Data presented at the 20th Conference on Retroviruses and Opportunistic Infections in March 2013 showed that a triple regimen of the nucleotide analog inhibitor sofosbuvir, ledipasvir, and ribavirin 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.[4][5] The sofosbuvir/ledipasvir coformulation is being tested with and without ribavirin. In February 2014 Gilead filed for United States Food and Drug Administration (FDA) approval of ledipasvir/sofosbuvir oral treatment, without interferon and ribavirin.[6]
On 10 October 2014 the FDA approved the combination product ledipasvir/sofosbuvir called Harvoni.[7]
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.[8]
Adverse effects
According to clinical trials, ledipasvir/sofosbuvir has been very well tolerated with the most common side effects being fatigue and headache.[9]
Interactions
Most drug-drug interactions with Harvoni involve Pgp-inducers such as St. John’s wort or rifampicin. Concomitant use will decrease the blood concentration of Harvoni and thus, have reduced therapeutic effects.[9]
Mechanism of action
Ledipasvir inhibits an important viral phosphoprotein, NS5A, which is involved in viral replication, assembly, and secretion.[10]
Sofosbuvir, on the other hand, is metabolized to a uridine triphosphate mimic, which acts as a RNA chain terminator when incorporated into RNA by NS5B polymerase.[10]
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.[10]
In July 2015 Gilead modified the eligibility criteria to receive Support Path benefits for HCV patients in the United States.[citation needed]