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Toxicological information

Developmental toxicity / teratogenicity

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Administrative data

Endpoint:
developmental toxicity
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
May 2003 to Sep 2004
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report Date:
2004

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: Recommendations for "Detection of Toxicity to Reproduction for Medicinal Products" - Guideline prepared within the International Conference on Harmonization (ICH) process, Washington (DC), June 24, 1993
Deviations:
no
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent

Test animals

Species:
rat
Strain:
Wistar
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan-Winkelmann GmbH, Borchen, Germany
- Strain: Hsd Cpb:Wu (SPF)
- Age at study initiation: 13-20 weeks
- Weight at study initiation: males: 490-603 g, females: 201-247 g
- Housing: individually in Makrolon® Type IIa (females) or Type III (males) cages
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: at least 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 2
- Humidity (%): approx. 50
- Air changes (per hr): >= 10
- Photoperiod (hrs dark / hrs light): 12 / 12

IN-LIFE DATES: May 2003 - Sep 2004

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
other: suspension of 0.5 % methylhydroxyethylcellulose (Tylopur MH 300 G4) in demineralized water
Details on exposure:
The male animals were used for mating only and were not treated. After insemination was ascertained, 22 females each were allocated to four experimental groups according to a randomization plan generated on a personal computer (HP Vectra PC). Five further inseminated females each were allocated to three satellite groups (0.27, 1.37 and 3.43 mg/kg body weight/day) for toxicokinetic investigations according to a randomization plan generated on a personal computer (HP Vectra PC).

The females were treated once daily between 05:00 and 12:00 CET from days 6 to 17 p.c. The females received the administration formulations orally by gavage according to the test guidelines. Gavage was also selected since oral exposure is the intended route of administration to humans.

The females of all experimental groups received a uniform administration volume of 10 ml/kg body weight/day. The females of the control group received vehicle (0.5% aqueous Tylopur® suspension), only.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Fresh formulations for each concentration were prepared after two to at maximum eight days of use. The administration formulations were stored at room temperature for the duration of use.

Investigations on the stability and homogeneity and a content check of the active ingredient in samples of 0.014, 0.137 and 2.06 mg/ml were performed before the start of this study and covered the concentrations used in this study. Data on stability and homogeneity were archived under the study number F6010988.

Two content checks each of the concentrations used (0.027, 0.137 and 0.343 mg/ml,respectively) as well as checks on homogeneity were carried out during the in-life period of the study (formulations prepared May 27, and June 25, 2003, respectively).
Details on mating procedure:
The animals were mated by placing two females overnight into a type III cage together with one male rat. If sperm was detected in the vaginal smear taken on the morning following mating, this day was regarded as day 0 of gestation.
Duration of treatment / exposure:
days 6 to 17 of gestation
Frequency of treatment:
once daily
Duration of test:
cesarean section and sacrifice on day 17 p.c. (satellite groups) or day 20 p.c. (main groups)
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 0.27, 1.37, 3.43 mg/kg bw
Basis:
actual ingested
No. of animals per sex per dose:
main groups: 22 females per dose
satellite groups for toxicokinetics: 5 females per dose
Control animals:
yes, concurrent vehicle
Details on study design:
DOSE SELECTION RATIONALE:
The dose levels were selected according to the results of a previous pilot developmental toxicity study with BAY 54-9085 in rats with dose levels of 0, 0.41, 1.37 and 4.11 mg/kg bw/day. Additionally, a maternal tolerability study in 4 pregnant rats with a dose level of 3.43 mg/kg was performed since 4 of 7 females of the 4.11 mg/kg dose group showed total resorption of the litter. Litter loss was not observed in the latter toleration study, so that 3.43 mg/kg was selected as the highest dose level in the actual study.

