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DEVELOPMENT AND PRE-CLINICAL EVALUATION OF A NEW MICROBICIDE GEL FOR THE PREVENTION OF HIV-1 AND HIV-2 INFECTION
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New prevention and treatment strategies for HIV infection
Publication . Costa, Ana Rita Ramos Diniz de Quadros e, 1988-; Taveira, Nuno, 1964-; Pereira, J. Moniz, 1949-
To successfully control the global spread of HIV, it is crucial to combine effective prevention and treatment strategies. The aims of this thesis are: a) to characterize the antiviral activity of dolutegravir (DTG) against HIV-2 primary isolates; b) to develop dendrimers as topical anti-HIV-2 microbicides; c) to evaluate P3 peptide as a potential microbicide to prevent HIV transmission in women. In Chapter 2, we observed that DTG had potent activity against all raltegravir (RAL)-resistant HIV-2 isolates, indicating its usefulness as second line therapy for patients failing RAL. Mutation Q148K was responsible for high-level of resistance to RAL, however, it did not affect the activity of DTG. Importantly, we described for the first time primary resistance to DTG and we propose a new mechanism of resistance: mutations K221Q and D222K increase the activity of reverse transcriptase, thus increasing viral replication, leading to indirect resistance to DTG. In Chapter 3, we showed that dendrimers G2-S16, G2-NS16 and G3-Sh16 inhibited HIV-2 infection acting in the early steps of the HIV-2 lifecycle. They blocked HIV-2 cell-free and cell-to-cell fusion and had synergistic effects with tenofovir and RAL. Vaginal application of 3% HEC-G2-S16 gel formulation in mice did not affect mucosa integrity, further confirming that these dendrimers are promising candidates for future topical microbicides. In Chapter 4, we proved that the fusion inhibitor peptide P3 was stable and active in the presence of body fluids and at different temperatures. P3 was also active in the acidic environment of the vagina, was not be affected by the H2O2 produced by Lactobacillus and did not have spermicidal activity. Importantly, we showed that a P3-1.5% HEC gel was very effective at blocking HIV-1 infection. These findings suggest that dendrimers and P3 are good microbicide candidates to prevent vaginal HIV transmission in humans.
High Instantaneous Inhibitory Potential of Bictegravir and the New Spiro-ß-Lactam BSS-730A for HIV-2 Isolates from RAL-Naïve and RAL-Failing Patients
Publication . Bártolo, Inês; Moranguinho, Inês; Gonçalves, Paloma; Ana Rita Diniz; Borrego, Pedro; Martin, Francisco; Figueiredo, Inês; Gomes, Perpetua; Gonçalves, Maria Fátima; Alves, Américo; Alves, Nuno; Caixas, Umbelina; Vaz-Pinto, Inês; Barahona, Isabel; Melo, Teresa M. V. D. Pinho E; Taveira, Nuno
Integrase inhibitors (INIs) are an important class of drugs for treating HIV-2 infection, given the limited number of drugs active against this virus. While the clinical efficacy of raltegravir and dolutegravir is well established, the clinical efficacy of bictegravir for treating HIV-2 infected patients has not been determined. Little information is available regarding the activity of bictegravir against HIV-2 isolates from patients failing raltegravir-based therapy. In this study, we examined the phenotypic and matched genotypic susceptibility of HIV-2 primary isolates from raltegravir-naïve and raltegravir-failing patients to raltegravir, dolutegravir, and bictegravir, and to the new spiro-β-lactam BSS-730A. The instantaneous inhibitory potential (IIP) was calculated to help predict the clinical activity of bictegravir and BSS-730A. Isolates from raltegravir-naïve patients were highly sensitive to all INIs and BSS-730A. Combined integrase mutations E92A and Q148K conferred high-level resistance to raltegravir, and E92Q and T97A conferred resistance to raltegravir and dolutegravir. The antiviral activity of bictegravir and BSS-730A was not affected by these mutations. BSS-730A displayed strong antiviral synergism with raltegravir. Mean IIP values at Cmax were similar for all INIs and were not significantly affected by resistance mutations. IIP values were significantly higher for BSS-730A than for INIs. The high IIP values of bictegravir and BSS-730A for raltegravir-naïve and raltegravir-resistant HIV-2 isolates highlight their potential value for treating HIV-2 infection. Overall, the results are consistent with the high clinical efficacy of raltegravir and dolutegravir for HIV-2 infection and suggest a promising clinical profile for bictegravir and BSS-730A.
