Researchers at the Mass General Brigham Cancer Institute have made an exciting discovery that could change how lung cancer is treated.
They found that a specific signal, or marker, on cancer cells found in a patient’s blood can help predict whether a new drug called tarlatamab will work for them. This test could give doctors a fast, simple, and noninvasive way to choose the right treatment for each person.
The study focused on patients with small cell lung cancer (SCLC), a fast-growing and aggressive type of lung cancer. This type of cancer is usually treated first with chemotherapy.
If it comes back after that, doctors need other options. Tarlatamab is a new drug that was fully approved in late 2025 for patients with SCLC whose cancer returned after chemotherapy.
Tarlatamab is a kind of immunotherapy. It helps the immune system fight cancer by bringing T cells (which attack harmful cells) directly to the cancer cells. It does this by finding a special marker called DLL3 that many small cell lung cancer cells have.
But even though most cases of this cancer were believed to show DLL3, the researchers found that this isn’t always true. In fact, only about half of the 20 patients they studied had a large number of cancer cells with DLL3 in their blood.
These were the patients who responded well to the new drug. The rest, who had fewer DLL3-positive cells, did not benefit from the treatment.
The team used a special technique to gather cancer cells from the blood. These cells are called circulating tumor cells, or CTCs. Using bioengineering tools, they were able to test these cells for the presence of DLL3.
The results were very promising: the test correctly identified 85% of the patients who got better after using tarlatamab, and it also correctly showed that 100% of the patients who didn’t benefit from the drug were unlikely to respond.
This kind of accuracy is rare and could make a big difference in how patients are treated. Instead of relying on trial and error, doctors could use this simple blood test to know in advance who is likely to benefit from the drug. That means fewer people taking medications that won’t help them and more people getting the right treatment faster.
The technology used in the study was developed by a team of engineers and doctors working together. Their tools for collecting and analyzing tumor cells in the blood have now been licensed to a company called TellBio, Inc., which could help bring this test to more clinics in the future.
Dr. Daniel A. Haber, a senior author of the study, explained that this may be the first time their method for analyzing blood-based cancer cells has such a clear and direct benefit for patient care.
Dr. Justin Gainor, another author, noted that the test may also help with other drugs that target DLL3, not just tarlatamab. Since DLL3 is also found in other types of cancer as they get worse, this method could be useful beyond lung cancer.
In summary, this study shows how a simple blood test could help match the right cancer treatment to the right patient. It helps avoid unnecessary treatments and supports the growing field of personalized medicine, where treatment is tailored to each person’s specific disease.
While more research is needed with larger groups of patients, the results offer hope for better care and outcomes for people with aggressive lung cancer.
If you care about lung health, please read studies about marijuana’s effects on lung health, and why some non-smokers get lung disease and some heavy smokers do not.
For more information about health, please see recent studies that olive oil may help you live longer, and vitamin D could help lower the risk of autoimmune diseases.
The study is published in Cancer Discovery.
Copyright © 2025 Knowridge Science Report. All rights reserved.
