient samples and multiple mouse model systems. Our preclinical findings suggest that cCAR, targeting two discrete AML antigens: CLL1 and CD33, is an effective two-pronged approach in treating bulk AML disease and eradicating leukemia stem cells. Patients enrolled in the phase 1 dose escalation trial have shown remarkable response to cCAR treatment. Noticeably, a 6-yr-old female patient diagnosed with a complex karyotype AML including FLT3-ITD mutation had achieved complete remission. The patient was diagnosed with Fanconi anemia, which had progressed to juvenile myelomonocytic leukemia and eventually transformed into AML. The patient had been resistant to multiple lines of treatments, including 5 cycles of chemotherapy with FLT3 inhibitor prior to receiving cCAR. Before the treatment, patient's leukemia blasts comprised 73% of the peripheral blood mononuclear cells and 81% of the bone marrow. Patient underwent lymphodepletion therapy (Fludarabine and Cyclophosphamide) prior to cCAR infusion. Two split doses, each consisting of 1x106/kg CAR T cells, were infused on day 1 and day 2 respectively. On day 12, while leukemia blast still counting up to 98% of the bone marrow (Fig. 1A), robust CAR T cell expansion was detected in both peripheral blood and bone marrow. On day 19, patient achieved MRD- complete remission with bone marrow aspirates revealing complete ablation of myeloid cells (Fig. 1B). Flow cytometry confirmed the absence of leukemia blasts and showed that CAR T cells comprised 36% of the PBMC and 60% of the bone marrow. The patient later underwent non-myeloablative hematopoietic cell transplantation with less toxicities compared to conventional total body radiation and high dose chemotherapies. Updated results on other patients enrolled in this clinical trial including adverse events will be presented. Conclusion Our first-in-human clinical trial demonstrates promising efficacy of cCAR therapy in treating patients with relapsed/ refractory AML. cCAR is able to eradicate leukemia blasts and leukemia stem cells, exerting a profound tumor killing effect that is superior to single target CAR T cell therapies. cCAR is also shown to induce total myeloid ablation in bone marrow, suggesting that it may act as a safer alternative to avoid the severe toxicities caused by standard bone marrow ablation regimens without sacrificing the anti-tumor efficacy. This strategy will likely benefit patients who are unable to tolerate total body radiation or high dose chemotherapies. In addition to AML, cCAR also has the potential to treat blast crisis developed from myelodysplastic syndrome, chronic myeloid leukemia, and chronic myeloproliferative neoplasm. Disclosures Pinz: iCell Gene Therapeutics LLC: Employment. Ma:iCAR Bio Therapeutics Ltd: Employment. Wada:iCell Gene Therapeutics LLC: Employment. Chen:iCell Gene Therapeutics LLC: Employment. Ma:iCell Gene Therapeutics LLC: Employment. Ma:iCell Gene Therapeutics LLC, iCAR Bio Therapeutics Ltd: Consultancy, Equity Ownership, Research Funding.

Layer-by-layer polyelectrolyte adsorption is a simple, convenient method for introducing ionexchange sites in porous membranes. This study demonstrates that adsorption of poly(acrylic acid) (PAA)-containing films at pH 3 rather than pH 5 increases the protein-binding capacity of such polyelectrolyte-modified membranes 3-to 6-fold. The low adsorption pH generates a high density of -COOH groups that function as either ion-exchange sites or points for covalent immobilization of metal-ion complexes that selectively bind tagged proteins. When functionalized with nitrilotriacetate (NTA)-Ni 2+ complexes, membranes containing PAA/polyethyleneimine (PEI)/ PAA films bind 93 mg of histidine 6 -tagged (His-tagged) ubiquitin per cm 3 of membrane. Additionally these membranes isolate His-tagged COP9 signalosome complex subunit 8 from cell extracts and show >90% recovery of His-tagged ubiquitin. Although modification with polyelectrolyte films occurs by simply passing polyelectrolyte solutions through the membrane for as little as 5 min, with low-pH deposition the protein binding capacities of such membranes are as high as for membranes modified with polymer brushes and 2-3 fold higher than for commercially available IMAC resins. Moreover, the buffer permeabilities of polyelectrolyte-modified membranes that bind His-tagged protein are ~30% of the corresponding permeabilities of unmodified membranes, so protein capture can occur rapidly with low pressure drops. Even at a solution linear velocity of 570 cm/h, membranes modified with PAA/PEI/PAA exhibit a lysozyme dynamic binding capacity (capacity at 10% breakthrough) of ~ 40 mg/cm 3 . Preliminary studies suggest that these membranes are stable under depyrogenation conditions (1 M NaOH).

A simple strategy tailors perfusable and permeable hierarchical microchannel networks from diverse materials.

Complementary DNA (cDNA) clones encoding bovine testicular 20 alpha-hydroxysteroid dehydrogenase (20 alpha-HSD) have been isolated from a bovine testicular lambda gt11 library using polyclonal antibodies against 20 alpha-HSD and DNA probe hybridization. Nucleotide sequencing of three independently isolated clones was used to establish a composite cDNA sequence that encodes the enzyme. It contains a coding sequence of 921 nucleotides, a stop codon, and a 264-nucleotide 3'-noncoding segment which allowed deduction of the amino acid sequence of the enzyme. A computer homology search of the 20 alpha-HSD cDNA performed against the GenBank DNA sequence database revealed it to be identical with bovine lens aldose reductase (alditol:NADPH oxidoreductase; EC 1.1.1.21), and a literature search reveals the deduced amino acid sequence to be identical with that reported for the bovine enzyme. Sequences obtained from the N-terminus of purified testicular 20 alpha-HSD and from random peptides obtained by treatment with endopeptidase Lys-C are all identical with regions of the deduced amino acid sequence of 20 alpha-HSD and/or the published sequence of aldose reductase. Further, the enzyme purified to homogeneity by following activity with 17-hydroxyprogesterone as a substrate was shown to reduce glucose, glyceraldehyde, and benzaldehyde (all classic aldose reductase substrates). Finally, 17-hydroxyprogesterone inhibited the reduction of benzaldehyde and glyceraldehyde. Because aldose reductase has been implicated in the etiology of diabetic complications, acceptance of steroid substrates may offer new implications for therapy.

Reasonable modifications to the attachment energy model were made for accurately predicting the crystal growth morphology of energetic materials in solution.