HIV-1
With an IC50 of 7.5± 0.3 nM, bictegravir (BIC) inhibits the strand transfer activity. With an IC50 of 241±51 nM, bictegravir is a much weaker inhibitor of HIV-1 IN's 3′-processing activity than it is of strand transfer activity. In comparison to the mock-treated control, bictegravir increases the accumulation of 2-LTR circles by approximately five times and decreases the quantity of real integration products in infected cells by a factor of 100. With EC50s of 1.5 and 2.4 nM, respectively, bictegravir potently inhibits HIV-1 replication in both MT-2 and MT-4 cells. With EC50s of 1.5±0.3 nM and 6.6±4.1 nM, respectively, bictegravir demonstrates strong antiviral effects in primary CD4+ T lymphocytes and monocyte-derived macrophages. These values are in line with those observed in T-cell lines.

With an IC50 of 7.5± 0.3 nM, bictegravir (BIC) inhibits the strand transfer activity. With an IC50 of 241±51 nM, bictegravir is a much weaker inhibitor of HIV-1 IN's 3′-processing activity than it is of strand transfer activity. In comparison to the mock-treated control, bictegravir increases the accumulation of 2-LTR circles by approximately five times and decreases the quantity of real integration products in infected cells by a factor of 100. With EC50s of 1.5 and 2.4 nM, respectively, bictegravir potently inhibits HIV-1 replication in both MT-2 and MT-4 cells. With EC50s of 1.5±0.3 nM and 6.6±4.1 nM, respectively, bictegravir demonstrates strong antiviral effects in primary CD4+ T lymphocytes and monocyte-derived macrophages. These values are in line with those observed in T-cell lines.

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Bictegravir (BIC) potently inhibits HIV-1 replication in MT-2 and MT-4 T-lymphoblastoid cell lines with EC50 values of 1.5 nM and 2.4 nM, respectively, and shows high selectivity indices (CC50/EC50 of 6,867 in MT-2 and 1,525 in MT-4). [1]
In primary human CD4+ T lymphocytes and monocyte-derived macrophages, BIC exhibits EC50 values of 1.5 nM and 6.6 nM, respectively, with selectivity indices of 8,700 and 4,500. [1]
BIC demonstrates potent antiviral activity against 14 clinical isolates of HIV-1 and one isolate of HIV-2 in human PBMCs, with a mean EC50 of 0.81 nM (range 0.04–1.7 nM). [1]
BIC shows synergistic antiviral effects in pairwise combinations with tenofovir alafenamide (TAF), emtricitabine (FTC), or darunavir (DRV), and additive effects with raltegravir (RAL) or elvitegravir (EVG). [1]
BIC maintains potent activity against a panel of HIV-1 mutants resistant to nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), and protease inhibitors (PIs). [1]
BIC shows minimal to intermediate resistance against nine site-directed INSTI-resistant HIV-1 mutants (fold change in EC50 ranging from 0.7 to 9.0 compared to wild-type). [1]
Against 47 patient-derived HIV-1 isolates with INSTI resistance mutations, BIC shows a statistically improved resistance profile (mean fold change of 2.8) compared to dolutegravir (DTG, 5.8-fold), elvitegravir (EVG, >106-fold), and raltegravir (RAL, >100-fold). [1]

HIV-1 IIIb is cultured in bulk on MT-2 cells for three hours at 37°C, with a cell density of 2×106 cells/mL. Bictegravir (BIC) or DMSO (mock-treated control) are given to infected MT-2 cells at a final concentration that is at least 20 times the antiviral 50% effective concentration (EC50) of each drug.The cells are harvested for total DNA isolation after these plates are incubated at 37°C for either 12 hours (for late reverse transcription product quantification) or 24 hours (for 2-LTR circle and Alu-LTR product quantification). Using the DNA minikit, DNA is extracted from each well and collected as a 100-μL eluate. The host globin gene level in each sample is used to normalize TaqMan real-time PCR-quantified 2-LTR junctions (2-LTR circles), late reverse transcription products, and integration junctions (Alu-LTR)[1].

