chemistry

Ledipasvir

Ledipasvir is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Ledipasvir rather than just read about it. In short: Ledipasvir is a drug for the treatment of hepatitis C that was developed by Gilead Sciences. After completing Phase III clinical trials, on February 10, 2014, Gilead filed for U.S. approval of a ledipasvir/sofosbuvir fixed-dose combination tablet for genotype 1 hepatitis C.

Key takeaways

Ledipasvir belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Ledipasvir to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Ledipasvir from memory before moving on to harder problems.

Reference excerpt

Ledipasvir is a drug for the treatment of hepatitis C that was developed by Gilead Sciences. After completing Phase III clinical trials, on February 10, 2014, Gilead filed for U.S. approval of a ledipasvir/sofosbuvir fixed-dose combination 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. Ledipasvir is an inhibitor of NS5A, a hepatitis C virus protein. 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. 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. 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-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, NS5A, which is involved in viral replication, assembly, and secretion. 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.

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.

See also Discovery and development of NS5A inhibitors

References

Worked examples

Example 1 — a first encounter with Ledipasvir

Start with the simplest possible case. Write down what Ledipasvir claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Ledipasvir before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Ledipasvir ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Ledipasvir

In research: Ledipasvir appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Ledipasvir in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Ledipasvir is common in secondary-school and first-year university syllabi. It links to neighbouring topics Benzimidazoles, Carbamates, Cyclopropanes, so understanding it makes those chapters shorter.
In everyday life: Look for Ledipasvir outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Ledipasvir in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Ledipasvir means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Ledipasvir out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Ledipasvir in simple terms?

Why does Ledipasvir matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Ledipasvir?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Ledipasvir.