Influence of CYP2D6, CYP3A5, ABCB1, APOE polymorphisms and nongenetic factors on donepezil treatment in patients with Alzheimer’s disease and vascular dementia

Figures & data

Figure 1 Association between CYP2D6 phenotypes and Cpss of donepezil at the 10 mg maintenance dose.

Abbrevations: IM, intermediate metabolizers; EM, extensive metabolizers.

Notes: Each pairwise comparison was calculated from Kruskal–Wallis test. Each box in the plots shows the median as the central line, the extremes of each box are the first and third quartiles and the whiskers represent the minimum and maximum values in the sample.

Table 1 Baseline demographic and clinical characteristic of 85 Thai patients with dementia

Demographic and clinical characteristics	Number (%)	Mean ± SD
Age (years)	–	78.42±7.91
Age of onset (years)	–	72.34±8.54
Gender
Male	38 (44.70)	–
Female	47 (55.30)	–
Body weight (kg)	–	56.69±9.88
Serum creatinine (mg/dL)	–	1.21±1.02
Creatinine clearance (mL/min)	–	60.04±19.71
Years of education	–	8.56±5.48
Types of dementia:
Alzheimer’s disease	51 (60.00)	–
Vascular dementia	32 (37.64)	–
Alzheimer’s disease dementia of frontal lobe type	1 (1.18)	–
Dementia with Lewy body	1 (1.18)	–
TMSE score at baseline	–	20.01±6.03
TMSE score at steady state	–	18.87±6.92
TMSE score change (ΔTMSE)	–	−0.81±3.09

Table 2 Genotype distribution and allele frequencies of the candidate gene in the study patients

Allele	Allele frequency	Genotype	Number	Genotype frequency	HWE p-value	MAF in other Asian populations
ABCB1c.3435C>T (rs 1045642)
C	0.583	CC	32	0.381	0.125	Chinese: 0.40 Japanese: 0.48 (T)
T	0.417	CT	34	0.405
		TT	18	0.214
ABCB1c.1236C>T (rs 1128503)
C	0.418	CC	16	0.188	0.60	Chinese: 0.34 Japanese: 0.32 (C)
T	0.582	CT	39	0.459
		TT	30	0.353
CYP2D6*2 (rs 1135840, g.4180G>C)
G	0.712	GG (*-/*-)	47	0.553	0.03	Chinese: 0.21 Japanese: 0.41 (C)
C	0.288	GC (*2/*-)	27	0.318
		CC (*2/*2)	11	0.130
CYP2D6*10 (rs 1065852, g.100G>A)
G	0.418	GG (*-/*-)	20	0.235	0.021	Chinese: 0.33 Japanese: 0.50 (G)
A	0.582	AG (*10/*-)	31	0.365
		AA (*10/*10)	34	0.400
CYP3A5*3 (rs 776746, g.6986T>C)
C	0.671	TT (*-/*-)	15	0.176	0.004	Chinese: 0.37 Japanese: 0.26 (T)
T	0.329	CT (*3/*-)	26	0.306
		CC (*3/*3)	44	0.518
APOE (rs429358, rs7412)
APOE ε2	0.055	APOE ε2/ε2	0	0.000		Chinese: 0.076^Citation45 Japanese: 0.078^Citation46 (APOE ε2)
APOE ε3	0.640	APOE ε2/ε3	7	0.098
APOE ε4	0.305	APOE ε2/ε4	2	0.019
		APOE ε3/ε3	34	0.412
		APOE ε3/ε4	30	0.373
		APOE ε4/ε4	9	0.098

Note: All MAF data from Applied Biosystems^® except APOE.

Abbreviation: MAF, minor allele frequency.

