This research study is evaluating the safety and efficacy of the IS-free Treg-cell graft-engineered haplo transplant method in people with relapsed/refractory and Ultra-high risk acute myeloid leukemia (AML) and/or myelodysplastic syndromes (MDS) receiving a haploidentical donor allogeneic hematopoietic stem cell transplant (HSCT).
The names of the study interventions involved in this study are:
* Radiation-Total Myeloid and Lymphoid Irradiation (TMLI) * Chemotherapy (Fludarabine, Thiotepa, Cyclophosphamide plus Mesna) * Infusion of haplo Treg-enriched donor cells (experimental therapy) * Infusion of unmodified haplo donor T cells (includes cancer-fighting T effector cells) * Infusion of haplo donor CD34+ Peripheral Blood Stem Cells
Cohort A: Histologically confirmed disease in the prior 4 weeks, despite at least 1 prior line of therapy (e.g., 3+7 chemotherapy, HMA therapy): Rel/ref AML (de novo or secondary) with ≥5% blasts in BM (or extramedullary sites); MDS EB-2 (BM ≥10% blasts, PB 5-19% blasts).
Cohort B: Ultra high-risk AML or MDS that meets definition of 'Myeloid Neoplasms with mutated TP53' per 2022 International Consensus Classification (Appendix L) regardless of response
Cohort C: Ultra high-risk AML or MDS that meets definition of 'Myeloid Neoplasms with multi-hit or complex karyotype (CK+) mutated TP53' per 2022 International Consensus Classification (Appendix L) with response: AML (de novo or secondary) with <5% blasts in BM; MDS with <10% blasts in BM or PB.
Available haploidentical HLA-matched (-A, -B, -C, -DRB1) related donor aged 18-65 years.
Participants who have had cytotoxic chemotherapy or radiotherapy within 2 weeks (4 weeks for nitrosoureas or mitomycin C) prior to entering the study. Use of hydroxyurea, HMA, e.g., azacytidine, decitabine) and/or FDA-approved novel targeted agents (e.g., venetoclax, FLT-3 inhibitors, IDH 1/2 inhibitors) are permitted up to a day prior to start of HCT conditioning.
Participants who have not recovered from adverse events due to prior anti-cancer therapy (i.e., have residual non-hematologic toxicities > Grade 1) with exception of alopecia, unless cleared by study PI.
Participants who received Mylotarg or other therapies associated with increased risk of hepatic veno-occlusive disease (VOD) or have known prior or active VOD. All novel therapies will be reviewed with PI.
Participants who are receiving any other investigational agents within 21 days (or 5 half-lives) prior to study entry, whichever is longer, unless cleared by the study PI.
Parallel
Radiation
RadiationFor MAC regimen: Total Myeloid and Lymphoid Irradiation (TMLI) delivered through Radiation Oncology institutional standards and comprised of 13.5 Gy TMI (9 fractions, 1.5 Gy per fraction, 2 fractions per day) and 11.7 Gy TLI (9 fractions, 1.3 Gy per fraction, 2 fractions per day). OR Total Body Irradiation (TBI) comprised of 12 Gy (6 fractions, 2 Gy per fraction, 2 fractions per day) For RIC regimen: TBI comprised of 2 Gy in 1 fraction.
Fludarabine
DrugFor MAC regimen: 30 mg/m\^2/d in 100 ml normal saline (NS) will be administered as a bolus infusion administered by IV infusion over approximately 30 minutes for 5 days (on day -10, -9, -8, -7, -6) For RIC regimen: 40 mg/m\^2/d in 100 ml NS will be administered as a bolus by IV infusion over approximately 30 minutes for 4 days (on day -10, -9, -8, -7)
Thiotepa
DrugFor MAC regimen: 3.75 mg/kg diluted in NS to a final concentration of 1mg/mL will be administered by IV infusion over approximately 4 hours daily for 2 days (on day -10, -9) For RIC regimen: 5 mg/kg diluted in NS to a final concentration of 1mg/mL will be administered by IV infusion over approximately 4 hours twice daily for 1 day (on day -11)
Cyclophosphamide
DrugFor MAC regimen only: 15 mg/kg diluted in NS per institutional standard and will be administered by IV over 1 hour or as directed per institutional standard practice, daily on D-8, -7.
Mesna
DrugFor MAC regimen only: 3.75mg/kg (25% of cyclophosphamide dose) diluted in 50 mL NS and administered IV over 30 min, will be infused starting 30 min prior to cyclophosphamide and for 3 doses thereafter, at 3, 6 and 9h after cyclophosphamide
Treg-enriched donor cell
Biological/VaccineTarget 'Treg-enriched' cell dose is 1-2 x 10\^6 cells/kg. Cells will be given intravenously on Day -4. The day -1 calculated unmodified PBMC T ('Teff') cell dose will be adjusted to maintain a targeted cell ratio of 2 'Treg-enriched' cells:1 'Teff' cell.
Unmodified donor T Cell
Biological/VaccineUnmodified donor PBMCs will be infused at a calculated 'Teff' dose of 1x10\^6 CD3+ T cells/kg, adjusted per the caveats below: A) If the 'Treg-enriched' product infused was at target dose of 2x106 cells/kg but had ≥30% CD4+CD25+CD127hi cells, the unmodified 'Teff' (calculated) cell dose infused on day -1 will be halved to 0.5x10\^6 CD3+ T cells/kg. B) If the 'Treg-enriched' product was in the range of 1-2x106 cells/kg, the unmodified 'Teff' (calculated) cell dose on day -1 will be adjusted to between 0.5-1x10\^6 CD3+ T cells/kg, dosed to maintain a 2 'Treg-enriched':1 'Teff' (calculated) ratio of infused cells. C) If the 'Treg-enriched' product infused met both caveats A and B above, the unmodified 'Teff' (calculated) cell dose infused on day -1 will be halved to 0.5x10\^6 CD3+ T cells/kg.
CD34+ Haplo Peripheral Blood Stem Cell
Procedure/SurgeryThe megadose donor CD34+ PBSC infusion target is \>10x10\^6 CD34+ cells/kg (ABW or IBW, whichever is greater). If the CD34+ graft has \<6x10\^6 CD34+ cells/kg (ABW or IBW, whichever is greater) (below megadose minimum) it WILL be infused in order to rescue recipient hematopoiesis, and the patient will remain on study.
Melphalan
DrugFor RIC regimen only: 100 mg/m2 will be administered as a bolus by IV infusion over approximately 30 minutes for 1 day (on day -6)
Dose-limiting toxicities (DLT)
Safety will be assessed by dose-limiting toxicities (DLT) summarized by patient, type and grade as defined by the CTCAE v5.0.
Engraftment rate
Will be summarized descriptively and estimated in the competing risks framework treating death without GVHD or without engraftment as a competing event depending on the actual enrolled and evaluable number of patients.
secondary graft failure rate
Will be summarized descriptively and estimated in the competing risks framework treating death without GVHD or without engraftment as a competing event depending on the actual enrolled and evaluable number of patients.
graft vs host disease (GVHD) Rate
Incidence of grade II-IV and III-IV acute graft vs host disease (GVHD) by day 180 after HCT
Mortality Rate-GVHD Relapse
Will also be summarized descriptively, estimated in the competing risks framework treating each event as a competing event. Corresponding 95% CIs will be provided.
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