science

Idelalisib

Idelalisib is a science 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 Idelalisib rather than just read about it. In short: Idelalisib, sold under the brand name Zydelig, is a medication used to treat certain blood cancers. Idelalisib acts as a phosphoinositide 3-kinase inhibitor; more specifically, it blocks P110δ, the delta isoform of the enzyme phosphoinositide 3-kinase.

Key takeaways

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

Reference excerpt

Idelalisib, sold under the brand name Zydelig, is a medication used to treat certain blood cancers. Idelalisib acts as a phosphoinositide 3-kinase inhibitor; more specifically, it blocks P110δ, the delta isoform of the enzyme phosphoinositide 3-kinase. It was developed by Gilead Sciences. It is taken orally (swallowed by mouth).

Medical uses Idelalisib is a second-line medication for people whose chronic lymphocytic leukemia (CLL) has relapsed. Used in combination with rituximab, idelalisib is to be used in people for whom rituximab alone would be considered appropriate therapy due to other existing medical conditions. It appears to be effective and leads to improvement of lymphadenopathy and splenomegaly. However, the lymphocyte counts take longer to decrease to normal levels with idelalisib. It is not recommended as a first-line treatment.

Adverse effects Clinical symptoms include diarrhea, fever, fatigue, nausea, cough, pneumonia, abdominal pain, chills and rash. Laboratory abnormalities may include: neutropenia, hypertriglyceridemia, hyperglycemia and elevated levels of liver enzymes. Idelalisib's safety and effectiveness to treat relapsed FL and relapsed SLL were established in a clinical trial with 123 participants with slow-growing (indolent) non-Hodgkin lymphomas. All participants were treated with idelalisib and were evaluated for complete or partial disappearance of their cancer after treatment (objective response rate, or ORR). Results showed 54% of participants with relapsed FL and 58% of participants with SLL experienced ORR. The US label for idelalisib has a boxed warning describing toxicities that can be serious and fatal, including liver toxicity, severe diarrhea, colon inflammation, lung tissue inflammation (pneumonitis) and intestinal perforation, and the manufacturer was required to put in place a Risk Evaluation and Mitigation Strategy (REMS) under which the risk of toxicities would be managed. In March 2016, as reports were made from three ongoing clinical trials of serious adverse events and deaths, mostly due to infections, the European Medicines Agency opened a review of the drug and its risks. On March 21, 2016 Gilead Sciences (the manufacturer of idelalisib) alerted healthcare providers about decreased overall survival and increased risk of serious infections in patients with CLL and indolent non-Hodgkin lymphoma (iNHL) treated with idelalisib. The company also disclosed that it stopped six clinical trials in patients with CLL, SLL and iNHL due to an increased rate of adverse events, including deaths. In 2016, the EMA recommended that people on idelalisib should be given medication against the lung infection Pneumocystis jirovecii pneumonia and this should be continued for up to 6 months after idelalisib has stopped. In addition, people should be monitored for signs of infection.

Pharmacology

Mechanism of action PI3Kδ is expressed in normal and malignant B-cells. By inhibiting it, idelalisib induces apoptosis and prevents proliferation in cell lines derived from malignant B-cells and in primary tumor cells. It also inhibits several cell signaling pathways, including B-cell receptor (BCR) signaling and the CXCR4 and CXCR5 signaling, which are involved in the trafficking and homing of B-cells to the lymph nodes and bone marrow.

Binding profile Idelalisib is a competitive inhibitor of the ATP binding site of the PI3Kδ catalytic domain. Its in vitro potency and selectivity relative to the other Class I PI3K isoforms is the following:

Society and culture

Legal status In July 2014, the FDA and EMA granted idelalisib approval to treat chronic lymphocytic leukemia. It was also approved by the FDA for the treatment of relapsed follicular lymphoma (FL) and small lymphocytic lymphoma (SLL), both in patients who had received at least two prior systemic therapies. This approval was voluntarily withdrawn by the manufacturer in May 2022 after they failed to complete post-marketing confirmatory studies required by the FDA. This has coincided with the withdrawal of every other PI3K inhibitor for follicular lymphoma: duvelisib in December 2021, umbralisib in January 2022, and copanlisib in November 2023. These withdrawals are attributed to a possibly detrimental effect on survival seen in multiple studies of this drug class, likely due to toxic side effects.

Economics Idelalisib had annual sales of $168 million (USD) during the year of 2016, up from $132 million (USD) in 2015.

References

Illustrations

Worked examples

Example 1 — a first encounter with Idelalisib

Start with the simplest possible case. Write down what Idelalisib claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Idelalisib 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 Idelalisib 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 Idelalisib

In research: Idelalisib appears in science 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 Idelalisib 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: Idelalisib is common in secondary-school and first-year university syllabi. It links to neighbouring topics Antineoplastic drugs, CYP3A4 inhibitors, Fluoroarenes, so understanding it makes those chapters shorter.
In everyday life: Look for Idelalisib 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 Idelalisib in 20 minutes

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

Frequently asked questions

What is Idelalisib in simple terms?

Why does Idelalisib matter?

Because it connects several science 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 Idelalisib?

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 Idelalisib.