(2R)-2-(2,4-difluorophenyl)-1,1-difluoro-1-{5-[4-(2,2,2-trifluoroethoxy)phenyl]pyridin-2-yl}-3-(1H-tetrazol-1-yl)propan-2-ol

Toxicity to reproduction

Administrative data

Endpoint:

fertility, other

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Data source

Reference

Reference Type:

other company data

Title:

Unnamed

Year:

2018

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

- Principle of test: Fertility study in male rats

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2-(2,4-difluorophenyl)-1,1-difluoro-3-(1H-1,2,3,4-tetrazol-1-yl)-1-{5-[4-(2,2,2-trifluoroethoxy)phenyl]pyridin-2-yl}propan-2-ol

EC Number:

841-499-2

Cas Number:

1340593-59-0

Molecular formula:

C23H16F7N5O2

IUPAC Name:

2-(2,4-difluorophenyl)-1,1-difluoro-3-(1H-1,2,3,4-tetrazol-1-yl)-1-{5-[4-(2,2,2-trifluoroethoxy)phenyl]pyridin-2-yl}propan-2-ol

Specific details on test material used for the study:

not specified

Test animals

Species:

rat

Strain:

Sprague-Dawley

Details on species / strain selection:

not specified

Sex:

male

Details on test animals or test system and environmental conditions:

not specified

Administration / exposure

Route of administration:

oral: unspecified

Vehicle:

CMC (carboxymethyl cellulose)

Details on exposure:

VEHICLE
- Concentration of vehicle : 0.5%

Details on mating procedure:

not specified

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

75 days

Frequency of treatment:

daily

Details on study schedule:

Male Sprague-Dawley rats were administered daily oral doses of 0, 0.5, 3, or 10 mg/kg (n, 25/group) in 0.5% CMC beginning 42 days prior to pairing with untreated females, through the mating and post-mating period until euthanasia on Day 76 of treatment.

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (nominal)

Remarks:

Control

Doses / concentrations 2

Dose / conc.:

0.5 mg/kg bw/day (nominal)

Remarks:

Low dose

Doses / concentrations 3

Dose / conc.:

3 mg/kg bw/day (nominal)

Remarks:

Mid dose

Doses / concentrations 4

Dose / conc.:

10 mg/kg bw/day (nominal)

Remarks:

High dose

No. of animals per sex per dose:

25

Control animals:

yes, concurrent vehicle

Details on study design:

- Other: Approximately 15 males of the 0 and 10 mg/kg bw/day groups were assigned to a 12-week recovery period. Additional animals (n, 6/group) were dosed for TK evaluation and sperm analysis.

Positive control:

no

Examinations

Parental animals: Observations and examinations:

not specified

Sperm parameters (parental animals):

not specified

Litter observations:

not specified

Postmortem examinations (parental animals):

not specified

Postmortem examinations (offspring):

not specified

Statistics:

not specified

Reproductive indices:

not specified

Offspring viability indices:

not specified

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:

no effects observed

Description (incidence and severity):

The test item did not affect clinical observations.

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Description (incidence):

The test item did not affect mortality.

Body weight and weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

For futher details see section "details on results" below.

Food consumption and compound intake (if feeding study):

effects observed, non-treatment-related

Description (incidence and severity):

For futher details see section "details on results" below.

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not specified

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

For futher details see section "details on results" below.

Histopathological findings: neoplastic:

not specified

Reproductive function / performance (P0)

Reproductive function: sperm measures:

effects observed, treatment-related

Description (incidence and severity):

For futher details see section "details on results" below.