Examinations

Statistics:
All data were recorded either online in parallel (directly during) or offline after termination of the respective investigations using the TASC-system (Scientific Computer Consultants, Inc., 547 Stonetown Road, Ringwood, NJ 07456, USA). Daily printouts (session data) of the parameters which were recorded directly online were signed by date and signature of the responsible experimenter and archived as raw data. Fetal visceral and skeletal data were recorded on paper first, which served as raw data, and were as well recorded offline using the TASC-system.

Females without implantation sites and females with total resorption were excluded from any statistical evaluation. The mean values in the tables calculated by computer are the rounded results of the calculations with unrounded raw data.

Differences between the control and BAY 54-9085 treated groups were considered to be significant when p < 0.05. Significant differences from the control are indicated with * for p < 0.05 or ** for p < 0.01.

Statistical significance was tested using the TASC - System (Scientific Computer Consultants, Inc., 547 Stonetown Road, Ringwood, NJ 07456, USA) on an ALPHA 800 5/500 computer using the following methods:

a. Analysis of variance (ANOVA), and in case of significant results Dunnett's test as posthoc test
b. 2 by N CHI2 test; in case of significant differences Fisher's exact test with Bonferroni correction
c. Kruskal-Wallis test, and in case of significant differences Dunn's test

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects:yes

Effect levels (maternal animals)

open allclose all
Dose descriptor:
NOAEL
Effect level:
1.37 mg/kg bw/day (actual dose received)
Based on:
test mat.
Basis for effect level:
other: maternal toxicity
Dose descriptor:
NOAEL
Effect level:
0.27 mg/kg bw/day (actual dose received)
Based on:
test mat.
Basis for effect level:
other: developmental toxicity

Results (fetuses)

Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:yes

Fetal abnormalities

Abnormalities:
not specified

Overall developmental toxicity

Developmental effects observed:
not specified

Any other information on results incl. tables

Mortality or clinical signs were not observed at a dose level up to and including 3.43 mg/kg bw/day except of reddish vaginal excretions in 2 females of the 3.43 mg/kg dose group which revealed either total resorption or a high number of late resorptions at cesarean section. Feed intake at the end of the treatment period was marginally decreased and absolute body weight gain during treatment and the overall gestation period was slightly impaired at the 3.43 mg/kg dose level, however, without effects on corrected body weight gain. Effects on body weight development might thus be related to lower litter size and impaired fetal weights at the 3.43 mg/kg dose level. Necropsy revealed no treatment-related gross pathological findings up to and including 3.43 mg/kg.

 

With respect to the parameters of intrauterine development, gestation rate, postimplantation loss, mean litter size, appearance and weight of placentas, fetal weight and fetal sex distribution were not affected by treatment with BAY 54-9085 at a dose level up to and including 1.37 mg/kg bw/day. Marginally increased postimplantation loss at the 1.37 mg/kg dose level was not considered treatment-related since incidence lay in the range of historical control data, statistical significance was not evident and mean litter size was not affected.

 

At the 3.43 mg/kg dose level gestation rate was decreased by one total late resorption. Mean postimplantation loss (late resorptions) in the remaining females was increased and consequently mean litter size decreased. Treatment relationship was not assumed for slightly increased percentage of male fetuses in the 3.43 mg/kg dose group (due to a possibly higher lethality of female progeny) as statistical significance was missing and as the value lay within the normal range of scattering of the rat strain used. Incidence of placental findings (necrotic placental borders, pale placentas) was increased and placental weight and fetal weights decreased. The latter finding was related to retarded fetal ossification of bones of the forepaws, sternum, vertebral column and skull.

 

Incidence of generally common fetal malformations of different types ¿ mainly affecting the vertebral column, ribs, pelvis and aorta and appending vessels ¿ was increased in the 3.43 mg/kg dose group. Furthermore, incidence of common skeletal variations (supernumerary 14th ribs) was as well increased and incidence of external and visceral deviations (pale appearance of fetuses, missing innominate artery) was slightly elevated in the 3.43 mg/kg dose group.

