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Toxicological information

Toxicity to reproduction

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Administrative data

Endpoint:
one-generation reproductive toxicity
Type of information:
experimental study
Adequacy of study:
key study
Study period:
13-3-1989 to 23-05-1989
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1989
Report Date:
1989

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 415 [One-Generation Reproduction Toxicity Study (before 9 October 2017)]
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Specific details on test material used for the study:
(1) Test Article:
MK-0217: Purity was 99.3 percent as determined by
HPLC analysis. Dosing concentrations as well as the
stability of MK-0217 in vehicle (deionized water)
were confirmed by chemical analyses as being
satisfactory.
(2) Identification and Lot Number of MK 0217:
L-670,452-005Y008
(3) Factor Used to Calculate Dose Levels as Base
Compound: 1.33

Test animals

Species:
rat
Strain:
Sprague-Dawley
Remarks:
Crl CD (SD) BR
Sex:
female
Details on test animals and environmental conditions:
Source: Charles River Breeding Laboratories, Wilmington, MA
Age of Females at Beginning of Study: 72 days
Starting Weight Range (grams): 198-253
Identification Method: FO: ear notches, Fl: foot tattoo

Environmental Conditions:
During the pre-breeding, gestational, and lactational
periods, females were singly housed. Up to Day 15 of
gestation, the females were in hanging metal cages;
thereafter, plastic boxes for deli very were used.
Bedding in the plastic boxes consisted of wooden chips
(Beta chips, Northeastern Products Corp., Warrensburg,
NY).
All FO females were housed at a temperature of
2o•-27•c. Timed lighting provided a 12-hour
light/12-hour dark cycle. All rats had free access to
Purina Certified Rodent Chow 115002 and tap water
throughout the study.

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Remarks:
deionised
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:
The dosing solution for the 15 mg/kg/day group
was prepared by dissolving MK-0217 in vehicle.
Aliquots of the high dose solution were diluted
with vehicle to prepare dosing solutions for the 5
and 10 mg/kg/day groups.
VEHICLE
- Concentration in vehicle: 1, 2 or 3 mg/ml
- Amount of vehicle (if gavage): 5ml/kg/day

Details on mating procedure:
In the evening of the 15th day of treatment, the
females were placed with untreated males of the same
strain, one female with one male. The mating period
was limited to 16 nights; after mating, the female
rats were removed from the cages of the males.
Mating was confirmed by the presence of a seminal
plug or by presence of sperm in the daily vaginal
lavage. The day either was found was considered Day
0 of gestation.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
MK-0217: Purity was 99.3 percent as determined by
HPLC analysis. Dosing concentrations as well as the
stability of MK-0217 in vehicle (deionized water)
were confirmed by chemical analyses as being
satisfactory
Duration of treatment / exposure:
Drug administration was once daily starting at
15 days prior to cohabitation for mating, during
cohabitation, and through Day 20 of gestation.
Frequency of treatment:
daily
Doses / concentrationsopen allclose all
Dose / conc.:
5 mg/kg bw/day (actual dose received)
Dose / conc.:
10 mg/kg bw/day (actual dose received)
Dose / conc.:
15 mg/kg bw/day (actual dose received)
No. of animals per sex per dose:
20 (twenty)
Control animals:
yes, concurrent vehicle
Details on study design:
The middle and low dosage levels were selected
on the basis of results of an oral developmental
toxicity study conducted in rats
at 5, 10 and 25 mg/kg/day. The low dose, 5
mg/kg/day, did not cause signs of materna­
toxicity, embryotoxicity, or fetotoxicity, but
at 10 mg/kg/day mean maternal weight gain was
reduced.
Twelve days of treatment at 25
mg/kg/day was associated with a 25 percent
decrease in mean maternal weight gain and a
decrease in fetal weights. It was decided that
a prolonged dosing period of 25 mg/kg/day in a
fertility study would likely cause an unaccept­
able effect on body weights of the dams as well
as a marked increase in embryo or fetal deaths.
Therefore 15 mg/kg/day was chosen as the high
dose in the current study.

