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Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
repeated dose toxicity: oral
Remarks:
combined repeated dose and carcinogenicity
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
March 2009 to March 2011
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2013
Report Date:
2013

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: OECD Guideline 451 (Carcinogenicity Studies)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Laboratories BV, 5961 Horst, Netherlands
- Strain: Hsd Cpb:Wu (SPF)
- Age at study initiation: approx. 7 weeks
- Weight at study initiation: males: 199-296 g, females: 153-218 g
- Housing: in groups of 2-3 rats in Makrolon® Type IV cages
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: approx. 3 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 2
- Humidity (%): approx. 55
- Air changes (per hr): >= 10
- Photoperiod (hrs dark / hrs light): 12 / 12

IN-LIFE DATES: March 2009 - March 2011

Administration / exposure

Route of administration:
oral: feed
Vehicle:
unchanged (no vehicle)
Details on oral exposure:
BAY 54-9085 was administered in the diet. The test substance was mixed into the diet at the appropriate concentrations at room temperature and maximally used over the stability period determined by analytical investigation. The test item was blended (using a mixing granulator manufactured by Loedige, Paderbom, Germany) with the diet Provimi Kliba 3883 G4 S15. For the preparation of the mixtures the content of test item was assumed to be nominally 100 %.

To ensure a constant test substance intake on a mean mg/kg body weight basis (separately for males and females) the concentrations of the diet (in ppm) were adjusted weekly, except in weeks 40, 41 and 93, to reach the scheduled dose (in mg/kg bw). The calculations were based on the data obtained from animals of the main groups.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
ANALYSES DONE PRIOR TO THE STUDY
Before the start of this study, the suitability of the test item/food mixtures was confirmed by the analysis of mixtures containing the test item in concentrations covering the concentration range to be used in the study.

- Homogeneity: Dosage forms including the highest and lowest concentration were prepared. Three samples were taken from different places of the mixture and analyzed for concentration of the test material.

- Stability: The dosage forms prepared for homogeneity analysis were analyzed shortly after preparation and 15 days thereafter. The analysis revealed that the test item was stable over this period within the defined limits.

ANALYSES DONE DURING THE IN-LIFE PHASE
The test item concentration (all doses including vehicle control formulation) and homogeneity (low and high dose only) were checked for each part of the formulation (males and females) at begin and termination of the study and about every three months in between as a rule. Additionally, the content was determined for all test item /food mixtures used for day 22 to 28 and day 29 to 35.
Duration of treatment / exposure:
up to 747 days (approx. 24.5 months)
Frequency of treatment:
daily
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 0.1, 0.3, 1.0 mg/kg bw
Basis:
other: dose-adjusted via diet
No. of animals per sex per dose:
main groups: 50
satellite groups (for laboratory investigations and toxicokinetics): 15
Control animals:
yes, plain diet
Details on study design:
DOSE SELECTION RATIONALE:
The doses were selected based on the results of a preceding 13-week dose finding study (PH-35480) and was agreed with the FDA in the special protocol assessment procedure.
Positive control:
no

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: for morbidity and mortality twice daily; daily from May 03, 2010 onwards

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: weekly

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes

WATER CONSUMPTION: Yes
- Time schedule for examinations: weekly for the first 13 weeks

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: before start of treatment all main groups; after 12 months only control and high dose main groups; after 24 months all male main groups as well as control and high dose female main groups

HAEMATOLOGY: Yes
- Time schedule for collection of blood: 6, 12, 18 and 24 months after start of treatment
- Preparation of blood smears: 12, 18 and 24 months after start of treatment
- Anaesthetic used for blood collection: Yes (CO2/room air)
- Animals fasted: Yes
- How many animals: first 10 alive animals per satellite group; blood smears: all alive and moribund main group animals
- Parameters examined - peripheral blood: erythrocyte count, hemoglobin concentration, hematocrit, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, mean corpuscular volume, reticulocyte count, erythrocyte morphology, thrombocyte count, thromboplastin time (Hepato-Quick), leukocyte count, differential blood count; blood smears: differential blood count

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: 6, 12, 18 and 24 months after start of treatment
- Animals fasted: Yes
- How many animals: first 10 alive animals per satellite group
- Parameters examined: alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, glutamate dehydrogenase, gamma-glutamyl transferase, glucose, cholesterol, triglyceride, creatinine, potassium, urea, total bilirubin, total protein, albumin, chloride, calcium, inorganic phosphate,
sodium

