Zalmoxis is a medicine used as an add-on treatment in adults who have received a haematopoietic stem cell transplant (HSCT, a transplant of cells that can develop into different types of blood cells) from a partially matched donor (a so-called haploidentical transplant). Zalmoxis is used in patients who have received a haploidentical HSCT because they have serious blood cancers, such as certain leukaemias and lymphomas. Before receiving an HSCT, the patient will have received treatment to remove existing cells from the bone marrow, including cancer cells and immune cells. Zalmoxis is given to help restore the patient’s immune system after the transplant. The product is composed of allogeneic T cells genetically modified with a retroviral vector encoding for a truncated form of the human low affinity nerve growth factor receptor (ΔLNGFR) and the herpes simplex I virus thymidine kinase (HSV-TK Mut2).

Zalmoxis is a type of advanced therapy medicine called a ‘somatic cell therapy product’. This is a type of medicine containing cells or tissues that have been manipulated so that they can be used to cure, diagnose or prevent a disease. Zalmoxis contains T cells (a type of white blood cell) that have been genetically modified1. To make Zalmoxis, T cells from the HSCT donor are separated from the rest of the cells in the transplant. These T cells are then genetically modified to include a ‘suicide gene’.

Because the number of patients undergoing haploidentical HSCT is low, Zalmoxis was designated an ‘orphan medicine’ (a medicine used in rare diseases) on 20 October 2003 by the EMA. Zalmoxis is developed by MolMed S.p.A and the product has been given ‘conditional approval’ by the European Medicines Agency (EMA) in September 2016. This means that there is more evidence to come about the medicine, which the company is required to provide.