HARVONI TABLET 90MG/400MG

Product Information

Registration Status: Active

HARVONI TABLET 90MG/400MG is approved to be sold in Singapore with effective from 2016-01-13. It is marketed by GILEAD SCIENCES SINGAPORE PTE LTD, with the registration number of SIN14920P.

This product contains LEDIPASVIR 90mg, and SOFOSBUVIR 400mg in the form of TABLET, FILM-COATED. It is approved for ORAL use.

This product is manufactured by Patheon Inc. in UNITED STATES,Gilead Sciences Ireland UC in CANADA,Gilead Sciences in IRELAND, and Inc. (Primary and secondary packager) in PORTUGAL.

It is a Prescription Only Medicine that can only be obtained from a doctor or a dentist, or a pharmacist with a prescription from a Singapore-registered doctor or dentist.

LEDIPASVIR
SOFOSBUVIR

Description

Ledipasvir is a direct acting antiviral (DAA) medication used as part of combination therapy to treat chronic Hepatitis C, an infectious liver disease caused by infection with Hepatitis C Virus (HCV). HCV is a single-stranded RNA virus that is categorized into nine distinct genotypes, with genotype 1 being the most common in the United States, and affecting 72% of all chronic HCV patients [L852]. Treatment options for chronic Hepatitis C have advanced significantly since 2011, with the development of Direct Acting Antivirals (DAAs) such as ledipasvir. More specifically, ledipasvir is an inhibitor of the Hepatitis C Virus (HCV) Non-Structural Protein 5A (NS5A), which is required for viral RNA replication and assembly of HCV virions. Although its exact mechanism of action is unknown, it is postulated to prevent hyperphosphorylation of NS5A which is required for viral protein production. It is effective against genotypes 1a, 1b, 4a, and 5a and with a lesser activity against genotypes 2a and 3a of HCV. Ledipasvir and other direct acting antivirals are very potent options for the treatment of Hepatitis C, as they exhibit a high barrier to the development of resistance [A19593]. This is an important advantage relative to HCV drugs that target other viral enzymes such as the protease, for which rapid development of resistance has proven to be an important cause of therapeutic failure. In a joint recommendation published in 2016, the American Association for the Study of Liver Diseases (AASLD) and the Infectious Diseases Society of America (IDSA) recommend ledipasvir as a first line therapy option in combination with [DB08934] for the treatment of HCV genotypes 1a, 1b, 4, 5, and 6 [L852]. Treatment with ledipasvir is used with the intent to cure, or achieve a sustained virologic response (SVR), after 12 weeks of daily therapy. SVR and eradication of HCV infection is associated with significant long-term health benefits including reduced liver-related damage, improved quality of life, reduced incidence of Hepatocellular Carcinoma, and reduced all-cause mortality [A19626]. Treatment with direct acting antivirals such as ledipasvir is associated with very minimal side effects, with the most common being headache and fatigue [FDA Label]. Lack of significant side effects and short duration of therapy is a considerable advantage over older interferon- and ribavirin-based regimens, which were limited by infusion site reactions, reduced blood count, and neuropsychiatric effects [A19635]. Since 2014, ledipasvir has been available as a fixed dose combination product with [DB08934] (tradename Harvoni) used for the treatment of chronic Hepatitis C. Approved in October 2014 by the FDA, Harvoni is indicated for the treatment of HCV genotypes 1, 4, 5, and 6 with or without [DB00811] depending on the level of liver damage or cirrhosis [FDA Label]. When combined together, ledipasvir and sofosbuvir as the combination product Harvoni has been shown to achieve a SVR between 93 and 99% after 12 weeks of treatment [FDA Label]. Its use has also proven successful in the treatment of HCV in patients co-infected with HIV [A19627].

Indication

When used in combination with the antiviral medication [DB08934] as the commercially available product Harvoni, ledipasvir is indicated for the treatment of HCV genotypes 1, 4, 5, and 6 with or without [DB00811] depending on the level of liver damage or cirrhosis [FDA Label]. Its use has also proven successful in the treatment of HCV in patients co-infected with HIV [A19627].

Mechanism of Action

Ledipasvir is an inhibitor of the Hepatitis C Virus (HCV) NS5A protein required for viral RNA replication and assembly of HCV virions. Although its exact mechanism of action is unknown, it is postulated to prevent hyperphosphorylation of NS5A which is required for viral production.

