Impact of integrase polymorphisms and minor quasispecies in HIV-1 infected individuals naive or treated with strand-transfer integrase inhibitors: a refined analysis by cloning and 454-pyrosequencing techniques

Introduzione: Raltegravir è un potente ed efficace inibitore dell’ integrasi (IN) di HIV-1, recentemente approvato dall’FDA anche nei regimi HAART di prima linea. Dagli studi attualmente disponibili in letteratura, il ruolo dei polimorfismi naturali e delle quasi specie minoritarie dell’integrasi sul responso virologico agli InSti e sullo sviluppo di resistenza durante il fallimento è ancora poco chiaro. Pertanto questo lavoro mira a verificare la presenza di mutazioni di resistenza agli InSti nelle quasispecie naturali di HIV-1 in pazienti naive a tali inibitori e a valutare l’impatto sulla suscettibilità fenotipica in vitro, sulla capacità replicativa virale e sul responso virologico a raltegravir utilizzando tre diversi approcci: il metodo clonale, il sequenziamento di popolazione e il pirosequenziamento massivo 454 (Ultra-deep 454 Pyrosequencing [UDPS]). Metodi: Per l’approccio clonale, le sequenze di RT-RNAse H-IN sono state amplificate tramite PCR da campioni di plasma da 49 individui infetti da HIV-1 sottotipo B (21 naive al trattamento e 28 in fallimento a regimi antiretrovirali non includenti gli InSti) e ricombinate con un vettore di espressione contenente lo stipite di HIV-1 HXB2D deleto della regione RT-IN. I virus ricombinanti ottenuti sono stati testati per la suscettibilità a raltegravir ed elvitegravir e per la capacità replicativa. Da 49 pazienti sono stati ottenuti 344 cloni ricombinanti testati genotipicamente e fenotipicamente in vitro. Per l’analisi con il sequenziamento di popolazione, sono stati analizzati 206 pazienti multi-trattati, provenienti da 8 diversi centri clinici italiani e francesi, che iniziavano il trattamento con un regime contenente raltegravir. Il genotipo dell’IN e la viremia sono stati effettuati prima e durate l’inizio della terapia. Alla 24esima settimana di trattamento erano disponibili valori di viremia per 177 pazienti. La prevalenza delle mutazioni è stata calcolata nella popolazione totale, nei pazienti che hanno raggiunto il successo virologico e nei i pazienti che hanno fallito alla 24esima settimana di trattamento. Per i polimorfismi con una prevalenza maggiore del 5% è stato anche considerato l’uso specifico dei codoni codificanti le mutazioni. Per valutare se i polimorfismi ed altre variabili (la viremia, i farmaci co-somministrati e il sottotipo) fossero predittori indipendenti di successo virologico, è stata effettuata un’analisi di regressione logistica (uni e multivariata). Per l’analisi con l’UDPS un sottogruppo di 27 pazienti trattati con raltegravir è stato genotipizzato al baseline e al fallimento. Inoltre è stato effettuato il test fenotipico delle popolazioni virali al fallimento. Per tutti e tre gli approcci sono state analizzate tutte le mutazioni dell’ integrasi con particore attenzione alle mutazioni di resistanza note. In particolare per l’UDPS, il rilevamento delle mutazioni è stato considerato attendibile osservando una prevalenza >0.1%(>50 varianti). Risultati: Dall’approcio clonale, la maggior parte dei cloni testati non ha mostrato resistenza fenotipica agli InSti: 0/344 cloni hanno mostrato resistenza per raltegravir e solo 3 cloni (0.87%) hanno mostrato bassi livelli di resistenza per elvitegravir. Non è stata osservata alcuna mutazione di resistenza primaria per raltegravir e/o elvitegravir. Nei cloni resistenti a elvitegravir sono state trovate alcune mutazioni secondarie, come la T97A e la G140S. Inoltre è stata osservata una nuova mutazione, E92G, anch’essa in quasispecie minoritaria, associata a resistenza fenotipica a elvitegravir. Tra i 206 pazienti analizzati con l’approccio di sequenziamento di popolazione, 186 (90.3%) sono risultati infetti da sottotipo B mentre 20 (9.8%) sono risultati infetti da sottotipi non B (4A, 1C, 2D, 5F, 2G, 5CRF_02AG, 1CRF_12BF2). Alla 24esima settimana di trattamento con raltegravir il 70% dei pazienti ha raggiunto il successo virologico (il 71.3% [114/160] e il 58.8% [10/17] infetti da virus di sottotipo B e non-B rispettivamente, p=NS). Al basale non è stata trovata alcuna mutazione di resistenza primaria mentre le secondarie (L74M, T97A, G140A, V151I, N155S, G163R) hanno mostrato una bassa frequenza (≤1%). La presenza al basale di tali mutazioni secondarie, come di altri polimorfismi (con l’eccezione della T125A, codone GCA, “vedi sotto”) non hanno influenzato statisticamente il responso virologico dei pazienti che hanno iniziato raltegravir (Fisher test, correzione di Benjamini-Hockberg). Dall’analisi di regressione logistica multivariata, i predittori indipendenti di negativo responso virologico erano: la viremia al basale (OR=0.42 [CI:0.3-0.7], p=0.0003), la co-somministrazione di AZT or D4T (OR=0.31 [CI:0.1-0.9], p=0.04) e la presenza al basale del polimorfismo T125A (specifico codone GCA, che è sequenza di riferimento per i sottotipi A, C, D, G and for CRF02_AG) (OR=0.30 [CI: 0.1-0.7], p=0.006). La prevalenza di questa mutazione, T125A(specifico codone GCA) risulta più alta nei pazienti infetti da sottotipi non-B (13/20 [65%]) vs B subtype (35/186 [19%]) (OR=0.12 [CI:0.05-0.33], P=0.00003) con una maggiore discrepanza tra i pazienti in fallimento ( 6/7 [86%] non-B subtype vs 14/46 [30%] B subtype, OR=0.07 [CI:0.01-0.52],p=0.009). Dall’approccio UDPS, al baseline, tra più di 200000 sequenze dell’IN analizzate, non è stata trovata alcuna variante minoritaria con resistenza primaria a raltegravir con una frequenza > 0.1%. Le mutazioni secondarie T97A, F121Y e V151I sono state trovate raramente e indifferentemente in pazienti in successo e/o in fallimento, con una frequenza compresa tra lo 0.3-99% delle specie virali. Indipendentemente dal metodo di sequenziamento utilizzato, la presenza di varianti resistenti secondarie al basale non correlava al fallimento, né con l’evoluzione alla stessa posizione amminoacidica, né con lo sviluppo di mutazioni primarie. Al basale non è stata osservata resistenza fenotipica a raltegravir, tuttavia al fallimento, i pazienti che hanno sviluppato le mutazioni primarie N155H, Q148H/R o Y143R, associate ad altre mutazioni secondarie (L74M, T97A, E92Q, G140S, V151I, E157Q, G163R, S230R) o non note (E92A, T112A) hanno mostrato un ridotta suscettibilita a raltegravir (Fold change >30-100). Di particolare interesse, in 1 paziente in fallimento, è stata trovata la combinazione delle mutazioni primarie N155H e Y143C, sia utilizzando il sequenziamento di popolazione sia l’UDPS. Queste mutazioni, apparse al fallimento nell’80% degli aplotipi del paziente, sono associate ad alta resistenza fenotipica particolarmente spiccata per raltegravir (FC raltegravir = 1255.3; FC elvitegravir = 625.3). Conclusioni: Dai saggi fenotipici e di genotipizzazione classici e ultra sensibili, la resistenza pre-esistente a raltegravir nei pazienti naive agli InSti è un evento raro e quando presente risulta confinato soltanto in quasi specie minoritarie secondarie. Al basale, solo la presenza della mutazione T125A(GCA), più prevalente nei sottotipi non-B, è risultata associata a un inferiore responso virologico a raltegravir. Questa osservazione nei sottotipi non-B è intrigante e necessita di ulteriori investigazioni. L’impatto clinico e la rilevanza di questo polimorfismo devono comunque ancora essere determinati. In conclusione, questo studio suggerisce che, allo stato attuale, effettuare il genotipo dell’integrasi in tutti i pazienti prima dell’inizio di raltegravir, potrebbe avere un rapporto costo-beneficio spostato verso il costo e non dovrebbe essere raccomandato, almeno fino a quando non si abbiano evidenze di resistenza trasmessa agli InSti o sia chiarita la rilevanza clinica dei polimorfismi e quasispecie minoritarie naturali.Background: Raltegravir (RAL) is a very potent and effective strand-transfer integrase-inhibitor (InSti), recently FDA-approved for use also in first-line highly active antiretroviral therapy (HAART) regimen. Nowadays, by the available literature, the knowledge about the role either of integrase (IN) polymorphisms or HIV-1 minor quasispecies on virologic response and development of resistance to raltegravir is still poor. Therefore, the aim of this study is to explore the presence of InSti resistance mutations in HIV-1 quasispecies present in InSti-naïve patients and to evaluate their impact on in vitro phenotypic susceptibility to InSTIs, on replication capacities and on virologic response to raltegravir, by 3 different approaches: Cloning, population sequencing and ultra-deep 454 pyrosequencing (UDPS). Methods: For the clonal approach, the RT-RNase H-IN region was PCR amplified from plasma viral RNA obtained from 49 HIV-1 subtype B-infected patients (21 drug naïve and 28 failing HAART not containing InSTIs) and recombined with an HXB2-based backbone with RT and IN deleted. Recombinant viruses were tested against raltegravir and elvitegravir and for replication capacity. Three-hundred forty-four recombinant viruses from 49 patients were successfully analyzed both phenotypically and genotypically. For the population sequencing approach, we analyzed 206 multi-experienced patients that received raltegravir plus optimized background therapy (OBT) from eight clinical centres within Italy and France. HIV-1 RNA and IN genotypes were assessed at baseline and at failure. For 177 patients, viremia values at 24-week were available. The prevalence of baseline integrase mutations was calculated in the overall population, and in the responding and non-responding patients at 24 weeks. For polymorphisms with prevalence >5%, the codon usage of mutated amino acids were also considered. Logistic regression