Evpler is a combination drug with a fixed dose of rilpivirin,tenofovir, emtricitabine.
Mechanism of action
Emtricitabine is a nucleoside analog of cytidine. Tenofovir disoproxil fumarate is converted in vivo in tenofovir, Analogue nucleoside (nucleotide) adenosine monophosphate. "As emtricitabine, and tenofovir, have specific activity against human immunodeficiency virus (HIV-1 and HIV-2) and hepatitis B virus.
Rilpivirin is a diaryl pyrimidine non-nucleoside inhibitor of HIV-1 reverse transcriptase. The activity of rilpivirin is mediated by the non-competitive inhibition of HIV-1 reverse transcriptase.
Emtricitabine and tenofovir phosphorylated by cellular enzymes to form tenofovir diphosphate triphosphate of FTC, respectively.
In vitro studies have shown that both emtricitabine, and tenofovir, can be completely phosphorylated while being in the cell. Emtricitabine triphosphate and tenofovir diphosphate inhibit HIV-1 reverse transcriptase by a competitive mechanism, leading to termination of viral DNA chain synthesis. Both emtricitabine triphosphate and tenofovir diphosphate are weak inhibitors of mammalian DNA polymerase. In vitro and in vivo data concerning their toxicity against mitochondria are not available. Rilpivirine does not inhibit cellular air to human DNA polymerase and mitochondrial DNA polymerase.
Antiviral activity in vitro
The combination of emtricitabine, rilpivirin and tenofovir shows a synergistic antiviral activity in the cell culture.
The antiviral activity of emtricitabine against laboratory and clinical isolates of HIV-1 was evaluated on the lymphoblastoid cell line, the MAGI-CCR5 cell line and on peripheral blood mononuclear cells. The values of 50% of the effective concentration (EC50) of emtricitabine were in the range of 0.0013 to 0.64 μmol.
Emtricitabine exhibits antiviral activity in the cell culture for subtypes A, B, C, D, E, F, and G of HIV-1 (range of EC50 values from 0.007 to 0.075 μmol), as well as specific activity for HIV-2 strains of EC50 values from 0.007 to 1.5 μmol).
In studies of a combination of emtricitabine with nucleoside reverse transcriptase inhibitors (NRTIs) (abacavir, didanosine, lamivudine, stavudine, tenofovir and zidovudine), non-nucleoside reverse transcriptase inhibitors (NNRTIs) (delavirdine, efavirenz, nevirapine and rilpivirine) and protease inhibitors (PIs) (amprenavir, nelfinavir, ritonavir and saquinavir) an additive or synergistic effect was observed.
Rilpivirin is active against laboratory strains of wild-type HIV-1 on an acute infected T cell line with a median EC50 value of HIV-1 / WB 0.73 nmol (0.27 ng / ml). Although in vitro rilpivirine showed limited HIV-2 activity with EC50 values ranging from 2.510 to 10.830 nmol (920 to 3970 ng / ml), and in the absence of clinical data, the treatment of HIV-2 infection with rilpivirin hydrochloride is not recommended.
Rilpivirin also demonstrated antiviral activity against a wide range of primary isolates of strains of HIV-1 group M (subtypes A, B, C, D, F, G, H) with EC50 values ranging from 0.07 to 1.01 nmol (from 0 , 03 to 0.37 ng / ml) and primary isolates of group O with EC50 values ranging from 2.88 to 8.45 nmol (1.06 to 3.10 ng / ml).
The antiviral activity of tenofovir against laboratory and clinical isolates of HIV-1 was evaluated on lymphoblastoid cell lines, mainly on monocytes / macrophages and peripheral blood lymphocytes.
The EC50 values of tenofovir were in the range of 0.04 to 8.5 μmol.
Tenofovir demonstrated antiviral activity in cell culture with respect to subtypes A, B, C, D,E, F, G and O HIV-1 (EC50 range from 0.5 to 2.2 μmol), as well as specific activity for HIV-2 strains (EC50 range from 1.6 μmol to 5.5 μmol) .
In studies of the combination of tenofovir with NRTI (abacavir, didanosine, emtricitabine, lamivudine, stavudine and zidovudine), NNRTI (delavirdine, efavirenz, nevirapine and rilpivirine) and IP (amprenavir, indinavir, nelfinavir, ritonavir and saquinavir) an additive or synergistic effect was observed.
Resistance
Cell culture
Resistance to emtricitabine or tenofovir has been observed in vitro and in some HIV-1 infected patients due to substitution in the M184V or Ml841 codons of reverse transcriptase (RT) for emtricitabine or the K65R reverse transcriptase codon for tenofovir. In addition, substitution in the K70E codon of HIV-1 reverse transcriptase causes a slight decrease in sensitivity to abacavir, emtricitabine, tenofovir and lamivudine. There were no other mechanisms of development of resistance to emtricitabine or tenofovir. Emtricitabine-resistant viruses with the M184V / I mutation showed cross-resistance to lamivudine, but remained sensitive to didanosine, stavudine, tenofovir, zalcitabine and zidovudine.
