Safety Study of MGD006 in Relapsed/Refractory Acute Myeloid Leukemia (AML) or Intermediate-2/High Risk MDS

Open to people ages 18 years and up

• Confirmed diagnosis of primary or secondary AML [any subtype except acute promyelocytic leukemia (APL)] according to World Health Organization (WHO) classification
• Patients with AML must be unlikely to benefit from recommended standard of care defined by any one of the following criteria:
• AML refractory to ≥ 2 (or ≥ 1 for patients > 65 years of age) induction attempts, including but not limited to the following:
• AML refractory to ≥ 1 intensive induction attempt(s), per institution, including high- and standard-dose cytarabine ± an anthracyclines/anthracenedione ± an anti-metabolite with or without growth factor or targeted therapy,

ii. for adults who are age 75 years or older, or who have comorbidities that preclude use of intensive induction chemotherapy, AML refractory to ≥ 2 lower intensity induction attempts including Bcl-2 or Hedgehog inhibitors with azacitidine/decitabine/LDAC or available targeted therapies such as FLT3/IDH1/IDH2/anti-CD33 antibodies;

1. AML in 1st relapse with initial CR duration < 6 months,
2. a maximum of up to 2 prior salvage attempts is allowed.
3. Eastern Cooperative Oncology Group (ECOG) performance status ≤2
4. Life expectancy of at least 4 weeks
5. Peripheral blast count </= 20,000/mm3 at the time of registration
6. Acceptable laboratory parameters and adequate organ reserve

• History of allogeneic stem cell transplantation.
• Prior treatment with an anti-CD123-directed agent, with the exception of patients with relapsed disease after flotetuzumab treatment
• Need for concurrent other cytoreductive chemotherapy
• Any prior history of or suspected current autoimmune disorders (with the exception of vitiligo, resolved childhood atopic dermatitis, prior Grave's disease now euthyroid clinically and by laboratory testing)
• Second primary malignancy that requires active therapy. Adjuvant hormonal therapy is allowed.
• Antitumor therapy or investigational agent within 14 days or 5 half-lives of Cycle 1 Day 1
• Requirement, at the time of study entry, for concurrent steroids > 10 mg/day of oral prednisone or the equivalent, except steroid inhaler, nasal spray or ophthalmic solution
• Use of immunosuppressant medications in the 2 weeks of Cycle 1 Day 1
• Use of granulocyte colony stimulating or granulocyte-macrophage colony stimulating factor in the 2 weeks of Cycle 1 Day 1
• Known central nervous system (CNS) leukemia.