A new treatment strategy for small cell lung cancer (SCLC), a type of lung cancer with a rapid progression and low survival rate, has been proposed by a Korean medical team.

Samsung Medical Center (SMC) said Tuesday that a research team, led by Professor Ahn Myung-ju of the Department of Hematology-Oncology, published a treatment strategy that will secure the efficacy and safety of the new drug tarlatamab as a second-line treatment for SCLC in the New England Journal of Medicine (NEJM), an internationally renowned medical journal.

Small cell lung cancer, which accounts for 10-15 percent of all lung cancers, is known for its small cell size, and it is more difficult to treat than non-small cell lung cancer (NSCLC). Due to its rapid progression, it relies on chemotherapy rather than surgery, and until now, there have been limited options for patients who do not respond to first-line treatment.

Even with second-line treatment, small cell lung cancer is deadly, with a short response period and survival rates rarely exceeding eight months. Professor Ahn and her colleagues have found promise in bispecific T-cell engagers (bispecific antibodies), such as tarlatamab, in small cell cancer.

Tarlatamab is a bispecific antibody drug that recognizes antigens from cancer and immune cells. It targets a protein called DLL3, expressed in a large proportion of small cell lung cancer patients (85-94 percent), and a receptor called CD3, which induces immune cells to attack cancer cells, even if the cancer tries to evade the immune cells.

To identify new treatment strategies to maximize the effectiveness of tarlatamab, which is currently in development, while maintaining patient safety, the research team recruited and randomized 220 patients from 56 institutions in 17 countries who had failed first-line treatment for small cell lung cancer. Following the U.S. Food and Drug Administration (FDA) guideline, the team administered different doses of tarlatamab 10 mg and 100 mg to the patients and monitored their outcomes, including treatment response and side effects.

The results showed that in terms of clinical effectiveness, 10 mg administered every two weeks was optimal for patients with improved outcomes and fewer side effects.

According to the researchers, the proportion of patients with an objective treatment response during follow-up was 40 percent in the 10 mg group, compared to 32 percent in the 100 mg group. Median progression-free survival was also favorable in the 10 mg group at 4.9 months, compared to 3.9 months in the 100 mg group. Estimated overall survival at nine months post-treatment was similarly 68 percent (10 mg) and 66 percent (100 mg).

The 10 mg dose was relatively more effective with fewer side effects. As a T-cell activating treatment, there is a risk of a "cytokine storm" due to over-expressed immune cells, which occurred in 51 percent of the 10 mg group and 61 percent of the 100 mg group. Other side effects, such as loss of appetite and fever, were also analyzed and found to be lower in the 10 mg group, which was the lower dose of the drug.

"Unlike other cancers, small cell carcinoma does not progress in stages that can be described as limited or extensive, but rather spreads," Professor Ahn said. "It has metastasized to other lungs or organs in most patients, making it difficult to treat. There is no cure, and we hope that research like this will continue to help reduce patient suffering."