analyses (uni- and multivariate) were performed to investigate if baseline integrase polymorphisms and other variables (such as: baseline HIV-1 RNA, drugs in co-usage and/or subtype) were independent predictors of virologic response. For the UDPS approach a sub-group of 27 patients treated with raltegravir were genotyped by UDPS at baseline and at failure. IN phenotyping was also performed at baseline and during treatment for failing patients. In all three approaches, all IN mutations, with particular attention to known InSti resistance associated mutations, have been analyzed. The cut-off limit of reliable detection for UDPS was considered >0.1% (≥50 reads). Results: Regarding clonal analysis, the majority of clones were not phenotypically resistant to InSTIs: 0/344 clones showed raltegravir resistance, and only 3 (0.87%) showed low-level elvitegravir resistance. No primary resistance mutations for raltegravir and elvitegravir were found as major or minor species. Secondary mutations, such as T97A and G140S, found rarely and only as minority quasispecies, were present in the elvitegravir-resistant clones. A novel mutation, E92G, although rarely found in minority quasispecies, showed elvitegravir resistance. Regarding the analyses of baseline IN mutations, among the 206 patients genotyped by population sequencing, 186 (90.3%) patients were infected by HIV-1 subtype B versus 20 (9.7%) infected by non-B viruses (4A, 1C, 2D, 5F, 2G, 5CRF_02AG, 1CRF_12BF2). At week 24, 70% of patients achieved virologic response (71.3% [114/160] and 58.8% [10/17] infected by B and non-B viruses, respectively, p=NS). At baseline, all major raltegravir resistance mutations were completely absent, and secondary mutations (L74M, T97A, G140A, V151I, N155S, G163R) were present at very low frequency (≤1%). The presence at baseline of these secondary resistance mutations, as well as all other polymorphisms (with the exception of T125A, specific codon GCA, “see below”) did not statistically influence the virologic response among patients starting raltegravir (Fisher test, Benjamini-Hockberg correction). By multivariate logistic regression, the independent predictors of worse virologic response were: baseline viremia (OR=0.42 [CI:0.3-0.7], p=0.0003), AZT or D4T co-usage (OR=0.31 [CI:0.1-0.9], p=0.04) and baseline presence of polymorphism T125A (specific GCA codon, that is consensus sequence for subtypes A, C, D, G and for CRF02_AG) (OR=0.30 [CI: 0.1-0.7], p=0.006). Such prevalence of T125A (specific GCA codon) was higher in patients infected with non-B subtype (13/20 [65%]) vs B subtype (35/186 [19%]) (OR=0.12 [CI:0.05-0.33], P=0.00003), with a greater consistence among failing patients ( 6/7 [86%] non-B subtype vs 14/46 [30%] B subtype, OR=0.07 [CI:0.01-0.52],p=0.009). Regarding UDPS analyses, among >200,000 IN sequences analyzed, no minor variants of primary raltegravir mutations with a prevalence of >0.1% were found at baseline. The secondary mutations such as T97A, F121Y and V151I secondary mutations, were rarely found at baseline, in both failing- and success-group of patients, with a frequency ranging from 0.3 to 99% of viral species. Independently of the sequencing method, the presence of secondary-resistant species at baseline was not associated, at failure, with evolution at the same amino acid position or to specific primary raltegravir resistance mutations. Raltegravir phenotypic resistance has never been observed at baseline. At failure, all patients carrying primary mutations N155H, Q148H/R or Y143R, in presence of secondary (L74M, T97A, E92Q, G140S, V151I, E157Q, G163R, S230R) and novel (E92A, T112A) mutations, showed fold changes on susceptibility to RAL >30-100. Interestingly, in 1 patient, we found the combination of two primary mutations at failure, Y143C and N155H, by both population sequencing and UDPS. These mutations appeared at failure for >80% on same haplotypes, and showed a very high phenotypic resistance, particularly for raltegravir (FC raltegravir = 1255.3; FC elvitegravir = 625.3). Conclusion: By classic and ultra sensitive genotyping (and phenotyping) methods, pre-existing raltegravir resistance is a rare event in InSti-naïve patients, and when present, is confined to a restricted minority of secondary variants only. At baseline, only T125A mutation (specific GCA codon), higher prevalent in non-b subtype viruses, was associated with poorer virologic response to raltegravir. This finding in non-B subtypes is intriguing and further research is warranted. The clinical implications and relevance of this polymorphism is still to be determined. Overall, this study suggests that at this point IN genotyping in all patients before raltegravir treatment may not be cost-effective and should not be recommended until evidence of transmitted drug resistance to InSTIs or the clinical relevance of IN minor variants/polymorphisms is determined

