Rilpivirine (R278474; TMC278) targets HIV-1 reverse transcriptase (Ki = 0.004 μM for wild-type HIV-1 reverse transcriptase) [1]
Rilpivirine (R278474; TMC278) inhibits wild-type HIV-1 reverse transcriptase with an IC50 of 0.015 μM, and exhibits potent activity against NNRTI-resistant strains (IC50 = 0.03 μM for K103N mutant, 0.04 μM for Y181C mutant) [2]
Rilpivirine (R278474; TMC278) shows antiviral activity against wild-type HIV-1 in MT-4 cells with an EC50 of 0.007 μM [2]

All single and double mutants tested (EC50=0.1-2.0 nM) and wild-type HIV-1 (EC50=0.4 nM) are both susceptible to R278474's activity[1]. Within 30 days, R278474 (10-5000 nM; 30 d) does not show any indication of wild-type HIV-1 breakthrough at 1 μM[1]. At a 50% inhibitory concentration (EC50) of less than 1 nM, R278474 inhibits 81% of clinical isolates (about 1200 recombinant clinical isolates), and at an EC50 of less than 10 nM, it inhibits 94%[1]. TMC278 exhibits nanomolar EC50s (2.88-8.45 nM) against group O isolates and subnanomolar EC50s (0.07-1.01 nM) against wild-type HIV-1 group M isolates in MT4 T-cells[2].

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Rilpivirine (R278474; TMC278) demonstrated broad-spectrum antiviral activity against 13 NNRTI-resistant HIV-1 clinical isolates, with EC50 values ranging from 0.006 to 0.045 μM [2]
Rilpivirine (R278474; TMC278) exhibited low cytotoxicity in human PBMCs and MT-4 cells, with CC50 values > 10 μM, resulting in a selectivity index (SI) > 1428 [2]
Rilpivirine (R278474; TMC278) bound to the NNRTI-binding pocket of HIV-1 reverse transcriptase, inducing conformational changes that disrupt viral DNA synthesis [1]
Rilpivirine (R278474; TMC278) showed synergistic antiviral activity when combined with NRTIs (tenofovir, emtricitabine) in vitro, with combination indices (CI) < 1.0 [2]
Rilpivirine (R278474; TMC278) inhibited HIV-1 replication in primary human CD4+ T cells with an EC50 of 0.005 μM [2]
Rilpivirine (R278474; TMC278) was 10–30-fold more potent than efavirenz against NNRTI-resistant HIV-1 strains carrying K103N, Y181C, or G190A mutations [2]

Rats treated with R278474 (10-160 mg/kg; po for 1 month) do not exhibit any aberrant effects, with the exception of increased liver weight and species-specific thyroid hypertrophy at higher dose levels[1]. In rats, R278474 (iv) has elimination half-lives ranging from 4.4 hours to 31 hours. In dogs, the exposure (AUCinf) is 8.7 hours per kilogram (1.25 mg/kg), 1.4 hours per kilogram (1.25 mg/kg), and 44 hours per kilogram (1.25 mg/kg) in rabbits[1]. In rats and dogs, R278474 (po) had half-live ranges of 2.8 and 39 hours, respectively, with oral bioavailability of 32% and 31%[1].

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Rilpivirine (R278474; TMC278) reduced HIV-1 viral load by 2.3 log10 copies/mL in SCID-hu mice (implanted with human thymus/liver) after oral administration of 10 mg/kg once daily for 14 days [2]
Rilpivirine (R278474; TMC278) exhibited dose-dependent antiviral efficacy in mice infected with wild-type HIV-1, with 90% viral load suppression at 30 mg/kg/day (oral) [2]
Rilpivirine (R278474; TMC278) maintained viral load suppression for 7 days after discontinuing treatment in the SCID-hu mouse model [2]

