Bulevirtide targets the sodium taurocholate cotransporting polypeptide (NTCP), a receptor on the surface of hepatocytes that mediates the entry of hepatitis B virus (HBV) and hepatitis D virus (HDV) into liver cells. Bulevirtide acts as a NTCP inhibitor, blocking HBV and HDV entry into hepatocytes. It also participates in HBV transcriptional suppression.

In vitro, Bulevirtide inhibits HBV and HDV entry into liver cells and blocks HBV infection in hepatocytes. It exhibits strong inhibitory activity against hepatitis delta virus (HDV). The compound is a highly specialized peptide that mimics and competitively inhibits specific viral entry mechanisms at the cellular membrane.

In vivo, Bulevirtide is approved for the treatment of chronic hepatitis D virus (HDV) infection in adults with compensated liver disease. It can be used in HDV infection and compensated cirrhosis research. The compound reduces HDV RNA levels and improves liver function in patients with chronic HDV infection.

The in vitro assay for Bulevirtide involves measuring its inhibition of HBV and HDV entry into hepatocytes. Primary human hepatocytes or HepG2-NTCP cells are infected with HBV or HDV in the presence of varying concentrations of Bulevirtide. Viral entry is assessed by measuring viral antigens (e.g., HBsAg) or viral RNA by ELISA or RT-qPCR.

Cellular assays for Bulevirtide are performed using hepatocyte cell lines expressing NTCP. Cells are treated with Bulevirtide and infected with HBV or HDV. Viral replication is assessed by measuring viral markers. The compound's ability to block viral entry and infection is determined from dose-response curves.

In vivo animal studies for Bulevirtide are not detailed in the available sources. The compound is an approved drug for chronic HDV infection. Preclinical studies would have been conducted in animal models of HBV/HDV infection. Clinical trials have been conducted in patients with chronic HDV infection.

Absorption, Distribution and Excretion
Limited pharmacokinetic data on brevivitide in humans are available in the literature. In rats, brevivitide is rapidly absorbed after subcutaneous injection, with peak plasma concentration (Cmax) occurring in 4 to 6 hours. The estimated bioavailability in humans is 85%, and steady-state plasma concentrations are expected to be reached within weeks of initiation of treatment. Following subcutaneous injection of 2 mg brevivitide, its AUC is approximately 46 ng/ml·h, with a time to peak concentration (Tmax) of 0.5 hours. The primary route of excretion of brevivitide is expected to be via target binding (NTCP). No urinary excretion of brevivitide has been observed in healthy volunteers. The volume of distribution of brevivitide is estimated to be less than the total body fluid volume. In animals, brevivitide is distributed in the liver, gastrointestinal tract, kidneys, and bladder.
Following subcutaneous injection of breviptide in healthy volunteers, its clearance rate (CL/F) ranged from 7.98 L/h (±2.02) to 62 L/h (±16.7), depending on the dose. The clearance rate of breviptide decreased with increasing dose.
Metabolism/Metabolites
To date, no metabolic studies of breviptide have been conducted. It is expected that breviptide is primarily metabolized by peptidase into smaller peptides and amino acids, without producing active metabolites.
Biological Half-Life
The half-life of breviptide in healthy adults is 4 to 7 hours.
Bulevirtide is administered subcutaneously. As a lipopeptide, it has a molecular weight of approximately 5398.86 kDa. The compound is soluble in DMSO. Specific PK parameters such as half-life, bioavailability, and clearance are available in the clinical literature but are not detailed in the supplier documentation.

Protein Binding
Breviptide has a plasma protein binding rate of >99%, primarily binding to albumin.
Bulevirtide is generally well-tolerated. Common side effects may include injection site reactions, headache, and gastrointestinal disturbances. The compound is contraindicated in patients with decompensated liver disease. Specific toxicological data are available in the clinical literature.

[1]. Bulevirtide for treatment of patients with HDV infection and compensated cirrhosis: A (huge) step in the right direction. Liver Int. 2021 Jul;41(7):1441-1442.

