Nitrilotrimethylenetris(phosphonic acid)

Carcinogenicity

Description of key information

In a well-conducted key chronic toxicity/carcinogenicity study, ATMP-H (CAS 6419-19-8, EC No., 229-146-5; powder, 100% active acid) was administered via the diet to Long-Evans rats at dose levels of 50, 150 or 500 mg active acid/kg bw/day for 24 months. The NOAEL for carcinogenicity and general toxicity was at least 500 mg active acid/kg bw/day (BioDynamics Inc., 1979c, Reliability 2).

Key value for chemical safety assessment

Carcinogenicity: via oral route

Link to relevant study records

Reference

Endpoint:

carcinogenicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

04.12.1975 to 03.12.1979

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 453 (Combined Chronic Toxicity / Carcinogenicity Studies)

Version / remarks:

Study conducted prior to adoption of OECD test guideline.

Deviations:

yes

Remarks:

No satellite groups, limited measurements of blood and clinical chemistry parameters.

GLP compliance:

no

Remarks:

pre-GLP

Species:

rat

Strain:

Long-Evans

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Blue Spruce Farms, Altamont, New York.
- Age at study initiation: 6-7 weeks
- Weight at study initiation: Mean 212.6 g (males) and 149.0 g (females)
- Fasting period before study: Not specified
- Housing: Individually in elevated stainless steel cages.
- Diet: Ad libitum
- Water: Ad libitum
- Acclimation period: 18 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): Monitored but no data
- Humidity (%): No data
- Air changes (per hr): No data
- Photoperiod (hrs dark / hrs light): 12 hours dark / 12 hours light


IN-LIFE DATES: From: 17.11.1976 To: 30.11.1978

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on exposure:

DIET PREPARATION
- Rate of preparation of diet: Weekly
- Mixing appropriate amounts with: Standard laboratory diet.
- Storage temperature of food: No data

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

50 gram samples of the control feed and each dietary level were taken weekly and shipped to the sponsor. No further details.

Duration of treatment / exposure:

24 months

Frequency of treatment:

Continuous

Post exposure period:

None.

Dose / conc.:

50 mg/kg bw/day (actual dose received)

Remarks:

active acid

Dose / conc.:

150 mg/kg bw/day (actual dose received)

Remarks:

active acid

Dose / conc.:

500 mg/kg bw/day (actual dose received)

Remarks:

active acid

No. of animals per sex per dose:

70

Control animals:

yes, plain diet

Details on study design:

Post-exposure period: None
Satellite groups: None

Positive control:

None

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Daily for the first two months and then twice daily until termination.
- Cage side observations: Mortality, gross signs of toxicology or pharmacologic effects.

Interim necropsies were performed on 10/sex/group after 6 and 12 months, then on all surviving animals after 24 months. Animals that died spontaneously or were killed in a moribund condition were also examined.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Weekly, for signs of local or systemic toxicity, pharmacologic effects and palpation for tissue masses.


BODY WEIGHT: Yes
- Time schedule for examinations: Twice pre-test, weekly through to week 13 of treatment, every two weeks for weeks 14 to 26, then monthly, and finally at termination.


FOOD CONSUMPTION AND COMPOUND INTAKE: pretest, weekly up to week 13, every other week for weeks 14 to 26 and then monthly.
- 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


FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No


WATER CONSUMPTION AND COMPOUND INTAKE: No


OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: Pretest, then 3, 6, 12, 18 and 24 months.
- Dose groups that were examined: No data


HAEMATOLOGY: Yes
- Time schedule for collection of blood: At 3, 6, 12, 18 and 24 months.
- Anaesthetic used for blood collection: Yes, ether.
- Animals fasted: Yes, overnight.
- How many animals: 6/sex from control and high dose groups.
- Parameters checked in table [No.1] were examined.


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: At 3, 6, 12, 18 and 24 months.
- Animals fasted: Yes, overnight
- How many animals: 6/sex from control and high dose groups.
- Parameters checked in table [No. 1] were examined.

URINALYSIS: Yes
- Time schedule for collection of urine: 6, 12 and 24 months all groups 6/sex; 3 months: 6/group (males) and 6/control and high dose groups (females); 18 months: 6/sex for control and high dose groups.
- Metabolism cages used for collection of urine: No data
- Animals fasted: No data
- Parameters checked in table [No.?] were examined.

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:

GROSS PATHOLOGY: Yes (see table 2)
HISTOPATHOLOGY: Yes (see table 2)

Other examinations:

None

Statistics:

Body weight, food consumption, haematology and clinical chemistry parameters, organ weights, organ/body weight ratios and organ/brain weight ratios were analysed. Mean values of all dose groups were compared to control at each time interval. Haematology and clinical chemistry: intergroup comparison v control by F-test and Student's t-test (using t-test modification if variances differed). Body weight, food consumption, organ weights and ratios by Dunnett's t-test.

Clinical signs:

no effects observed

Description (incidence and severity):

There were no physical observations that were attributed to the administration of the test substance.

