Structural and Preclinical Studies of Computationally Designed Non-Nucleoside Reverse Transcriptase Inhibitors for Treating HIV infection

Abstract

The clinical benefits of HIV-1 non-nucleoside reverse transcriptase (RT) inhibitors (NNRTIs) are hindered by their unsatisfactory pharmacokinetic (PK) properties along with the rapid development of drug-resistant variants. However, the clinical efficacy of these inhibitors can be improved by developing compounds with enhanced pharmacological profiles and heightened antiviral activity. We used computational and structure-guided design to develop two next-generation NNRTI drug candidates, compounds I and II, which are members of a class of catechol diethers. We evaluated the preclinical potential of these compounds in BALB/c mice because of their high solubility (510 mg/ml for compound I and 82.9 mg/ml for compound II), low cytotoxicity, and enhanced antiviral activity against wild-type (WT) HIV-1 RT and resistant variants. Additionally, crystal structures of compounds I and II with WT RT suggested an optimal binding to the NNRTI binding pocket favoring the high anti-viral potency. A single intraperitoneal dose of compounds I and II exhibited a prolonged serum residence time of 48 hours and concentration maximum (C max ) of 4000-to 15,000-fold higher than their therapeutic/effective concentrations. These C max values were 4-to 15-fold lower than their cytotoxic concentrations observed in MT-2 cells. Compound II showed an enhanced area under the curve (0-last) and decreased plasma clearance over compound I and efavirenz, the standard of care NNRTI. Hence, the overall (PK) profile of compound II was excellent compared with that of compound I and efavirenz. Furthermore, both compounds were very well tolerated in BALB/c mice without any detectable acute toxicity. Taken together, these data suggest that compounds I and II possess improved anti-HIV-1 potency, remarkable in vivo safety, and prolonged in vivo circulation time, suggesting strong potential for further development as new NNRTIs for the potential treatment of HIV infection.

Structural insights into the recognition of nucleoside reverse transcriptase inhibitors by HIV‐1 reverse transcriptase: First crystal structures with reverse transcriptase and the active triphosphate forms of lamivudine and emtricitabine

“…To date, there are no structural data available for (−)/(+)FTC‐TP and (−)3TC‐TP in complex with RT. The recent success in structure‐based design of novel nonnucleoside reverse transcriptase inhibitors (NNRTIs) with improved pharmacokinetics and less susceptibility toward drug resistance underscore the value of structural data . Similarly, in order to understand the molecular basis of recognition for NRTIs by RT and host Pols important in toxicity, obtaining structural data of RT in complex with (−)FTC‐TP and (−)3TC‐TP is imperative.…”

Challenges and approaches in the discovery of human immunodeficiency virus type‐1 non‐nucleoside reverse transcriptase inhibitors

“…Lower plasma clearance than EFV also suggested that the catechol derivative had improved metabolic stability. In addition, no acute toxic effects were observed after the administration of a higher dose of 100 mg/kg over a period of 96 hours . In a humanized mouse model of HIV‐1 infection, compound 120 significantly reduced the viral load and prevented the loss of human CD4 + T cells following a 100 mg/kg daily dose regime .…”

“…In addition, no acute toxic effects were observed after the administration of a higher dose of 100 mg/kg over a period of 96 hours. 138 In a humanized mouse model of HIV-1 infection, compound 120 significantly reduced the viral load and prevented the loss of human CD4 + T cells following a 100 mg/kg daily dose regime. 139 Furthermore, a long-acting nanoformulation of the compound was developed, which was able to maintain therapeutic plasma concentration and anti-HIV activity for almost 3 weeks after a single dose, and synergic effect of the catechol was demonstrated with different NRTIs and integrase inhibitors in cell-based assays.…”

“…In vitro determination of potential off‐targets (Eurofins Panlabs), showed that the compound only inhibited CYP2 C19 from a set of 34 important metabolic proteins at 10 μM. In comparison, EFV inhibited calcium and sodium channels and 5‐HT2B serotonin receptor . Additionally, in pharmacokinetics studies performed in BALB/c mice, the compound maintained nontoxic and therapeutic concentration for more than 24 hours after a single dose of 20 mg/kg, suggesting that a daily dose regime would be possible.…”

“…In comparison, EFV inhibited calcium and sodium channels and 5-HT2B serotonin receptor. 138 Additionally, in pharmacokinetics studies performed in BALB/c mice, the compound maintained nontoxic and therapeutic concentration for more than 24 hours after a single dose of 20 mg/kg, suggesting that a daily dose regime would be possible. Lower plasma clearance than EFV also suggested that the catechol derivative had improved metabolic stability.…”