HSC100 Tacitus

Clinical Stage Program


HSC100 is an investigational therapy based on allogeneic hematopoietic stem cells (HSCs) expanded from umbilical cord blood (CB). HSC100 is being investigated currently in an open-label Phase I clinical trial1 in the United States for treatment of hematological malignancies.

The success of unmanipulated CB as a source of stem cells has been hampered by the small number of stem cells present in a single cord, leading to delayed engraftment and frequent graft failure. Our proprietary technology includes the use of an epigenetic modifier, valproic acid (VPA), to expand the number and the quality of HSCs found in cord blood collections.

For more information on HSC100 clinical trials, please visit www.clinicaltrials.gov.


HSC Therapy

HSC transplantation has been in medical practice for over 60 years. Tens of thousands of procedures are conducted annually in the U.S. for patients with blood cancers and other severe conditions. Despite this success, many patients fail to receive the treatment because they cannot be matched to a suitable donor for a transplant. Some patients suffer serious, lifelong adverse events, such as infections, or graft versus host disease (GVHD). Although the use of umbilical cord blood HSC units has allowed patients without suitable donors receive life saving therapy, it has been associated with delayed recovery of peripheral blood cell counts, immune reconstitution, and increased risk of graft failure. With HSC100 we aim to overcome these limitations and enable all patients to safely benefit from readily available HSC therapy.


Tacitus Therapeutics’ proprietary CB expansion technology retains and improves inherent advantages of CB-sourced stem cells while solving traditional CB problems such as low cell numbers, engraftment inefficiency, infection, and cost. Advantages of CB-sourced stem cells over bone-marrow (BM)-sourced stem cells for transplantation include quick availability from banks where cords are stored, enhanced graft-versus-leukemia (GVL) effect, lower risk of chronic GVHD, and greater tolerance of mismatch. HSC100 is being investigated as a superior and safer alternative therapy to haploidentical BM transplantations.

1ClinicalTrials.gov identifier NCT03885947.

HSC100 Advantages


Hematologic malignancies are cancers that affect the body’s blood, bone marrow, or lymphatic systems. They are the fifth most commonly occurring cancers and the second leading cause of cancer death. The most common forms of hematologic cancers include leukemia, lymphoma, and multiple myeloma.