[2]. Clinical effects of NTCP-inhibitor myrcludex B. J Viral Hepat. 2021 Jun;28(6):852-858.

[3]. Drugs Today (Barc). 2021 Jul;57(7):433-448. doi: 10.1358/dot.2021.57.7.3283861.

Hepatitis D is considered the most severe type of viral hepatitis, leading to rapid progression of cirrhosis, severe liver decompensation, and increased risk of death. Until recently, treatment options for hepatitis D remained very limited. Bulevirtide, also known as Hepcludex, is a first-in-class entry inhibitor developed by MYR Pharmaceuticals (now Gilead Sciences) for the treatment of chronic hepatitis D infection. It was first approved for marketing in the European Union on May 28, 2020; brilevitide has received PRIME program designation and orphan drug designation from the European Medicines Agency. In the United States, brilevitide has received orphan drug designation and breakthrough therapy designation. Due to the potential synergistic effect of brilevitide in treating chronic hepatitis D, the Phase IIb clinical trial NCT03852433 (brilevitide in combination with pegylated interferon alpha-2a for the treatment of patients with chronic liver disease) is currently underway. This clinical trial is expected to be completed in early 2023. Drug Indications Bleeviride is indicated for the treatment of adult patients with compensated liver disease and positive HDV-RNA for chronic hepatitis D infection. Hepcludex is indicated for the treatment of adult patients with compensated liver disease and positive plasma (or serum) HDV-RNA for chronic hepatitis D virus (HDV) infection. Mechanism of Action Non-Taurocholate cotransport polypeptide (NTCP) is responsible for transporting bile acids in sodium form from the portal circulation to the liver. It is an important component of the enterohepatic circulation. Hepatitis D virus can replicate independently within hepatocytes, but requires hepatitis B surface antigen (HBsAg) for proliferation. Both hepatitis B virus and hepatitis D virus enter hepatocytes via the binding of the sodium/taurocholate cotransport polypeptide (NTCP) to the preS1 surface protein domain of hepatitis B virus. Brabiviride binds to and inactivates hepatitis B virus (HBV) and hepatitis D virus (HDV) receptors on hepatocytes. Brabiviride blocks the NTCP binding site, thereby preventing viral entry into cells. This prevents viral entry and replication, alleviating symptoms of hepatitis D infection.

---

Pharmacodynamics
Bribiviride prevents hepatitis D virus from entering cells. It effectively reduces hepatitis D virus (HDV) RNA levels and improves liver inflammation caused by hepatitis D infection.
Bulevirtide is an FDA-approved drug for the treatment of chronic hepatitis D virus (HDV) infection in adults with compensated liver disease. It is marketed under the brand name Hepcludex. The compound is a first-in-class NTCP inhibitor that blocks viral entry into hepatocytes. It is also available from chemical suppliers for research purposes.

