. 2022 Aug;41(4):276–290. doi: 10.1177/10915818221095489

Table 5.

Group Incidences and Severities of Nirmatrelvir-Related Microscopic Findings in a 1-Month Rat Toxicity Study.

			Male				Female
			Dose (mg/kg) (q.d.)				Dose (mg/kg) (q.d.)
Study phase	Tissue	Findings	0	60	200	1,000	0	60	200	1,000
Dosing	Liver	Hypertrophy, hepatocyte; periportal	0/10	0/10	2/10^a	9/10^a	0/10	0/10	2/10^a	10/10^a
		Minimal (Grade 1)	0/10	0/10	2/10^a	8/10^a	0/10	0/10	2/10^a	6/10^a
		Mild (Grade 2)	0/10	0/10	0/10	1/10^a	0/10	0/10	0/10	4/10^a
		Vacuolation, hepatocyte; periportal	5/10	8/10	5/10	2/10	7/10	8/10	7/10	6/10
		Minimal (Grade 1)	5/10	8/10	5/10	2/10	7/10	8/10	7/10	3/10
		Mild (Grade 2)	0/10	0/10	0/10	0/10	0/10	0/10	0/10	3/10^a
	Thyroid gland	Hypertrophy, follicular cell	0/10	1/10^a	4/10^a	10/10^a	0/10	0/10	2/10^a	10/10^a
		Minimal (Grade 1)	0/10	1/10^a	4/10^a	6/10^a	0/10	0/10	2/10^a	2/10^a
		Mild (Grade 2)	0/10	0/10	0/10	4/10^a	0/10	0/10	0/10	8/10^a
	Pituitary gland	Vacuolation, endocrine cells, pars distalis	0/10	2/10^a	2/10^a	5/10^a	0/10	ND	ND	0/10
		Minimal (Grade 1)	0/10	2/10^a	2/10^a	4/10^a	0/10	ND	ND	0/10
		Mild (Grade 2)	0/10	0/10	0/10	1/10^a	0/10	ND	ND	0/10
Recovery	Liver	Hypertrophy, hepatocyte; periportal	0/5	ND	0/5	2/5^a	0/5	ND	ND	0/5
		Minimal (Grade 1)	0/5	ND	0/5	2/5^a	0/5	ND	ND	0/5
		Vacuolation, hepatocyte; periportal	3/5	ND	5/5	3/5	3/5	ND	ND	2/5
		Minimal (Grade 1)	3/5	ND	5/5	3/5	3/5	ND	ND	2/5
	Thyroid gland	Hypertrophy, follicular cell	0/5	ND	0/5	2/5^a	0/5	ND	ND	0/5
	Thyroid gland	Minimal (Grade 1)	0/5	ND	0/5	2/5^a	0/5	ND	ND	0/5
	Pituitary gland	Vacuolation, endocrine cells, pars distalis	0/5	ND	0/5	2/5^a	ND	ND	ND	ND
	Pituitary gland	Minimal (Grade 1)	0/5	ND	0/5	2/5^a	ND	ND	ND	ND

^aDenotes nirmatrelvir-related finding.

Values represent the number of animals with findings compared with the total number of animals per group. ND, not determined.