Examinations

Parental animals: Observations and examinations:
a. Physical Signs:
FO females were examined daily for physical signs from
initiation of the study to lactational Day 21 or
sacrifice. Examinations for postdosing signs were
conducted 1 to 5 hours after each daily treatment.
b. Body Weights:
Body weights of FO females were recorded as follows:
premating Days 1, 8 and 15; weekly, when needed, during
cohabitation; gestational Days 0, 6, 12, 16, 18, 20 and
(if needed) 24; and on lactation Days 0, 7, 14 and 21.
Females which did not mate were weighed on study Days
22, 29, 36, 43, 51 and 55.
c. Food Consumption:
Food consumption was measured for all females for the
following intervals:
Premating: Day 1 to Day 5.
Day 8 to Day 12.
Gestation: Day 1 to Day 5.
Day 8 to Day 12.
Day 15 to Day 19.
Postpartum: Day 1 to Day 5.
Day 8 to Day 12.
Oestrous cyclicity (parental animals):
not examined
Sperm parameters (parental animals):
not examined
Litter observations:
Delivery of Fl Pups:
On postnatal Day 0 (day of delivery), the pups were
counted, weighed, extemally examined, and sexed.
Wherever possible, 10 pups/litter were identified by
foot tattoo (five of each sex). Excess pups (i.e., > 10
pups) were kept with the dams until postnatal Day 3 when
litter size was standardized by random selection to 8
pups, four of each sex whenever possible, fostering as
necessary within the same treatment groups. Excess pups
were discarded after litter standardization without
further examination.

b. Physical Signs:
Pups were observed once daily for physical signs until
postnatal Day 21.

c. Body Weights: Confirmation of Gender;
In addition to weighing and sexing the pups on
postnatal Day 0, pup weights were recorded on postnatal
Days 7, 14 and 21, and the sex of each pup was confirmed
on postnatal Days 3, 7, 14 and 21.

d. Dead Pups:
Dead pups were fixed in 10 percent buffered formalin
so that the trachea and esophagus could be examined for
 presence of bedding chips, which would suggest
suffocation as a possible cause of death.

e. Sacrifice of Fl Pups;
All surviving Fl pups were killed by co2
inhalation on postnatal Days 21 to 23 and discarded without further
examination.
Postmortem examinations (parental animals):
On postpartum Days 21 to 24, the FO females were
killed by co2 inhalation and the thoracic, abdominal,
and pelvic viscera were examined grossly by a
pathologist. Lesions fonnd at gross examination were
processed for histologic examination. The numbers of
uterine metria! glands were recorded. Females which did
not deliver were killed on Day 24 of presumed gestation
and grossly examined as above. Females which did not
mate were killed 24 days after the end of the mating
period and grossly examined as above. Early death
females were given gross and histomorphologic
examinations as described above.
Postmortem examinations (offspring):
not conducted
Statistics:
In statistically analyzing selected data, statistical
significance at P = 0. 05 was based on trend analysis after
ranki t transformation when appropriate. The trend analysis
determined if there was a significant (P ~ 0.05) trend with
increasing dosage including all treatment groups. If there
was a significant (P ~ 0.05) trend, data from the high dose
group was excluded and the trend test was repeated. ,This
process was repeated Imtil the trend test was not
significant (P > 0.05). The highest dosage level with no
significant (P > 0.05) trend was designated the NOSTASOT (or
no-statistical-significance-of-trend) dose. References for
detailed explanations of the statistical methodology are in
Appendix I.
The following were examined to determine if they should be
used as a covariate for the indicated parameters:
Body weights of FO females on prebreeding Day 1 (for
possible effects on body weight gains during prebreeding
Days 1 to 15).
Number of live Fl pups/litter (for possible effects on pup
body weights on postnatal Days O, 7, 14 and 21).
Length of the gestation period of the FO females (for
possible effects on pup body weights during postnatal Days
0, 7, 14 and 21).
Reproductive indices:
Mated females/females cohabited
Pregnant females/mated females (Fecundity Index)
Pregnant females/cohabited females (Fertility
Index)
Length of gestation
Implants/pregnant female
Postimplantation survival rate
Offspring viability indices:
Live pups/litter (litter mean on postnatal
Day 0).
Pup deaths during postnatal Days 1 to 3 and 4
to 21.
Mean body weights of pups on postnatal Days O,
7, 14 and 21.

