Table 4.

Model-based lifetime projections for single-dose nevirapine-exposed women initiating antiretroviral therapy.

ART strategy	Life expectancy (years)	Per-person costs (2008 US$)	Cost-effectiveness ratio ($/YLS)
A. Entire OCTANE cohort (trial data)
No ART	1.6	2,980
1^st-line NVP	15.2	13,990	810
1^st-line LPV/r	16.3	15,630	1,520

B. Subgroup analyses (trial data)
Presence or absence of NNRTI resistance at ART initiation
No baseline resistance detected
No ART	1.6	2,980
1^st-line NVP	16.0	13,800	750
1^st-line LPV/r	16.3	15,600	5,650

Baseline resistance ^a
No ART	1.6	2,980
1^st-line NVP	12.2	14,000	Dominated ^b
1^st-line LPV/r	15.5	15,390	890

Time from sdNVP exposure to ART initiation
6–12 months
No ART	1.6	2,980
1^st-line NVP	14.2	14,220	Dominated ^b
1^st-line LPV/r	16.1	15,640	870
12–24 months
No ART	1.6	2,980
1^st-line NVP	15.3	13,790	790
1^st-line LPV/r	16.4	15,650	1,690
Greater than 24 months
No ART	1.6	2,980
1^st-line NVP	15.2	13,780	790
1^st-line LPV/r	15.1	14,940	Dominated ^c

C. Standard genotype assay for selection of 1^st-line ART
Genotype: Initiate LPV/r if NNRTI resistance detected; NVP if resistance not detected (genotype cost: $300 ^d)
No ART	1.6	2,980
1^st-line NVP for all	15.2	13,990	Dominated ^b
Genotype strategy	15.9	14,320	790
1^st-line LPV/r for all	16.3	15,630	4,080

D. Sensitivity analyses
“Worst-case” clinical scenario for 1^st-line LPV/r
No ART	1.6	2,980
1^st-line LPV/r	10.5	12,280	Dominated ^b
1^st-line NVP	13.6	12,370	780
“Best-case” clinical scenario for 1^st-line LPV/r
No ART	1.6	2,980
1^st-line NVP	14.6	13,500	811
1^st-line LPV/r	17.2	15,670	813 ^e
HIV RNA monitoring available for both NVP and LPV/r strategies ^f
No ART	1.6	2,980
1^st-line NVP	15.3	15,840	940
1^st-line LPV/r	16.1	17,300	1,720

ART: antiretroviral therapy; CE: cost-effectiveness; NVP: nevirapine; LPV/r: lopinavir/ritonavir; YLS: year of life saved

Assumes 2^nd-line NVP with efficacy 43% will follow 1^st-line LPV/r despite detected resistance. Results change minimally (cost-effectiveness ratio for 1^st-line NVP compared to no ART: $890/YLS) if NVP is avoided in 2^nd-line and 1^st-line LPV/r failure is followed by LPV/r/lamivudine maintenance therapy

Extended dominance: In the subgroup with baseline NNRTI resistance and the subgroup of women initiating ART within 6–12 months after sdNVP, the cost-effectiveness ratio of the 1^st-line LPV/r strategy compared to 1^st-line NVP is less than the cost-effectiveness ratio of 1^st-line NVP compared to no ART. This indicates that the 1^st-line NVP strategy represents an inefficient use of healthcare resources, if LPV/r is available. By convention in these cases, the cost-effectiveness ratio of 1^st-line NVP compared to no ART is not reported. By the same mechanism, in the “worst-case” clinical scenario for 1^st-line LPV/r, 1^st-line LPV/r represents an inefficient use of resources compared to 1^st-line NVP, and the cost-effectiveness ratio of 1^st-line LPV/r compared to no ART is not shown.

Strong dominance occurs in the subgroup with sdNVP exposure >24 months prior to ART initiation because 1^st-line LPV/r is both less effective and more expensive than 1^st-line NVP.

Results are shown assuming a standard genotype assay cost of $300. Variations in genotype assay cost from $0-$585 do not change extended dominance of the NPV strategy by the genotype strategy. At assay costs from $585-$1000, incremental cost-effectiveness ratios of the genotype strategy compared to the nevirapine strategy range from $810–1,360/YLS. Results in table assume no HIV RNA monitoring availability; available RNA monitoring does not substantially change results.

The cost-effectiveness ratios in the “best-case” scenario are presented without rounding, to demonstrate that 1^st-line nevirapine is not dominated. However, the nearly equivalent cost-effectiveness ratios of 1^st-line NVP compared to no ART and of 1^st-line LPV/r compared to 1^st-line NVP suggest that, if all of the most favorable parameters for 1^st-line LPV/r were true, any program able to afford 1^st-line NVP-based ART would achieve greater health benefits at nearly the same cost by instead choosing 1^st-line LPV/r.

First-line ART switched to second-line ART for a one-log increase in RNA or return to peak pre-ART RNA value. Shown are scenarios in which HIV RNA monitoring was performed every 6 months; results of 3-monthly RNA monitoring or RNA monitoring applied only to 1^st-line NVP strategy are not substantially different. Lower life expectancy in the 1^st-line lopinavir/ritonavir strategy with RNA monitoring, compared to the base case, result from earlier switching to a less effective 2^nd-line regimen (2^nd-line NVP, efficacy 43%).