HIV Reverse transcription (IC50 = 119 nM); NNRTI

In line with the promising results seen against isolated RT enzymes, lerivirine shows outstanding efficacy against a variety of drug-resistant and wild-type HIV strains. [1]
Lersivirine is a second-generation NNRTI undergoing clinical development for the treatment of HIV-1. Lersivirine is structurally divergent from efavirenz and binds the RT enzyme in a novel way [2].

Lersivirine causes skeletal variations in mated Crl:CD1(ICR) mice, which are linked to developmental delays and reduced fetal ossification. Lersivirine (oral gavage; 0, 150, 350, and 500 mg/kg; once daily; days 6 to 17 of gestation, followed by caesarean section on day 18 of gestation) induces hepatic metabolic enzymes at 250 mg for the first 2 days/ kg, followed by increasing the dose to 500 mg/kg/day.

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Maternal and Cesarean Section Observations [2]
There was no effect of treatment on maternal survival, abortion, or early delivery; 21, 19, 18, and 22 females carried a litter to term at 0, 150, 350, and 500 mg/kg/day, respectively (Table 1). Body weights and body weight gains were unaffected by lersivirine treatment; GD 18 body weights were 100, 99, and 102% of controls at 150, 350, and 500 mg/kg/day, respectively (Table 2). Feed consumption was decreased at 350 and 500 mg/kg/day (Table 2). Feed consumption for the entire dosage period (GD 6–18) was significantly lower (p < 0.05 or p < 0.01) than the concurrent control group values at 350 and 500 mg/kg/day (92 and 90%, respectively, of the control).

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Fetal Morphology [2]
There were no external, visceral, or skeletal malformations associated with maternal lersivirine treatment (Table 4). A medial cleft in the palate was observed at external examination for three fetuses (1.3%/litter) at 350 mg/kg/day and three fetuses (1.1%/litter) at 500 mg/kg/day; however, given the background incidence in this laboratory ranges to 3.2% per litter, the occurrence was not considered lersivirine-related. Rotated fore- and/or hindlimbs were noted in five (2.1%/litter), four (1.6%/litter), five (2.1%/litter), two (0.7%/litter) at 0, 150, 350, and 500 mg/kg/day, respectively; however, given the lack of a dose-response increase in incidence, this finding was not attributed to lersivirine. The only skeletal malformation that occurred in the 500 mg/kg/day group was fused lumbar arch in two (1.4%/litter) fetuses, given the lack of other evidence of skeletal dysmorphogenesis this occurrence in two fetuses from a single litter was not attributed to lersivirine.

Animals and Treatment [2]
One hundred presumed pregnant female Crl:CD1(ICR) mice were randomly assigned to four groups of 25 mice per group. Sixty-three additional presumed pregnant mice were assigned for use in toxicokinetic sample collection; control group of 9 and 18 per group for lersivirine dose groups. Mice were approximately 72 days of age and approximately 28 gm in weight upon arrival. Mice were individually housed in stainless steel, wire-bottomed cages. Water and feed were given ad libitum and the room was on a 12-hr light/dark cycle.
Suspensions of lersivirine in 0.5% methylcellulose aqueous solution with 0.1% Tween 80 were administered orally via gavage once daily on days 6 through 17 of presumed gestation (gestation days 6–17) at doses of 0, 150, 350, and 500 mg/kg/day at a dosage volume of 10 ml/kg. At the highest dose tested (500 mg/kg/day), an initial dose of 250 mg/kg/day at a dosage volume of 5 ml/kg was administered for the first 2 days of dosage administration after which the mice were treated at 500 mg/kg/day. This dosing regimen allowed for maintenance of the maximum tolerable exposure following metabolizing enzyme induction; lersivirine has previously been shown to induce metabolism in rodents (Walker et al., 2009). The doses were based on a preliminary study in which pregnant mice (10/group) were dosed from GD 6 to 17 at doses of 150, 350, and 700 mg/kg/day (the 700 mg/kg/day group was dosed the first 2 days at 350 mg/kg/day). In this study, 4 of 10 mice in the 700 mg/kg/day group were euthanized moribund; all other animals survived until the scheduled euthanasia. Therefore, 500 mg/kg/day (with first 2 dose days at 250 mg/kg/day) was estimated to be the maximum tolerated dose in pregnant mice.

