Normal Neurodevelopment and Fertility in Juvenile Male Rats Exposed to Polyethylene Glycol Following Dosing With PEGylated rFIX (Nonacog Beta Pegol, N9-GP): Evidence from a 10-Week Repeat-Dose Toxicity Study.

N9-GP/Rebinyn®/Refixia® is an approved PEGylated (polyethylene glycol-conjugated) recombinant human factor IX intended for prophylactic and/or on-demand treatment in adults and children with haemophilia B. A juvenile neurotoxicity study was conducted in male rats to evaluate effects on neurodevelopment, sexual maturation, and fertility following repeat-dosing of N9-GP. Male rats were dosed twice weekly from Day 21 of age with N9-GP or vehicle for 10 weeks, followed by a dosing-free recovery period for 13 weeks and terminated throughout the dosing and recovery periods. Overall, dosing N9-GP to juvenile rats did not result in any functional or pathological effects, as measured by neurobehavioural/neurocognitive tests, including motor activity, sensory function, learning and memory as well as growth, sexual maturation, and fertility. This was further supported by the extensive histopathologic evaluation of brain tissue. Exposure and distribution of polyethylene glycol was investigated in plasma, choroid plexus, cerebrospinal fluid, and brain sections. PEG did not cross the blood brain barrier and PEG exposure did not result in any effects on neurodevelopment. In conclusion, dosing of N9-GP to juvenile rats did not identify any effects on growth, sexual maturation and fertility, clinical and histological pathology, or neurodevelopment related to PEG exposure and supports the prophylactic use of N9-GP in children.

Neonatal subchronic toxicity and in vitro genotoxicity studies of the human-identical milk oligosaccharide 3-fucosyllactose.

Human milk oligosaccharides, such as 3-fucosyllactose (3-FL), are bioactive components of breast milk associated with benefits for infant growth and development. Structurally identical compounds (human-identical milk oligosaccharides-HiMOs) can be produced using microbial fermentation, allowing their use in infant formula to increase its similarity with human milk. Toxicological studies are required to demonstrate safety of HiMOs and that of any impurities potentially carried over from the manufacturing process. Biotechnologically produced 3-FL was tested for potential genotoxicity (bacterial reverse mutation test and in vitro mammalian micronucleus test) and subchronic toxicity (90-day study with neonatal rats). In the 90-day study, 3-FL was administered by gavage to rats once daily from Day 7 of age, at doses up to 4000 mg/kg body weight (bw)/day (the maximum feasible dose), followed by a 4-week recovery period. Reference controls received 4000 mg/kg bw/day of oligofructose, an ingredient permitted for use in infant formula. Results for the genotoxicity studies were negative. In the 90-day study, there were no adverse effects of 3-FL on any of the parameters measured; thus, the no-observed-adverse-effect level (NOAEL) was 4000 mg/kg bw/day (the highest dose tested). These results support the safety of biotechnologically produced 3-FL for use in infant formula and other foods.

The potential developmental neurotoxicity of calcium cyclamate in CD rats.

The developmental neurotoxicity of calcium cyclamate was evaluated in Sprague Dawley [Crl:CD(SD)] rats, administered in drinking water, in comparison to a concurrent control group (water) and a positive control group given propylthiouracil (PTU). Calcium cyclamate was administered to F0 females for 4 weeks prior to pairing, throughout mating, gestation and lactation and to F1 offspring from weaning to 12 weeks of age, PTU was administered by gavage to F0 females from Day 6 of gestation up to Day 20 of lactation. Target calcium cyclamate doses were 0, 250, 500 and 1,000 mg/kg bw/day, while the PTU dose was 0.5 mg/kg bw/day. No treatment-related effects of cyclamate were observed in either the F0 or F1 generations on reproductive performance or neurobehavioral development. In comparison, PTU exposure resulted in developmental delays, memory impairment and a number of neuropathological and morphometric outcomes. The results from the unique developmental neurotoxicity study design, corroborate the absence of hyperactivity and any other neurotoxic effects following cyclamate administration at levels up to 878 mg/kg bw/day in F0 females and 784 mg/kg bw/day in F1 animals. This demonstrates the suitability of PTU as a positive control and confirms the safe use of cyclamate as a no-calorie sweetener.

Genotoxicity and neonatal subchronic toxicity assessment of a novel mixture of the human-identical milk oligosaccharides lacto-N-fucopentaose I and 2'-fucosyllactose.

Human milk oligosaccharides (HMOs) are a complex group of bioactive molecules largely observed in human breast milk but also occurring in limited amounts in other mammalian milks. Advances in biotechnology have enabled production of human-identical milk oligosaccharides (HiMOs), structurally identical molecules to HMOs found naturally in human milk, intended for addition to infant formula to more closely replicate breast milk. Biosynthesis of a novel mixture of two major HMOs, lacto-N-fucopentaose I and 2'-fucosyllactose (LNFP-I/2'-FL), recently became possible. To support the safety of LNFP-I/2'-FL for use in infant formula and other foods, it was subject to a safety assessment comprising a bacterial reverse mutation test, an in vitro mammalian cell micronucleus test, and a 90-day oral gavage study in neonatal rats. In the 90-day study (the first HiMO study to include the new endocrine-sensitive endpoints described in the 2018 version of OECD Test Guideline 408), LNFP-I/2'-FL was administered by oral gavage to neonatal rats once daily (from Day 7 of age) for 90 consecutive days, at doses up to 5000 mg/kg bw/day, followed by a 4-week recovery period. Concurrent reference controls received 5000 mg/kg bw/day of the approved infant formula ingredient oligofructose. LNFP-I/2'-FL was nongenotoxic in vitro. The highest dose tested (5000 mg/kg bw/day) was established as the no-observed-adverse-effect level in the 90-day study, as there were no test article-related adverse effects on clinical observations, body weight, food consumption, clinical pathology, and organ weights nor any noteworthy macroscopic or microscopic findings. This supports the safety of LNFP-I/2'-FL for its intended uses in food.

