PH 1 Study to Evaluate Safety and Tolerability of XmAb14045 in Patients With CD123-expressing Hematologic Malignancies

Inclusion Criteria: * Diagnosis of 1 of the following diseases: * Primary or secondary AML (including erythroleukemia and eosinophilic leukemia, but excluding acute promyelocytic leukemia) * B-cell ALL * BPDCN * CML in blast phase, resistant or intolerant to tyrosine kinase inhibitor therapy * Patients with relapsed or refractory disease with no available standard therapy * ECOG performance status 0-2 * Not a candidate for, or refusing treatment with hematopoietic stem cell transplantation * Fertile patients must agree to use effective contraception during and for 4 weeks after the last dose of XmAb14045 * Male patients must agree to use highly effective contraception, and refrain from donating sperm during the treatment period and for at least 4 weeks after the last dose of XmAb14045 * Able and willing to complete the entire study Exclusion Criteria: * Systemic antineoplastic therapy (including cytotoxic chemotherapy and toxin immunoconjugates, but excluding hydroxyurea), unconjugated antibody therapy, or radiotherapy within 2 weeks of the first dose of study treatment, or small molecule kinase inhibitors within 6 elimination half-lives of the first dose of study treatment. * Prior therapy with CD123- or IL-3R-directed immunotherapies, including monospecific and bsAbs, immunoconjugates, or chimeric antigen receptor- modified T-cell therapy * Failure to recover from Grade 3 or 4 toxicity from previous treatment (unrelated to malignant bone marrow involvement) * Kn…