The role of response as predictor of improved outcome in advanced pancreatic cancer (APC) patients (pts) treated with first-line Gemcitabine plus Nab-paclitaxel (GemNab).

e16758 Background: GemNab is one of the first-line standard treatment (tx) of APC. To date, no predictive factors, both clinical and molecular, of benefit from this regimen exist. Two retrospective studies showed that early tumor shrinkage (ETS) can predict an improved outcome in APC pts receiving a first-line tx with FOLFIRINOX or GemNab. However, data regarding GemNab, limited to a small population of only 57 pts, seem to not confirm the association of ETS with a better outcome. Hence, we retrospectively analysed an homogeneous population of APC treated with first-line GemNab at our Institution, investigating the impact of several clinical factors, including response and ETS. Methods: APC pts receiving a first-line tx with GemNab were included in the analysis. The association of RECIST response and ETS with PFS and OS was evaluated. The following variables were collected: gender; age ( > vs ≤ 55 years and ≥ vs < 70 years ); baseline ECOG PS; Ca 19.9 baseline level (≥ vs < 200); anamnesis of diabetes; site of primary tumor (head/uncinate process vs body/tail); locally A vs metastatic (m) PC; synchronous vs metachronous; number of m sites (1 vs > 1); m sites (liver, peritoneum, lung, nodes); number of tx lines (1 vs > 1). Univariate and multivariate analyses for PFS and OS were performed. Results: A total of 184 APC pts receiving first-line GemNab at our Institution from February 2014 to May 2019 were included in the analysis. RR and ETS were assessed in 174 and 168 pts, respectively. RR was 30%, disease control rate (DCR) 63% and ETS was 24%. Responders had a significant better PFS (12.5 vs 5.7 months, p < 0.0001) and OS (25.1 vs 12.1 months, p < 0.0001). ETS was significantly associated with improved PFS (12.3 vs 6.2 months, p < 0.0001) and OS (24.0 vs 12.8 months, p < 0.0001). At the multivariate analysis a significant association with survival parameters was confirmed for RECIST response, but not for ETS. At the multivariate analysis, also metachronous disease and number of tx lines > 1 were independently associated with better OS. Conclusions: Despite its retrospective nature, this is one of the largest series of APC pts treated with first-line GemNab investigating the role of RECIST response and ETS in predicting outcome. On the basis of our results, RECIST response may be considered a positive prognostic factor, whereas ETS does not. In conclusion, achieving tumor shrinkage, not necessarily early, significantly delays PC progression and prolongs survival in pts treated with first-line GemNab.