Human platelet lysate (HPL), rich in growth factors, is an efficient alternative supplement to fetal bovine serum (FBS) for ex vivo propagation of stromal cell-based medicinal products.

Since 2014, HPL has been a focus of the Working Party for Cellular Therapies of the International Society of Blood Transfusion (ISBT). Currently, as several Good Manufacturing Practice (GMP)-compliant manufacturing protocols exist, an international consensus defining the optimal modes of industrial production, product specification, pathogen safety, and release criteria of this ancillary material (AM) is needed.

This opinion article by the ISBT Working Party summarizes the current knowledge on HPL production and proposes recommendations on manufacturing and quality management in line with current technological innovations and regulations of biological products and advanced therapy medicinal products.

Human platelet lysate (HPL) is an effective novel growth medium supplement for xenofree ex vivo propagation of human cells for cell therapy and regenerative medicine.

Consensus is needed to ensure the quality and safety of HPL supplements regarding the source of platelet concentrates, donor variability, manufacturing processes, and minimum release criteria.

It is critical to guarantee HPL pathogen safety by implementing measures including screening blood donors, pathogen testing of platelet concentrates, and, for large pools, implementing dedicated virus reduction treatments. International consensus between the various stakeholders (blood establishments, the biotechnology industry, and regulators) seems close to delineating the required quality and safety criteria.

The development of functional correlates for the various cell types supported by HPL is needed.