Antibody-Drug Conjugates: — The Smart Bombs of Cancer Treatment

An ADC is neither standard chemotherapy nor immunotherapy, though it borrows technology from both. The antibody component uses similar technology to monoclonal antibody therapies. The payload is usually a highly potent cytotoxic drug, similar in type to chemotherapy. What makes ADCs distinct is that the two are joined — the antibody acts as a precision guide, and the drug is released specifically where it binds. Calling it a targeted chemotherapy is a reasonable shorthand, though your oncologist may describe it differently depending on the specific drug you are receiving.

It depends on which ADC you are receiving. Each ADC targets a specific protein that appears on the surface of cancer cells for a given cancer type. Common targets include HER2, found in some breast, stomach and lung cancers; Trop-2, found in some breast and bladder cancers; and CD30, found in some lymphomas. Your oncologist will tell you which protein yours targets and what your biomarker test showed. If testing has not yet been done, ask when it will be — it is the step that confirms the ADC is appropriate for your specific tumour.

ADCs are given as an intravenous infusion — a drip — in a day care setting. You come in on the day, receive the infusion over a set period, and go home the same day. The schedule — how often you receive it and for how many cycles — depends on the specific ADC and your treatment plan. Your team will explain the full schedule and what to watch for in the days after each infusion before you start.

ADCs produce a different pattern of side effects from conventional chemotherapy, and the specific profile depends on which ADC you are receiving. Severe hair loss is less common with many ADCs. Side effects that arise more specifically from ADC treatment include interstitial lung disease, peripheral neuropathy — tingling or numbness in the hands and feet — and in some cases eye-related symptoms. Your team will tell you which side effects are most relevant to your specific drug, and which ones to report the same day rather than waiting for your next appointment.

Interstitial lung disease is an inflammation of the lung tissue, and with some ADCs it is a recognised risk that NCCN and other oncology guidelines ask teams to monitor throughout treatment. Early signs include a new dry cough or breathlessness that is gradually worsening. ILD caught early is usually manageable; if it progresses undetected it can become serious. This is why your team asks about your breathing at every visit, and why a new respiratory symptom means calling the same day rather than waiting for your next appointment.

Some ADCs are given as single agents — alone. Others are combined with targeted therapies or, less commonly, with chemotherapy. Whether a combination applies to you depends on your cancer type, stage and the current clinical evidence. ASCO and ESMO regularly update guidance on which combinations are supported by trial data. Your oncologist will explain whether your treatment is a single agent or part of a combination, and why that choice was made for your situation. Tell your team about everything you are taking, including anything bought without a prescription.

Response is typically assessed through imaging — usually a CT scan or PET-CT — after a set number of treatment cycles. Your team compares scans taken after treatment starts against a baseline taken before, looking at whether the cancer has reduced, stabilised or grown. Blood markers are also followed in some cancer types. The assessment schedule will be explained before you start. If you are unsure when your first evaluation scan is planned, ask at your next visit — knowing the checkpoint often makes the in-between period easier to manage.

Several ADCs have received regulatory approval from CDSCO and are available in India, though which ones are in routine use at any given centre depends on that centre's approvals and the patient's eligibility. CION provides targeted therapies as day care infusions across its centres in Telangana and Andhra Pradesh. Whether an ADC is part of your recommended treatment depends on your cancer type, biomarker result and stage. Ask your oncologist directly — if an approved ADC is indicated for your situation, your team will confirm what is available and where it can be administered.