Chemotherapy: cladribine in hairy cell leukaemia: practice question

A Pharmacology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Pharmacology · Chemotherapy: cladribine in hairy cell leukaemia

Sample item

A 55-year-old man has pancytopenia, massive splenomegaly and a dry marrow tap. Flow cytometry shows B cells with hair-like projections that stain positive for tartrate-resistant acid phosphatase. Which purine analogue gives durable remission with a single short course?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Cladribine

Cladribine is resistant to adenosine deaminase and accumulates in lymphocytes as a triphosphate, causing DNA strand breaks. A single course produces long remissions in hairy cell leukaemia. Cytarabine, gemcitabine and fluorouracil are pyrimidine analogues with no such role.

Option by option

  • A. Gemcitabine

    Gemcitabine is a pyrimidine analogue used in pancreatic, lung and bladder cancers.

  • B. Cladribine (correct)

    Correct. Cladribine is the purine analogue of first choice for hairy cell leukaemia.

  • C. Fluorouracil

    Fluorouracil is a pyrimidine antimetabolite used in solid tumours of the gut and breast.

  • D. Cytarabine

    Cytarabine is a pyrimidine analogue used in acute myeloid leukaemia.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More Pharmacology questions

Questions about this Pharmacology question

What is the answer to this Pharmacology question?

The best answer is B, Cladribine. Cladribine is resistant to adenosine deaminase and accumulates in lymphocytes as a triphosphate, causing DNA strand breaks.

Why is "Gemcitabine" not the answer?

Gemcitabine is a pyrimidine analogue used in pancreatic, lung and bladder cancers.

Why is "Fluorouracil" not the answer?

Fluorouracil is a pyrimidine antimetabolite used in solid tumours of the gut and breast.

Why is "Cytarabine" not the answer?

Cytarabine is a pyrimidine analogue used in acute myeloid leukaemia.

What concept does this question test?

It tests Chemotherapy: cladribine in hairy cell leukaemia in Pharmacology. A single course produces long remissions in hairy cell leukaemia. Cytarabine, gemcitabine and fluorouracil are pyrimidine analogues with no such role.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Chemotherapy: cladribine in hairy cell leukaemia?

Learn drugs as classes, then the exception in each class that an examiner would pick. Then use the flashcards and the other Pharmacology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.