Toxicological safety evaluation of the human-identical milk oligosaccharide 6'-sialyllactose sodium salt.

Human milk oligosaccharides (HMOs) are abundant in breastmilk, but their presence in infant formula is negligible. Sialylated HMOs, such as 6'-sialyllactose, constitute a significant portion of the HMO fraction of human milk and are linked to important biological functions. To produce infant formula that is more comparable with human milk, biosynthesized sialyllactoses known as human-identical milk oligosaccharides (structurally identical counterparts to their respective naturally occurring HMOs in breastmilk) are proposed for use in infant formula and other functional foods for the general population. To support the safety of 6'-sialyllactose sodium salt (6'-SL), a 90-day oral (gavage) toxicity study and in vitro genotoxicity tests were conducted. The 90-day study is the first to be conducted with 6'-SL using neonatal rats (day 7 of age at the start of dosing), thus addressing safety of 6'-SL for consumption by the most sensitive age group (infants). In the 90-day study, neonatal rats received 6'-SL at doses up to 5000 mg/kg body weight (BW)/day and reference controls received 5000 mg/kg BW/day of fructooligosaccharide (an ingredient approved for use in infant formula) for comparison with the high-dose 6'-SL group, followed by a 4-week recovery period. There was no evidence of genotoxicity in vitro. No test item-related adverse effects were observed on any parameter in the 90-day study, thus the high dose (5000 mg/kg BW/day) was established as the no-observed-adverse-effect level. These results confirm that 6'-SL is safe for use in formula milk for infants and in other functional foods for the general population.

Toxicological safety assessment of the human-identical milk oligosaccharide 3'-sialyllactose sodium salt.

Human breastmilk is a mixture of nutrients, hormones and bioactive molecules that are vital for infant growth and development. Infant formula (IF) lacks many of these compounds, most notably human milk oligosaccharides (HMOs), which are abundant in breastmilk but scarce in IF. Sialyllactoses, such as 3'-sialyllactose, constitute a large portion of the HMO fraction. To produce IF that matches breastmilk more closely, biosynthesized human-identical milk oligosaccharides (structurally identical to HMOs) such as 3'-sialyllactose sodium salt (3'-SL) are proposed for use in IF and foods for the general population. The safety assessment of 3'-SL comprised in vitro genotoxicity tests and a 90-day oral (gavage) toxicity study. This is the first 90-day study conducted with 3'-SL using neonatal rats (7 days old at the start of dosing-equivalent age to newborn human infants in terms of central nervous system and reproductive development), demonstrating the safety of 3'-SL for consumption by infants, the most sensitive age group. The neonatal rats received 3'-SL at doses up to 5,000 mg/kg body weight (BW)/day and reference controls received 5,000 mg/kg BW/day of fructooligosaccharide (an ingredient approved for use in IF) for comparison with the high-dose 3'-SL group, followed by a 4-week recovery period. There was no evidence of genotoxicity in vitro. In the absence of any test item-related adverse effects in the 90-day study, the high dose (5,000 mg/kg BW/day) was established as the no-observed-adverse-effect level. This confirms the safety of 3'-SL for use in IF for infants, as well as in functional foods for the general population.

Preclinical safety evaluation of the human-identical milk oligosaccharide lacto-N-tetraose.

Lacto-N-tetraose (LNT) is one of the most abundant oligosaccharides that are endogenously present in human breast milk. To simulate the composition of human breast milk more closely, commercial infant formula can be supplemented with human-identical milk oligosaccharides, which are manufactured structurally identical versions of their naturally occurring counterparts. As part of the safety evaluation of LNT, in vitro genotoxicity tests and a subchronic oral gavage toxicity study (in neonatal Sprague-Dawley rats) were conducted. In the subchronic study, LNT was administered at dose levels of 0, 1,000, 2500 or 4000 mg/kg body weight (bw)/day, once daily for at least 90 days, followed by a 4-week treatment-free period. An identically comprised reference control group received fructooligosaccharides powder (a non-digestible oligosaccharide used in infant formula) at 4000 mg/kg bw/day, to allow for direct comparison against the high-dose LNT group. LNT was non-genotoxic in the in vitro tests. There were no compound-related adverse effects in the 90-day study; therefore, 4000 mg/kg bw/day (the highest feasible dose) was established as the no-observed-adverse-effect-level. These results support the safe use of LNT in infant formula and as a food ingredient, at levels not exceeding those found naturally in human breast milk.