RAINIER: A randomized, double-blinded, placebo-controlled phase II trial of gemcitabine (gem) plus nab-paclitaxel (nab-P) combined with apatorsen (A) or placebo (Pl) in patients (pts) with metastatic pancreatic cancer (mPC).

419 Background: Heat shock protein 27 (Hsp27) is over-expressed in PC, enabling tumor growth and metastasis. A is an antisense oligonucleotide that binds to Hsp27 mRNA and inhibits production of Hsp27 protein. This randomized phase II trial evaluates the efficacy of gem/nab-P plus A or Pl in pts with mPC. Methods: Pts with untreated mPC were randomized 1:1 to Arm A (gem, nab-P, A) or Arm B (gem, nab-P, Pl). 3 loading doses of 600mg A IV or Pl IV were given, then 600 mg A or Pl weekly with chemotherapy in 28 day cycles. Both arms received gem 1000mg/m2 IV, nab-P 125mg/m2 IV days 1, 8, and 15. Restaging was every 2 cycles. Serum Hsp27 levels were collected at baseline and on treatment. Primary endpoint compared overall survival (OS); secondary endpoints were progression free survival (PFS), response rate (RR), CA 19-9 response, and toxicity. Results: 132 pts were randomized: median age 66 yrs, 57% male, 47% ECOG 0. Demographics were similar for both arms. 36% of pts on Arm A and 48% of pts Arm B discontinue...