Science & TechnologyImportant2025-05-08

CDSCO Approves Trastuzumab Deruxtecan for HER2-Low Breast Cancer

Q: Which of the following statements is/are correct regarding Trastuzumab deruxtecan?

B. 2 only — Statement 1 is incorrect because it is a targeted antibody-drug conjugate (ADC), not traditional systemic chemotherapy that attacks all rapidly dividing cells. Statement 2 is correct as the CDSCO recently approved it for metastatic breast cancer exhibiting HER2-low or HER2-ultralow expression.

In News

What Happened

On May 8, 2025, the Central Drugs Standard Control Organisation (CDSCO) approved AstraZeneca's Trastuzumab deruxtecan (brand name Enhertu) for a new indication in India. It is now authorized as a monotherapy for adult patients with unresectable or metastatic HER2-low or HER2-ultralow breast cancer. This specific approval applies to patients who have already received at least one endocrine therapy in a metastatic setting.

Why It Matters

This approval introduces a targeted antibody-drug conjugate (ADC) therapy for patients who previously had limited options beyond standard chemotherapy. With breast cancer incidence surging in India, this precision oncology approach significantly boosts survival rates and extends progression-free survival for a much larger subset of patients.

Background

History & Context

Trastuzumab deruxtecan was first introduced in India in 2024 for HER2-positive breast and gastric cancers. The May 2025 approval is based on the global Phase-3 DESTINY-Breast06 trial, which demonstrated a median progression-free survival of 13.2 months for the drug compared to 8.1 months for standard chemotherapy. This pivotal trial validated the drug's efficacy in hormone receptor-positive patients with significantly lower levels of HER2 expression.

What Changed

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Target Demographics: BEFORE, targeted anti-HER2 therapies were primarily restricted to HER2-positive breast cancer patients. NOW, patients with HER2-low and the newly defined HER2-ultralow expressions are eligible for this targeted therapy.
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Treatment Line: BEFORE, patients with HER2-low or ultralow metastatic breast cancer typically resorted to systemic chemotherapy after endocrine therapy failed. NOW, they can receive this targeted Antibody-Drug Conjugate (ADC) directly after progressing on just one line of endocrine therapy.
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Diagnostic Approach: BEFORE, immunohistochemistry (IHC) testing mainly looked for high HER2 overexpression (IHC 3+). NOW, pathologists must carefully identify HER2-low (IHC 1+, IHC 2+/ISH-) and HER2-ultralow (IHC 0 with membrane staining) to unlock this treatment pathway.

Prelims Angle

NCERT Connection

This connects to Class 12 Biology Chapter 8 - Human Health and Disease, specifically the sections on Cancer and its treatment. Trastuzumab deruxtecan is an advanced application of targeted immunotherapy, using monoclonal antibodies conjugated with a cytotoxic drug to precisely seek and destroy cancer cells expressing the HER2 protein while minimizing damage to normal cells.

Practice Questions

Q1

Correct Statement(s)

Which of the following statements is/are correct regarding Trastuzumab deruxtecan?

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