Background: Immune checkpoint inhibitors are used as frontline therapy in mRCC, providing a durable response and a favourable safety profile, however only a subset of patients respond. The ABO blood group type and the associated difference in relative diversity of the T-cell repertoire may affect response to immunotherapy.
Methods: Clinical data of patients receiving immunotherapy for mRCC between 2015 and 2022 at our institution were retrospectively collected. Patients without blood type and toxicity information were excluded. Evaluated outcomes included time-to-treatment-failure (TTF) due to any cause, prognosis-free survival (PFS) and occurrence of immune-related adverse events (irAEs). Kaplan-Meier plots and Cox regression models were used for statistical analysis.
Results: A total of 69 patients were included, of which 28 (40.6%) had group O, 29(42.1%) had group A, 11(15.9%) had group B and 1 (1.4%) had group AB. TTF was observed in 64 patients, including 45(65.2%) due to progression, 16(23.2%) due to toxicity, and 4(5.8%) due to death. Median TTF for Group O patients was 8.09 months (95% CI:5.92 - 20.35 months) compared to 3.88 months (95% CI: 2.89-5.88 months) for Group A/B/AB patients (p=0.017). Among patients who discontinued immunotherapy due to progression/death(n=49), group O patients had significantly longer PFS (median 5.93 months) than non-O patients (median 3.29 months, P=0.04). There was no significant difference in frequency of irAEs between group O and non-O patients (P=0.09), however the presence of irAEs is significantly associated with improved TTF (aHR= 0.49, 95% CI 0.28 to 0.86).
Conclusions: Although limited by small sample size, the findings suggest that patients with blood group O may have a preferential response to immunotherapy, especially with the presence of irAEs. Validation in larger cohorts and investigations for underlying biological mechanisms are warranted.