Fox Chase Cancer Center Researchers Present Data on Use of Checkpoint Inhibitors and Test Measuring Their Benefit to Patients

Jasmeet Kaur, MBBS, MD, lead author on the study and a second-year fellow in the Department of Hematology/Oncology at Fox Chase.

PHILADELPHIA (January 24, 2025) - The number of patients receiving immune checkpoint inhibitors and PD-L1 testing for treatment of gastroesophageal cancer (GEC) increased following Food and Drug Administration (FDA) approval, according to a new study presented by researchers at Fox Chase Cancer Center.

"GEC is a leading cause of cancer-related death, with poor survival rates due to late-stage diagnoses. Immune checkpoint inhibitors have shown promise in treating advanced GEC, especially for patients with high expression of PD-L1, a protein," said Jasmeet Kaur, MBBS, MD, lead author on the study and a second-year fellow in the Department of Hematology/Oncology at Fox Chase.

"Recent clinical trials and FDA approvals have made immune checkpoint inhibitors a standard first-line treatment, but their use depends on PD-L1 testing," she said.

Immune checkpoint inhibitors are used to block proteins called checkpoints, which includes PD-L1, which are made by immune cells such as T cells. PD-L1 helps keep the body's immune response in check, thus keeping T cells from killing tumors.

The drugs have significantly improved overall survival in patients with high PD-L1 scores, because when these checkpoints are blocked T cells are able to kill cancer cells more effectively. PD-L1 testing is used to determine if a patient will benefit from immunotherapy by measuring levels of the protein in a patient's cancer cells.

Kaur and other researchers from Fox Chase, Temple University Hospital, and Temple Health used real-world data from a large health database from Flatiron Health that contained anonymous electronic health records from cancer patients.

They focused on 9,573 adults who were diagnosed with advanced GEC between 2011 and 2021. The study compared how many patients received immune checkpoint inhibitors and had PD-L1 testing at four different times: before new treatment data was presented at a medical meeting in 2020, after that data came out, when the FDA approved new guidelines for immune checkpoint inhibitor treatment in early 2021, and later in 2021 after those guidelines were widely adopted.

The results showed that the number of patients receiving immune checkpoint inhibitors went up significantly after the FDA approved the drugs as a treatment for advanced GEC. Before FDA approval, about 11% of patients were receiving these inhibitors, but by the second half of 2021, that number jumped to 37%.

At the same time, the percentage of patients getting PD-L1 testing increased from 68% to 77.4%. This trend showed that as more patients were tested for PD-L1, more of them were able to get the immune checkpoint inhibitor treatments that could potentially help them.

"The approval of immune checkpoint inhibitors for advanced GEC led to more patients getting the right treatments and tests, but there are still gaps," said Kaur. "Some patients, especially those from minority backgrounds, still face barriers to accessing these treatments and tests. It is important that policies and programs exist to ensure all patients, regardless of their background, have equal access to the latest cancer treatments."

The study, "Patterns of Immune Checkpoint Inhibitor Utilization and PD-L1 Testing in Advanced Gastroesophageal Cancers Using Real-World Data," was presented in a poster session at the American Society of Clinical Oncology Gastrointestinal Cancer Symposium, which was held January 23-25 in San Francisco.