Dec 19, 2024 Story by: Editor
In a retrospective cohort study published in The Lancet Oncology, Dr. Sean Miller of the Veterans Affairs Ann Arbor Healthcare System and colleagues examined the efficacy and toxicity of immune checkpoint inhibitor treatment for cancer in Black patients compared to White patients within the U.S. Veterans Health Administration (VHA) system.
The researchers noted, “Black patients were severely under-represented in the clinical trials that led to the approval of … [immune checkpoint inhibitors] for all cancers. The aim of this study was to characterise the effectiveness and safety of [immune checkpoint inhibitors] in Black patients.”
Study Overview
The study analyzed VHA system data for non-Hispanic Black or African American (Black) and non-Hispanic White (White) patients who received PD-1, PD-L1, CTLA-4, or LAG-3 inhibitors from January 1, 2010, to December 31, 2023. The team used a random sample of patients matched for baseline characteristics to evaluate comparative toxicity.
Key Findings
The study included 26,398 patients: 4,943 (18.7%) were Black, and 21,455 (81.3%) were White. Of these patients, 895 (3.4%) were female, and 25,503 (96.6%) were male. Additionally, 11,859 (45%) had non–small cell lung cancer, and 26,045 (98.7%) received PD-1 or PD-L1 inhibitors. At the study’s data cutoff in August 2024, the median follow-up was 40.3 months for Black patients and 43.9 months for White patients.
At 2 years, 10.7% (95% CI = 9.8%–11.7%) of Black patients compared to 8.6% (95% CI = 8.2%–9.0%) of White patients had discontinued treatment (adjusted hazard ratio [HR] = 0.91, 95% CI = 0.87–0.95, P < .0001). Additionally, 23.5% (95% CI = 22.3%–24.8%) of Black patients and 25.6% (95% CI = 25.0%–26.2%) of White patients had started a new treatment (adjusted HR = 1.00, 95% CI = 0.95–1.05, P = .96). The overall survival rate was 36.5% (95% CI = 35.2%–38.1%) for Black patients, compared to 36.5% (95% CI = 35.8%–37.1%) for White patients (adjusted HR = 0.95, 95% CI = 0.90–0.99, P = .036).
In a safety analysis of 862 Black and 848 White patients, immune-related adverse events (irAEs) of any grade occurred in 33.1% of Black patients compared to 44.1% of White patients (adjusted HR = 0.75, 95% CI = 0.62–0.90, P = .0026). Immune-related adverse events requiring systemic steroids occurred in 15.0% of Black patients vs 22.6% of White patients (adjusted HR = 0.61, 95% CI = 0.46–0.81, P = .0005), and those leading to permanent discontinuation of treatment were observed in 14.6% vs 21.7%, respectively (adjusted HR = 0.58, 95% CI = 0.44–0.78, P = .00024).
Exploratory analysis of specific immune-related adverse event subtypes showed significant reductions in Black patients for colitis (HR = 0.46, P = .0026) and thyroid dysfunction (HR = 0.63, P = .011).
Conclusion
The researchers concluded, “Compared with White patients, Black patients had similar [immune checkpoint inhibitor] effectiveness and lower toxicities among those treated in the national VHA system, potentially reflecting an important difference in the therapeutic ratio (ratio of benefit to harm) of [immune checkpoint inhibitors]. Our findings of decreased toxicity among Black patients require further investigation to assess their generalisability.” Source: The ASCO Post