The strand transfer activity of purified recombinant HIV-1 integrase was measured using a homogeneous time-resolved fluorescence resonance energy transfer (HTRF) assay. The assay measures the transfer of a fluorescently labeled donor DNA to a biotinylated target DNA, which is then detected by fluorescence resonance energy transfer. Inhibitors are serially diluted and incubated with the enzyme and DNA substrates to determine IC50 values. [1]
A similar HTRF-based assay was used to measure the 3′-processing activity of HIV-1 integrase, utilizing a specially designed non-processed donor DNA in the absence of target DNA. [1]

In bulk culture, MT-2 cells are infected with HIV-1 IIIb for three hours at 37°C at a cell density of 2×106 cells/mL. Bictegravir (BIC) or DMSO (mock-treated control) are given to infected MT-2 cells at a final concentration that is at least 20 times the antiviral 50% effective concentration (EC50) of each drug. The cells are harvested for total DNA isolation after these plates are incubated at 37°C for either 12 hours (for late reverse transcription product quantification) or 24 hours (for 2-LTR circle and Alu-LTR product quantification).Using the DNA minikit, DNA is extracted from each well and collected as a 100-μL eluate. The host globin gene level in each sample serves as the standard for TaqMan real-time PCR quantification of 2-LTR junctions (2-LTR circles), late reverse transcription products, and integration junctions (Alu-LTR)[1].

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For antiviral assays in MT-2 and MT-4 cells, cells were infected with HIV-1 IIIb at a multiplicity of infection (MOI) of 0.1 for 3 hours. Infected cells were then added to 96-well plates containing serial dilutions of the test compound. Plates were incubated for 5 days, and cell viability was assessed using a luminescent cell viability reagent. Cytotoxicity was assessed similarly using uninfected cells. [1]
For antiviral assays in primary CD4+ T lymphocytes, cells were infected in bulk with HIV-1 BaL at an MOI of 15 ng p24 per million cells for 3 hours, washed, seeded into 96-well plates, and incubated with serial dilutions of compound for 5 days. Supernatants were harvested for p24 ELISA. [1]
For antiviral assays in monocyte-derived macrophages, differentiated macrophages were infected with HIV-1 BaL, washed, and incubated with compound-containing medium for 12 days with medium changes. Supernatants were harvested for p24 ELISA. [1]
Integration inhibition was assessed in MT-2 cells infected with HIV-1 IIIb. Cells were treated with compounds at ≥20× EC50 for 12 or 24 hours. Total DNA was isolated, and quantitative PCR was used to measure late reverse transcription products, 2-LTR circles, and integrated proviral DNA (Alu-LTR junctions), normalized to a host globin gene. [1]

Absorption, Distribution and Excretion
Bictegravir is rapidly absorbed in the body. Time to peak concentration (Tmax) = 2.0–4.0 hours. Bictegravir is primarily eliminated via UGT1A1 glucuronidation and CYP3A4 oxidation, in roughly equal proportions. Approximately 1% of the bicelavir dose is excreted unchanged in the urine. The clearance of bicelavir in the human body is 0.2 L/kg. Bictegravir is primarily cleared by the kidneys. Patients with renal clearance <30% should not take bicelavir. [FDA Label]

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Metabolism/Metabolites In a 10-day dose-range study, in previously untreated adults receiving bicelavir monotherapy (5 mg to 100 mg once daily), the median half-life of bicelavir was 15.9 to 20.9 hours. Bictegravir is metabolized in the liver and kidneys. CYP3A4 and UGT1A are the main enzymes involved in the metabolism of bicelavir. Bictegravir is not recommended for patients with renal creatinine clearance <30 mL/min or for patients with liver disease [FDA label].

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Biological half-life
The half-life is 17.3 hours.

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Structural modifications of bicelavir (BIC) reduce activation of the pregnane X receptor (PXR), thereby minimizing the risk of drug interactions. Increased plasma protein binding leads to the reduced in vivo clearance observed in preclinical and clinical studies. These changes also improve solubility. [1]
The protein binding corrected EC95 (PAEC95) value of BIC was calculated to be 361 nM, which was derived from the change in human serum concentration (43.6-fold) as determined by in vitro EC95 (8.3 nM) and equilibrium dialysis. [1]

Hepatotoxicity
In large clinical trials, 11% of patients treated with bicretiva in combination with emtricitabine and tenofovir alafenamide experienced elevated alanine aminotransferase (ALT) levels (1.5 times the upper limit of normal), but this proportion was similar to that in the control group (12% to 15%) receiving matched, optimized antiretroviral therapy without bicretiva. Only 1.4% of patients in the bicretiva group experienced ALT elevations exceeding 5 times the upper limit of normal, compared to 0.9% to 1.3% in the control group. These elevations were unrelated to clinical symptoms and generally did not require dose adjustment. Furthermore, no acute hepatocellular liver injury with jaundice occurred. The bicretiva product label states that adverse reactions such as acute exacerbation of hepatitis B and liver failure may occur upon discontinuation of bicretiva in combination with emtricitabine and tenofovir. This adverse reaction can occur upon discontinuation of any antiretroviral regimen with concurrent anti-hepatitis B virus activity; this is a combined effect of tenofovir and emtricitabine. However, since the approval and widespread use of bicretiva, no published clinical case reports have confirmed that bicretiva causes significant liver damage or acute exacerbations of hepatitis B.
Probability Score: E (Unproven but suspected potential cause of liver damage).

