Cost-effectiveness of efavirenz vs rilpivirine in HIV patients initiating first-line combination antiretroviral therapy

Figures & data

Figure 1.  Model structure.

Table 1.  Efficacy inputs—event probabilities.

Probability of events prompting switch from 1st line to 2nd line treatment*	First year		Second year
	EFV	RPV	EFV	RPV
Treatment failure with drug resistance	0.0146	0.0289	0.0023	0.0049
Treatment failure without drug resistance	0.0094	0.0161	0.0030	0.0077
Treatment discontinuation	0.0620	0.0325	0.0164	0.0214
Per cycle probability of switching
From 2nd line to 3rd line treatment	0.0745
From 3rd line to non-suppressive treatment	0.0760

*Year 1 event probabilities are adapted from Cohen et al.10; year 2 event probabilities are adapted from Cohen et al.9. Subsequent switching probabilities are taken from Brogan et al.3.

EFV, efavirenz; RPV, rilpivirine.

Table 2.  Cost inputs.

	Costs (2011 US$)*	Source
Treatment costs
EFV	$9899 per cycle	Wholesale List Price, June 2011
RPV	$10,370 per cycle	Wholesale List Price, June 2011
Second Line	$11,735 per cycle	Brogan et al.3
Third Line	$24,561 per cycle	Brogan et al.3
Non-Suppressive	$24,561 per cycle	Brogan et al.3
Switching	$885 per treatment line switch	Brogan et al.3
Short-term adverse events
Mental disturbances (dizziness, abnormal dreams, etc.)	$97 per cycle	Sanders et al.18
EFV (prevalence: 38%)	$36.86 per cycle	Cohen et al.9, cost calculated
RPV (prevalence: 17%)	$16.49 per cycle	Cohen et al.9, cost calculated
Rash Management	$97 per cycle	Sanders et al.18
EFV (prevalence: 15%)	$14.55 per cycle	Cohen et al.9, cost calculated
RPV (prevalence: 4%)	$3.88 per cycle	Cohen et al.9, cost calculated
Long-term adverse events
Lipid Lowering Medication	$1 per day	Heart Protection Study 200919
EFV (prevalence: 22%)	$0.22 per day	Cohen et al.9, cost calculated
RPV (prevalence: 7%)	$0.07 per day	Cohen et al.9, cost calculated

*Costs adjusted to 2011 US$ using the Medical Care cost component of the Consumer Price Index.

EFV, efavirenz; RPV, rilpivirine.

Table 3.  Model base case summary and incremental cost effectiveness ratios (ICER).

	3 years			5 years			10 years
	EFV	RPV	Difference (EFV − RPV)	EFV	RPV	Difference (EFV − RPV)	EFV	RPV	Difference (EFV − RPV)
Total cost	$55,023	$57,483	−$2460	$96,319	$100,655	−$4335	$214,031	$222,090	−$8060
Total life years	2.8525	2.8525	0.00000	4.5965	4.5965	0.00000	8.4426	8.4426	0.00002
ICER: Additional life year: RPV vs EFV	>$10,000,000			>$10,000,000			EFV dominates
Person years in virologic suppression	2.6005	2.6007	−0.0081	4.3245	4.3252	−0.0007	7.8694	7.8571	0.012
ICER: Additional year in virologic suppression: RPV vs EFV	>$10,000,000			>$5,000,000			EFV dominates
Total life years with AIDS	0.0001	0.0001	0.0000	0.0015	0.0014	0.0001	0.0383	0.0394	−0.0011
ICER: Additional year without AIDS: RPV vs EFV	>$10,000,000			>$10,000,000			EFV dominates
Cases of virologic failure during 1st line treatment, per 100 patients	6.6	12.8	−6.21	11.9	21.3	−9.49	20.5	33.7	−13.13
Cases of virological failure with drug resistance during  1st line treatment, per 100 patients	3.6	7.1	−3.49	5.9	10.4	−4.56	9.6	15.2	−5.63

EFV, efavirenz; RPV, rilpivirine. Dominates indicates better outcomes and lower costs.

Table 4.  Model base case summary and incremental cost effectiveness ratios (ICER): non-discounted outcomes.

