Targeted Therapy (Smart Drugs)

What is it?

Targeted therapy refers to drugs directed at a specific protein, receptor or gene change in the cancer cell. In everyday language they are also called smart drugs. The aim is to cut the growth signal of cells that carry that target.

There is no smart drug that can be used in every tumour. A drug enters the plan only if the relevant target has been shown in the tumour, or if it is approved in that cancer type independently of the target. Treatment is therefore often tied to a test result, which is interpreted together with pathology and imaging. The drug list and dose are written according to kidney and liver function and the other drugs being used.

How does it work?

Small-molecule drugs can block signalling proteins inside the cell. Osimertinib is used with this logic for EGFR changes, alectinib for ALK and dabrafenib for BRAF changes; PARP inhibitors such as olaparib are used in some tumours carrying BRCA changes. Palbociclib and ribociclib affect the cell cycle in some breast cancers together with hormone therapy.

Antibodies such as trastuzumab, bevacizumab and cetuximab also bind to a target; the antibody form is described on a separate page. The side effects and areas of use of drugs in the same name group are not identical.

In which cancers is it used?

In non-small cell lung cancer EGFR, ALK and other markers, in melanoma BRAF, in breast cancer HER2 and hormone receptors, and in some ovarian, prostate, colorectal and thyroid tumours the relevant changes alter the choice of treatment.

Which treatment is appropriate is discussed at the tumour board, with the relevant specialties taking part, by considering the type, stage and molecular features of the cancer and the person’s general condition together. Starting a smart drug without testing, based only on the name of the cancer, is often not correct.

How is it given?

Some are taken by mouth every day, others are given intravenously at set intervals. For tablets, taking them fasting or with food, grapefruit and interactions with other drugs are discussed. At check-ups, blood tests, blood pressure and effects such as rash or diarrhoea are monitored.

Treatment can continue as long as the disease is under control. The dose may be reduced or a break taken because of side effects. Imaging intervals are planned according to the tumour type.

During follow-up, blood tests, imaging and symptom review are read together. The dose or date may be changed according to side effects and organ function. The list of medicines used at home is updated at every visit. Sudden fever, shortness of breath, uncontrolled diarrhoea or bleeding should be reported the same day.

Possible side effects

Rash, diarrhoea, fatigue, changes in blood pressure, raised liver tests and delayed wound healing may occur depending on the drug group. Some drugs can affect heart rhythm, lung tissue or blood sugar.

When symptoms appear, it is necessary to report them the same day rather than stopping the drug on one’s own. Many effects are managed by dose adjustment or supportive drugs.