Clinical and biological markers predictive of treatment response associated with metastatic pancreatic adenocarcinoma.

BACKGROUND

Chemotherapy for metastatic pancreatic adenocarcinoma (PDAC) offers limited benefits, but survival outcomes vary. Reliable predictive response biomarkers to guide patient management are lacking.

METHODS

Patient performance status, tumour burden (determined by the presence or absence of liver metastases), plasma protein biomarkers (CA19-9, albumin, C-reactive protein and neutrophils) and circulating tumour DNA (ctDNA) were assessed in 146 patients with metastatic PDAC prior to starting either concomitant or sequential nab-paclitaxel + gemcitabine chemotherapy in the SIEGE randomised prospective clinical trial, as well as during the first 8 weeks of treatment. Correlations were made with objective response, death within 1 year and overall survival (OS).

RESULTS

Initial poor patient performance status, presence of liver metastases and detectable KRAS ctDNA all correlated with worse OS after adjusting for the different biomarkers of interest. Objective response at 8 weeks also correlated with OS (P = 0.026). Plasma biomarkers measured during treatment and prior to the first response assessment identified ≥10% decrease in albumin at 4 weeks predicted for worse OS (HR 4.75, 95% CI 1.43-16.94, P = 0.012), while any association of longitudinal evaluation of KRAS ctDNA with OS was unclear (β = 0.024, P = 0.057).

CONCLUSIONS

Readily measurable patient variables can aid the prediction of outcomes from combination chemotherapy used to treat metastatic PDAC. The role of KRAS ctDNA as a tool to guide treatment warrants further exploration.

CLINICAL TRIAL REGISTRATION

ISRCTN71070888; ClinialTrials.gov (NCT03529175).