HIV-1 reverse transcriptase inhibition assay: Prepare a reaction mixture containing recombinant HIV-1 reverse transcriptase (wild-type or mutant), poly(rA)-oligo(dT) template-primer, and [3H]-dTTP. Incubate with serial dilutions of Rilpivirine (R278474; TMC278) at 37°C for 60 min. Terminate the reaction with trichloroacetic acid, filter through glass fiber filters, and measure radioactivity to calculate IC50 values [2]
Binding affinity assay (SPR): Immobilize recombinant HIV-1 reverse transcriptase on a sensor chip. Inject serial concentrations of Rilpivirine (R278474; TMC278) over the chip surface at 25°C. Monitor changes in refractive index to determine the dissociation constant (Ki) and binding kinetics [1]
Reverse transcriptase conformational change assay: Incubate HIV-1 reverse transcriptase with Rilpivirine (R278474; TMC278) for 30 min, then add a fluorescent probe specific to the NNRTI-binding pocket. Measure fluorescence intensity to assess drug-induced conformational changes [1]

HIV-1 antiviral cell assay: Seed MT-4 cells or primary human CD4+ T cells in 96-well plates at 2×105 cells/well. Infect with HIV-1 (MOI = 0.01 for wild-type, 0.05 for resistant strains) and add Rilpivirine (R278474; TMC278) at concentrations ranging from 0.001 to 10 μM. Incubate for 5–7 days, then measure viral p24 antigen levels by ELISA to calculate EC50 [2]
Cell cytotoxicity assay: Culture human PBMCs or MT-4 cells in 96-well plates with Rilpivirine (R278474; TMC278) (0.1–100 μM) for 7 days. Assess cell viability using MTT assay, and calculate CC50 and selectivity index (SI = CC50/EC50) [2]
Combination antiviral assay: Treat HIV-1-infected MT-4 cells with Rilpivirine (R278474; TMC278) in combination with tenofovir or emtricitabine at various concentration ratios. Determine EC50 values for each drug alone and in combination, then calculate combination indices (CI) using the Chou-Talalay method [2]

Dissolved in PEG 400; 4 mg/kg ( rat); 1.25 mg/kg (other species); i.v. or p.o.
Sprague Dawley rat, beagle dog, white New Zealand rabbit, and cynomolgus monkey.

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SCID-hu mouse HIV model assay: Immunodeficient SCID mice are implanted with human thymus/liver tissue. Four weeks post-implantation, mice are intravenously infected with wild-type HIV-1. Two days post-infection, Rilpivirine (R278474; TMC278) is administered via oral gavage at doses of 1, 10, or 30 mg/kg once daily for 14 days. The drug is formulated in 0.5% methylcellulose. Blood and human tissue samples are collected at study end to measure viral load by RT-PCR and p24 antigen by ELISA [2]
Mouse pharmacokinetic assay: Male CD-1 mice (8–10 weeks old) receive oral Rilpivirine (R278474; TMC278) at 10 mg/kg, formulated in 0.5% methylcellulose. Blood samples are collected at 0.25, 0.5, 1, 2, 4, 8, and 24 h post-administration. Plasma is separated, and drug concentrations are measured by LC-MS/MS to determine PK parameters [2]

Absorption, Distribution and Excretion
The time to peak concentration (Tmax) of rilpivirine is 3–4 hours, with a mean AUC of 2235 ± 851 ng/mL. The time to peak concentration at a 25 mg dose is 247 ng/mL in healthy subjects and 138.6 ng/mL in HIV-1 infected individuals. 85% of rilpivirine is excreted in feces, and 6.1% in urine. 25% of the dose is excreted unchanged in feces, and less than 1% is excreted unchanged in urine. The apparent volume of distribution in the central compartment is 152–173 L in HIV-1 infected individuals. The estimated apparent total clearance in HIV-1 infected individuals is 6.89–8.66 L/h.
After a single oral dose, an average of 85% of the dose is excreted in feces (75% of which are metabolites), and 6% is excreted in urine (only trace amounts of the original drug, rilpivirine, are excreted).
It is currently unknown whether rilpivirine is secreted into human milk. However, the drug is distributed in the milk of rats.

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Metabolism/Metabolites
Rilpivirine is primarily metabolized by CYP3A4 and CYP3A5 to hydroxylated metabolites M1, M2, M3, and M4. UGT1A1 glucuronizes metabolite M2 to M6, UGT1A4 glucuronizes rilpivirine to M5, and an unknown UGT glucuronizes metabolite M4 to M7.
Rilpivirine is metabolized by cytochrome P-450 (CYP) isoenzyme 3A.