URINALYSIS: Yes
- Time schedule for collection of urine: 6, 12, 18 and 24 months after start of treatment
- Metabolism cages used for collection of urine: Yes
- Animals fasted: Yes
- Parameters examined: density, volume, protein concentration, creatinine concentration, protein excretion, creatinine excretion, protein/creatinine ratio, pH, blood, bilirubin, glucose, ketone bodies, urobilinogen, microscopy of sediment

NEUROBEHAVIOURAL EXAMINATION: No

OTHER: toxicokinetics on days 3, 311/312 and 640 after start of treatment in all satellite groups
Sacrifice and pathology:
GROSS PATHOLOGY: Yes
- How many animals: all animals of the main groups living on the date of their scheduled necropsy and all animals killed in moribund state were sacrificed by exsanguination under deep diethyl etheranesthesia, necropsied and their organs and tissues subjected to thorough gross pathological examination; since March 9, 2009 this was true also for all satellite group rats; animals that died spontaneously during the study were necropsied at the earliest opportunity

HISTOPATHOLOGY: Yes
- How many animals: all main group animals
- Organs/tissues examined: abnormalities including tissue masses (tumors), adrenals, aorta, brain (3 regions), cecum, colon, duodenum, epididymitis, esophagus, exorbital lacrimal glands, eyes, femur (with bone marrow/joint), harderian glands, head with skull cap, heart, ileum, jejunum, kidneys, larynx, liver, lungs, lymph node (mandibular), lymph node (mesenteric), lymph nodes (popliteal), nasal cavities/nasopharnyx, ovaries/oviducts, optic nerves, pancreas, Peyer's patches, pharynx, pituitary gland, preputial/clitoral gland, prostate, rectum, salivary glands, sublingual gland, submandibular gland, parotid gland, sciatic nerve, seminal vesicles with coagulation glands, skeletal muscle, skin/mammary region, spinal cord 3x, spleen, sternum (with bone marrow), stomach, teeth, testes, thymus, thyroid/parathyroids, tongue, trachea, uterus with cervix, ureters, urethra, urinary bladder, vagina, zymbal glands
Statistics:
The statistical evaluation of data related to clinical chemistry, hematology, body and organ weights were performed using routines of the validated Pristima System. Statistical evaluations on body weight and organ weight data were done using the Dunnett test. Clinical chemistry and hematology data were evaluated using a Dunnett test, an adjusted U-test or an adjusted Welsh test.

All variables that are not dichotomous are described by sex, dose group and date using appropriate measures of central tendency (mean, median) and general variability (standard deviation, minimum, maximum). Statistical tests were not performed for groups, which are smaller than 3.

Data of food and water intake are reported only as group means, because individual data are not available due to the group wise measurement. In these types of statistical processing of measurement values a large number of comparisons were made, which may also lead to false-positive statements. On account of this problem for the evaluation not only the statistical significance but also the biological and toxicological relevance was considered.

For statistical evaluations of histopathological findings, statistical procedures implemented in the PATHDATA program were used.

Results and discussion

Results of examinations

Clinical signs:
no effects observed
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
no effects observed
Ophthalmological findings:
no effects observed
Haematological findings:
no effects observed
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
no effects observed
Behaviour (functional findings):
not examined
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Description (incidence and severity):
see "Details on results"
Histopathological findings: neoplastic:
no effects observed
Description (incidence and severity):
see also chapter 7.7 "Details on results"
Details on results:
CLINICAL SIGNS AND MORTALITY:
Intercurrent mortality was unaffected by dosing with BAY 54-9085. Causes of death were mostly related to common pathological findings in aging rats and were similar throughout the groups. Only in females of the satellite groups mortality at 1 mg/kg was higher compared to the other groups from 18 months onwards. However, as these unscheduled deaths occurred near the end of the study and as in main groups with a higher number of animals per group this was not observed, a treatment-related effect was not assumed.

At the dose of 1.0 mg/kg b.w./day detailed clinical observations revealed slightly higher incidences of males showing increased urine excretion, narrowed eye lids, emaciation, palpable masses and/or piloerection. However, there were no correlates (e.g. quantitative urinalysis or at histopathological evaluation) and no clear dose dependence occurred. As furthermore findings as emaciation, piloerection and/or narrowed eyelids were noted for animals shortly before unscheduled death these findings are not regarded to indicate a specific test substance related effect.

