The world has seen major advances against cancer in recent years in the form of a new group of drugs to treat cancer which can best be described as medicine's answer to Trojan horses. As small and harmless 'packages', the drug circulates in the patient's bloodstream until it meets a cancer cell. It is then invited inside. Inside the cancer cell, the innocent guest completes its real—and for the cancer cell malicious—mission: It releases its toxic payload, killing the cancer cell.
It may sound simple, but it's not. Because sometimes the Trojan horse-type cancer drug is invited into healthy cells, which then die, and that of course is not desirable. Other times, the drug is released prematurely, i.e. while it is still circulating in the bloodstream, and thus the effect of the treatment is reduced as smaller amounts of medicine are delivered to their actual destination, the sites of the cancer. Last but not least, due to certain chemical challenges, very few drugs can be attached to the Trojan medicine horses.
This new group of drugs is known as antibody-drug conjugates, or ADCs. An ADC consists of an antibody that will recognize the cancer cell, as well as a substance designed to kill the cancer cell. The two substances are conjugated by a chemical molecule called a linker. Today, there are only about a dozen ADCs in the world.
For an ADC to work as intended, it is crucial that the linker is stable in the bloodstream and effectively releases the active substance that is supposed to kill the cancer cell. Over the past couple of years, chemist and DTU Associate Professor Katrine Qvortrup has been researching possible ways of improving the linker molecule.
"In research circles, the general consensus was that a new linker design could improve the ADCs in several ways: We would be able to increase the selectivity of the ADC, i.e. make sure that it gets better at targeting only the cancer cells, and we would be able to avoid inefficiencies, for example by making sure that the medicine is not released prematurely, and finally, we may be able to achieve improvements that would make it possible to connect more types of drugs to the linker than has been possible so far," says Katrine Qvortrup.