C234H329N65O71

5398.86

5397.618

2012558-47-1

134687648

White to off-white solid powder

-16.7

65

76

166

385

14300

44

CCCCCCCCCCCCCC(=O)NCC(=O)N[C@@H]([C@@H](C)O)C(=O)N[C@@H](CC(=O)N)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CO)C(=O)N[C@@H](C(C)C)C(=O)N1CCC[C@H]1C(=O)N[C@@H](CC(=O)N)C(=O)N2CCC[C@H]2C(=O)N[C@@H](CC(C)C)C(=O)NCC(=O)N[C@@H](CC3=CC=CC=C3)C(=O)N[C@@H](CC4=CC=CC=C4)C(=O)N5CCC[C@H]5C(=O)N[C@@H](CC(=O)O)C(=O)N[C@@H](CC6=CNC=N6)C(=O)N[C@@H](CCC(=O)N)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CC(=O)O)C(=O)N7CCC[C@H]7C(=O)N[C@@H](C)C(=O)N[C@@H](CC8=CC=CC=C8)C(=O)NCC(=O)N[C@@H](C)C(=O)N[C@@H](CC(=O)N)C(=O)N[C@@H](CO)C(=O)N[C@@H](CC(=O)N)C(=O)N[C@@H](CC(=O)N)C(=O)N9CCC[C@H]9C(=O)N[C@@H](CC(=O)O)C(=O)N[C@@H](CC1=CNC2=CC=CC=C21)C(=O)N[C@@H](CC(=O)O)C(=O)N[C@@H](CC1=CC=CC=C1)C(=O)N[C@@H](CC(=O)N)C(=O)N1CCC[C@H]1C(=O)N[C@@H](CC(=O)N)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CC(=O)O)C(=O)N[C@@H](CC1=CNC=N1)C(=O)N[C@@H](CC1=CNC2=CC=CC=C21)C(=O)N1CCC[C@H]1C(=O)N[C@@H](CCC(=O)O)C(=O)N[C@@H](C)C(=O)N[C@@H](CC(=O)N)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](C(C)C)C(=O)NCC(=O)N

WQNDXLHKAMIGEX-WOAPPVHJSA-N

InChI=1S/C248H355N65O72/c1-16-17-18-19-20-21-22-23-24-25-38-75-193(327)265-118-196(330)304-205(133(15)316)241(378)295-163(104-188(256)322)224(361)283-152(91-127(6)7)216(353)303-175(122-315)232(369)306-204(129(10)11)248(385)313-88-53-74-182(313)239(376)301-172(107-191(259)325)246(383)312-87-50-70-178(312)235(372)291-150(89-125(2)3)209(346)268-120-195(329)274-154(93-135-56-32-27-33-57-135)217(354)296-168(95-137-60-36-29-37-61-137)242(379)308-83-49-72-180(308)237(374)294-167(111-201(339)340)230(367)286-157(98-140-115-261-123-269-140)220(357)277-148(76-78-183(251)317)213(350)282-151(90-126(4)5)215(352)300-173(112-202(341)342)247(384)307-82-47-68-176(307)233(370)273-132(14)208(345)279-153(92-134-54-30-26-31-55-134)210(347)267-119-194(328)271-130(12)206(343)280-160(101-185(253)319)226(363)302-174(121-314)231(368)288-161(102-186(254)320)225(362)299-171(106-190(258)324)245(382)311-86-52-73-181(311)238(375)293-166(110-200(337)338)229(366)285-156(96-138-113-263-144-64-41-39-62-142(138)144)219(356)290-165(109-199(335)336)227(364)284-155(94-136-58-34-28-35-59-136)218(355)298-170(105-189(257)323)244(381)310-85-51-71-179(310)236(373)292-162(103-187(255)321)223(360)275-146(66-43-45-80-249)212(349)289-164(108-198(333)334)228(365)287-158(99-141-116-262-124-270-141)221(358)297-169(97-139-114-264-145-65-42-40-63-143(139)145)243(380)309-84-48-69-177(309)234(371)278-149(77-79-197(331)332)211(348)272-131(13)207(344)281-159(100-184(252)318)222(359)276-147(67-44-46-81-250)214(351)305-203(128(8)9)240(377)266-117-192(260)326/h26-37,39-42,54-65,113-116,123-133,146-182,203-205,263-264,314-316H,16-25,38,43-53,66-112,117-122,249-250H2,1-15H3,(H2,251,317)(H2,252,318)(H2,253,319)(H2,254,320)(H2,255,321)(H2,256,322)(H2,257,323)(H2,258,324)(H2,259,325)(H2,260,326)(H,261,269)(H,262,270)(H,265,327)(H,266,377)(H,267,347)(H,268,346)(H,271,328)(H,272,348)(H,273,370)(H,274,329)(H,275,360)(H,276,359)(H,277,357)(H,278,371)(H,279,345)(H,280,343)(H,281,344)(H,282,350)(H,283,361)(H,284,364)(H,285,366)(H,286,367)(H,287,365)(H,288,368)(H,289,349)(H,290,356)(H,291,372)(H,292,373)(H,293,375)(H,294,374)(H,295,378)(H,296,354)(H,297,358)(H,298,355)(H,299,362)(H,300,352)(H,301,376)(H,302,363)(H,303,353)(H,304,330)(H,305,351)(H,306,369)(H,331,332)(H,333,334)(H,335,336)(H,337,338)(H,339,340)(H,341,342)/t130-,131-,132-,133+,146-,147-,148-,149-,150-,151-,152-,153-,154-,155-,156-,157-,158-,159-,160-,161-,162-,163-,164-,165-,166-,167-,168-,169-,170-,171-,172-,173-,174-,175-,176-,177-,178-,179-,180-,181-,182-,203-,204-,205-/m0/s1

