Study of [68Ga]FAPI-46 PET in Patients With Pancreatic Ductal Carcinoma

Sensitivity was defined as the proportion of participants with histopathology-confirmed PDAC who had a positive [⁶⁸Ga]FAPI-46 PET result for the primary lesion. Sensitivity was calculated by comparing positive and negative [⁶⁸Ga]FAPI-46 PET findings with the corresponding histopathology results, using a single readable PET image matched to its reference histopathology assessment. Sensitivity was calculated as A / (A + C), where A represents true-positive findings and C represents false-negative findings. Higher sensitivity indicates a greater ability of [⁶⁸Ga]FAPI-46 PET to detect FAP-expressing disease and a lower likelihood of false-negative results, thereby reflecting the effectiveness of the imaging modality relative to the histopathological reference standard.

The association between [⁶⁸Ga]FAPI-46 PET uptake, measured by maximum standardized uptake value (SUVmax), and FAP expression, assessed by H-score from histopathology, was evaluated. The relationship between SUVmax and H-score was assessed using the Spearman rank correlation coefficient, with corresponding 95% confidence intervals, in participants with evaluable PET imaging and histopathology results may not be linear owing in part to the H score ceiling of 300. All available paired PET and H-score measurements were included; when both pre- and post-neoadjuvant therapy data were available, each time point was analyzed separately. Spearman's rho was selected because it assesses monotonic relationships between ordinal or continuous variables and does not assume linearity, which may not be appropriate for the relationship between SUVmax and H-score.

Sensitivity was defined as the proportion of participants with IHC confirmed FAP-expressing cells who had a positive [68Ga]FAPI-46 PET result for the primary lesion. Sensitivity was calculated as A / (A + C), where A represents true positive findings and C represents false negative findings. Higher sensitivity indicates a greater ability of [68Ga]FAPI-46 PET to detect IHC confirmed FAP expression and a lower likelihood of false negative results, thereby reflecting the effectiveness of the imaging modality relative to the IHC reference standard. Sensitivity was presented considering IHC-positive results using 3 IHC cut-off values: > 50: Overall positive versus negative expression; > 100: Moderate to high expression and > 200: High expression only.

Specificity was defined as the proportion of participants without IHC-confirmed FAP-expressing cells who had a negative [68Ga]FAPI-46 PET result for the primary lesion. Specificity was calculated by comparing positive and negative [68Ga]FAPI-46 PET findings with the corresponding IHC results, using a single readable PET image matched to its reference IHC assessment. Specificity was calculated as D / (B + D), where B represents false-positive findings and D represents true-negative findings. PET results were compared with the corresponding IHC reference assessment using a single readable PET image per participant. Specificity was evaluated considering IHC-positive results using 3 IHC cut-off values > 50: Overall positive versus negative expression; > 100: Moderate to high expression and > 200: High expression only.

An AE is any untoward medical occurrence in a clinical study participant whether or not considered related to the study intervention. A TEAE is any AE that occurs after receipt of one or more doses of study drug through the end of study for that participant. A SAE is defined as any untoward medical occurrence that, at any dose: results in death or is life-threatening or requires inpatient hospitalization or prolongation of existing hospitalization or results in persistent disability/incapacity or is a congenital anomaly/birth defect or is a medically significant / important event or reaction.