OncoMed Pharmaceuticals, Inc. presented final safety, efficacy and biomarker data from the company's Phase 1b "ALPINE" clinical trial of tarextumab (anti-Notch2/3, OMP-59R5) in 40 patients with frontline metastatic pancreatic cancer. Tarextumab was generally well tolerated when administered with gemcitabine and Abraxane (paclitaxel protein-bound particles for injectable suspension) (albumin bound), with manageable, on-target drug-related toxicities. The Phase 2 dose of tarextumab was determined to be 15 mg/kg every two weeks in combination with the standard-of-care.

Among patients evaluable for response using RECIST criteria, 38% (11 of 29) achieved partial responses, with an additional 35% achieving stable disease (10 of 29) for an overall clinical benefit rate of 73% (21 of 29 patients). The data presented included biomarker analyses that showed that among patients whose tumor samples had elevated levels of Notch3 gene expression, trends toward higher response rates and longer survival were noted, as compared to patients with low Notch3 expression. Median PFS and OS for patients with high Notch 3 expression (using a 50% cut-off) were 6.6 months and 14.6 months, respectively.

In the Phase 1b study, tarextumab was administered to standard-of-care chemotherapy to 40 patients with previously untreated, metastatic pancreatic cancer. Thirty-one of the patients received the combination of gemcitabine, Abraxane and tarextumab. Escalating doses of tarextumab were administered every two weeks, ranging from 2.5 mg/kg to 15 mg/kg.

Diarrhea, fatigue and anemia were the most common treatment-related toxicities, and the events were mostly Grade 1 or 2, and managed with supportive care.