Virological response and resistance profile in highly treatment-experienced HIV-1-infected patients switching to dolutegravir plus boosted darunavir in clinical practice

Objectives: We evaluated the virological response and resistance profile in combined antiretroviral therapy (cART)-experienced HIV-1-infected patients starting a dual therapy with dolutegravir (DTG) and boosted darunavir (bDRV) for the first time. Methods: Survival analyses were used to evaluate virological success (VS) and virological rebound (VR) in viraemic and virologically suppressed patients, respectively. Major resistance mutations (MRMs) and genotypic susceptibility score (GSS) were evaluated at baseline and after switch. Results: Overall, 130 patients [62 (47.7%) viraemic; 68 (52.3%) virologically suppressed] were retrospectively analysed. At the moment of switch, 81.5% accumulated one or more MRM [protease inhibitor (PI), 35.7%; nucleoside(t)ide reverse transcriptase inhibitor (NRTI), 77.5%; non-NRTI, 69.0%; integrase inhibitor (INI), 10.1%), but 77.7% harboured strains fully susceptible to DTG + bDRV. In viraemic patients, the overall probability of VS by 12 months of treatment was 91.7%. In virologically suppressed patients, the overall probability of VR was 10.5% by 24 months after therapy start. Patients with previous time under virological suppression ≤ 6 months showed a higher VR probability compared with others (37.5% vs. 6.7%, P < 0.002). Among 13 non-responding patients for whom a genotypic resistance test result at failure was available, only two (15.4%) accumulated further resistance in integrase (Y143C/H/R; S147G and N155H) and protease (V32I, L33F, I54L). Conclusions: In highly treatment-experienced patients, the use of dual therapy based on DTG + bDRV appears to be a very good regimen for switch therapy, with a high rate of virological control in both viraemic and virologically suppressed patients. Among non-responding patients, the selection of further resistance is a rare event

