TIL therapy has demonstrated remarkable efficacy in melanoma; however, clinical responses remain highly heterogeneous among patients. Traditional cell product quality attributes, such as cell count and viability, have limited predictive value for clinical outcomes. A major challenge is the inability to accurately identify tumor-resident T-cell clones with genuine antitumor activity.By longitudinally tracking millions of TCR clonotypes throughout treatment—from the baseline tumor (T0), to the ACT product, and to post-infusion tumor samples (T30)—TCR sequencing enables:
Source identification: Quantification of the proportions of tumor-resident and blood-derived clonotypes.
Expansion efficiency assessment: Evaluation of the expansion and enrichment of tumor-specific clonotypes during ex vivo culture.
In vivo pharmacokinetic (PK) monitoring: Quantitative tracking of the persistence of reinfused clonotypes and their homing efficiency to tumor lesions, providing biomarkers for predicting clinical response.