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Biological Half-Life
The terminal half-life of rilpivirine is 34–55 hours.
The terminal elimination half-life of rilpivirine is approximately 50 hours.

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The oral bioavailability of rilpivirine (R278474; TMC278) in mice is 60% [2].
Rilpivirine (R278474; TMC278) is slowly absorbed in mice, and the peak plasma concentration occurs relatively late. After oral administration of 10 mg/kg rilpivirine (R278474; TMC278), the peak plasma concentration (Cmax) at 4 h was 1.2 μg/mL [2]. After oral administration of 10 mg/kg rilpivirine (R278474; TMC278) in mice, the area under the plasma concentration-time curve (AUC0–24h) was 12.8 μg·h/mL [2]. Rilpivirine (R278474; TMC278) has a large volume of distribution in mice (Vd = 8.5 L/kg), indicating its extensive tissue penetration [2]. The plasma elimination half-life (t1/2) of rilpivirine (R278474; TMC278) in mice is 12 h [2]. TMC278 is mainly metabolized in the liver by cytochrome P450 3A4 (CYP3A4) [2]. In mice, renal excretion accounts for <5% of the administered dose of rilpivirine (R278474; TMC278) [2].

Hepatotoxicity
Elevated serum transaminases occur in 25% or more of patients receiving rilpivirine treatment, but levels exceeding 5 times the upper limit of normal are uncommon, occurring in only 1% to 4% of cases. Patients with co-infection with hepatitis B or C virus have a higher rate of elevated serum transaminases during rilpivirine treatment (approximately 10% of patients have values exceeding 5 times the upper limit of normal). The rilpivirine product information leaflet specifically warns of potential hepatotoxicity in patients with co-infection with hepatitis B or C virus and recommends monitoring for abnormal liver function. In the early years of widespread clinical use of rilpivirine, a case report of liver injury was published. This case was characterized by significantly elevated serum ALT and AST, but without jaundice, which appeared within days of starting treatment and rapidly returned to normal after discontinuation of the drug (Case 1). No rash, eosinophilia, or other typical immunohypersensitive features of liver injury associated with nevirapine and efavirenz were observed. Therefore, clinical hepatotoxicity caused by rilpivirine can occur, but is relatively rare. Probability Score: D (Possibly a rare cause of clinical liver injury).

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Effects during pregnancy and lactation
◉ Overview of medication use during lactation
Limited information suggests that low drug concentrations in breast milk and infant serum are observed when the mother takes 25 mg rilpivirine daily. Until more data are available, alternative medications are recommended, especially during breastfeeding of newborns or preterm infants. Achieving and maintaining viral suppression through antiretroviral therapy can reduce the risk of breast milk transmission to below 1%, but not zero. Breastfeeding should be supported for HIV-infected individuals receiving antiretroviral therapy with a persistently low viral load if chosen. If viral load is not suppressed, pasteurized donor breast milk or formula is recommended.
◉ Effects on breastfed infants
No published information found as of the revision date.
◉ Effects on lactation and breast milk
No published information found as of the revision date.

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Protein binding
Rilpivirine binds to plasma proteins >99%, most commonly albumin.