Baseline integrase drug resistance mutations and conserved regions across HIV-1 clades in Cameroon: implications for transition to dolutegravir in resource-limited settings

Background: Transition to dolutegravir-based regimens in resource-limited settings (RLS) requires prior understanding of HIV-1 integrase variants and conserved regions. Therefore, we evaluated integrase drug resistance mutations (DRMs) and conserved regions amongst integrase strand transfer inhibitor (INSTI)-naive patients harbouring diverse HIV-1 clades in Cameroon. Methods: A cross-sectional study was conducted amongst 918 INSTI-naive patients from Cameroon (89 ART-naive and 829 ART-experienced patients). HIV-1 sequences were interpreted regarding INSTI-DRMs using the Stanford HIVdb v8.9-1 and the 2019 IAS-USA list. Amino acid positions with <1% variability were considered as highly conserved. Subtyping was performed by phylogeny. Results: Overall prevalence (95% CI) of INSTI-DRMs was 0.8% (0.4-1.7), with 0.0% (0.0-4.0) amongst ART-naive versus 0.9% (0.5-1.9) amongst ART-experienced patients; P = 0.44. Accessory mutations (95% CI) were found in 33.8% (30.9-37.0), with 38.2% (28.1-49.1) amongst ART-naive versus 33.4% (30.4-36.7) amongst ART-experienced patients; P = 0.21. Of 288 HIV-1 integrase amino acid positions, 58.3% were highly conserved across subtypes in the following major regions: V75-G82, E85-P90, H114-G118, K127-W132, E138-G149, Q168-L172, T174-V180, W235-A239 and L241-D253. Wide genetic diversity was found (37 clades), including groups M (92.3%), N (1.4%), O (6.2%) and P (0.1%). Amongst group M, CRF02_AG was predominant (47.4%), with a significantly higher frequency (95% CI) of accessory mutations compared with non-AG [41.4% (36.8-46.0) versus 27.1% (23.3-31.2) respectively; P < 0.001]. Conclusions: The low baseline of INSTI-DRMs (<1%) in Cameroon suggests effectiveness of dolutegravir-based regimens. In spite of high conservation across clades, the variability of accessory mutations between major circulating strains underscores the need for monitoring the selection of INSTI-DRMs while scaling up dolutegravir-based regimens in RLS

Evaluation of virological response and resistance profile in HIV-1 infected patients starting a first-line integrase inhibitor-based regimen in clinical settings