	3 years			5 years			10 years
	EFV	RPV	Difference (EFV − RPV)	EFV	RPV	Difference (EFV − RPV)	EFV	RPV	Difference (EFV − RPV)
Total cost	$57,794	$60,380	−$2586	$104,336	$109,036	−$4699	$251,968	$261,294	−$9326
Total life years	2.9815	2.9815	−0.00000	4.9456	4.9456	−0.00000	9.7473	9.7473	0.00003
ICER: Additional life year: RPV vs EFV	>$10,000,000			>$10,000,000			EFV dominates
Person years in virologic suppression	2.7293	2.7295	−0.0002	4.6707	4.6715	−0.0008	9.0877	9.0718	0.01589
ICER: Additional year in virologic suppression:  RPV vs EFV	>$10,000,000			>$5,000,000			EFV dominates
Total life years with AIDS	0.0001	0.0001	0.0000	0.00165	0.00158	0.000075	0.04899	0.05043	−0.001434
ICER: Additional year without AIDS: RPV vs EFV	>$10,000,000			>$10,000,000			EFV dominates
Cases of virologic failure during 1st line treatment,  per 100 patients	6.82	13.27	−6.45	12.79	22.93	−10.14	23.42	38.01	−14.59
Cases of virological failure with drug resistance during  1st line treatment, per 100 patients	3.74	7.35	−3.60	6.30	11.10	−4.80	10.86	16.97	−6.11

EFV, efavirenz; RPV, rilpivirine. Dominates indicates better outcomes and lower costs.

Table 5.  Sensitivity analysis results.

Input item	Incremental cost of an additional year of benefit when input value is varied from the base case
	Additional year of life		In virologic suppression		Without AIDS
	value + 25%	value − 25%	value + 25%	value − 25%	value + 25%	value − 25%
Transition or Event Probability Inputs
Resistant failure for EFV in first year	RPV ICER = $295,147,256	EFV dominates	EFV dominates	EFV dominates	EFV dominates	EFV dominates
Resistant failure for EFV in second year	EFV dominates	EFV dominates	EFV dominates	EFV dominates	EFV dominates	EFV dominates
Non-resistant failure for EFV in first year	RPV ICER = $889,681,757	EFV dominates	EFV dominates	EFV dominates	EFV dominates	EFV dominates
Non-resistant failure for EFV in second year	EFV dominates	EFV dominates	EFV dominates	EFV dominates	EFV dominates	EFV dominates
Discontinuation for EFV in first year	RPV ICER = $36,009,840	EFV dominates	RPV ICER = $507,222	EFV dominates	RPV ICER = $2,515,892	EFV dominates
Discontinuation for EFV in second year	RPV ICER = $344,556,896	EFV dominates	EFV dominates	EFV dominates	EFV dominates	EFV dominates
Resistant failure for RPV in the first year	EFV dominates	RPV ICER = $95,951,941	EFV dominates	EFV dominates	EFV dominates	RPV ICER = $12,386,353
Resistant failure for RPV in the second year	EFV dominates	EFV dominates	EFV dominates	EFV dominates	EFV dominates	EFV dominates
Non-resistant failure for RPV in the first year	EFV dominates	RPV ICER = $265,895,070	EFV dominates	EFV dominates	EFV dominates	EFV dominates
Non-resistant failure for RPV in the second year	EFV dominates	EFV dominates	EFV dominates	EFV dominates	EFV dominates	EFV dominates
Discontinuation for RPV in the first year	EFV dominates	RPV ICER = $91,123,291	EFV dominates	RPV ICER = $33,610,990	EFV dominates	RPV ICER = $9,847,628
Discontinuation for RPV in the second year	EFV dominates	RPV ICER = $220,734,431	EFV dominates	EFV dominates	EFV dominates	RPV ICER = $34,416,439
Health State or Event Cost Inputs
Cost of EFV treatment	EFV ICER = $673,214,824	EFV dominates	EFV ICER = $1,099,894	EFV dominates	EFV ICER = $12,369,319	EFV dominates
Cost of RPV treatment	EFV dominates	EFV ICER = $688,495,337	EFV dominates	EFV ICER = $1,124,859	EFV dominates	EFV ICER = $12,650,075

EFV, efavirenz; RPV, rilpivirine; ICER, incremental cost-effectiveness ratio. Dominates indicates better outcomes and lower costs.

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