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Updated: Oct 29, 2026
Preparation and Pathogen Inactivation of Double Dose Buffy Coat Platelet Products using the INTERCEPT Blood System
Published on: December 7, 2012
Pretreatment platelet count exhibits a U-shaped association with outcomes after immune checkpoint blockade with a
1Human Disease Continuum Project Consortium, Beijing, China; New City of Chang'an, No. 28 Dacheng Road, Fengtai District, Beijing, 100141, China.
Background:
Platelets contribute to tumor progression and immune regulation, but the relationship between pretreatment platelet count and immune checkpoint blockade (ICB) outcomes across the clinical range remains unclear.
Methods:
This study conducted a retrospective multicohort study of patients treated with ICB. In a Memorial Sloan Kettering pan-cancer cohort (n = 1,479), platelet count was modeled using penalized cubic splines and clinically defined strata, with 150-249 × 10⁹/L as the reference. Cox models adjusted for age, sex, prior chemotherapy, ICB class, tumor stage, cancer type, and tumor mutational burden. Findings were evaluated in a validation cohort (n = 717) and in non-small cell lung cancer (n = 666) and melanoma (n = 377) analyses. An exploratory pooled analysis (n = 2,196) compared mono-ICB with dual PD-1/PD-L1 plus CTLA-4 blockade across platelet strata.
Results:
Platelet count showed a U-shaped association with overall survival. Relative to 150-249 × 10⁹/L, adjusted mortality hazards were higher at 49-124 × 10⁹/L (hazard ratio [HR], 1.83; p = 0.0001), 300-399 × 10⁹/L (HR, 1.56; p < 0.0001), and 400-977 × 10⁹/L (HR, 1.93; p < 0.0001). High counts were also associated with shorter progression-free survival (HR, 1.27 for 300-399 × 10⁹/L and 1.32 for 400-977 × 10⁹/L; both p = 0.003), whereas associations at low counts were weaker. Similar patterns were observed in the validation and cancer-specific cohorts. Dual ICB was associated with longer median overall survival than mono-ICB only in the 150-300 × 10⁹/L stratum (2.34 vs 1.42 years; p < 0.0001).
Conclusions:
Pretreatment platelet count is an inexpensive biomarker with a nonlinear association with ICB outcomes. Both low and high counts identify increased mortality risk, supporting flexible modeling rather than a single thrombocytosis threshold. The platelet-defined signal for dual ICB is hypothesis-generating and requires prospective validation before treatment selection.
