Table 2. Effects of etravirine on HIV-1 reverse transcriptase, recovered from plasma of HIV-1 infected patients.

			Mutations at amino acid											Antiviral score according to
Patient/Sample	Fold difference in ETR IC50	90 V	98 A	100 L	101 K	103 K	106 V	108 V	138 E	179 V	181 Y	190 G	238 K	Stanford	Tibotec	Monogram
BH10*	1.0													NA	NA	NA
L100I*	12.0													15 (i)	2.5 (i)	4 (r)
1	11.8		S				A							0 (s)	0 (s)	2 (s)
2	>100					N			Q				T	10 (s)	1 (s)	2 (s)
3a	4.5		S							D				10 (s)	1 (s)	1 (s)
3b	>100	I	S							D	C			45 (i)	4.5 (r)	6 (r)
4	3.9					R								0 (s)	0 (s)	1 (s)
5a	45.8				I/R		G							0 (s)	0 (s)	0 (s)
5b	71.4				I/R		G							0 (s)	0 (s)	0 (s)
6	>100	I		I		N								20 (i)	3.5 (i)	5 (r)
7	0.7													0 (s)	0 (s)	0 (s)
8a	>100					N					C			30 (i)	2.5 (i)	4 (r)
8b	>100					N					C			30 (i)	2.5 (i)	4 (r)
9a	4.6		S			N		I					T	0 (s)	0 (s)	1 (s)
9b	9.2		S			N		I					T	0 (s)	0 (s)	1 (s)
10	13.6					N		I						0 (s)	0 (s)	0 (s)
11a	7.3					N				I				0 (s)	0 (s)	1 (s)
11b	4.1									I				0 (s)	0 (s)	1 (s)
12	2.0					N								0 (s)	0 (s)	0 (s)
13	68.8					N						A		10 (s)	1 (s)	1 (s)
14	29.1		S			N			A					5 (s)	1.5 (s)	3 (s)
15	2.9					N								0 (s)	0 (s)	0 (s)
16	1.7					N								0 (s)	0 (s)	0 (s)
17	2.9					N								0 (s)	0 (s)	0 (s)
18	4.1	I				N								0 (s)	1 (s)	1 (s)
19	6.4					N								0 (s)	0 (s)	0 (s)
20	7.2					N								0 (s)	0 (s)	0 (s)

*Two recombinant reverse transcriptase, (BH10)-wild-type (WT) and its mutant form L100I, were used as references. Based on the IC₅₀ value of BH10-wild-type (1.0±0.18 µM), which was included in every run, the IC₅₀ value and the fold-difference in susceptibility of each isolate were determined. A fold-difference of <5 was considered as sensitive, between 5–15 as decreased susceptibility, and above 15 as resistant.

Abbreviations: NA, not applicable; IC₅₀, inhibitory effect; ETR etravirine.

**Genotype result was obtained six months earlier. The results of three genotypic scoring systems (Stanford, Monogram Weighted Score, Tibotec Weighted Genotype Score) predicting ETR susceptibility are presented. s: sensitive; i: intermediate; r: resistant. A Stanford score of 0-<15, ≥15-<60 and ≥60 are defined as susceptible, intermediate and resistant. Tibotec weighted genotypic score of 0–2, 2.5–3.5 and ≥4 are predictive of susceptible, intermediate and reduced response. Monogram defines a weighted score of 0–3 as susceptible and ≥4 as resistant.