The objective of this study was to elucidate patterns evolved under treatment regimens containing NNRTI. To this end, we have comparatively analysed the genetic variation in the RT gene of subtype B and subtype C HIV-1 from drug-naive and drug-experienced patients. We compared the frequency at which individual drug resistance mutations were selected in subtype B and C patients who failed therapy. We further compared our results to a large public-access database.
Patients in our study were not randomized into specific treatment arms. The patients had different ethnic backgrounds, and this may have affected both adherence and pharmacokinetics. Such issues were not studied here. However, patients were treated by the same physicians in the same clinics. The drugs received, follow-up time, baseline viral load and CD4 cell counts were similar (Table 1). Although all the mutations associated with resistance to NNRTI in subtype B-infected patients were found also in subtype C-infected patients, different patterns and frequencies of specific mutations were found in each subtype. Significant differences in frequency of individual mutations were found only for A98G/S, V106M and Y188C. However, the frequency differences for all of the other mutations combined reached significance, with more NNRTI resistance-associated mutations in subtype C patients. This applies to each of the three groups, drug-naive, NNRTI-naive and NNRTI-treated patients. The relatively high frequency of NNRTI resistance-associated mutations in subtype C-infected patients is conspicuous when compared with other RT mutations, the NAM and M184V. As previously reported, the frequency of NAM was higher in B infected patients and that of M184V was equal in subtype B- and subtype C-infected patients. In contrast, NNRTI resistance-associated mutations appear to accumulate rapidly in subtype C patients and to manifest a unique pattern. Even in subtype C patients who were treated with NRTI, and not with NNRTI, there was an increased frequency of mutations associated with resistance to NNRTI. The implied cross-reactivity between NRTI and NNRTI should be further investigated.
V106M and K103N can coexist: of 13 patients who developed V106M, five (38.5%) also had K103N. The prevalence of K103N following EFV treatment was significantly lower in EFV-treated subtype C patients than in subtype B patients treated with this drug. It seems that in some cases V106M arose in subtype C-infected patients at the expense of K103N. Our findings confirm Brenner's in vitro evidence that EFV selects preferentially for V106M in subtype C-infected patients.
Although not conclusive, these data suggest that baseline polymorphism in the subtype C RT influences the rate at which certain mutations develop in patients failing therapy and the mutation pattern. This may be the case also for other non-B subtypes. In spite of the higher mutation frequency in NNRTI-associated RT positions in subtype C-infected patients, we cannot conclude at this stage that the efficacy of NNRTI in the treatment of subtype C patients is lower in these patients than in subtype B patients (differences in viral load or CD4 cell count were insignificant). Prospective clinical trials and phenotypic assays are needed to address this issue.
We thank M. Ofir, of VGI, Israel, for excellent technical assistance. M. Amit and Y. Shaked helped in database development. The Stanford HIV database is under the direction of R. Shafer.
Sponsorship: This work was supported by Bristol-Myers Squibb, Israel.
1. Falloon J, Piscitelli S, Vogel S, Sadler B, Mitsuya H, Kavlick MF, et al. Combination therapy with amprenavir, abacavir, and efavirenz in human immunodeficiency virus (HIV)-infected patients failing a protease-inhibitor regimen: pharmacokinetic drug interactions and antiviral activity. Clin Infect Dis
2. UNAIDS. Report on the global HIV/AIDS Epidemic.
Geneva: UNAIDS; 2000.