Pharmacokinetics

Absorption
When given orally, ledipasvir reaches its maximum plasma concentration in about 4 to 4.5 hours with a maximum concentration (Cmax) of 323 ng/mL [FDA Label].
Distribution
Metabolism
In vitro, no detectable metabolism of ledipasvir was observed by human CYP1A2, CYP2C8, CYP2C9, CYP2C19, CYP2D6, and CYP3A4. Evidence of slow oxidative metabolism via an unknown mechanism has been observed. Following a single dose of 90 mg [14C]-ledipasvir, systemic exposure was almost exclusively to the parent drug (>98%). Unchanged ledipasvir is the major species present in feces [FDA Label].
Elimination

Toxicity

There is very little toxicity associated with the use of ledipasvir in combination products. The most common adverse reactions are headache and fatigue.

Active Ingredient/Synonyms

methyl [(2S)-1-{(6S)-6-[4-(9,9-difluoro-7-{2-[(1R,3S,4S)-2-{(2S)-2-[(methoxycarbonyl)amino]-3-methylbutanoyl}-2-azabicyclo[2.2.1]hept-3-yl]-1H-benzimidazol-5-yl}-9H-fluoren-2-yl)-1H-imidazol-2-yl]-5-azaspiro[2.4]hept-5-yl}-3-methyl-1-oxobutan-2-yl]carbamate | Ledipasvir |


Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.


Description

Sofosbuvir (tradename Sovaldi) is a direct acting antiviral medication used as part of combination therapy to treat chronic Hepatitis C, an infectious liver disease caused by infection with Hepatitis C Virus (HCV). HCV is a single-stranded RNA virus that is categorized into nine distinct genotypes, with genotype 1 being the most common in the United States, and affecting 72% of all chronic HCV patients [L852]. Treatment options for chronic Hepatitis C have advanced significantly since 2011, with the development of Direct Acting Antivirals (DAAs) such as sofosbuvir. As a prodrug nucleotide analog, Sofosbuvir is metabolized into its active form as the antiviral agent 2'-deoxy-2'-α-fluoro-β-C-methyluridine-5'-triphosphate (also known as GS-461203), which acts as a defective substrate for NS5B (non-structural protein 5B) [synthesis]. NS5B, an RNA-dependent RNA polymerase, is essential for the transcription of Hepatitis C viral RNA and for its high replicative rate and genetic diversity [A19594]. Sofosbuvir and other direct acting antivirals are therefore very potent options for the treatment of Hepatitis C, as they exhibit a high barrier to the development of resistance [A19593]. This is an important advantage relative to HCV drugs that target other viral enzymes such as the protease, for which rapid development of resistance has proven to be an important cause of therapeutic failure. In a joint recommendation published in 2016, the American Association for the Study of Liver Diseases (AASLD) and the Infectious Diseases Society of America (IDSA) recommend Sofosbuvir as first line therapy in combination with other antivirals for all six genotypes of Hepatitis C [L852]. Depending on the genotype, sofosbuvir is often used in combination with other antivirals such as [DB09027], [DB11613], [DB09102], [DB06290], [DB11574], [DB11575], [DB00811], [DB00008], or [DB00022] with the intent to cure, or achieve a sustained virologic response (SVR), after 12 weeks of daily therapy. SVR and eradication of HCV infection is associated with significant long-term health benefits including reduced liver-related damage, improved quality of life, reduced incidence of Hepatocellular Carcinoma, and reduced all-cause mortality [A19626]. Treatment with direct acting antivirals such as sofosbuvir is associated with very minimal side effects, with the most common being headache and fatigue [FDA Label]. Lack of significant side effects and short duration of therapy is a considerable advantage over older interferon- and ribavirin-based regimens, which were limited by infusion site reactions, reduced blood count, and neuropsychiatric effects [A19635]. Since 2014, sofosbuvir has been available as a fixed dose combination product with [DB09027] (tradename Harvoni) used for the treatment of chronic Hepatitis C. Approved in October 2014 by the FDA, Harvoni is indicated for the treatment of HCV genotypes 1, 4, 5, and 6 with or without [DB00811] depending on the level of liver damage or cirrhosis [FDA Label]. When combined together, ledipasvir and sofosbuvir as the combination product Harvoni has been shown to achieve a SVR between 93 and 99% after 12 weeks of treatment [A7535]. Its use has also proven successful in the treatment of HCV in patients co-infected with HIV [A19627]. Sofosbuvir is also available as a fixed dose combination product with [DB11613] as the commercially available product Epclusa. First approved in June 2016, Epclusa is the first combination HCV product indicated for the treatment of all genotypes of Hepatitis C with or without cirrhosis. Epclusa is also currently the most potent HCV antiviral medication on the market with a sustained virologic response (SVR) after 12 weeks of therapy of 93-99% depending on genotype and level of cirrhosis [L852]. Both Canadian and American guidelines list Epclusa as a first line recommendation for all genotypes of HCV [L852, A19626]. Notably, sofosbuvir has come under intense scrutiny since its release to market in 2013. With the price per pill set at $1000, a 12-week treatment can cost upwards of $84,000 per patient [A19636].

