A Phase 2 Study of Donor-Derived Multi-Tumor-Associated Antigen Specific T Cells (MT-401) Administered to Patients With Acute Myeloid Leukemia (AML) Following Hematopoietic Stem Cell Transplantation

This study is in patients aged ≥18 years old undergoing or having relapsed after their first allogeneic HSCT (matched sibling, matched unrelated donor, or haploidentical transplants) for AML.

Potential patients for the study may be screened/enrolled:

• Prior to their first allogeneic HSCT.

or

• Patients experiencing their first relapse post-allogeneic transplant.

Patients eligible for the study will be placed into one of two groups:

• Adjuvant (Group 1): Patients screened prior to their HSCT with CR without minimal residual disease (CRMRD-) at 90 days post transplant will be randomized (1:1) in an unblinded fashion to:
  • MT-401 (Arm A)
  • SOC (Arm B)
• Active Disease: (Group 2): Patients meeting the following criteria will be assigned to Group 2 and will receive MT 401:
  • Patients who experience relapse (patients with MRD [MRD+] or frank relapse) at or prior to post-transplant Day 90
  • Patients in Arm B of Group 1 (SOC) who develop relapse (MRD+ or frank relapse) post-HSCT (crossover patients)
  • Patients who do not consent prior to HSCT but are experiencing their first relapse (MRD+ or frank relapse) and have the same donor available for manufacturing

Inclusion Criteria

1. First allogeneic HSCT, in ≤ CR2, and MRD negative prior to transplant (including matched sibling, MUD with at least 6 of 8 HLA markers, or haploidentical with at least 5 of 10 HLA markers) as:
   • Adjuvant therapy for AML (Group 1) at 90 days (±10 days) post-HSCT defined as patients with CRMRD; or
   • Treatment for refractory/relapsed AML (first relapse post-HSCT) when disease occurs after transplant (Group 2) defined as
     • First relapse (MRD+ or frank relapse) post-HSCT
     • Patients in Arm 1B (SOC) who experience first relapse (MRD+ or frank relapse) post HSCT
   • Safety Lead-in defined as patients who fit all the criteria for Group 2 only
2. Are ≥18 years of age
3. Karnofsky/Lansky score of ≥60
4. Life expectancy ≥12 weeks
5. Adequate blood, liver, and renal function
   • Blood: Hemoglobin ≥7.0 g/dL (can be transfused)
   • Liver: Bilirubin ≤2X upper limit of normal; aspartate aminotransferase ≤3X upper limit of normal
   • Renal: Serum creatinine ≤2X upper limit of normal or measured or calculated creatinine clearance ≥45mL/min

7. Patients are allowed to be on experimental conditioning regimens prior to transplant if no planned maintenance therapy post-transplant.

8. In Group 2, patients may receive bridging therapy at the investigators' discretion in situations where MT-401 is not ready for administration or the treating physician believes the patient would benefit

Exclusion Criteria

1. Clinically significant or severely symptomatic intercurrent infection
2. Pregnant or lactating
3. For Group 1, anti-neoplastic therapy after HSCT and prior to or during dosing of MT-401
4. For Group 2, concomitant anti-neoplastic therapy during or after dosing of MT-401
5. Evidence of acute or chronic GVHD ≥Grade 2 (exception: acute or chronic Grade 2 GVHD of skin allowed if stable) within one week prior to receiving MT-401