BODY WEIGHT GAIN:
Body weight development was not relevantly affected by the treatment.

FOOD CONSUMPTION AND COMPOUND INTAKE:
Food intake was not relevantly affected by the treatment.

The test item was administered orally dose-adjusted via diet in intended daily doses of 0, 0.1, 0.3 or 1 mg/kg body weight for a period of up to two years. Homogeneity and stability of the test item in the food mixtures were checked prior to study start. This analytical investigation showed the test item to be homogeneously distributed and stable in the concentration range used during the period of use.
Analyses during the study verified that the test item content agreed with the target concentrations and that the test item was homogeneously distributed in the food mixtures within the defined limits.

Single content values were out of the company defined limits. This is regarded to be due to the very low target concentrations. However, with one exception these mixtures were omitted for treatment of animals. The period of use extended the period of confirmed stability for the low dose diet formulation once during the study. Principally this is no matter of concern because high dose analytical data confirm sufficient stability for the feeding period. Taken together, it can be summarized that the animals were treated according to the scheduled doses and rare exceptions during the long treatment period did not affect the integrity of the study.

WATER CONSUMPTION:
Water intake was not relevantly affected by the treatment. Slightly lower water intake in the last weeks of the study was without treatment-related correlate at clinical pathology or histopathology of kidneys. A toxicological relevance is therefore not assumed.

OPHTHALMOSCOPIC EXAMINATION:
The ophthalmoscopical examinations of the control and 1.0 mg/kg dose group animals performed after about 12 months of treatment afforded no evidence for treatment-related effects. At the end of the dosing phase the examinations revealed an increased incidence of eyes showing diffuse cornea opacity at the dose of 0.3 mg/kg b.w./day and at 1.0 mg/kg b.w./day in males. This finding is known to occur predominantly in older male rats in feeding studies. This finding is not regarded due to the treatment as more as histopathological investigation did not reveal treatment-related effects on eyes.

HAEMATOLOGY AND CLINICAL CHEMISTRY INCL. URINALYSIS:
Hematological and clinico-chemical investigation gave no evidence for treatment-related effects.

ORGAN WEIGHTS:
Determination of organ weights revealed as the only conspicuous finding statistically significant decreased liver weights at 1.0 mg/kg (absolute weight was also decreased at the dose of 0.3 mg/kg b.w./day). A toxicological relevance is not inferred from these data as the differences were relatively slight, as no such observation was present for females and as histopathology gave no treatment-related corresponding findings.

GROSS PATHOLOGY:
In the testes, consistency changes were slightly more often recorded in males at the dose of 1.0 mg/kg b.w./day in the main groups (5/3/7/10) but considering also the satellite groups (2/4/1/0), distribution was similar in all groups. In the parathyroid glands of males, the finding of nodule/s was slightly increased at the dose of 1.0 mg/kg b.w./day (main groups 6/6/7/14, satellite groups 2/2/0/2). Most of these findings were seen in decedents where they did not correlate to any increase in incidence of severe diffuse hyperplasia.

In females, in the liver the incidence of cysts (main groups 8/12/10/4, satellite groups 211/7/1) and of distinct lobulation (main groups 13/10/4/5, satellite groups 1/1/1/0) was particularly low at the dose of 1.0 mg/kg b.w./day.

All other findings were distributed equally throughout the groups.

HISTOPATHOLOGY - NON-NEOPLASTIC CHANGES:
The incidence of vasculopathy was higher in animals of both sexes at the dose of 1.0 mg/kg b.w./day in the abdominal organs which are frequently affected by spontaneous vascular findings. In the stomach both arteritis/periarteritis and vasculopathy were positive in the trend test in males. In the other organs, only vasculopathy showed a positive trend in males (pancreas, spleen, mesentery lymph node). In females, for vasculopathy a positive trend was calculated in the pancreas and in the spleen.

In extraabdominal organs, no effect was discernible. The grade of the findings was most severe in the region of the pancreas and showed high inter-individual variation. No clear increase of severity of vasculopathy or periarteritis could be found up to and including the dose of 1.0 mg/kg b.w./day.

