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Antimicrobial Agents and Chemotherapy, March 2003, p. 1176, Vol. 47, No. 3
0066-4804/03/$08.00+0 DOI: 10.1128/AAC.47.3.1176.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.
Stavudine Protective Function and Emergence of Lamivudine Resistance

LETTER
Joly et al. presented an interesting paper (
1) comparing the
efficacy and toxicity of zidovudine (AZT) versus that of stavudine
(d4T), in combination with lamivudine (3TC) and indinavir, in
170 patients treated with AZT, dideoxyinosine, and/or dideoxycytosine
in a randomized comparative multicenter trial (Novavir trial).
No M184V mutation was detected in the reverse transcriptase
gene before starting highly active antiretroviral therapy (HAART).
At week 80, 15 patients in the AZT arm and 14 patients in the
d4T arm reached virological failure, defined as plasma human
immunodeficiency virus type 1 (HIV-1) RNA levels of >5,000
copies/ml. Time to virological failure did not differ between
the two arms (
P = 0.98). In the d4T and AZT arms, 67 and 73%
of patients, respectively, had HIV-1 RNA levels of <500 copies/ml
(
P = 0.50). Moreover, the proportions of patients with HIV-1
RNA levels of <50 copies/ml at weeks 8, 16, and 24 were similar
in the two arms.
In this study, no details about the genotypic resistance pattern of the 29 patients failing an AZT- or d4T-including regimen were reported. In a previous study (2) conducted on 56 HIV-seropositive patients treated with 3TC or d4T, including dual antiretroviral therapy, we observed that d4T-3TC was at least as effective as the AZT-3TC regimen in terms of viral suppression and immune recovery. Interestingly, a higher prevalence of M184V mutation was found in patients failing AZT-3TC therapy than that in patients treated with the d4T-3TC regimen: 41 and 14%, respectively. This difference had only a weak statistical significance (P = 0.05) because of the limited power of the study. However, in the discussion section, we suggested the occurrence of a hypothetical protective role of d4T on the emergence of 3TC resistance. Until now, no other studies have confirmed this observation.
It could be noteworthy to verify whether the d4T protective function on the emergence of 3TC resistance has been reported in HIV-infected patients failing HAART during the Novavir trial.

REFERENCES
1 - Joly, V., P. Flandre, V. Meiffredy, F. Brun-Vezinet, J.-A. Gastaut, C. Goujard, G. Remy, D. Descamps, A. Ruffault, A. Certain, J.-P. Aboulker, and P. Yeni for the Novavir Study Group. 2002. Efficacy of zidovudine compared to stavudine, both in combination with lamivudine and indinavir, in human immunodeficiency virus-infected nucleoside-experienced patients with no prior exposure to lamivudine, stavudine, or protease inhibitors (Novavir trial). Antimicrob. Agents Chemother. 46:1906-1913.[Abstract/Free Full Text]
2 - Sarmati, L., E. Nicastri, S. G. Parisi, G. D'Ettorre, P. Narciso, G. Mancino, I. Gallo, V. Abbadessa, N. E. Dalle, C. Traina, V. Vullo, and M. Andreoni. 2001. Failure of stavudine-lamivudine combination therapy in antiretroviral-naïve patients with AZT-like HIV-1 resistance mutations. J. Med. Virol. 65:631-636.[CrossRef][Medline]
| | | | | |
Emanuele Nicastri
National Institute of Infectious Diseases IRCCS L. Spallanzani
Loredana Sarmati Massimo Andreoni*
Department of Public Health University of Rome Tor Vergata Rome, Italy
|
| | | | | |
* Phone and fax: 39 06 725 96873, E-mail: andreoni{at}uniroma2.it |
Authors' Reply

LETTER
When considering the 12-month-extended follow-up, we observed
that 35 patients17 and 18 patients receiving d4T-3TC-IDV
and AZT-3TC-IDV, respectivelyreached virological failure
defined as a viral load of >5,000 copies/ml in two consecutive
samples. Genotypic resistance data were available at the baseline
and at the time of failure in 27 out of these 35 patients. Sixteen
and 11 patients were in the zidovudine and stavudine arms, respectively.
The M184V mutation was never found at baseline, i.e., before
initiating HAART. At the time of failure, the M184V mutation
was found in 13 of 16 patients (81%) of the zidovudine arm and
9 of 11 patients (82%) of the stavudine arm. Thus, we did not
observe any protective role of stavudine on the emergence of
genotypic resistance to lamivudine. It has to be stressed that,
in our study, lamivudine was administered in the context of
HAART, in combination with indinavir, contrarily to the study
of Sarmati et al. (
1), in which patients were subject to dual-nucleoside
therapy.

REFERENCES
1 - Sarmati, L., E. Nicastri, S. G. Parisi, G. D'Ettorre, P. Narciso, G. Mancino, I. Gallo, V. Abbadessa, N. E. Dalle, C. Traina, V. Vullo, and M. Andreoni. 2001. Failure of stavudine-lamivudine combination therapy in antiretroviral-naïve patients with AZT-like HIV-1 resistance mutations. J. Med. Virol. 65:631-636.
| | | | | |
Véronique Joly* Diane Descamps Philippe Flandre Patrick Yeni
Agence Française de Recherche sur le SIDA Paris, France
|
| | | | | |
* Phone and fax: 39 06 725 96873, E-mail: andreoni{at}uniroma2.it |
Antimicrobial Agents and Chemotherapy, March 2003, p. 1176, Vol. 47, No. 3
0066-4804/03/$08.00+0 DOI: 10.1128/AAC.47.3.1176.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.