GTB-3550 Tri-Specific Killer Engager (TriKE®) for High Risk Hematological Malignancies

Inclusion Criteria: Eligible Diseases * Diagnosis of one of the following CD33-expressing myeloid malignancies with greater than or equal to 50% CD33+ target cells with no good standard of care treatment options including: * High Risk Myelodysplastic Syndromes (MDS) progressive on two or more prior regimens and requiring treatment that meets at least one of the following: * Revised International Prognostic Scoring System (IPSS-R) High or Very High Risks * World Health Organization (WHO) Classification: Refractory anemia with excess blasts-1 (RAEB-1) or RAEB-2 * Poor and very-poor risk cytogenetic abnormality as defined by the IPSS-R cytogenetic classifications * WHO Based Prognostic Scoring System (WPSS): High or Very High Risk * Therapy related MDS and not a candidate for induction chemotherapy or had an inadequate treatment response after induction chemotherapy. * Refractory or Relapsed Acute Myelogenous Leukemia (AML) meeting at least one of the following: * Refractory AML defined as failure to achieve remission after at least 3 induction attempts \*\* Elderly AML not fit for induction therapy can be enrolled after 2 failed inductions * Relapsed AML * Not a candidate for hematopoietic stem cell transplant (HSCT), at least one re-induction attempt required * Prior HSCT relapse beyond 3 months may be included only if off immunosuppression for a minimum of 4 weeks and do not have graft-versus-host disease (GVHD) * Advanced systemic mastocytosis (d…