NCT04849910

Allogeneic Engineered Hematopoietic Stem Cell Transplant (HCT) Lacking the CD33 Protein, and Post-HCT Treatment With Mylotarg, for Patients With CD33+ AML or MDS

A First-In-Human, Open-Label, Multicenter Study of VOR33 in Patients With Acute Myeloid Leukemia Who Are at High-Risk for Leukemia Relapse Following Hematopoietic Cell Transplantation

• Status: Terminated
• Phase: Phase 1 / Phase 2
• Study type: Interventional
• Enrollment: 67 (actual)
• Sponsor: Vor Biopharma · Industry
• Sex: All
• Age: 18 Years – 70 Years
• Healthy volunteers: Not accepted

Summary

This is a Phase 1/2a, multicenter, open-label, first-in-human (FIH) study of VOR33 in participants with AML or MDS who are undergoing human leukocyte antigen (HLA)-matched allogeneic hematopoietic cell transplant (HCT).

Detailed description

High risk acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) frequently relapses despite hematopoietic stem cell transplant (HCT). Post-HCT targeted therapy to reduce relapse is limited by toxicity to the engrafted cells. VOR33, an allogeneic CRISPR/Cas9 genome-edited hematopoietic stem and progenitor cell (HSPC) therapy product, lacking the CD33 protein, is being investigated for participants with CD33+ AML or MDS at high risk for relapse after HCT to allow post-HCT targeting of residual CD33+ acute AML cells using Mylotarg™ without toxicity to engrafted VOR33 cells. Participants will undergo a myeloablative HCT with matched related or unrelated donor CD34+-selected hematopoietic stem and progenitor cells (HSPCs) engineered to remove CD33 expression (VOR33 product). Mylotarg™ will be given after engraftment for up to 4 cycles. The primary endpoint assessing safety of VOR33 will be the incidence of successful engraftment at 28 days. Part 1 of this study will evaluate the safety of escalating Mylotarg™ dose levels to determine the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D). Part 2 will expand the number of participants to evaluate the Mylotarg™ RP2D.

Conditions

• Leukemia, Myeloid, Acute
• Myelodysplastic Syndromes

Interventions

Type	Name	Description
BIOLOGICAL	VOR33	Allogeneic, human leukocyte antigen (HLA) matched, genome edited hematopoietic stem and progenitor cell (HSPC) therapy product lacking the CD33 myeloid protein
DRUG	Mylotarg	Infusion of Mylotarg

Timeline

• Start date: 2021-12-16
• Primary completion: 2025-05-28
• Completion: 2025-05-28
• First posted: 2021-04-19
• Last updated: 2025-07-29

Locations

15 sites across 2 countries: United States, Canada

Regulatory

• FDA-regulated drug study