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Description (incidence):

Mortality data did not reveal any treatment-related effect. Males (per 70): 18 (controls), 22 (low), 21 (medium) and 18 (high) died. Females (per 70): 23 (controls), 24 (low), 19 (medium) and 19 (high) died during study.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Mean body weight values for the high dose males were slightly reduced (5-10%) from week 16 to 87 resulting in slight reduction in terminal body weight, however, this was not statistically significant. Values for the low and mid dose groups were comparable to the controls.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

Mean food consumption values for the high dose males were generally comparable to or greater than those of the control group (3-17%) during most weeks. Values for the low and mid dose groups were comparable to the controls.

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

no effects observed

Description (incidence and severity):

There were no treatment-related effects.

Haematological findings:

no effects observed

Description (incidence and severity):

No treatment-related effects were observed.

Clinical biochemistry findings:

no effects observed

Description (incidence and severity):

No treatment-related effects were observed.

Endocrine findings:

not examined

Urinalysis findings:

no effects observed

Description (incidence and severity):

No treatment-related effects were observed.

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

Changes were observed in the highest dose group only. No other groups were affected at any sample time. Males: 15% reduction in absolute spleen weight at 24 months; 14% reduction in absolute and relative liver weight at 24 months; 23% increase in relative testes weight at 12 months, 14% increase in relative kidney weight at 12 months, 14% decrease in absolute liver weight at 6 months. Females: 13% decrease in absolute kidney weight at 12 months; 8% decrease in relative liver weight at 6 months. These changes were not considered adverse.

Gross pathological findings:

no effects observed

Description (incidence and severity):

There were no gross lesions attributable to treatment.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

No treatment-related findings.

Histopathological findings: neoplastic:

no effects observed

Description (incidence and severity):

No treatment-related findings were observed. Isolated miscellaneous tumours were present in all dose groups, however, there is no evidence that this would be a treatment-related effect. 

Other effects:

not examined

Key result

Dose descriptor:

NOAEL

Effect level:

>= 500 mg/kg bw/day (nominal)

Based on:

act. ingr.

Remarks:

active acid

Sex:

male/female

Basis for effect level:

other: No neoplastic findings.

Critical effects observed:

no

Table 3 Summary of number of in-lfe masses observed at necropsy.

Group (mg/kg bw/day)	I (0)		II (50)		III (150)		IV (500)
	Number	%	Number	%	Number	%	Number	%
Males	20/70	28.6	20/70	28.6	21/70	30	15/70	21.4
Females	22/70	31.4	23/70	32.9	17/70	24.3	20/70	28.6

Table 4 Summary of observed tumours.

Time of examination	Type of neoplastic change
	Group I	Group II	Group III	Group IV
6 months	None	None	None	None
12 months	Adrenal pharochonacytoma (1f)	Pituitary chromaphobic adenoma (1f)	Uterine polyp (1f)	Pituitary chromophobe adenoma (1f)
24 months*				Osteosarcoma axilla (1m)

*pituitary and mammary tumours common. 

Conclusions:

In a carcinogenicity study (reliability score 2), conducted in a similar manner to OECD Test Guideline 453 but pre-GLP, ATMP-H (powder, 100% active acid) was administered via the diet to Long-Evans rats at dose levels of 50, 150 or 500 mg active acid/kg bw/day for 24 months. The NOAEL for carcinogenicity and general toxicity in male and females was ≥ 500 mg active acid/kg bw/day.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

500 mg/kg bw/day

Study duration:

chronic

Species:

rat

Carcinogenicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Carcinogenicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the available data, ATMP-H does not require classification for carcinogenicity according to Regulation (EC) No 1272/2008.

Additional information

In the key chronic toxicity and carcinogenicity study, conducted in a similar manner to OECD Test Guideline 453 but pre-GLP, ATMP-H (powder, 100% active acid) was administered via the diet to Long-Evans rats (70/sex/dose) at dose levels of 50, 150 or 500 mg/kg bw/day (groups II to IV) for 24 months. Control animals received untreated diet (Group I). Animals were regularly observed for clinical signs of toxicity and body weights and food consumption were measured. Interim necropsies were performed at 6 and 12 months (10/sex/dose). Ophthalmoscopic examination, haematology, clinical chemistry and urinalysis were performed at months 3, 6, 12, 18 and 24. Histopathological examinations were conducted on all animals that died or had to be killed in extremis. In addition, histopathological examinations were conducted for 10 animals/sex for groups I and IV at 6 months and for all survivors in Groups I and IV at 24 months. The mean body weight values for the high dose males were slightly reduced (5-10%) from week 16 to 87. Mean food consumption values for the high dose males were generally comparable to or greater than those of the control group (3-17%) during most weeks. In the high dose group, statistically significant changes to organ weights occurred (adrenal glands, spleen, liver, pituitary). No treatment-related gross lesions or histopathological findings occurred in any of the groups. The NOAEL for carcinogenicity and general toxicity was concluded to be at least 500 mg active acid/kg bw/day (BioDynamics Inc., 1979c, Reliability 2).