In the pancreas, focal atrophy of acinar cells was significantly increased in males at the dose of 0.3 mg/kg b.w./day and 1.0 mg/kg b.w./day (males 1/1/6*/7*; females 3/3/4/6). This finding is likely related to vascular changes in the abdomen described above.

With respect to possible treatment-related non-neoplastic alterations, in the abdominal organs, an increased incidence of peri-/arteritis and vasculopathy was observed at the dose of 1.0 mg/kg b.w./day. The findings at the dose of 1.0 mg/kg b.w./day were, however, morphologically similar to those of controls and animals dosed at the dose of 0.1 mg/kg b.w./day or 0.3 mg/kg. The mean severity of findings was also not elevated. Vascular changes of this kind tend to develop in animals with advanced stages of chronic progressive nephropathy (CPN). The severity scores of CPN were, however, similar throughout the groups up to and including the dose of 1.0 mg/kg b.w./day. In the pancreas, some animals showed a focal atrophy of acinar cells which was increased at the dose of 0.3 and 1.0 mg/kg. This finding may be related to vascular changes observed in this organ at a higher rate in all groups including control. However, a direct treatment-relation is not assumed since there was only a slight numerical increase but the severity score (mostly minimal or slight) was unaffected by dosing with the test compound.

In the teeth, dysplasia/fracture was significantly increased in incidence and severity in males at the dose of 1.0 mg/kg b.w./day. A treatment-relation is assumed as the finding is in line with findings known from other studies with this test substance.

In the pituitary gland of males, an increased incidence of cholesterol clefts in Rathke's pouch was observed between the pars intermedia and pars distalis. This finding was mostly rated as minimal and was not associated with proliferative of inflammatory changes in the pituitary gland. It is thus not regarded as adverse. A biological relevance is not assumed in humans since Rathke's cleft does not exist in this species.

TOXICOKINETICS:
Toxicokinetic investigation of plasma levels of BAY 43-9006 (free base of BAY 54-9085) showed that there was no evidence of a relevant sex-related difference in exposure and that the observed Cmax concentrations and AUC(0-24) increased dose-dependently in male and female dose groups. An about dose linear increase in terms of Cmax and AUC(0-24) was observed in male dose groups. In female dose groups Cmax and AUC(0-24) increased slightly more than dose-proportional. Peak plasma concentrations were reached in the time frame between 5 and 19 h in the observation period (23:00 to 13:00 CET). The concentration time profile under steady state conditions was flat in the entire observed time frame. Trough plasma concentrations of BAY 43-9006 were in the high range independent of administered dose or gender accounting for 69.5% to 91.9% relative to Cmax in the respective dose groups.

Effect levels

Dose descriptor:
NOAEL
Effect level:
0.3 other: mg/kg bw/day (dose-adjusted via diet)
Based on:
test mat.
Sex:
male/female

Target system / organ toxicity

Critical effects observed:
not specified

Applicant's summary and conclusion

Executive summary:

BAY 54-9085 is the tosylate salt of BAY 43-9006 (sorafenib), which is used as an anti-cancer drug.

 

Within the scope of a carcinogenicity study the systemic toxicity of BAY 54-9085 was investigated after oral treatment over 2 years (OECD TG 451). For this purpose BAY 54-9085 was administered orally dose-adjusted via diet to 50 male and 50 female Wistar rats per main dose group in daily doses of 0, 0.1, 0.3 or 1.0 mg/kg bw for a period of up to 747 days. Dose selection was based on MTD criteria in a 13-week dose finding study.

The treatment with BAY 54-9085 was well tolerated as e.g. no relevant treatment-related clinical findings, effects on body weight development or on parameters of clinical pathology were observed.

 

At histopathology, in the abdominal organs such as stomach, spleen, pancreas and mesentery lymph nodes, age-related vascular changes arteritis/periarteritis and vasculopathy occurred at an increased incidence in both sexes at a dose of 1.0 mg/kg bw /day. Furthermore, in the teeth, fracture/dysplasia was slightly more frequent in males at the dose of 1.0 mg/kg bw /day. Dental findings are likely of no relevance in humans since permanent growth of teeth is lacking.

 

Thus, under the conditions described the no observed adverse effect level (NOAEL) for oral administration of BAY 54-9085 via the diet was 0.3 mg/kg bw /day in male and female rats with regard to systemic toxicity.