Background: MM-398 is a nanoliposomal encapsulation of irinotecan. OS in the ITT population was significantly longer with MM-398+5FU/LV over 5FU/LV alone, and the most frequent grade 3+ AEs included neutropenia, fatigue, and GI effects (diarrhea and vomiting). Expanded, pre-specified analyses of the Phase 3 study are presented. Methods: Patients (n=417) with mPAC previously treated with gemcitabine-based therapy, were randomized 1:1:1 in an open-label study to receive: (A) MM-398 (120 mg/m² IV over 90 min) q3w; (B) 5FU (2,000 mg/m² over 24 h) plus racemic leucovorin (LV) (200 mg/m² over 30 min) x 4w followed by 2w rest; or (C) combination of MM-398 (80 mg/m² IV over 90 min) prior to 5FU (2,400 mg/m² over 46 h) and racemic LV (400 mg/m² over 30 min) q2w. The primary endpoint was OS. The Intent To Treat (ITT) population included all randomized patients; the Per Protocol (PP) population included patients who received at least 80% of the target dose in the first 6 weeks and did not violate any inclusion/exclusion criteria. Results: Analysis of the PP populations confirmed the favorable OS, which was also reflected by the PFS, ORR and CA19-9 levels, of the combination MM-398+5FU/LV arm over the control 5FU/LV arm. The MM-398 monotherapy arm did not show a statistically significant improvement in OS compared with the control arm. Analysis of subgroups, based on pretreatment characteristics including stage at diagnosis, time since initial histological diagnosis, prior lines of therapy, time since last prior therapy, and CA19-9 levels, consistently favored OS for the MM-398+5FU/LV arm over the 5FU/LV arm. Conclusions: Expanded analysis of the PP population and sensitivity analyses support the favorability of MM-398+5FU/LV over 5FU/LV, with a manageable safety profile. Clinical trial information: NCT01494506