Medication use evaluation of programmed death-1 inhibitors in a veteran population

To evaluate the safety and efficacy of programmed death-1 immune checkpoint inhibitors in a clinical practice setting.

Chart reviews were conducted on a total of 21 Veterans with advanced or metastatic cancers treated with programmed death-1 checkpoint inhibitors between 1 January 2015 and 31 July 2017. Among them, 16 patients were treated with nivolumab, including 12 with non-small cell lung cancer, 2 with melanoma, and 2 with bladder cancer. Pembrolizumab was used in 5 patients, including 4 with melanoma and 1 with head and neck cancer. The clinical outcomes were assessed based on overall disease control rates, objective response rates, median progression free survival, and median overall survival. The safety of programmed death-1 checkpoint inhibitors was evaluated based on the incidence and the severity of immune-related adverse events as defined by National Cancer Institute Common Terminology Criteria for Adverse Events v4.0.

For nivolumab, the overall disease control rate was 63%, including 67% in non-small cell lung cancer and 100% in melanoma patients. The objective response rate was 31%, with partial response 25% and complete response 6%. The overall disease control rate was 100% for pembrolizumab, with objective response rate 100%, partial response 40%, and complete response 60%. The median progression free survival was 4.5 months with nivolumab, with 4.5 months in non-small cell lung cancer and 6 months in melanoma. Nivolumab showed median overall survival of 14 months across all patients and 13 months for non-small cell lung cancer. The median progression free survival and overall survival for pembrolizumab have not yet been reached, but 6-month progression free survival and overall survival rates were 80% and 100%, respectively. With nivolumab, 6-month and 12-month overall survival rates were 81% and 69%, respectively. The rate of overall toxicities (grades 2-4) was 90% for programmed death-1 checkpoint inhibitors, including 88% with nivolumab and 100% with pembrolizumab. The overall incidences of grade ≥ 3 immune-related adverse events was 24% (n = 5), occurring 25% (n = 4) with nivolumab and 20% (n = 1) with pembrolizumab. The major toxicities were endocrine and gastrointestinal related, occurring 71% and 33%, respectively. Most adverse events were clinically manageable.

The clinical outcomes and the incidence of adverse events for programmed death-1 checkpoint inhibitors in our clinic patients are different from the data that have been published. This difference should be further investigated with a large real-world patient population.