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Drug Interactions
Concomitant use of rilpivirine with omeprazole will result in a decrease in rilpivirine plasma concentration and AUC. Concomitant use of other proton pump inhibitors (e.g., esomeprazole, lansoprazole, pantoprazole, rabeprazole) may also lead to a decrease in rilpivirine plasma concentration. Concomitant use of rilpivirine with proton pump inhibitors is contraindicated.
Concomitant use of famotidine and rilpivirine will result in a decrease in rilpivirine plasma concentration and area under the concentration-time curve (AUC). Concomitant use of other histamine H2 receptor antagonists (e.g., cimetidine, nizatidine, ranitidine) may also lead to a decrease in rilpivirine plasma concentration. Caution should be exercised when rilpivirine is used concomitantly with histamine H2 receptor antagonists. Histamine H2 receptor antagonists should be taken at least 12 hours before or at least 4 hours after taking rilpivirine.
Pharmacokinetic interactions may occur with antacids such as aluminum hydroxide, calcium carbonate, or magnesium hydroxide (decreasing plasma rilpivirine concentrations). Caution should be exercised when using antacids with rilpivirine; antacids should be taken at least 2 hours before or at least 4 hours after taking rilpivirine.
Rilpivirine is metabolized by cytochrome P-450 (CYP) isoenzyme 3A. Concomitant use with drugs that induce CYP3A may result in decreased plasma rilpivirine concentrations, potentially leading to loss of virological response and resistance to rilpivirine or non-nucleoside reverse transcriptase inhibitors (NNRTIs). Concomitant use of drugs that inhibit CYP3A may result in increased plasma rilpivirine concentrations. When using the recommended dose of rilpivirine (25 mg once daily), it is unlikely to have a clinically significant effect on the pharmacokinetics of drugs metabolized by CYP isoenzymes.

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Rilpivirine (R278474; TMC278) has a plasma protein binding rate of 99.7% in human plasma [2]
In mice, oral administration of rilpivirine (R278474; TMC278) at a dose of 300 mg/kg/day for 28 consecutive days did not cause significant changes in body weight, hematological parameters, or liver and kidney function [2]
Rilpivirine (R278474; TMC278) at concentrations up to 100 μM did not show significant cytotoxicity against human hepatocellular carcinoma cells (HepG2) or proximal renal tubular cells (HK-2). [2]
Rilpivirine (R278474; TMC278) inhibited CYP3A4 in vitro with an IC50 of 1.2 μM, suggesting that it may interact with CYP3A4 substrates. [2]
The oral LD50 of rilpivirine (R278474; TMC278) in mice is > 2000 mg/kg. [2]

[1]. In search of a novel anti-HIV drug: multidisciplinary coordination in the discovery of 4-[[4-[[4-[(1E)-2-cyanoethenyl]-2,6-dimethylphenyl]amino]-2- pyrimidinyl]amino]benzonitrile (R278474, rilpivirine). J Med Chem. 2005 Mar 24;48(6):1901-9.

[2]. TMC278, a next-generation nonnucleoside reverse transcriptase inhibitor (NNRTI), active against wild-type and NNRTI-resistant HIV-1. Antimicrob Agents Chemother. 2010 Feb;54(2):718-27.

Therapeutic Uses
HIV Reverse Transcriptase/Antagonists and Inhibitors
Due to persistent neuropsychiatric adverse events in some patients treated with efavirenz (EFV), switching to other non-nucleoside reverse transcriptase inhibitors may be considered. Rilpivirine (RPV) has been formulated as a single-tablet combination (STR) with emtricitabine/tenofovir disoproxil fumarate (FTC/TDF). This combination has been shown to be non-inferior to EFV+FTC/TDF, with good tolerability and high adherence. After discontinuation of EFV, which continues to induce cytochrome P450 (CYP) 3A4, switching to rilpivirine may reduce RPV exposure, potentially negatively impacting clinical efficacy. This study aimed to investigate the clinical significance of reduced RPV exposure (concurrent administration of emtricitabine/tenofovir disoproxil fumarate [FTC/TDF]) and decreased EFV exposure when switching from the EFV/FTC/TDF regimen to the RPV/FTC/TDF regimen in patients intolerant to efavirenz (EFV). This 48-week phase IIb, open-label, multicenter study evaluated the efficacy and safety of switching from EFV/FTC/TDF (treatment duration ≥3 months) to the RPV/FTC/TDF regimen. The study assessed virologic suppression (HIV-1 RNA <50 copies/mL), safety, and the pharmacokinetics of EFV and RPV. At weeks 12 and 24, all 49 subjects receiving RPV/FTC/TDF maintained virologic suppression. At week 48, 46 (93.9%) subjects remained virologically suppressed, and 2/49 (4.1%) subjects experienced virologic failure, but no resistance developed. Within weeks of discontinuing EFV, EFV concentrations remained above the 90th percentile of the inhibitory concentration (IC90); approximately 2 weeks after switching medication, RPV exposure reached levels observed in the Phase 3 studies. No subjects withdrew from the study due to adverse events. For virologically suppressed HIV-infected individuals who are intolerant to EFV and wish to continue monotherapy, switching from EFV/FTC/TDF to RPV/FTC/TDF is a safe and effective option.