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Assessment of Lersivirine Exposure [2]
On GD 17, blood samples (approximately 0.5 ml) were collected from the vena cava of three mice/group/time point after sacrifice. For lersivirine-treated mice, samples were collected before dosage and at approximately 0.5, 2, 4, 8, and 24 hr post-dose. Blood samples were transferred into lithium heparin–coated tubes, plasma was separated from whole blood by centrifugation and stored frozen at –20°C until analyzed. Plasma concentrations of lersivirine were determined by a validated HPLC assay.

Maternal Toxicokinetics [2]
Plasma levels of lersivirine on GD 17 following administration of lersivirine from GD 6 to 17 are presented in Table 6. Maternal plasma lersivirine exposure was similar across all three dose groups.

Lersivirine is a second-generation nonnucleoside reverse transcriptase inhibitor undergoing clinical development for the treatment of HIV-1. An embryo-fetal developmental toxicity study was performed to evaluate the maternal and developmental toxicity of lersivirine in pregnant mice. Mated Crl:CD1(ICR) mice were administered 0, 150, 350, and 500 mg/kg lersivirine once daily by oral gavage on gestation days 6 to 17, followed by cesarean section on gestation day 18. The first 2 days of dosing for the high-dose group were done at 250 mg/kg to allow induction of hepatic metabolizing enzymes, after which the dose was increased to 500 mg/kg/day. This dosing paradigm allowed for maintenance of exposure in the high-dose group despite the considerable autoinduction that occurs in rodents following lersivirine treatment. Lersivirine did not cause an increase in external, visceral, or skeletal malformations. Intrauterine growth retardation, demonstrated by reduced fetal body weights and increased variations associated with delayed skeletal ossification, was noted at 350 and 500 mg/kg/day. The results of these studies indicate that lersivirine is not teratogenic in mice.[2]

[1]. Pyrazole NNRTIs 4: selection of UK-453,061 (lersivirine) as a development candidate. Bioorg Med Chem Lett. 2009 Oct 15;19(20):5857-60.

[2]. Developmental toxicity study of lersivirine in mice. Birth Defects Res B Dev Reprod Toxicol. 2012 Jun;95(3):225-30.

Lersivirine is an aromatic ether.
Lersivirine has been used in trials studying the treatment of HIV-1.
Lersivirine is a next-generation, pyrazole non-nucleoside reverse transcriptase inhibitor. Lersivirine retains activity against HIV viruses with mutations at position Y181, which confers resistance to efavirenz, etravirine, and nevirapine.