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Use during Pregnancy and Lactation
◉ Overview of Use during Lactation
Limited information suggests that pregnant women taking 50 mg bicretiva once daily have low drug concentrations in breast milk and infant serum. Until more data are available, especially during breastfeeding of newborns or preterm infants, alternative medications may be preferred. Achieving and maintaining viral suppression with antiretroviral therapy can reduce the risk of transmission through breastfeeding to below 1%, but not zero. This decision should be supported for HIV-infected individuals receiving antiretroviral therapy with a persistently low viral load who choose to breastfeed. If viral load is not suppressed, pasteurized donated breast milk or formula is recommended.
◉ Effects on breastfed infants
As of the revision date, no relevant published information was found.
◉ Effects on lactation and breast milk
Gynecomastia has been reported in men receiving highly active antiretroviral therapy. Gynecomastia is initially unilateral, but about half of the cases develop into bilateral gynecomastia. No changes in serum prolactin levels were observed, and it usually resolves spontaneously within one year even with continued treatment. Some case reports and in vitro studies suggest that protease inhibitors may cause hyperprolactinemia and galactorrhea in some male patients, but this conclusion remains controversial. The implications of these findings for lactating women are unclear. Prolactin levels in established lactating mothers may not affect their ability to breastfeed.

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Protein binding
>99% bound to human plasma plasma ratio: 0.64

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Bicotinavir (BIC) has low cytotoxicity in a variety of cell types. In resting human peripheral blood mononuclear cells (PBMCs), the CC50 was 8.4 μM; in activated PBMCs, the CC50 was 5.7 μM. [1]
BIC showed no cytotoxicity to non-target cell lines (including hepatocellular carcinoma cell lines (Huh7, HepG2), prostate cancer cell line (PC3), normal embryonic lung fibroblast cell line (MRC5), and primary human hepatocytes). [1]
BIC showed no antiviral activity against non-retroviral viruses (such as hepatitis B virus (HBV), hepatitis C virus (HCV), influenza virus, human rhinovirus, or respiratory syncytial virus (RSV)), indicating its selectivity for HIV. [1]

[1]. Antimicrob Agents Chemother.2016 Nov 21;60(12):7086-7097.

Bictegravir is a monocarboxylic acid amide formed by the condensation of the carboxyl group of (2R,5S,13aR)-8-hydroxy-7,9-dioxo-2,3,4,5,7,9,13,13a-octahydro-2,5-methylenepyrido[1',2':4,5]pyrazino[2,1-b][1,3]oxazapyro-10-carboxylic acid with the amino group of 2,4,6-trifluorobenzylamine. It is a second-generation integrase strand transfer inhibitor (INSTI) used (in its sodium salt form) for the treatment of HIV-1 infection. It is an HIV-1 integrase inhibitor. It is a monocarboxylic acid amide, secondary amide, trifluorobenzene, and organic heterotetracyclic compound. It is the conjugate acid of bicelavir (1-). Bictegravir is a recently approved investigational drug used in clinical trials investigating the treatment of HIV-1 and HIV-2 infections. It is approved for HIV-1 monotherapy and can be used in combination with two other antiretroviral drugs in the same tablet. Bictegravir is a human immunodeficiency virus (HIV) integrase strand transfer inhibitor, the fourth in its class of drugs targeting viral integrase. Bictegravir is used only in combination with other antiretroviral drugs to treat HIV infection, and its use is limited. The incidence of elevated serum transaminases during bicelavir treatment is low, but no cases of acute, clinically significant liver injury have been found. Bictegravir is a human immunodeficiency virus type 1 (HIV-1) integrase strand transfer inhibitor (INSTI) used to treat HIV infection. Oral bicelavir inhibits the strand transfer activity of HIV-1 integrase. HIV-1 integrase is an enzyme encoded by HIV-1 and is essential for viral replication. Inhibition of integrase prevents linear HIV-1 DNA from integrating into the host genomic DNA.