Indication

Sofosbuvir is used in combination therapy with other antiviral medications to treat chronic hepatitis C virus (HCV) infected patients with HCV genoptypes 1-6, and to treat HCV and HIV co-infected patients. Depending on the level of cirrhosis or decompensation, combination therapy can also include either ribavirin alone or ribavirin and peg-interferon alfa. When used in combination with [DB09027] as the combination product Harvoni, sofosbuvir has the following indications: treatment of genotypes 1, 4, 5, or 6 infection without cirrhosis or with compensated cirrhosis; in combination with [DB00811] for genotype 1 infection with decompensated cirrhosis; or in combination with [DB00811] for the treatment of genotype 1 or 4 infection who are liver transplant recipients without cirrhosis or with compensated cirrhosis. When used in combination with [DB11613] as the combination product Epclusa, sofosbuvir is indicated for the treatment of adult patients with chronic hepatitis C virus (HCV) genotypes 1, 2, 3, 4, 5, or 6 infection without cirrhosis or with compensated cirrhosis, or in combination with [DB00811] if associated with decompensated cirrhosis. Resistance: Reduced susceptibility to sofosbuvir has been associated with the NS5B substitution mutation S282T [A19634].

Mechanism of Action

Sofosbuvir is nucleotide analog inhibitor, which specifically inhibits HCV NS5B (non-structural protein 5B) RNA-dependent RNA polymerase. Following intracellular metabolism to form the pharmacologically active uridine analog triphosphate (GS-461203), sofosbuvir incorporates into HCV RNA by the NS5B polymerase and acts as a chain terminator [synthesis, A7533]. More specifically, Sofosbuvir prevents HCV viral replication by binding to the two Mg2+ ions present in HCV NS5B polymerase's GDD active site motif and preventing further replication of HCV genetic material [A19638, FDA Label].

Pharmacokinetics

Absorption
When given orally, sofosbuvir reaches its maximum plasma concentration in about 0.5 to 2 hours with a maximal concentration (Cmax) of 567 ng/mL [FDA Label].
Distribution
The volume of distribution for sofosbuvir has yet to be determined [FDA Label].
Metabolism
In vitro studies in human liver microsomes showed that sofosbuvir was an efficient substrate for Cathepsin A (Cat A) and carboxyl esterase 1 (CES1). Sofosbuvir was cleaved by CatA and CES1 and subsequent activation steps included amino acid removal by histidine triad nucleotide-binding protein 1 (HINT1) and phosphorylation by uridine monophosphate-cytidine monophosphate (UMP-CMP) kinase and nucleoside diphosphate (NDP) kinase. In vitro data indicated that Cat A preferentially hydrolysed sofosbuvir (the S-diastereomer) while CES1 did not exhibit stereoselectivity [A19628, A19631].
Elimination

Clearance

The clearance of sofosbuvir has yet to be determined [FDA Label].

Toxicity

Sofosbuvir, as a single agent, has very mild toxicity. The most common adverse reactions are headache and fatigue. The FDA Label currently warns of a risk of symptomatic bradycardia when Epclusa is used in combination with amiodarone [FDA Label].

Active Ingredient/Synonyms

S)-Isopropyl 2-((S)-(((2R,3R,4R,5R)-5-(2,4-dioxo-3,4- dihydropyrimidin-1(2H)-yl)-4-fluoro-3-hydroxy-4-methyltetrahydrofuran-2-yl)methoxy)- (phenoxy)phosphorylamino)propanoate | Sofosbuvir |


Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.

References

  1. Health Science Authority of Singapore - Reclassified POM
  2. Drugbank