 

In the 1.37 mg/kg dose group retarded ossification of few localisations (single bones of forepaws and sternum, thoracic vertebrae) and a single malformation of the aorta (retroesophageal aortic arch) could not be excluded.

 

Based on the findings described above, embryotoxicity of BAY 54-9085 comprised skeletal retardations and possibly an aortic malformation at the 1.37 mg/kg dose level and lethality, retarded development (fetal weight, degree of ossification) and a broad spectrum of common malformations and deviations at the 3.43 mg/kg dose level.

 

Toxicokinetic evaluation was performed for BAY 43-9006, the free base of the tosylate salt BAY 54-9085 and its metabolites. The results might be summarized as cited below: AUC(0-7) and Cmax of BAY 43-9006 on day 17 p.c. increased slightly to moderately less than dose-proportionally after administration of 0.270, 1.37 and 3.43 mg/kg bw BAY 54-9085 (0.200, 1.00 and 2.50 mg/kg bw referring to free base BAY 43-9006). Peak plasma concentrations of BAY 43-9006 were reached in a time interval between 2 and 7 h after oral administration for all 3 applied doses. In this time interval a flat concentration time profile of BAY 43-9006 was observed for the majority of the individuals. Consequently, the residual concentrations of BAY 43-9006 found at 7 h were high in all investigated dose groups. The observed concentrations for the last sampling time point ranged between 30 % and 100 % of Cmax . Under consideration of a missing sample time point at 24 h after administration the high concentrations at 7 h, the AUC(0-7) indicates a marked underestimation of the AUC in the dosing interval.

Applicant's summary and conclusion

Executive summary:

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

Twenty-two inseminated female Wistar rats each were treated orally by gavage with BAY 54-9085 with daily doses of 0, 0.27, 1.37 or 3.43 mg/kg (corresponding to 0, 0.2, 1.0 or 2.5 mg/kg/day BAY 43-9006) from day 6 to day 17 post conceptionem. Five additional females per group were treated likewise and were used for toxicokinetic analysis on BAY 43-9006 and metabolites. Females of these satellite groups were sacrificed on day 18 post conceptionem after the last blood sampling and status of pregnancy was ascertained. In the main groups the fetuses were delivered by cesarean section on day 20 of gestation. Investigations were performed on general tolerance of the test compound by the females and possible effects on intrauterine development in the main groups, only.

 

Maternal findings were restricted to the high-dose (3.43 mg/kg) group, and comprised reddish vaginal excretion in two females which revealed either total resorption or a high number of late resorptions, marginally impaired feed intake at the end of treatment and slightly impaired body weight gain during treatment and the overall gestation period. Effects on body weight development might be related to lower litter size and impaired fetal weights at 3.43 mg/kg.

 

With respect to the parameters of intrauterine development, treatment-related effects were evident at 3.43 mg/kg and included impaired gestation rate (one total late resorption), increased post-implantation loss (late resorptions) in the remaining litters and consequently decreased mean litter size, increased incidence of necrotic placental borders and pale placentas, decreased placental and fetal weights, retarded fetal skeletal ossification in relation to reduced fetal weights and increased incidence of external and visceral deviations (pale appearance, missing innominate artery) and skeletal variations (supernumerary 14th ribs). Incidence of generally common fetal malformations of different types was as well increased at 3.43 mg/kg. At 1.37 mg/kg, treatment-relationship could not be excluded for retarded ossification of few localizations (single bones of forepaws and sternum, thoracic vertebrae), and a single malformation of the aorta (retroesophageal aortic arch).

 

In summary, BAY 54-9085 produced maternal toxicity at a dose of 3.43 mg/kg/day. Developmental toxicity was observed at doses of 1.37 mg/kg/day and above. Therefore, under the conditions described the no-observed-adverse-effect-level (NOAEL) for systemic maternal toxicity in rats was 1.37

mg/kg/day and the NOAEL for intrauterine development in rats was 0.27 mg/kg/day.