Efficacy and safety of gemcitabine in combination with TH-302 compared with gemcitabine in combination with placebo in previously untreated patients with metastatic or locally advanced unresectable pancreatic adenocarcinoma: The MAESTRO trial.
TPS4148 Background: Tumors often consist of highly hypoxic subregions that are resistant to chemotherapy and radiotherapy. The investigational hypoxia-targeted drug TH-302 is reduced at its nitroimidazole group, and under hypoxic conditions releases the DNA alkylator bromo-isophosphoramide mustard (Br-IPM). A randomized Phase IIb trial of TH-302 in pts with metastatic or locally advanced unresectable pancreatic adenocarcinoma (PDAC) confirmed a significant PFS improvement (p=0.008) in pts treated with TH-302 at 340 mg/m2+ gemcitabine compared with gemcitabine alone (Borad et al, ESMO 2012). Skin and mucosal toxicities, mainly Grade 1/2, and myelosuppression (thrombocytopenia, neutropenia and anemia) were the most common AEs related to TH-302 and did not lead to increases in treatment discontinuation. Grade 3/4 myelosuppression was more frequent in the TH-302 + gemcitabine arm. AEs leading to treatment discontinuation as well as non-hematological serious AEs were balanced across arms. Methods: This is a Phase III, randomized, double-blind, placebo-controlled trial (NCT01746979) of gemcitabine + TH-302 compared with gemcitabine + placebo in pts with locally advanced unresectable or metastatic PDAC. The study is designed to detect a 25% risk reduction of death with 90% power and two-sided alpha of 5%. A total of 660 pts are planned to be randomized 1:1. Key eligibility criteria include histologically or cytologically confirmed disease, no prior chemotherapy or systemic therapy (except as specified in the protocol), ECOG performance status 0 – 1, and bilirubin ≤ 1.5x upper limit of normal. Randomized pts receive TH-302 + gemcitabine or gemcitabine + placebo in 4-week cycles until progressive disease, intolerable toxicity, or pt withdrawal. The primary objective is to evaluate OS. Secondary objectives include PFS, objective response, and disease control; safety and tolerability; pt-reported QoL and pain; CA 19-9 levels and PK of TH-302; exploratory pharmacogenomic markers and potential predictive biomarkers. Enrollment to the study is ongoing. Clinical trial information: NCT01746979.