chemistry

Narlaprevir

Narlaprevir 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 Narlaprevir rather than just read about it. In short: Narlaprevir (trade name Arlansa, codenamed SCH 900518), is an inhibitor of NS3/4A serine protease, intended for the treatment of chronic hepatitis C caused by genotype 1 virus in combination with other antiviral drugs. Narlaprevir is the first Russian tableted medication for the treatment of chronic hepatitis C.

Key takeaways

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

Reference excerpt

Narlaprevir (trade name Arlansa, codenamed SCH 900518), is an inhibitor of NS3/4A serine protease, intended for the treatment of chronic hepatitis C caused by genotype 1 virus in combination with other antiviral drugs. Narlaprevir is the first Russian tableted medication for the treatment of chronic hepatitis C.

Mechanism of action Narlaprevir is an oral NS3 serine protease inhibitor of hepatitis C virus. It inhibits viral replication in infected host cells. The mechanism of inhibition involves reversible covalent binding of narlaprevir with NS3 protease active site via the ketoamide functional group. Narlaprevir does not bind to human proteases, with the exception of cathepsin B (69% inhibition). Overexpression of cathepsin B is associated with the development of malignancies.

Usage Indications Treatment of chronic hepatitis C virus (HCV) infection genotype 1 in combination with ritonavir, pegylated interferon alfa and ribavirin, in patients older than 18 years with compensated liver disease who are treatment-naïve or have failed dual combination of pegylated interferon alfa and ribavirin. Narlaprevir cannot be used as a single agent.

Contraindications Narlaprevir has some contraindications. In particular:

pregnancy or lactation children up to 18 years of age severe neutropenia liver failure prior treatment with HCV protease inhibitors lactase deficiency, lactose intolerance, glucose-galactose malabsorption.

Efficacy studies H. Reesink et al. (2009) demonstrated narlaprevir safety and antiviral activity both as a single agent and in dual combination with pegylated interferon alfa-2b. X. Tong et al. (2010) demonstrated narlaprevir activity against HCV mutations causing resistance to boceprevir and telaprevir. In the year 2016 a large-scale phase III multicenter PIONEER study was completed. Sustained virologic response (SVR) was 89% in treatment-naïve and 70% in treatment-experienced patients 24 weeks after the end of treatment in the narlaprevir group, whereas in the control group SVR was only 59.6% in treatment-naïve and 24.5% in treatment-experienced patients on dual therapy with pegylated interferon alfa and ribavirin. Adding narlaprevir to dual therapy with pegylated interferon alfa and ribavirin did not affect narlaprevir safety profile. A phase I study of narlaprevir pharmacokinetics in combination with ritonavir in patients with compensated cirrhosis was also completed (Liver Meeting AASLD, 13–17 February 2015, San Francisco, California, USA). According to professor I.G. Bakulin, the head of the Department of Hepatology of the Moscow clinical research center and chief gastroenterologist of Moscow government healthcare department, the regulatory approval of narlaprevir has become a major milestone accomplished in the fight against hepatitis C in Russia.

History In 2012, the pharmaceutical group R-Pharm acquired a license to manufacture narlaprevir from the Merck & Co. (MSD). Further development of the drug was conducted by R-Pharm in cooperation with Texas Liver Institute (USA), with the support of the Federal Target Program "Development of the Pharmaceutical and Medical Industry of the Russian Federation for the period up to 2020 and beyond". About 700 million rubles were invested in clinical trials and the development of the drug, of which 120 million rubles came from the Russian Government. Preclinical and clinical studies of the drug were conducted in Schering-Plough Research Institute (USA), as well as in a number of clinical centers in Europe, USA and Russia.The drug is manufactured at a pharmaceutical factory in the Russian city of Yaroslavl.

References

Illustrations

Worked examples

Example 1 — a first encounter with Narlaprevir

Start with the simplest possible case. Write down what Narlaprevir 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 Narlaprevir 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 Narlaprevir 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 Narlaprevir

In research: Narlaprevir 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 Narlaprevir 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: Narlaprevir is common in secondary-school and first-year university syllabi. It links to neighbouring topics Carboxamides, Cyclopropyl compounds, Heterocyclic compounds with 2 rings, so understanding it makes those chapters shorter.
In everyday life: Look for Narlaprevir 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 Narlaprevir in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Narlaprevir 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 Narlaprevir out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Narlaprevir in simple terms?

Why does Narlaprevir 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 Narlaprevir?

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 Narlaprevir.