Chemotherapy: anti-EGFR antibodies: 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: anti-EGFR antibodies

Sample item

A patient with metastatic colorectal cancer whose tumour carries a KRAS mutation is being considered for cetuximab. What is the correct decision?

ACetuximab causes cumulative cardiotoxicityBCetuximab works best in KRAS mutated tumoursCMutation status is irrelevantDCetuximab is not effective in RAS-mutant tumours, and is used in RAS wild-type disease with acneiform rash as a typical effect

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

The answer and the reasoning

D. Cetuximab is not effective in RAS-mutant tumours, and is used in RAS wild-type disease with acneiform rash as a typical effect

Downstream RAS mutations make the pathway constitutively active, so anti-EGFR antibodies such as cetuximab and panitumumab are used only in RAS wild-type tumours. Acneiform rash correlates with response, and hypomagnesaemia can occur.

Option by option

A. Cetuximab causes cumulative cardiotoxicity
Cardiotoxicity is not a typical feature.
B. Cetuximab works best in KRAS mutated tumours
Mutant tumours do not respond.
C. Mutation status is irrelevant
Status determines eligibility.
D. Cetuximab is not effective in RAS-mutant tumours, and is used in RAS wild-type disease with acneiform rash as a typical effect (correct)
Correct. RAS wild-type status is required.

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.

Questions about this Pharmacology question

What is the answer to this Pharmacology question?

The best answer is D, Cetuximab is not effective in RAS-mutant tumours, and is used in RAS wild-type disease with acneiform rash as a typical effect. Downstream RAS mutations make the pathway constitutively active, so anti-EGFR antibodies such as cetuximab and panitumumab are used only in RAS wild-type tumours.

Why is "Cetuximab causes cumulative cardiotoxicity" not the answer?

Cardiotoxicity is not a typical feature.

Why is "Cetuximab works best in KRAS mutated tumours" not the answer?

Mutant tumours do not respond.

Why is "Mutation status is irrelevant" not the answer?

Status determines eligibility.

What concept does this question test?

It tests Chemotherapy: anti-EGFR antibodies in Pharmacology. Acneiform rash correlates with response, and hypomagnesaemia can occur.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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: anti-EGFR antibodies?

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.