3. Gonzales MJ, Machekano RN, Shafer RW. Human immunodeficiency virus type 1 reverse-transcriptase and protease subtypes: classification, amino acid mutation patterns, and prevalence in a northern California clinic-based population. J Infect Dis
4. Carr JK, Salminen MO, Albert J, Sanders-Buell E, Gotte D, Birx DL, et al. Full genome sequences of human immunodeficiency virus type 1 subtypes G and A/G intersubtype recombinants. Virology
5. Carr JK, Laukkanen T, Salminen MO, Albert J, Alaeus A, Kim B, et al. Characterization of subtype A HIV-1 from Africa by full genome sequencing. AIDS
6. Buonaguro FM, Buonaguro L, Del Gaudio E, Tornesello ML, Monaco M, Greco D, et al. V3 region genotyping of HIV isolates in northern Uganda: heteroduplex mobility assay, nucleotide sequence and phylogenetic analysis. Italian-Ugandan Cooperation AIDS Program. Antibiot Chemother
7. Cornelissen M, van den Burg R, Zorgdrager F, Lukashov V, Goudsmit J. Pol gene diversity of five human immunodeficiency virus type 1 subtypes: evidence for naturally occurring mutations that contribute to drug resistance, limited recombination patterns, and common ancestry for subtypes B and D. J Virol
8. Quinnan GV, Jr., Zhang PF, Fu DW, Dong M, Alter HJ. Expression and characterization of HIV type 1 envelope protein associated with a broadly reactive neutralizing antibody response. AIDS Res Hum Retroviruses
9. Kantor R, Fessel WJ, Zolopa AR, Israelski D, Shulman N, Montoya JG, et al. Evolution of primary protease inhibitor resistance mutations during protease inhibitor salvage therapy. Antimicrob Agents Chemother
10. Kantor R, Machekano R, Gonzales MJ, Dupnik K, Schapiro JM, Shafer RW. Human Immunodeficiency Virus Reverse Transcriptase and Protease Sequence Database: an expanded data model integrating natural language text and sequence analysis programs. Nucl Acids Res
11. Grossman Z, Vardinon N, Chemtob D, Alkan ML, Bentwich Z, Burke M, et al. Genotypic variation of HIV-1 reverse transcriptase and protease: comparative analysis of clade C and clade B. AIDS
:1453–1460 [erratum appears in AIDS 2001 15
12. Cane PA, de Ruiter A, Rice P, Wiselka M, Fox R, Pillay D. Resistance-associated mutations in the human immunodeficiency virus type 1 subtype c protease gene from treated and untreated patients in the United Kingdom. J Clin Microbiol
13. Grossman Z, Paxinos E, Auerbuch D, Maayan S, Parkin N, Engelhard D, et al. D30N is not the preferred resistance pathway in subtype C patients treated with nelfinavir.
[Abstract] Antiviral Ther
14. Frater AJ, Beardall A, Ariyoshi K, Churchill D, Galpin S, Clarke JR, et al. Impact of baseline polymorphisms in RT and protease on outcome of highly active antiretroviral therapy in HIV-1-infected African patients. AIDS
15. Vergne L, Peeters M, Mpoudi-Ngole E, Bourgeois A, Liegeois F, Toure-Kane C, et al. Genetic diversity of protease and reverse transcriptase sequences in non-subtype-B human immunodeficiency virus type 1 strains: evidence of many minor drug resistance mutations in treatment-naive patients. J Clin Microbiol
16. Pillay C, Bredell H, McIntyre J, Gray G, Morris L. HIV-1 subtype C reverse transcriptase sequences from drug-naive pregnant women in South Africa. AIDS Res Hum Retroviruses
17. Clevenbergh P, Cua E, Dam E, Durant J, Schmit JC, Boulme R, et al. Prevalence of nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance-associated mutations and polymorphisms in NNRTI-naive HIV-infected patients. HIV Clin Trials
18. Conway B. Initial therapy with protease inhibitor-sparing regimens: evaluation of nevirapine and delavirdine. Clin Infect Dis