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The results of this study indicate that lersivirine is not teratogenic in mice. In addition, lersivirine was not teratogenic in rabbits (Campion et al., same issue). The results of the lersivirine studies, in concert with the apparent lack of signal for teratogenesis with other first-generation NNRTIs such as delavirdine and nevirapine (Watts et al., 2004), support a conclusion that the teratogenic signal attributed to efavirenz (Lewis-Hall, 2005; Mofenson, 2005), if real, is specific to that compound and does not represent an NNRTI class effect. While no fetal malformations were attributed to lersivirine treatment, developmental toxicity was noted in fetuses from mothers treated with lersivirine at 350 and 500 mg/kg/day. The primary expression of developmental toxicity was intrauterine growth retardation, demonstrated by reduced fetal weight, increased skeletal variations, and decreased ossification sites. The skeletal variations that were increased were mainly those associated with delayed ossification and interrupted ribs. Skeletal variations are defined as common findings that occur in the experimental species and strain that represent reversible delays or accelerations in development. This is in contrast to fetal malformations that are defined as irreversible changes that occur at low incidences in this species and strain. The primary measure of intrauterine growth retardation is fetal body weight. Fetal body weights were 16 and 21% less than controls at 350 and 500 mg/kg/day, respectively; with no effect on fetal body weight at 150 mg/kg/day. In addition to reduced fetal body weight, skeletal variations indicative of developmental delay that were attributed to maternal treatment with lersivirine at 350 and 500 mg/kg/day were incomplete ossification of the supraoccipital, nasals, frontals, cervical arches, pubes, or ischia, and absence of an ossified supraoccipital. In addition, reduced ossification was noted for the hyoid, caudal vertebrae, sternal centers, forelimb phalanges, hindlimb tarsals, and hindlimb phalanges in the 350 and 500 mg/kg/day groups. Ossification delays are well known to correlate with reductions in fetal weight in mice (Deol and Truslove, 1957; McLaren and Michie, 1958) that are considered unrelated to pathogenesis associated with structural malformations (Grüneberg, 1955). In addition to intrauterine growth retardation, two dead fetuses were found in the 500 mg/kg/day treatment group. There was no other evidence of impaired fetal viability, the numbers of viable fetuses were comparable between groups and lersivirine treatment was not associated with increases in resorbed fetuses. However, because the incidence of dead fetuses is historically low, a potential relationship to treatment could not be dismissed. Maternal plasma lersivirine exposure on GD 17 following repeated daily dosing from GD 6 was essentially flat across the approximately threefold increase in dose from 150 to 500 mg/kg/day. Lersivirine is characterized by moderate clearance and volume of distribution leading to good oral bioavailability and all of the clearance is hepatic (Allan et al., 2008). However, lersivirine administration to rodents causes hepatic enzyme induction and this autoinduction limits the systemic exposure that can be achieved at steady state (Walker et al., 2009). The extent of autoinduction results in a decrease in AUC (area under curve)(0–24 hr), exposure of 8- to 10-fold between day 1 and day 12 of dosing in mice (Walker et al., 2009). Therefore, while GD 17 exposures are essentially flat across dose groups, the day 1 exposure over the same dose range showed approximately 5- and approximately 10-fold increase in Cmax and AUC(0–24 hr), respectively (unpublished data from 1-month toxicology study). Therefore, although not measured in this study, lersivirine exposure over this dose range during the period of early organogenesis likely had a dose proportional increase not indicated by the GD 17 measurements, and would have showed toxicologically relevant differences in exposures between dose levels. In conclusion, the results of this study demonstrated that lersivirine treatment does not cause fetal malformations in mice. The primary effect produced by maternal lersivirine exposure was intrauterine growth retardation as indicated by reduced fetal weight, and skeletal variations associated with delays in ossification.[2]

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We prepared three discreet cohorts of potent non-nucleoside HIV reverse transcriptase inhibitors (NNRTIs) based on the recently reported 3-cyanophenoxypyrazole lead 3. Several of these compounds displayed very promising anti-HIV activity in vitro, safety, pharmacokinetic and pharmaceutical profiles. We describe our analysis and conclusions leading to the selection of alcohol 5 (UK-453,061, lersivirine) for clinical development.[1]

C17H18N4O2

310.3504

310.142

C, 65.79; H, 5.85; N, 18.05; O, 10.31

473921-12-9

147362-57-0 (Loviride); 16837-52-8 (Oxymatrine）

16739244

Light yellow to khaki solid powder

1.2±0.1 g/cm3

455.4±45.0 °C at 760 mmHg

229.2±28.7 °C

0.0±1.2 mmHg at 25°C

1.595

3.3

1

5

6

23

456

0

MCPUZZJBAHRIPO-UHFFFAOYSA-N

InChI=1S/C17H18N4O2/c1-3-15-17(16(4-2)21(20-15)5-6-22)23-14-8-12(10-18)7-13(9-14)11-19/h7-9,22H,3-6H2,1-2H3

5-((3,5-diethyl-1-(2-hydroxyethyl)-1H-pyrazol-4-yl)oxy)isophthalonitrile

UK 453061; UK-453061; UK-453,061; UK453,061; Lersivirine; 473921-12-9; 3-CYANO-5-[[3,5-DIETHYL-1-(2-HYDROXYETHYL)-1H-PYRAZOL-4-YL]OXY]BENZONITRILE; UK-453,061; 5-((3,5-diethyl-1-(2-hydroxyethyl)-1H-pyrazol-4-yl)oxy)isophthalonitrile; 5-[3,5-diethyl-1-(2-hydroxyethyl)pyrazol-4-yl]oxybenzene-1,3-dicarbonitrile; R3ZGC15A9A; UK453061; UK 453,061

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~50 mg/mL (~161.11 mM)

Solubility in Formulation 1: ≥ 3 mg/mL (9.67 mM) (saturation unknown) in 10% DMSO + 40% PEG300 +5% Tween-80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 30.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 + to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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 (Please use freshly prepared in vivo formulations for optimal results.)