In the results of a meta-analysis of solid organ transplant recipients who have received immune checkpoint inhibitors as cancer treatment, the study authors concluded that immunotherapy may be “high risk yet promising” for these patients. These findings are being presented during the 2025 ASCO Annual Meeting (Abstract 2511). Response rates varied according to the type of immune checkpoint inhibitor received as well as the type of cancer.
“This work [is] one of the most comprehensive studies to date on the use of checkpoint inhibitors in transplant recipients,” said senior author Muhammad Awidi, MD, a hematology/oncology fellow at Roswell Park Comprehensive Cancer Center, Buffalo, New York. “Our study lays essential groundwork for developing safe treatment protocols and expanding access to life-saving immunotherapies for a high-risk group often excluded from immune therapy clinical trials.”
With the results of the study, researchers may be able to suggest approaches that could help improve response rates for patients undergoing solid organ transplants.
Study Methods and Results
The study authors conducted a meta-analysis to determine how immune checkpoint inhibitor therapy impacts the risk of transplant rejection in patients with cancer who have received a solid organ transplant. Researchers conducted a systematic review of PubMed, EMBASE, and SCOPUS databases, in accordance with PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines, looking for rejection and efficacy outcomes for solid organ transplant recipients who have received immune checkpoint inhibitors. They found 198 relevant studies including 331 patients with solid organ transplants of the liver, kidneys, and heart.
Rejection rates were highest for kidney transplants (46.3%), then followed by heart (40.0%) and liver (26.9%) transplants. Rejection rates by class of immune checkpoint inhibitors were highest for anti–PD-1 antibodies (40.6%) followed by anti–CTLA-4 antibodies (25%); there were no rejections seen with anti–PD-L1 antibodies. Patients who received immune checkpoint inhibitors prior to transplant had lower rejection rates than did those who received treatment after transplant (25.9% vs 40.9%).
Objective response rates were highest with anti–PD-L1 antibodies (72.7%) compared with 41.8% with anti–PD-1 antibodies, 28% with anti–PD-1 plus anti–CTLA-4 antibodies, and 25% with anti–CTLA-4 antibodies. By type of cancer, objective response rates were highest in patients with cutaneous squamous cell carcinoma (49.1%), followed by hepatocellular carcinoma (40.8%) and melanoma (25.3%).
By multivariate analysis, posttransplant rejection risk was lower with anti–CTLA-4 antibodies (odds ratio [OR] = 0.22; P = .04), third-line or later immune checkpoint inhibitor treatment (OR = 0.24; P = .01), and corticosteroids (OR = 0.46). Pretransplant rejection risk was lower with a greater-than-60-day washout period (OR = 0.1; P < .001).
Disclosure: For full disclosures of the study authors, visit coi.asco.org.