Reproductive performance:

no effects observed

Details on results (P0)

- Body weight: Decreases in mean body weight gain and/or body weight loss was observed at 3 and 10 mg/kg bw/day sporadically throughout the dosing period, correlating with slightly decreased food consumption during weeks 3-5 only at 10 mg/kg bw/day.
- Mean sperm motility (78.6%) was considered low after treatment for 75 days at 3 mg/kg bw/day compared with controls (82.3%) and was statistically significantly lower than controls at 10 mg/kg/day (60.7%). In addition, at 10 mg/kg/day, total sperm count per cauda epididymis and sperm concentration per gram cauda epididymis were lower, and while these values were within recent historical control data, the values were 20-25% lower than controls and considered test article-related. At 3 and 10 mg/kg bw/day, percent abnormal sperm was significantly higher (8.08% and 23.55%, respectively, compared with 3.55% abnormal in controls) and considered test article-related.
- Treatment-related microscopic findings in the epididymides (increased cellular debris, residual bodies) at 10 mg/kg bw/day which, ingeneral, correlated with increased percentages of morphologic abnormalities in sperm. Leydig cell hypertrophy/hyperplasia was observed at 10 mg/kg/day. A trend towards complete resolution of sperm parameters and microscopic changes in the epididymides and testes was observed at 10 mg/kg/day following the 12-week recovery period.

Effect levels (P0)

1

Dose descriptor:

NOAEL

Remarks:

general toxicity

Effect level:

10 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: no adverse effects observed

2

Dose descriptor:

NOAEL

Remarks:

fertility

Effect level:

10 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: Mating parameters, fertility and fecundity were not affected after 42 days of dosing

3

Dose descriptor:

NOAEL

Remarks:

sperm measures

Effect level:

3 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

reproductive function (sperm measures)

Applicant's summary and conclusion

Conclusions:

Under the given conditions reported, the NOAEL for general toxicity and for reproductive and fertility parameters in male rats was determined to be 10 mg/kg bw/day. The NOAEL for sperm parameters was 3 mg/kg bw/day, based on statistically significant decreases in sperm motility, an increase in the percent of abnormal sperm, and a decrease in epididymal sperm count observed at 10 mg/kg bw/day.

Executive summary:

In reproductive toxicity study, the test item in 0.5% CMC was administered to 25 male SD ,rats/dose orally at dose levels of 0, 0.5, 3, or 10mg/kg bw/day for 75 days (treatment started 42 days prior to pairing with untreated females, through the mating and post-mating period until euthanasia on Day 76 of treatment). Approximately 15 males of the 0 and 10 mg/kg bw/day groups were assigned to a 12-week recovery period. Additional animals (n, 6/group) were dosed for TK evaluation and sperm analysis. The treatment did not affect mortality or clinical observations. Mating parameters, fertility, and fecundity were also not affected after 42 days of dosing. However, decreases in mean body weight gain and/or body weight loss was observed at 3 and 10 mg/kg bw/day sporadically throughout the dosing period, correlating with slightly decreased food consumption during weeks 3-5 only at 10 mg/kg bw/day.

The mean sperm motility (78.6%) was considered low after treatment for 75 days at 3 mg/kg bw/day compared with controls (82.3%) and was statistically significantly lower than controls at 10 mg/kg/day (60.7%). In addition, at 10 mg/kg/day, total sperm count per cauda epididymis and sperm concentration per gram cauda epididymis were lower, and while these values were within recent historical control data, the values were 20-25% lower than controls and considered test article related. At 3 and 10 mg/kg bw/day, percent abnormal sperm was significantly higher (8.08% and 23.55%, respectively, compared with 3.55% abnormal in controls) and considered test article related. Furthermore, treatment-related microscopic findings in the epididymides (increased cellular debris, residual bodies) at 10 mg/kg bw/day which, in general, correlated with increased percentages of morphologic abnormalities in sperm. Leydig cell hypertrophy/hyperplasia was observed at 10 mg/kg/day.

Based on these results, a NOAEL for general toxicity and for reproductive and fertility parameters in males was determined to be 10 mg/kg bw/day. The NOAEL for sperm parameters was 3 mg/kg bw/day, based on statistically significant decreases in sperm motility, an increase in the percent of abnormal sperm, and a decrease in epididymal sperm count after treatment at 10 mg/kg bw/day. These effects on sperm motility, count, and morphology as well as the microscopic changes were trending towards complete resolution during the 12-week recovery period.