No adverse effects were seen in this acute study. In a repeated administration toxicity study, male Sprague Dawley rats were treated iv with PEG-60 in doses up to 11.0 mg kg−1 every other day for 4 weeks. Clinical parameters and laboratory assays as noted above and postmortem examination, such as necropsy, organ weight analysis and light microscopic histopathology of all organs and tissues, were conducted to assess potential adverse

changes. The highest dose of 11 mg kg−1 used in the repeated administration study is in the range of the total expected cumulative lifetime dose of PEG-60 Silmitasertib ic50 to be given with BAY 94–9027 in humans. Rats received up to 11 mg kg−1 every other day for 4 weeks and no adverse effects or histopathological changes were observed after treatment with PEG-60. Standard genotoxicity studies with the PEG-60 part of BAY 94–9027 were negative. In addition, the non-clinical programme with BAY 94-9027 assessed systemic toxicity, including male reproductive organ effects (addressing reproduction and fertility) and local tolerance. BAY 94–9027 did not induce any protein- or PEG-related adverse effects. No vacuolation of any organ or tissue was seen. Carcinogenicity studies were not considered necessary, as neither the protein (FVIII) nor

the PEG part of BAY 94–9027 has any genotoxic potential, nor do they express any mechanism that is related with tumour formation. The non-clinical safety programme is based on the ICH Romidepsin S6 (R1) guideline of biotechnology products and accepted practice in biotechnology industry. The majority of published metabolism studies have investigated low molecular weight PEGs [13]. Although no data have been published on the metabolism of PEGylated biologics, there is evidence that the protein part is degraded by proteases with release of their PEG-moieties Bay 11-7085 [12, 13]. The only comprehensive

and often cited data set on the elimination of different molecular weight PEGs have been generated in mice by Yamaoka et al. [38, 39]. Polyethylene glycol in the range of 50 kDa had a long half-life in circulation, but lower organ accumulation compared with PEGs of other molecular weights (higher and lower). The following summarizes some of their findings in mice: Small PEG molecules are more rapidly cleared from circulation than large ones (which are still cleared, but slower), e.g. the half-life for a 3 kDa PEG increases from 18 min to 24 h for a 190 kDa PEG. PEG excretion is closely related to the half-life in circulation. Larger PEG molecules do not permeate into tissue to the degree as smaller PEGs of molecular weight 20 kDa and below.