Background: Virological response and resistance profile were evaluated in drug-naïve patients starting their first-line integrase inhibitors (INIs)-based regimen in a clinical setting. Study design: Virological success (VS) and virological rebound (VR) after therapy start were assessed by survival analyses. Drug-resistance was evaluated at baseline and at virological failure. Results: Among 798 patients analysed, 38.6 %, 27.1 % and 34.3 % received raltegravir, elvitegravir and dolutegravir, respectively. Baseline resistance to NRTIs, NNRTIs, PIs and INIs was: 3.9 %, 13.9 %, 1.6 % and 0.5 %, respectively. Overall, by 12 months of treatment, the probability of VS was 95 %, while the probability of VR by 36 months after VS was 13.1 %. No significant differences in the virological response were found according to the INI used. The higher pre-therapy viremia strata was (<100,000 vs. 100,000-500,000 vs. > 500,000 copies/mL), lower was the probability of VS (96.0 % vs. 95.2 % vs. 91.1 %, respectively, P < 0.001), and higher the probability of VR (10.2 % vs. 15.8 % vs. 16.6 %, respectively, P = 0.010). CD4 cell count <200 cell/mm3 was associated with the lowest probability of VS (91.5 %, P < 0.001) and the highest probability of VR (20.7 %, P = 0.008) compared to higher CD4 levels. Multivariable Cox-regression confirmed the negative role of high pre-therapy viremia and low CD4 cell count on VS, but not on VR. Forty-three (5.3 %) patients experienced VF (raltegravir: 30; elvitegravir: 9; dolutegravir: 4). Patients failing dolutegravir did not harbor any resistance mutation either in integrase or reverse transcriptase. Conclusions: Our findings confirm that patients receiving an INI-based first-line regimen achieve and maintain very high rates of VS in clinical practice

Genotypic Resistance Testing of HIV-1 DNA in Peripheral Blood Mononuclear Cells.

HIV-1 DNA exists in nonintegrated linear and circular episomal forms and as integrated proviruses. In patients with plasma viremia, most peripheral blood mononuclear cell (PBMC) HIV-1 DNA consists of recently produced nonintegrated virus DNA while in patients with prolonged virological suppression (VS) on antiretroviral therapy (ART), most PBMC HIV-1 DNA consists of proviral DNA produced months to years earlier. Drug-resistance mutations (DRMs) in PBMCs are more likely to coexist with ancestral wild-type virus populations than they are in plasma, explaining why next-generation sequencing is particularly useful for the detection of PBMC-associated DRMs. In patients with ongoing high levels of active virus replication, the DRMs detected in PBMCs and in plasma are usually highly concordant. However, in patients with lower levels of virus replication, it may take several months for plasma virus DRMs to reach detectable levels in PBMCs. This time lag explains why, in patients with VS, PBMC genotypic resistance testing (GRT) is less sensitive than historical plasma virus GRT, if previous episodes of virological failure and emergent DRMs were either not prolonged or not associated with high levels of plasma viremia. Despite the increasing use of PBMC GRT in patients with VS, few studies have examined the predictive value of DRMs on the response to a simplified ART regimen. In this review, we summarize what is known about PBMC HIV-1 DNA dynamics, particularly in patients with suppressed plasma viremia, the methods used for PBMC HIV-1 GRT, and the scenarios in which PBMC GRT has been used clinically

Genotypic Resistance Testing of HIV-1 DNA in Peripheral Blood Mononuclear Cells

HIV-1 DNA exists in nonintegrated linear and circular episomal forms and as integrated proviruses. In patients with plasma viremia, most peripheral blood mononuclear cell (PBMC) HIV-1 DNA consists of recently produced nonintegrated virus DNA while in patients with prolonged virological suppression (VS) on antiretroviral therapy (ART), most PBMC HIV-1 DNA consists of proviral DNA produced months to years earlier. Drug-resistance mutations (DRMs) in PBMCs are more likely to coexist with ancestral wild-type virus populations than they are in plasma, explaining why next-generation sequencing is particularly useful for the detection of PBMC-associated DRMs. In patients with ongoing high levels of active virus replication, the DRMs detected in PBMCs and in plasma are usually highly concordant. However, in patients with lower levels of virus replication, it may take several months for plasma virus DRMs to reach detectable levels in PBMCs. This time lag explains why, in patients with VS, PBMC genotypic resistance testing (GRT) is less sensitive than historical plasma virus GRT, if previous episodes of virological failure and emergent DRMs were either not prolonged or not associated with high levels of plasma viremia. Despite the increasing use of PBMC GRT in patients with VS, few studies have examined the predictive value of DRMs on the response to a simplified ART regimen. In this review, we summarize what is known about PBMC HIV-1 DNA dynamics, particularly in patients with suppressed plasma viremia, the methods used for PBMC HIV-1 GRT, and the scenarios in which PBMC GRT has been used clinically