19. Moyle GJ, Wilkins E, Leen C, Cheesbrough A, Reynolds B, Gazzard BG. Salvage therapy with abacavir plus efavirenz or nevirapine in HIV-1-infected persons with previous nucleoside analogue and protease inhibitor use. AIDS
20. Raboud JM, Rae S, Vella S, Harrigan PR, Bucciardini R, Fragola V, et al. Meta-analysis of two randomized controlled trials comparing combined zidovudine and didanosine therapy with combined zidovudine, didanosine, and nevirapine therapy in patients with HIV. INCAS study team. J Acquir Immune Defic Syndr
21. Smeaton LM, DeGruttola V, Robbins GK, Shafer RW. ACTG (AIDS Clinical Trials Group) 384: a strategy trial comparing consecutive treatments for HIV-1.[comment]. Control Clin Trials
22. Robbins WA, Witt KL, Haseman JK, Dunson DB, Troiani L, Cohen MS, et al. Antiretroviral therapy effects on genetic and morphologic end points in lymphocytes and sperm of men with human immunodeficiency virus infection . J Infect Dis
23. Loemba H, Brenner B, Parniak MA, Ma'ayan S, Spira B, Moisi D, et al. Genetic divergence of human immunodeficiency virus type 1 Ethiopian clade C reverse transcriptase (RT) and rapid development of resistance against nonnucleoside inhibitors of RT. Antimicrob Agents Chemother
24. Brenner B, Turner D, Oliveira M, Moisi D, Detorio M, Carobene M, et al.
A V106M mutation in HIV-1 clade C viruses exposed to efavirenz confers cross-resistance to non-nucleoside reverse transcriptase inhibitors. AIDS
25. Morris L, Pillay C, Chezzi C, Lupondwana P, Ntsala M, Levin L, et al. Low frequency of the V106M mutation among HIV-1 subtype C-infected pregnant women exposed to nevirapine. AIDS
26. Yust I, Maayan S, Burke M, Vardinon N, Moses A, Burstein R, et al. Clinical, epidemiological and natural history study of HIV-1 infection among seropositive homo/bisexuals in Israel, 1986–92. A collaborative study in three medical centers. Isr J Med Sci
27. Slater PE, Costin C. The epidemiology of adult AIDS and HIV infection in Israel. Isr J Med Sci
28. Pollack S, Ben-Porath E, Fuad B, Raz R, Etzioni A. Epidemiological and serological studies in HIV-infected Ethiopian immigrants to Israel. Acta Paediatr Suppl
29. Pollack S. Epidemiological and immunological study of HIV-seropositive Ethiopian immigrants in Israel. The Israel AIDS Study Group. Isr J Med Sci
30. Maayan S, Shinar E, Aefani M, Soughayer M, Alkhoudary R, Barshany S, et al. HIV-1 prevalence among Israeli and Palestinian blood donors. AIDS
31. Kaplan EH, Kedem E, Pollack S. HIV incidence in Ethiopian immigrants to Israel. J Acquir Immune Defic Syndr Hum Retrovirol
32. Hirsch MS, Brun-Vezinet F, D'Aquila RT, Hammer SM, Johnson VA, Kuritzkes DR, et al. Antiretroviral drug resistance testing in adult HIV-1 infection: recommendations of an International AIDS Society-USA Panel. JAMA
33. Yeni PG, Hammer SM, Carpenter CC, Cooper DA, Fischl MA, Gatell JM, et al. Antiretroviral treatment for adult HIV infection in 2002: updated recommendations of the International AIDS Society-USA Panel. JAMA
Additional contributing coauthors
Dan Engelhard, Shlomo Maayan, Hadassah University Hospital, Jerusalem; Zvi Bentwich, Dina Torten, Kaplan Hospital, Hebrew University Hadassah Medical School, Rehovot; Ella Mendelson, Fernando Mileguir, Daniela Ram, Hagit Rudich, National HIV Reference Center, Central Virology Lab, Public Health Laboratories, Ministry of Health; Eduardo Shahar, Einat Kedem, Sholomo Pollack, Rambam Medical Center, Haifa; Bat Sheva Gotessman, Giora Gotessman, Meir Medical Center, Kfar-Saba, Israel.