Dose Escalation Study of JNJ-63709178, a Humanized CD123 x CD3 DuoBody in Participants With Relapsed or Refractory Acute Myeloid Leukemia (AML)

This is first-in-human (FIH) Phase 1, open-label (identity of assigned study drug will be
known), multicenter, dose escalation study with dose expansion to identify the RP2D and to
evaluate the safety, tolerability, and preliminary antitumor activity of JNJ-63709178 in
adult participants with relapsed or refractory acute myeloid leukemia (AML) who are
ineligible for or have exhausted standard therapeutic options. The study is divided into 3
periods: a Screening Phase (within 28 days before the first dose of study drug), a Treatment
Phase (first dose of study drug until the last dose of study drug) and a Post-treatment
Follow-up Phase (up to the end of study participation or end of study). Participants' safety
will be monitored throughout the study.

Inclusion Criteria:

- A diagnosis of acute myeloid leukemia (AML) according to the World Health Organization
2008 criteria with relapsed or refractory disease and ineligible for or have exhausted
standard therapeutic options

- Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1

- Hematology laboratory parameters within the Protocol specified range

- Chemistry laboratory parameters within the Protocol specified range

- A woman of childbearing potential must have a negative highly sensitive serum (beta
human chorionic gonadotropin [b-hCG]) or urine test prior to the first dose of study
drug

Exclusion Criteria:

- Acute promyelocytic leukemia

- Active central nervous system involvement

- Prior solid organ transplantation

- Prior hematopoietic stem cell transplant within 6 months of enrollment. If the
participant had an allogenic transplant there must be no apparent signs of graft
versus host disease and participants must have discontinued all immunosuppressive
therapies for at least 4 weeks

- Prior treatment with a CD123xCD3 bispecific agent, T cells expressing CD123 specific
chimeric antigen receptor, or toxin-conjugated to CD123 antibodies; prior treatment
with naked anti-CD123 monoclonal antibody is permitted