Antibody-drug conjugates

Antibody-drug conjugates deliver a strong cancer-killing drug straight to cells that carry a specific marker.

Rosa: Hi, I'm Rosa. Antibody-drug conjugates are like a guided delivery that carries medicine to cancer cells. Let me explain how they work and what to watch for.

Antibody-drug conjugates, or ADCs, combine two treatments in one medicine. An antibody, which is a protein that finds a specific target, is linked to a powerful cancer-killing drug. Examples include trastuzumab deruxtecan (Enhertu), sacituzumab govitecan (Trodelvy), enfortumab vedotin (Padcev), and brentuximab vedotin (Adcetris).

Think of an ADC as a guided delivery truck. The antibody is the driver with the address. It looks for a marker on the surface of cancer cells, such as HER2 or TROP2. When it finds the marker, the cell pulls the ADC inside, and the drug is released to kill the cell. Some ADCs can also leak a little drug to nearby cancer cells.

ADCs are used for many cancers, including breast, lung, bladder, stomach, ovarian, and cervical cancers, and some lymphomas, leukemias, and myeloma. Your care team may test the tumor for the marker first. Some ADCs work even when the marker level is low.

ADCs are given through a vein (IV), usually every 1 to 3 weeks. Treatment often continues as long as it is working and side effects are manageable. Because the drug is aimed at cancer cells, ADCs may be easier than standard chemo for some people. But the attached drug is still a type of chemo, so side effects can happen.

Common side effects include tiredness, nausea, low blood counts, hair thinning or loss, and diarrhea. Some ADCs have special side effects. Certain ones can cause lung inflammation (called ILD or pneumonitis). Others can cause eye problems, numbness and tingling in the hands and feet, skin reactions, or high blood sugar. Your team will tell you which ones apply to your drug and may check your eyes, lungs, or blood sugar.

Call your care team right away for new or worse cough, shortness of breath, or fever with breathing changes. Also call for fever of 100.4°F (38°C) or higher, blurry vision or eye pain, a rash that blisters or peels, severe diarrhea, or very high blood sugar readings. If it feels very bad, call 911.

Know your drug's special risks

Each ADC has its own pattern of side effects. Ask your team for a written list of the specific ones to watch for with your ADC.

Lungs

With ADCs that can affect the lungs, report any new cough or breathlessness the same day. Catching lung inflammation early makes it easier to treat.

Eyes

Some ADCs need regular eye exams and eye drops. Avoid contact lenses if your team advises it, and report vision changes right away.

Nausea and diarrhea

Take anti-nausea medicines as prescribed. For drugs that cause diarrhea, ask what medicine to keep at home and when to call.

Questions to ask

What marker does this ADC target? Which side effects are most important for this drug? Will I need eye exams, lung scans, or blood sugar checks? How often will I get treatment?

Myth: ADCs have no chemo side effects

Fact: ADCs aim a chemo drug at cancer cells, but some of the drug still affects healthy cells. Side effects can be milder than standard chemo but are still real.

Myth: My tumor must have a lot of the marker

Fact: Some ADCs work even when the marker is low. Ask your care team what your test results mean for your options.

Last updated: 2026-10-27. Medically reviewed by Veli Bakalov, MD, medical oncologist (October 2026). General education from Step by Step, the patient portal of HemeOncBuddy.