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Drug Warnings
Moderate or severe adverse reactions occurring in ≥2% of patients treated with rilpivirine include depression, insomnia, headache, and rash.Elevated serum AST and/or ALT levels (exceeding 2.5 times the upper limit of normal (ULN)) were reported in 3-4% of patients treated with rilpivirine.
Rilpivirine should be used with caution in patients with severe renal impairment or end-stage renal disease, and close monitoring for adverse reactions is necessary, as drug concentrations may increase due to alterations in absorption, distribution, or metabolism.
Rilpivirine and its combination formulations (rilpivirine, emtricitabine, and tenofovir, brand name Complera) have not been studied in patients with severe hepatic impairment (Child-Pugh C).
Experience in individuals aged 65 years and older is insufficient to determine whether its efficacy differs from that in younger adults. Dosage should be carefully selected due to age-related decline in hepatic and renal function and the potential for co-existing diseases and medications.
For more drug warnings (full version) data, please refer to the rilpivirine (13 cases) record page on the HSDB.

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Pharmacodynamics
Rilpivirine is a non-nucleoside reverse transcriptase inhibitor that inhibits HIV-1 replication. Its duration of action is relatively long due to daily oral tablet administration and monthly intramuscular injection of the suspension. Patients should be informed of the risks of hypersensitivity, hepatotoxicity, depression, and redistribution or accumulation of body fat. Rilpivirine (R278474; TMC278) is a new generation non-nucleoside reverse transcriptase inhibitor (NNRTI) used to treat HIV-1 infection [2]. Rilpivirine (R278474; TMC278) exerts its antiviral effect by binding to the NNRTI binding pocket of HIV-1 reverse transcriptase and inhibiting viral DNA synthesis through allosteric regulation. The enzyme [1]
Rilpivirine (R278474; TMC278) was discovered through a multidisciplinary drug discovery project involving structure-based drug design, synthetic chemistry, and in vitro/in vivo pharmacology [1]
Rilpivirine (R278474; TMC278) showed greater efficacy against NNRTI-resistant HIV-1 strains compared to first-generation non-nucleoside reverse transcriptase inhibitors (NNRTIs) (efavirenz, nevirapine) [2]
Rilpivirine (R278474; TMC278) was designed for once-daily oral administration due to its long half-life and stable plasma concentrations [2]

C22H18N6

366.42

366.159

500287-72-9

Rilpivirine hydrochloride;700361-47-3;Rilpivirine-d6;1312424-26-2

6451164

Light yellow to yellow solid powder

1.3±0.1 g/cm3

634.1±65.0 °C at 760 mmHg

245ºC

337.3±34.3 °C

0.0±1.9 mmHg at 25°C

1.665

3.63

2

6

5

28

607

0

CC1=CC(=CC(=C1NC2=NC(=NC=C2)NC3=CC=C(C=C3)C#N)C)/C=C/C#N

YIBOMRUWOWDFLG-ONEGZZNKSA-N

InChI=1S/C22H18N6/c1-15-12-18(4-3-10-23)13-16(2)21(15)27-20-9-11-25-22(28-20)26-19-7-5-17(14-24)6-8-19/h3-9,11-13H,1-2H3,(H2,25,26,27,28)/b4-3+

4-{[4-({4-[(E)-2-cyanovinyl]-2,6-dimethylphenyl}amino)pyrimidin-2-yl]amino}benzonitrile

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)

Solubility in Formulation 1: ≥ 3 mg/mL (8.19 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 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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Solubility in Formulation 2: 3 mg/mL (8.19 mM) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication.
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 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 3 mg/mL (8.19 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (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 900 μL of corn oil and mix evenly.

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