The mutation in the K65R codon can also be associated with resistance to abacavir or didanosine and lead to a decrease in sensitivity to these drugs, as well as to lamivudine, emtricitabine, and tenofovir. Tenofovir It should not be used in patients with K65R mutation of HIV-1. HIV-1 with mutations in the codons K65R, M184V and K65R + M184V remains completely sensitive to rilpivirin.
Resistant to rilpivirin and to NNRTI strains were isolated on cell cultures from wild types of HIV-1 of different nature and subtypes. The most frequently observed mutations associated with resistance were L1001, K101E, V1081, E138K, V179F, Y181C, H221Y, F227C and M230I.
Taking into account all available in vitro and in vivo data, the following mutations can influence the activity of the Evipler drug in patients who have not previously received antiretroviral therapy: K65R, K101E, K101P, E138A, E138G, E138K, E138Q, E138R, V179L, Y181C, Y181I, Y181V, M184I, M184V, H221Y, F227C, M230I and M230L (if detected prior to treatment).
These resistance-related mutations should only be considered when using the Evpler medication to treat patients who have not previously received antiretroviral therapy.
These resistance-related mutations were detected in vivo only in patients who had not previously received treatment,and therefore can not be used to predict the activity of the drug Evpleler in patients with virological ineffectiveness of antiretroviral therapy.
As with the use of other antiretroviral drugs, the study of genotypic resistance should be conducted against the background of taking Evipler.
HIV-1 infected patients who had not previously received antiretroviral therapy
In a combined analysis of the data obtained during phase III clinical trials (C209 and C215) among patients receiving emtricitabine / tenofovir +rilpivirine In 62 patients, virological failure of therapy was established, while information on the development of resistance was available for 54 of 62 patients. Amino acid substitutions were identified that were associated with NNRTI resistance and were most commonly encountered in such patients: V90I, K101E, E138K / Q, Y181C, VI891 and H221Y. However, the presence of mutations such as V90I and VI891 did not affect the effectiveness of treatment. More than 3 patients during the therapy had mutations associated with resistance to NRTIs: K65R, K70E, M184V / I and K219E.
Cross-resistance
With the development of HIV-1 resistance to rilpivirin, there has been no development of cross-resistance to emtricitabine and tenofovir and vice versa.
Resistance to cell culture
Emtricitabine: Emtricitabine-resistant strains with substitution in codon M184V / I demonstrated cross-resistance to lamivudine, but remained sensitive to didanosine, stavudine, tenofovir and zidovudine.
Strains of viruses with substitutions causing a decrease in sensitivity to stavudine, and resistance mutations to analogues of zidovudine thymidine (M41L, D67N, K70R, L210W, T215Y / F, K219Q / E) or didanosine (L74V) remained sensitive to emtricitabine. HIV-1, containing K103N substitution or other substitutions associated with resistance to rilpivirin and other NNRTIs, remained sensitive to emtricitabine. Rilpivirin: in a group of 67 recombinant laboratory strains of HIV-1 with a mutation of resistance to NNRTIs in one OT codon, including the most common K103N and Y181C mutations, rilpivirine demonstrated antiviral activity against 64 (96%) of these strains. Resistance mutations in one codon associated with a loss of sensitivity to rilpivirin were: K101P and Y181V / I.
Tenofovir: mutations in codons K65R and K70E cause a decrease in sensitivity to abacavir, didanosine, lamivudine, emtricitabine and tenofovir, while maintaining sensitivity to zidovudine.
In patients with three or more mutations of HIV-1 resistance to zidovudine-thymidine analogs, including M41L or L210W, there was a decrease in the response rate to tenofovir. Virological response to tenofovir was not reduced in patients with HIV-1 infection and with the M184V mutation associated with resistance to abacavir / emtricitabine / lamivudine.
Patients with mutations K103N and Y181C, or with substitutions, associated with resistance to rilpivirin and NNRTI, were sensitive to tenofovir.
HIV-1 infected patients who had not previously received antiretroviral therapy
In a combined analysis of the data obtained during phase III clinical trials (C209 and C215) among patients receiving emtricitabine / tenofovir + rilpivirine, phenotypic information on resistance development was available in 54 patients with virologic failure, 37 patients lost sensitivity to emtricitabine, 29 to rilpivirin, and 2 to tenofovir, respectively. Among these patients, 37 were resistant to lamivudine, 28 to etravirine, 26 to efavirenz, and 12 to nevirapine. In some cases, a decrease in the sensitivity of cabacavir and / or didanosine was observed.