The purpose of this study is to evaluate the safety and the efficacy of SMART101 (Human T Lymphoid Progenitors (HTLP)) injection to accelerate immune reconstitution after haploidentical hematopoietic stem cell transplantation (HSCT) with post-transplant cyclophosphamide (PT-Cy) in adult patients with hematological malignancies.

Main Inclusion Criteria:

• Patients with AML, ALL or MDS eligible for an allogeneic HSCT with a haploidentical donor with post-transplant cyclophosphamide.
• Patients must be ≥ 18 years of age at the time of signing the ICF.
• Patients must have a Karnofsky index ≥ 70%.
• Patients must have a left ventricular ejection fraction of ≥40%.
• Patients must have an intact pulmonary function or Diffusing capacity of the Lungs for Carbon Monoxide (DLCO) ≥ 45% of predicted.
• Patients must have adequate hepatic and renal functions, as assessed by standard laboratory criteria.

Main Exclusion Criteria:

• Patients who have received prior allogeneic stem cell transplantation.
• Patients who have received prior treatment with another cellular therapy within 4 weeks before the planned day of SMART101 infusion.
• Patients who plan to receive, are concurrently receiving or have received any investigational agent within 4 weeks before the planned day of SMART101 infusion.