Toxicological testing of allogeneic secretome derived from peripheral mononuclear cells (APOSEC): a novel cell-free therapeutic agent in skin disease

Abstract

A cell-free approach using secretomes derived from stem cells or peripheral blood mononuclear cells is an active area of regenerative medicine that holds promise for therapies. Regulatory authorities classify these secretomes as biological medicinal products, and non- clinical safety assessment thus falls under the scope of ICH S6. A secretome of stressed peripheral blood mononuclear cells (APOSEC) was successfully tested in a toxicology program, supporting clinical use of the new drug candidate. Here, to allow for topical, dermal treatment of patients with diabetic foot ulcer, several non-clinical safety studies were performed. Acute toxicity (single dose) and neuropharmacological screening were tested intravenously in a rat model. Risk for skin sensitisation was tested in mice. A 4-week intravenous toxicity study in mice and a 4-week subcutaneous toxicity study in minipigs were conducted to cover the clinical setting and application in a rodent and a non-rodent model. Acute and repeated-dose toxicity studies show that APOSEC administered intravenously and subcutaneously does not involve major toxicities or signs of local intolerance at levels above the intended total human maximal dose of 3.3 U/kg/treatment, 200 U/wound/treatment, and 100 U/cm 2 /treatment. The non-clinical data support the safe topical use of APOSEC in skin diseases related to deficient wound healing.

Reproducibility of GMP-compliant production of therapeutic stressed peripheral blood mononuclear cell-derived secretomes, a novel class of biological medicinal products

“…Since allergic reactions to methylene blue treatments have been reported, too high concentrations of methylene blue in the final product represent an exclusion criterion. As safety and tolerability of PBMC secretome have already been demonstrated in our toxicology study [40] and our phase I clinical trial, we consider the presence of methylene blue and other impurities of our secretome as low risk. Taken together, the most appropriate and most meaningful parameters reflecting identity, potency, purity, and safety of each secretome may be determined by extensive drug product characterization and, optionally, after consultation with responsible authorities.…”

“…Moreover, secretomes may be provided as off-the-shelf products. Toxicity studies for subcutaneous administration of PBMC sec have already been conducted in which subcutaneous injection of PBMC sec was well tolerated [40]. With this in mind, use of cell-free secretomes may be preferable to using cells for therapeutic approaches whenever feasible.…”

“…Suitability of culture media for clinical use requires thorough risk management, and the quality of the media therefore needs to be carefully assessed in the course of incoming goods inspections. With regard to PBMC sec , we performed toxicology studies with repeated intravenous and subcutaneous application of the secretome containing medium in two animal models, which was well tolerated [40]. Moreover, a phase I safety clinical trial with topical application of PBMC sec was successfully performed (ClinicalTrials.gov Identifier: NCT02284360), where safety and tolerability were demonstrated and no therapy-related, serious adverse events were observed [48].…”

Tissue-regenerative potential of the secretome of γ-irradiated peripheral blood mononuclear cells is mediated via TNFRSF1B-induced necroptosis

“…Thus, future clinical studies on damaged tissue will elucidate the full tissue-regenerative efficacy of the PBMC-derived secretome. Since toxicological studies and studies on the viral safety of an allogeneic secretome from γ-irradiated PBMC produced under Good Manufacturing Practice (GMP) conditions have already been successfully conducted, our study paves the way for a first clinical trial in the indication of diabetic foot ulcer 45,46 .…”

Role for Lipids Secreted by Irradiated Peripheral Blood Mononuclear Cells in Inflammatory Resolution in Vitro

“…Previously, efficacy of viral clearance has been demonstrated by Gugerell et al [35]. Moreover, toxicological testing with subcutaneous and intravenous application of PBMC secretome has been performed with no adverse events related to the PBMC secretome [36]. Reproducibility and good manufacturing practice-compliant production of the PBMC secretome have been successfully demonstrated [37] and a phase I clinical trial confirmed pre-clinical findings when no secretome-related adverse events were observed when topically administering autologous irradiated PBMC-derived secretomes in healthy volunteers (ClinicalTrials.gov Identifier: NCT02284360) [38].…”