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Antibody-drug conjugates: how these drugs work
An antibody-drug conjugate, or ADC, is often called a "smart bomb". It's an antibody that finds a target on cancer cells, linked to a powerful chemo drug. The antibody delivers the chemo straight to the cancer, so more of it reaches the tumor. Because they still carry chemo, ADCs can cause chemo-like side effects such as nausea, tiredness, low blood counts, and hair loss, plus a few unique ones tied to each drug. ADCs are one of the fastest-growing areas of cancer treatment, and several now treat breast, lung, and ovarian cancer.
ℹ️ General information to help you and your loved ones talk with your care team, not medical advice. Read our disclaimer.
On this page: HER2-directed ADCs · TROP-2-directed ADCs · Folate receptor alpha ADCs
HER2-directed ADCs
Enhertu (fam-trastuzumab deruxtecan) and Kadcyla (ado-trastuzumab emtansine) both use trastuzumab to find HER2. Enhertu works even when HER2 is low or ultralow, and its key risk is lung inflammation (interstitial lung disease). Kadcyla is used after surgery when cancer remains and in metastatic HER2-positive breast cancer, with liver tests and platelet counts watched.
TROP-2-directed ADCs
Trodelvy (sacituzumab govitecan) targets TROP-2, found on many breast cancers. It's used in metastatic triple-negative breast cancer and HR-positive, HER2-negative breast cancer after other treatments. Its boxed warning covers low white blood cells and severe diarrhea, so you'll get medicine to prevent and treat both.
Folate receptor alpha ADCs
Elahere (mirvetuximab soravtansine) targets FRα in platinum-resistant ovarian cancer. Its boxed warning is about eye problems, such as blurry vision and dry eyes, so you'll use steroid and lubricating eye drops and have eye exams.
Why your exact test result matters
Each ADC needs its target. HER2 scores (0, ultralow, low, or positive), TROP-2, and folate receptor alpha (FRα) all decide who can get which drug. Ask for a copy of your pathology report. Our HER2 and FRα test guides can help you read it.
Side effect guides that may help
- Nausea and vomiting (CINV)
- Neutropenia (low blood counts and infection risk)
- Alopecia (hair loss from chemo)
- Fatigue (extreme tiredness)
❓ Questions you and your loved ones can ask
- What is the goal of this treatment for me?
- How will we know if it's working?
- Which side effects should I call about right away, and what number do I call after hours?
- Which medicines, vitamins or supplements should I avoid?
- Will this affect my ability to work, drive, or care for my family?
- What will this cost me, and who can help me with coverage?
Written by the CSE Team from FDA labels and leading cancer centers. Not medical advice. · Last updated: October 15, 2026 · How we write
Sources
Last updated: October 15, 2026. We summarize these sources in our own words.