Results and discussion

Results: P0 (first parental generation)

General toxicity (P0)

Clinical signs:
effects observed, treatment-related
Description (incidence and severity):
laboured breathing, lethargy, ptosis, dystocia on gestation at 10 mg/kg/day extended to including tremors at 15 mg/kg/day
Mortality:
mortality observed, treatment-related
Description (incidence):
1 decedent at 10mg/kg/day on day GD 22; 3 animals sacrified and one decedent at 15 mg/kg/day on GD 21/22
Body weight and weight changes:
no effects observed
Description (incidence and severity):
There were no treatment-related effects on mean maternal
body weight gains.
Food consumption and compound intake (if feeding study):
no effects observed
Description (incidence and severity):
There were no treatment-related effects on food consumption by FO females.
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
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 examined
Histopathological findings: neoplastic:
not examined
Other effects:
no effects observed

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:
not examined
Reproductive function: sperm measures:
not examined
Reproductive performance:
effects observed, treatment-related
Description (incidence and severity):
There was a treatment-related reduction in post- implantation survival in the low, middle and high dose
groups by 9, 10, and 27%, respectively, as compared to the control group.
The change in the high dose group was statistically significant (P ~ 0.05).
There were no treatment-related effects on reproductive
performance or fertility as measured by time to mating,
percentage of females which mated, pregnant females/mated
females, pregnant females/ cohabited females, or numbers of
implants.

Effect levels (P0)

Key result
Dose descriptor:
LOAEL
Effect level:
5 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
female
Basis for effect level:
reproductive performance

Results: F1 generation

General toxicity (F1)

Clinical signs:
not specified
Dermal irritation (if dermal study):
not examined
Mortality / viability:
mortality observed, treatment-related
Description (incidence and severity):
PND0- 11 dead pups from dams dosed with 10 mg/kg/day and 9 dead pups from dams dosed with 15 mg/kg/day.
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
not examined
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
not examined
Urinalysis findings:
not examined
Sexual maturation:
not examined
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
not examined
Histopathological findings:
not examined
Other effects:
not examined

Developmental neurotoxicity (F1)

Behaviour (functional findings):
not examined

Developmental immunotoxicity (F1)

Developmental immunotoxicity:
not examined

Effect levels (F1)

Key result
Dose descriptor:
LOAEL
Generation:
F1
Effect level:
5 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
viability

Overall reproductive toxicity

Key result
Reproductive effects observed:
yes
Lowest effective dose / conc.:
5 mg/kg bw/day (actual dose received)
Treatment related:
yes
Relation to other toxic effects:
reproductive effects occurring together with other toxic effects, but not as a secondary non-specific consequence of other toxic effects
Dose response relationship:
yes
Relevant for humans:
yes

Any other information on results incl. tables

Reproductive indices- see attachment

Applicant's summary and conclusion

Conclusions:
Treatment of pregnant rats with MK-0217 was associated with
pronounced physical signs of toxicity or death in late gestation
(Day 21 or 22) in 4 of 19 FO females at 10 mg/kg/day and in 5
out of 18 FO females at 15 mg/kg/day. The delivered pups from
females with physical signs had decreased body weights and
viability was also decreased. One female at 5 mg/kg/day which
did not deliver was sacrificed on gestational Day 24 and was
found to have 4 dead intrauterine pups, and this was considered
treatment-related. Based on the female in the 5 mg/kg/day which had the 4 dead
intrauterine pups at sacrifice on gestational Day 24, there was
no no-effect dose level in this study.