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Drug Indications
Bimetiravir is indicated for the treatment of HIV-1 infected patients who have not previously received antiretroviral therapy. Additionally, it is indicated for HIV-1 infected patients who are virologically suppressed (HIV-1 RNA <50 copies/mL) and have received standard antiretroviral therapy for at least three months, have no history of treatment failure, and have no known factors associated with resistance to the drug components. It is used in combination with tenofovir and emtricitabine.
FDA Label

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Mechanism of Action
This single-dose drug inhibits the transfer of viral DNA strands into the human genome, thereby preventing HIV-1 replication and transmission. In vitro studies have shown that bismetiravir has potent antiviral activity against HIV-2 and multiple HIV-1 subtypes. It can produce synergistic effects when used in combination with other antiretroviral drugs (ARVs), such as tenofovir alafenamide (TAF), emtricitabine (FTC), and darunavir (DRV). The first drug approved in the United States (trade name: Biktarvy) contains the following three components: Bictegravir: an integrase strand transfer inhibitor (INSTI), an enzyme encoded by HIV-1 essential for viral replication. Inhibition of integrase prevents HIV-1 from integrating into the host DNA, thereby blocking HIV-1 proviral conversion and viral progression [FDA label]. Emtricitabine (FTC) is phosphorylated by cellular enzymes to emtricitabine 5'-triphosphate. Emtricitabine is phosphorylated intracellularly to emtricitabine 5'-triphosphate. This metabolite inhibits the activity of human immunodeficiency virus (HIV) reverse transcriptase by competing with its substrate deoxycytidine 5'-triphosphate and incorporating into viral DNA to prevent DNA chain elongation [FDA label]. Tenofovir alafenamide (TAF) is a phosphonamide prodrug of tenofovir (a 2'-deoxyadenosine monophosphate analog). Upon plasma exposure to TAF, TAF leaks into cells and is then hydrolyzed intracellularly by cathepsins to tenofovir. Tenofovir is then phosphorylated by cellular kinases to produce the metabolite tenofovir disoproxil fumarate, which is the active form of the drug. Tenofovir disoproxil fumarate is incorporated into viral DNA via HIV reverse transcriptase, thereby inhibiting HIV-1 replication and causing DNA strand termination. Tenofovir disoproxil fumarate also has a weak inhibitory effect on mammalian DNA polymerase [FDA label].

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Bicotilavir (BIC) is a novel, potent, once-daily, no-boost HIV-1 integrase strand transfer inhibitor. [1]
BIC has a higher barrier to in vitro resistance development compared to raltelavin (RAL) and elvigravir (EVG), and is comparable to dolutegravir (DTG). [1]
In dose-escalation resistance selection experiments, BIC screened for HIV-1 variants with the M50I/R263K double mutation in the integrase, which showed only a 2.8-fold reduction in sensitivity to BIC. These variants exhibited low to moderate cross-resistance to other integrase inhibitors (INSTIs). [1] In viral breakthrough studies under sustained drug stress, BIC (similar to DTG) did not show viral breakthrough within 32 days, indicating a high resistance barrier. [1] Overall virological characteristics support clinical studies of its use in combination with other antiretroviral drugs in treatment-naïve and treatment-experienced HIV-infected patients. [1]

C21H18F3N3O5

449.37

449.119

C, 56.13; H, 4.04; F, 12.68; N, 9.35; O, 17.80

1611493-60-7

Bictegravir sodium;1807988-02-8;Bictegravir-15N,d2

90311989

Solid powder

1.62±0.1 g/cm3

682.5±55.0 °C at 760 mmHg

366.6±31.5 °C

0.0±2.2 mmHg at 25°C

1.664

-1.26

2

9

3

32

912

3

FC1C=C(C=C(C=1CNC(C1C(C(=C2C(N3[C@@H](CN2C=1)O[C@@H]1CC[C@H]3C1)=O)O)=O)=O)F)F

SOLUWJRYJLAZCX-LYOVBCGYSA-N

InChI=1S/C21H18F3N3O5/c22-9-3-14(23)12(15(24)4-9)6-25-20(30)13-7-26-8-16-27(10-1-2-11(5-10)32-16)21(31)17(26)19(29)18(13)28/h3-4,7,10-11,16,29H,1-2,5-6,8H2,(H,25,30)/t10-,11+,16+/m0/s1

(2R,5S,13aR)-8-hydroxy-7,9-dioxo-N-(2,4,6-trifluorobenzyl)-2,3,4,5,7,9,13,13a-octahydro-2,5-methanopyrido[1',2':4,5]pyrazino[2,1-b][1,3]oxazepine-10-carboxamide

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment (e.g. under nitrogen), avoid exposure to moisture and light.

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

DMSO : 83.3 ~90 mg/mL ( 185.37 ~200.27 mM）

Solubility in Formulation 1: ≥ 2.5 mg/mL (5.56 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 25.0 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: ≥ 2.5 mg/mL (5.56 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in 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 25.0 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: ≥ 2.5 mg/mL (5.56 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 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: ≥ 2.5 mg/mL (5.56 mM) (saturation unknown) in 5% DMSO + 95% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
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 5: 10% DMSO+40% PEG300+5% Tween-80+45% Saline: ≥ 2.5 mg/mL (5.56 mM)

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