Evaluation of the fusion inhibitor P3 peptide as a potential microbicide to prevent HIV transmission in women
Publication . Bártolo, Inês; Diniz, Ana Rita; Borrego, Pedro; Ferreira, João Pedro; Bronze, Maria Rosário; Barroso, Helena; Pinto, Rui; Cardoso, Carlos; Pinto, João F.; Diaz, Rafael Ceña; Broncano, Pilar Garcia; Muñoz-Fernández, Maria Angel; Taveira, Nuno
Microbicides are an important strategy for preventing the sexual transmission of HIV but, so far, the most advanced tenofovir-based microbicides have had modest efficacy. This has been related to adherence problems and high prevalence of tenofovir-resistant HIV-1 strains. P3 is a new peptide with potent activity against HIV that may be a good microbicide candidate. In this work P3 was formulated in a gel of hydroxyethyl cellulose and its activity, stability and safety profile in Balb/c mice were evaluated. HIV infection was fully blocked by a 1.5% gel containing P3 at the IC90 (366.4 nM) concentration. The antiviral activity did not change at 4°C during 4 months and at 25, 37 and 65°C for 1 week. P3 was stable and fully functional at acidic pH up to 24h, under different concentrations of hydrogen peroxide and in the presence of genital fluids up to 48h. P3 had no antibacterial activity and did not affect sperm motility and vitality. Finally, P3 didn’t cause significant alterations in the vaginal epithelium of Balb/c mice at 0.06 (456.8 μM) and 0.2 mg/day (1522.7 μM) doses. These findings indicate that P3 is an excellent candidate for further development as a microbicide gel for the prevention of HIV transmission in women.
Evaluation of the fusion inhibitor P3 peptide as a potential microbicide to prevent HIV transmission in women
Publication . Bártolo, Inês; Diniz, Ana Rita; Borrego, Pedro; Ferreira, João Pedro; Bronze, MR; Barroso, Helena; Pinto, Rui; Cardoso, Carlos; Pinto, João F.; Ceña Diaz, Rafael; Broncano, Pilar Garcia; Muñoz-Fernandez, Maria Angel; Taveira, Nuno
Microbicides are an important strategy for preventing the sexual transmission of HIV but, so far, the most advanced tenofovir-based microbicides have had modest efficacy. This has been related to adherence problems and high prevalence of tenofovir-resistant HIV-1 strains. P3 is a new peptide with potent activity against HIV that may be a good microbicide candidate. In this work P3 was formulated in a gel of hydroxyethyl cellulose and its activity, stability and safety profile in Balb/c mice were evaluated. HIV infection was fully blocked by a 1.5% gel containing P3 at the IC90 (366.4 nM) concentration. The antiviral activity did not change at 4°C during 4 months and at 25, 37 and 65°C for 1 week. P3 was stable and fully functional at acidic pH up to 24h, under different concentrations of hydrogen peroxide and in the presence of genital fluids up to 48h. P3 had no antibacterial activity and did not affect sperm motility and vitality. Finally, P3 didn’t cause significant alterations in the vaginal epithelium of Balb/c mice at 0.06 (456.8 μM) and 0.2 mg/day (1522.7 μM) doses. These findings indicate that P3 is an excellent candidate for further development as a microbicide gel for the prevention of HIV transmission in women.
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Fundação para a Ciência e a Tecnologia
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SFRH/BD/89140/2012