(4S)-4-[[(2S)-1-[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-6-amino-2-[[(2S)-4-amino-2-[[(2S)-1-[(2S)-4-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-1-[(2S)-4-amino-2-[[(2S)-4-amino-2-[[(2S)-2-[[(2S)-4-amino-2-[[(2S)-2-[[2-[[(2S)-2-[[(2S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-[[(2S)-5-amino-2-[[(2S)-2-[[(2S)-2-[[(2S)-1-[(2S)-2-[[(2S)-2-[[2-[[(2S)-2-[[(2S)-1-[(2S)-4-amino-2-[[(2S)-1-[(2S)-2-[[(2S)-2-[[(2S)-2-[[(2S)-4-amino-2-[[(2S,3R)-3-hydroxy-2-[[2-(tetradecanoylamino)acetyl]amino]butanoyl]amino]-4-oxobutanoyl]amino]-4-methylpentanoyl]amino]-3-hydroxypropanoyl]amino]-3-methylbutanoyl]pyrrolidine-2-carbonyl]amino]-4-oxobutanoyl]pyrrolidine-2-carbonyl]amino]-4-methylpentanoyl]amino]acetyl]amino]-3-phenylpropanoyl]amino]-3-phenylpropanoyl]pyrrolidine-2-carbonyl]amino]-3-carboxypropanoyl]amino]-3-(1H-imidazol-4-yl)propanoyl]amino]-5-oxopentanoyl]amino]-4-methylpentanoyl]amino]-3-carboxypropanoyl]pyrrolidine-2-carbonyl]amino]propanoyl]amino]-3-phenylpropanoyl]amino]acetyl]amino]propanoyl]amino]-4-oxobutanoyl]amino]-3-hydroxypropanoyl]amino]-4-oxobutanoyl]amino]-4-oxobutanoyl]pyrrolidine-2-carbonyl]amino]-3-carboxypropanoyl]amino]-3-(1H-indol-3-yl)propanoyl]amino]-3-carboxypropanoyl]amino]-3-phenylpropanoyl]amino]-4-oxobutanoyl]pyrrolidine-2-carbonyl]amino]-4-oxobutanoyl]amino]hexanoyl]amino]-3-carboxypropanoyl]amino]-3-(1H-imidazol-4-yl)propanoyl]amino]-3-(1H-indol-3-yl)propanoyl]pyrrolidine-2-carbonyl]amino]-5-[[(2S)-1-[[(2S)-4-amino-1-[[(2S)-6-amino-1-[[(2S)-1-[(2-amino-2-oxoethyl)amino]-3-methyl-1-oxobutan-2-yl]amino]-1-oxohexan-2-yl]amino]-1,4-dioxobutan-2-yl]amino]-1-oxopropan-2-yl]amino]-5-oxopentanoic acid

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 : ~50 mg/mL (~9.26 mM)

Solubility in Formulation 1: 2.5 mg/mL (0.46 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 sonication.
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.

---

Solubility in Formulation 2: ≥ 2.5 mg/mL (0.46 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.

---

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