Table 3 Association of the non-genetic factors and Cpss of donepezil at the 10 mg maintenance dose

	Categorical variables			Continuous variables
Factors	Frequency (%)	Cpss (ng/mL)	p-value	Factors	Correlation Coefficients (r)	p-value
Gender				Bodyweight (Kg)	−0.165	0.131
Male	38	71.31 (36.31,110.48)	0.081	BMI (Kg/m^2)	−0.050	0.651
Female	47	99.16 (52.53,137.31)		Age (year)	0.178	0.103
Concomitant use of CYP2D6 inhibitors				TFDI (hour)	−0.064	0.558
No	60	74.82 (52.71,137.45)	0.401	CrCL (mL/min)	−0.057	0.282
Yes	25	72.04 (40.06,121.00)
Concomitant use of CYP3A4 inhibitors
No	37	72.04 (37.83,126.77)	0.454
Yes	48	83.14 (52.89,129.39)
Concomitant use of P-glycoprotein inhibitors
No	39	71.73 (39.25,123.78)	0.232
Yes	46	87.45 (52.17, 136.92)
Concomitant use of memantine
No	66	69.09 (37.83,123.78)	0.007
Yes	19	102.77(75.50,161.27)

Notes: The data were represented as median (IQR). CYP3A4 inhibitors included amlodipine, atorvastatin, diltiazem, and omeprazole. P-glycoprotein inhibitors included atorvastatin, carvedilol, diltiazem, and simvastatin. p-value <0.05 for bold text.

Abbreviations: TFDI, time from drug intake; BMI, body mass index; CrCL, creatinine clearance.

Figure 2 Association between the combined effect of CYP2D6*10 carriers and concomitant use of memantine on Cpss of donepezil.

Notes: Each pairwise comparison was calculated from Kruskal-Wallis test. Each box in the plots shows the median as the central line, the extremes of each box are the first and third quartile and the whiskers represent the minimum and maximum values in the sample.

Table 4 The final model of multiple linear regression analysis of explanatory variables for Cpss of donepezil at the 10 mg maintenance dose

Predictive variables	Unstandardized coefficients		Standardized coefficients	95% CI of B	p-value
	B	S.E.	β
Constant	3.420	0.353	–	2.718/4.122	<0.001
CYP2D6 phenotypes	0.478	0.220	0.225	0.041/0.916	0.032
Concomitant memantine use	0.511	0.203	0.261	0.107/0.915	0.014
R^2=0.133, p-value =0.003

Notes: Adjusted for CYP3A5 phenotypes, time from drug intake, age, and gender. CYP2D6 phenotypes: 1.0= homozygous EM (CYP2D6*1/*1 or CYP2D6*1/*2 or CYP2D6*2/*2). 1.5= heterozygous EM (CYP2D6*1/*10, CYP2D6*2/*10). 2.0= IM (CYP2D6*10/*10). Concomitant memantine use: 0= non-user, 1= user. Transformed level by using natural logarithmic function. p-value <0.05 for bold text.

Abbrevations: B, unstandardized coefficient; β, standardized coeffeicients; S.E. standard error of B; R², determination coefficient.

Figure 3 Association between CYP2D6 phenotypes and TMSE score at steady state (A) or ΔTMSE score (B) in AD patients.

Abbrevations: TMSE, Thai Mental State Examination score; IM, intermediate metabolizers; EM, extensive metabolizers.

Notes: Multiple comparisons were performed by Scheffe’s method. Each whisker represents the standard deviation (SD).

Table 5 The final models of stepwise multiple linear regression analysis of explanatory variables for donepezil treatment outcomes as measured by Thai Mental State Examination (TMSE) score at steady state and ΔTMSE in patients with Alzheimer's disease (AD) and vascular dementia (VAD)

Type of Dementia	Dependent variables	Predictive variables	Unstandardized coefficients		Standardized coefficients	95% CI of B	p-Value
			B	S.E.	β
AD	TMSE score^a	Constant	−4.113	2.544	–	−9.234/1.008	0.113
		Baseline TMSE score	0.832	0.085	0.738	0.661/1.004	<0.001
		CYP2D6 phenotypes	4.527	1.280	0.265	1.150/5.945	0.001
		Concomitant antidepressant use	−2.719	1.052	−0.193	−4.837/-0.602	0.013
		R^2=0.747, p-value <0.001
	ΔTMSE score^b	Constant	−8.060	2.092	–	−12.270/-3.850	<0.001
		CYP2D6 phenotypes	4.107	1.259	0.397	1.573/6.641	0.002
		Duration of use (year)	0.024	0.011	0.261	0.001/0.047	0.037
		Concomitant antidepressant use	−2.348	1.038	−0.275	−4.437/-0.259	0.028
		R^2=0.321, p-value =0.002
VAD	TMSE score^c	Constant	24.816	8.326	-	7.787/41.844	0.006
		Baseline TMSE score	0.845	0.119	0.723	0.602/1.089	<0.001
		Age (year)	−0.292	0.095	−0.311	−0.488/-0.097	0.005
		R^2=0.714, p-value <0.001
	ΔTMSE score^d	Constant	19.729	7.433		4.549/34.910	0.013
		Age (year)	−0.266	0.094	−0.458	−0.459/-0.073	0.008
		R^2=0.210, p-value =0.008

