Ledipasvir is a drug for the treatment of

hepatitis C Hepatitis C is an infectious disease caused by the hepatitis C virus (HCV) that primarily affects the liver; it is a type of viral hepatitis. During the initial infection people often have mild or no symptoms. Occasionally a fever, dark urine, a ...

that was developed by

Gilead Sciences Gilead Sciences, Inc. () is an American biopharmaceutical company headquartered in Foster City, California, that focuses on researching and developing antiviral drugs used in the treatment of HIV/AIDS, hepatitis B, hepatitis C, influenza, and C ...

. After completing

Phase III clinical trials The phases of clinical research are the stages in which scientists conduct experiments with a health intervention to obtain sufficient evidence for a process considered effective as a medical treatment. For drug development, the clinical phases ...

, on February 10, 2014, Gilead filed for U.S. approval of a

ledipasvir/sofosbuvir Ledipasvir/sofosbuvir, sold under the trade name Harvoni among others, is a medication used to treat hepatitis C. It is a fixed-dose combination of ledipasvir and sofosbuvir. Cure rates are 94% to 99% in people infected with hepatitis C virus ...

fixed-dose combination A combination drug or a fixed-dose combination (FDC) is a medicine that includes two or more active ingredients combined in a single dosage form. Terms like "combination drug" or "combination drug product" can be common shorthand for a FDC pr ...

tablet for genotype 1 hepatitis C. The ledipasvir/sofosbuvir combination is a direct-acting antiviral agent that interferes with HCV replication and can be used to treat patients with genotypes 1a or 1b without PEG-interferon or

ribavirin Ribavirin, also known as tribavirin, is an antiviral medication used to treat RSV infection, hepatitis C and some viral hemorrhagic fevers. For hepatitis C, it is used in combination with other medications such as simeprevir, sofosbuvir, pe ...

. Ledipasvir is an inhibitor of

NS5A Nonstructural protein 5A (NS5A) is a zinc-binding and proline-rich hydrophilic phosphoprotein that plays a key role in Hepatitis C virus RNA replication. It appears to be a dimeric form without ''trans''-membrane helices. Structure NS5A is deriv ...

, a

hepatitis C virus The hepatitis C virus (HCV) is a small (55–65 nm in size), enveloped, positive-sense single-stranded RNA virus of the family ''Flaviviridae''. The hepatitis C virus is the cause of hepatitis C and some cancers such as liver cancer ( hepato ...

protein. Data presented at the 20th Conference on Retroviruses and Opportunistic Infections in March 2013 showed that a triple regimen of the nucleotide

analog Analog or analogue may refer to: Computing and electronics * Analog signal, in which information is encoded in a continuous variable ** Analog device, an apparatus that operates on analog signals *** Analog electronics, circuits which use analog ...

inhibitor sofosbuvir, ledipasvir, and

produced a 12-week post-treatment sustained virological response (SVR12) rate of 100% for both treatment-naive patients and prior non-responders with HCV genotype 1. The sofosbuvir/ledipasvir coformulation is being tested with and without ribavirin. In February 2014 Gilead filed for United States

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a List of United States federal agencies, federal agency of the United States Department of Health and Human Services, Department of Health and Human Services. The FDA is respon ...

(FDA) approval of ledipasvir/sofosbuvir oral treatment, without interferon and ribavirin. On 10 October 2014 the FDA approved the combination product ledipasvir/sofosbuvir called ''Harvoni''.

Medical uses

Ledipasvir is most commonly used in combination with sofosbuvir for treatment in chronic hepatitis C genotype 1 patients. This drug has been tested and shown efficacy in treatment-naive and treatment experienced patients.

Adverse effects

According to clinical trials, ledipasvir/sofosbuvir has been very well tolerated with the most common side effects being fatigue and headache.

Interactions

Most drug-drug interactions with Harvoni involve

Pgp PGP or Pgp may refer to: Science and technology * P-glycoprotein, a type of protein * Pelvic girdle pain, a pregnancy discomfort * Personal Genome Project, to sequence genomes and medical records * Pretty Good Privacy, a computer program for the ...

-inducers such as St. John’s wort or rifampicin. Concomitant use will decrease the blood concentration of Harvoni and thus, have reduced therapeutic effects.

Mechanism of action

Ledipasvir inhibits an important viral phosphoprotein,

, which is involved in viral replication, assembly, and secretion. Sofosbuvir, on the other hand, is metabolized to a

uridine Uridine (symbol U or Urd) is a glycosylated pyrimidine analog containing uracil attached to a ribose ring (or more specifically, a ribofuranose) via a β-N1-glycosidic bond. The analog is one of the five standard nucleosides which make up nuclei ...

triphosphate mimic, which acts as a

RNA Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid ( DNA) are nucleic acids. Along with lipids, proteins, and carbohydra ...

chain terminator when incorporated into RNA by

NS5B Nonstructural protein 5B (NS5B) is a viral protein found in the hepatitis C virus (HCV). It is an RNA-dependent RNA polymerase, having the key function of replicating HCV's viral RNA by using the viral positive RNA strand as a template to catalyze ...

polymerase.

Cost

Similar to sofosbuvir, the cost of Harvoni has been a controversial topic. It costs $1,125 per pill in the US, translating to $63,000 for an 8-week treatment course, $94,500 for a 12-week treatment course, or $189,000 for a 24-week treatment course. Gilead justifies the cost by outweighing the benefit of curing hepatitis C over the cost of spending double on liver transplants or temporarily treating liver diseases. Gilead has provided a ledipasvir/sofosbuvir assistance program for eligible underserved or underinsured hepatitis C patients who cannot afford the costs of treatment. In July 2015 Gilead modified the eligibility criteria to receive Support Path benefits for HCV patients in the United States.

References