Integrase S119P mutation correlates with disease progression in HIV-1 naïve patients

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Virological response and resistance profile in highly treatment‐experienced HIV‐1‐infected patients switching to dolutegravir plus boosted darunavir in clinical practice

Objectives: We evaluated the virological response and resistance profile in combined antiretroviral therapy (cART)-experienced HIV-1-infected patients starting a dual therapy with dolutegravir (DTG) and boosted darunavir (bDRV) for the first time. Methods: Survival analyses were used to evaluate virological success (VS) and virological rebound (VR) in viraemic and virologically suppressed patients, respectively. Major resistance mutations (MRMs) and genotypic susceptibility score (GSS) were evaluated at baseline and after switch. Results: Overall, 130 patients [62 (47.7%) viraemic; 68 (52.3%) virologically suppressed] were retrospectively analysed. At the moment of switch, 81.5% accumulated one or more MRM [protease inhibitor (PI), 35.7%; nucleoside(t)ide reverse transcriptase inhibitor (NRTI), 77.5%; non-NRTI, 69.0%; integrase inhibitor (INI), 10.1%), but 77.7% harboured strains fully susceptible to DTG + bDRV. In viraemic patients, the overall probability of VS by 12 months of treatment was 91.7%. In virologically suppressed patients, the overall probability of VR was 10.5% by 24 months after therapy start. Patients with previous time under virological suppression ≤ 6 months showed a higher VR probability compared with others (37.5% vs. 6.7%, P < 0.002). Among 13 non-responding patients for whom a genotypic resistance test result at failure was available, only two (15.4%) accumulated further resistance in integrase (Y143C/H/R; S147G and N155H) and protease (V32I, L33F, I54L). Conclusions: In highly treatment-experienced patients, the use of dual therapy based on DTG + bDRV appears to be a very good regimen for switch therapy, with a high rate of virological control in both viraemic and virologically suppressed patients. Among non-responding patients, the selection of further resistance is a rare event

Virological efficacy of switch to DTG plus 3TC in a retrospective observational cohort of suppressed HIV-1 patients with or without past M184V: the LAMRES study

International audienceObjectives: The aim of this study was to assess the efficacy of dolutegravir plus lamivudine (DTG + 3TC) in a large set of virologically suppressed HIV-1 infected individuals with or without past M184V mutation. Methods: This observational study included individuals who switched to DTG + 3TC with ≥1 genotype before switch. Survival analysis was used to evaluate the role of past M184V on virological rebound (VR) or blips after DTG + 3TC switch. Results: A total of 712 individuals followed in several clinical centres in France, Italy and Spain were analysed. Past M184V was present in 60 (8.4%) individuals. By 3 years after switch, the overall probability of VR and blips was 6.7% and 6.9%, respectively, without any statistical significance according to the presence/absence of past M184V. A significantly higher probability of VR was found in individuals harbouring M184V before DTG + 3TC with a duration of virological suppression (Ts) ≤.3.5 years compared to others (M184V + Ts ≤.3.5 years: 22.7%; M184M + Ts ≤.3.5 years: 9.0%; M184V + Ts > 3.5 years: 7.8%; M184M + Ts > 3.5 years: 4.9%; P = 0.007). This finding was not confirmed in multivariable models adjusting for behavioural and demographic variables. Genotypic resistance test after VR under DTG + 3TC was available for 8/39 individuals; one poorly adherent individual developed M184V. No resistance to INIs was found. Conclusion: In this retrospective observational study, the probability of VR and blips in patients switching to DTG + 3TC was very low after 3 years of treatment regardless M184V. The effect of a short duration of previous virological suppression in individuals with M184V remains troubling and needs ad hoc clinical trials to be confirmed