Targeted and Effective Tumor Therapy
Conventional cancer therapy often comes with severe side effects. With new treatment methods, some tumors can be targeted effectively, reducing these adverse effects. Read what experts are saying about precision oncology’s potential.
Every day, our bodies produce up to 10,000 potential cancer cells. They usually die off on their own or are destroyed by the immune system. But sometimes, our bodies’ security systems fail. In that case, cells that should be discarded grow uncontrollably. A tumor forms, and the patient is confronted with a devastating diagnosis: cancer.
“Cancer is a disease that is created from the patient’s own cells,” said Dominik Mumberg, who is Translational Innovation Lead in Early Development at Bayer. “Treatment is much more difficult than fighting a pathogen that is foreign to the body, like a virus.”
Besides, cancer is a multifaceted adversary. “There isn’t just one kind of cancer,“ Mumberg said. „So far, we have identified over 100 forms of cancer, and there are many more. That’s also why there isn’t just one therapy. We need many differentiated forms of treatment.”
Cancer’s many faces
Scientists have recently gained numerous new insights into this disease. Thanks to improved molecular diagnostic methods, they now know that there are variations even within categories like lung or stomach cancer, for example. Instead of concentrating on a cancer’s location, they pay close attention to the molecular structure of individual tumors and look for ways to develop a bespoke treatment.
This field of research and treatment is called precision oncology. “Conventional treatment methods like chemotherapy are comparable to a lawn sprinkler’s broad application. Precision oncology is more like a fine jet of water you can direct at a single plant,” said Mathias Rossberg, Director of Oncology at Bayer Vital.
Precision oncology aims to apply just the right treatment at the right time and at the right dosage for a specific patient. Mumberg describes the different approaches used for this kind of therapy: “One option is to attempt to decode the mechanism within the tumor that causes the unbridled cell growth and develop a treatment for it. You can also look for characteristics on the tissue surface specific to the tumor that provide a point of access for targeted treatments. The third option is to activate the immune system in the area surrounding the tumor so it will attack the cancer cells.”
Better treatment success, fewer side effects
All these approaches have several things in common: They are often more effective and come with potentially far fewer adverse side effects for patients than conventional therapies. Chemotherapy, for example, often attacks healthy tissue like mucous membranes as well as the tumor. Precision treatments on the other hand attack almost exclusively cancer cells which have the specific characteristics the drug was designed for. One unavoidable “side effect” of a course of precision treatment: The patient needs to provide a tissue sample for molecular analysis of the tumor.
Such an analysis is the starting point for any course of precision cancer treatment. It aims to identify the driver of the tumor growth and potential leverage points for treatment. One such underlying cause of the disease is the so-called NTRK gene fusion. Simply put, this gene fusion causes a signaling pathway within a cell, that should normally only be active in very few cases, to be permanently overactive, leading to uncontrolled cell growth.
Initial successes, but significant challenges remain
Researchers have identified the product of this gene fusion as one driver of cancer growth. Based on this insight, medications have been developed that can be used to treat this form of cancer. The first drug was approved in the United States in 2018, followed by many other markets,including Europe, where it was the first tumor-agnostic product to ever enter the market. This means that it can be used to treat any tumor caused by gene fusion regardless of where the cancer originated. Another drug for this type of cancer was approved first in Japan, followed by additional approvals around the world.
This is a major breakthrough, but precision oncology is still faced with significant challenges. NTRK gene fusion is a rare form of cancer that is only observed in one percent of cancer patients. “While the driver of some tumor growth has now been identified, there are still many varieties of cancer like the big ‘killers’ lung and colon cancer that, for the most part, can’t be traced back to a single driver,” Mumberg said. “With these cases, we have to assume that there is more than one driver causing the disease. That means we also need a combination of different approaches that counteract a number of drivers. But do such substances even work in combination? And how does this type of treatment affect the body overall?”
Getting the word out on precision oncology
Precision oncology will need to answer a number of questions before it can be an effective treatment for all cancer patients. Nonetheless, Mathias Rossberg argues that molecular analysis of tumors should more commonly be used at the beginning of treatment. “It would be downright unethical to subject a patient to chemotherapy and the associated side effects if they can be treated in a more targeted way and without severe side effects.”
Expanding the use of molecular testing will require additional laboratory capacities, medical personell, and financial resources. It also needs to become better known among patients too, not only among doctors. Patients should ultimately decide which type of treatment they prefer.
Rossberg and Mumberg agree that even precision oncology won’t end the fight against cancer any time soon. But Rossberg concludes: “I do think cancer could become a disease that people can live with, just like people live with diabetes today. The goal of our research is to give patients as long and painless a life as possible.”