Notes: ^aAdjusted for concomitant memantine use, age, and gender. ^bAdjusted for CYP3A5 phenotypes, age, and Cpss of donepezil. ^cAdjusted for CYP3A5 phenotypes, concomitant memantine use, and concomitant CYP3A4 inhibitors use. ^dAdjusted for ABCB1 1236 genotype, concomitant antidepressant use, duration of use and gender. CYP2D6 phenotypes: 1.0= homozygous EM (CYP2D6*1/*1 or CYP2D6*1/*2 or CYP2D6*2/*2). 1.5= heterozygous EM (CYP2D6*1/*10, CYP2D6*2/*10). 2.0= IM (CYP2D6*10/*10). Concomitant antidepressant use: 0= non-user, 1= user. p-value <0.05 for bold text.

Abbrevations: B, unstandardized coefficient; β, standardized coeffeicients; S.E., standard error of B; R², determination coefficient.

Table S1 Cpss of donepezil and TMSE score in association with CYP2D6, CYP3A5, ABCB1, and APOE genotypes at the 10 mg maintenance dose

Genotypes/Phenotypes	N	Cpss(ng/mL)	AD (N=50)			VAD (N=32)
			N	TMSE score	ΔTMSE score	N	TMSE score	ΔTMSE score
CYP2D6
Homozygous EM	20	54.08 (32.22, 82.17)	12	14.30±8.10	−3.67±4.64	8	19.40±4.90	−1.90±2.50
Heterozygous EM	33	72.85 (52.17, 126.77)	21	20.20±5.30	−1.57±2.71	11	18.30±9.00	−0.50±2.40
IM	32	103.24 (65.63,164.29)	17	21.10±5.12	0.59±3.95	13	18.20±8.20	−0.50±4.90
p-value		0.029		0.010	0.023		0.935	0.647
CYP3A5
CYP3A5*1/*1 (EM)	15	55.49 (18.9,0.101.77)	10	18.60±5.80	−1.90±2.50	4	19.50±5.90	−1.80±3.10
CYP3A5*1/*3 (IM)	26	100.97 (70.32, 126.77)	15	19.30±6.20	−0.60±2.90	10	13.40±7.10	−1.80±4.00
CYP3A5*3/*3 (PM)	44	73.04 (41.40, 137.45)	26	19.20±7.20	−0.80±2.70	18	21.10±7.00	−0.10±3.50
p-value		0.058		0.962	0.467		0.029	0.421
ABCB1 3435
CC	32	88.96 (57.51, 129.47)	19	20.263±5.362	−1.473±3.322	12	19.417±7.668	−2.166±3.459
CT	34	75.33 (40.06, 137.31)	21	18.095±7.429	−0.904±4.217	11	18.182±7.359	0.727±4.221
TT	18	72.19 (35.09, 121.00)	9	19.556±6.930	−2.000±5.000	9	17.667±8.5440	−2.000±6.304
p-value		0.563		0.579	0.799		0.868	0.280
ABCB1 1236
CC	17	71.73 (55.49, 120.60)	10	19.900±7.766	−1.700±2.311	7	19.286±4.572	0.000±3.162
CT	39	75.50 (39.25, 126.77)	22	17.955±6.425	−1.500±3.776	16	16.625±8.437	−2.687±4.527
TT	29	75.16 (55.27, 136.46)	18	20.056±6.033	−0.944±4.916	9	21.222±7.661	0.777±5.449
p-value		0.902		0.554	0.866		0.343	0.163
APOE ε4
APOE ε4 carriers	-	-	28	18.143±6.392	−1.6071±4.201	11	16.545±9.501	−1.277±5.344
APOE ε4 non-carriers	-	-	22	20.318±6.614	−1.000±3.664	18	19.222±6.431	−1.000±2.932
p-value				0.245	0.594		0.372	0.876

