BOSTON — Across the VA system, immune checkpoint inhibitors (ICIs) are being prescribed for a growing number of cancer types including renal cell carcinoma, lung cancer, head and neck cancers, and melanoma. That provides valuable insight into the usage and outcomes associated with the powerful immunotherapies across a large group of real-world patients.
Researchers at the VA Boston Healthcare System led by Jennifer La, PhD, examined the frequency of ICI therapy at the VA and the conditions for which the drugs were used. The information was presented in an abstract published as part of the 2020 American Society of Clinical Oncology Annual Meeting held May 29-31.1
Immune checkpoint inhibitors are monoclonal antibodies that block various checkpoint proteins from turning off the immune system by binding with their partner proteins. Ordinarily, checkpoint proteins keep the immune system from attacking healthy cells.
Some cancer cells, however, also have checkpoint proteins that they use as duplicate keys to turn off the immune system, enabling the cancer to grow unimpeded. Blocking the checkpoints on the cancer cells keeps them from “tricking” the immune system and exposes the cancer cells to attack by T cells.
The most common ICIs target one of three proteins: PD-1, PD-L1, or CTLA-4. Drugs in this category include pembrolizumab, nivolumab, cemiplimab, atezolizumab, avelumab, durvalumab, and ipilimumab.
The researchers identified 13,276 veterans treated in the VA system with ICIs through April 2019. The veterans had an average age of 69 years and were 97.2% male and 76.9% white. Nearly 17% of the patients were African American.
ICIs were most common in the treatment of non-small cell lung cancer with 975 veterans receiving the immunotherapy in the first line and 2,545 receiving it in the second line or later. Melanoma was the next most common malignancy, with 1,654 veterans with that diagnosis receiving an ICI.
The immunotherapies were prescribed to 777 veterans with squamous cell carcinoma of the head and neck, as well as 497 veterans with renal cell carcinoma, in both first and subsequent lines. Other malignancies treated with ICIs included hepatocellular carcinoma (533) and urothelial cancer (477).
One-year survival rates varied significantly depending on the type of cancer treated and the line of therapy. Veterans receiving ICIs as first-line therapy for renal cell carcinoma had the best one-year survival rate, 74%, followed by melanoma patients at 67%, and non-small cell lung cancer patients who received the drugs as their first-line therapy, 60%.
Veterans who received ICIs for renal cell carcinoma in the second line or later and those who received the drugs for hepatocellular carcinoma had one-year survival rates of 51%. The lowest survival rates were seen in patients who received ICIs as second-line therapy for urothelial cancer (38%), followed by squamous cell carcinoma of the head and neck (42%), first-line treatment of urothelial cancer (45%), and second-line or later therapy for non-small cell lung cancer (45%).
- La J, Cheng D, Do N, Brophy MT, Fillmore N, Tuck DP. “Real-world usage and outcomes for patients treated with immune checkpoint inhibitors across multiple treatment indications in the Veterans Affairs system.” Abstract e15063. 2020 ASCO Annual Meeting. May 29-31, 2020.