Notes: For Cpss, the data were represented as median (IQR). For TMSE and ΔTMSE score, the data were represented as mean ± SD. ΔTMSE score = change in TMSE score initial treatment to final observation. CYP2D6 phenotypes: homozygous EM ie, CYP2D6*1/*1 or CYP2D6*1/*2 or CYP2D6*2/*2. heterozygous EM ie, CYP2D6*1/*10 or CYP2D6*2/*10. IM ie, CYP2D6*10/*10. p-value <0.05 for bold text.

Abbrevations: AD, Alzheimer's disease; VAD, vascular dementia; TMSE, Thai Mental State Examination score; IM, intermediate metabolizers; EM, extensive metabolizers; PM, poor metabolizers.

Table S2 Association of non-genetic factor and TMSE score of donepezil at 10-mg maintenance dose

Mutant alleles	AD (N=50)			VAD (N=32)
	N	TMSE score	ΔTMSE score	N	TMSE score	ΔTMSE score
Gender
Male	19	20.947±5.317	−1.2105 ±2.573	17	19.765±7.370	−0.1176±4.226
Female	31	17.968±6.993	−1.4194±4.631	15	17.067±7.851	−2.266±5.091
p-value		0.118	0.839		0.324	0.202
Concomitant use of antidepressant drugs
No	35	20.343±6.121	−0.5714±3.483	22	18.364±8.144	−0.2727±4.682
Yes	15	16.200±6.689	−3.133±4.486	10	18.800±6.629	−3.000±4.396
p-value		0.038	0.034		0.883	0.130
Concomitant use of CYP3A4 inhibitors
No	22	18.364±7.267	−1.9091±5.107	12	20.667±7.475	0.166±4.281
Yes	28	19.679±5.932	−0.8929±2.739	20	17.200±7.557	−1.900±4.876
p-value		0.484	0.406		0.564	0.235
Concomitant use of P-glycoprotein inhibitors
No	26	18.731±5.848	−1.5385±3.313	10	15.400±9.045	−2.600±2.547
Yes	24	19.500±7.277	−1.125±4.599	22	19.909±6.596	−0.454±5.324
p-value		0.681	0.714		0.121	0.238
Concomitant use of memantine
No	36	19.861±6.961	−1.555±4.101	28	19.357±7.592	−0.8929±4.693
Yes	14	17.143±4.881	−0.785±3.598	4	12.500±4.795	−2.750±5.123
p-value		0.188	0.541		0.092	0.469

Note: p-value <0.05 for bold text.

Abbrevations: AD, Alzheimer's disease; VAD, vascular dementia; TMSE, Thai Mental State Examination score; ΔTMSE, TMSE score change.

Table S3 Bivariate analysis: Association of non-genetic continuous variable and TMSE score

Dependent variables	AD				VAD
	TMSE score		ΔTMSE score		TMSE score		ΔTMSE score
Independent variables	Correlation coefficients (r)	p-value	Correlation coefficients (r)	p-value	Correlation coefficients (r)	p-value	Correlation coefficients (r)	p-value
Age (year)	0.205	0.153	0.270	0.058	−0.464	0.008	−0.458	0.008
Baseline TMSE score	0.800	<0.001	−0.143	0.323	0.788	<0.001	−0.107	0.559
Cpss (ng/mL)	0.046	0.749	0.244	0.087	−0.046	0.804	−0.014	0.937
Duration of use (month)	−0.137	0.343	0.286	0.044	0.060	0.744	−0.259	0.152
Education levels (year)	0.124	0.391	0.059	0.685	0.199	0.276	0.059	0.748

Note: p-value <0.05 for bold text.

Abbrevations: AD, Alzheimer's disease; VAD, vascular dementia; TMSE, Thai Mental State Examination score; ΔTMSE, TMSE score change.

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