OncoMed Shares Fall After Discouraging News on Pancreatic Cancer Drug

Xconomy San Francisco — 

OncoMed Pharmaceuticals has been adept at bringing in partners like GlaxoSmithKline and Celgene to help fund its cancer stem cell work. But the Redwood City, CA, company took a big hit this morning, as word emerged that one of its most advanced drugs—a potential cancer treatment that’s part of an alliance with GlaxoSmithKline—isn’t performing as hoped in a test against pancreatic cancer.

OncoMed (NASDAQ: OMED) said this morning that an independent data safety monitoring board took a look at the interim data from an ongoing Phase 2 trial of its experimental drug tarextumab, and the results weren’t good.

The board said there was a “strong trend to lack of benefit” of tarextumab—namely, it looks as if there’s a “low probability” it’s helping extend the lives of pancreatic cancer patients. Tarextumab is one of the drug candidates to come out of an alliance OncoMed formed with GSK in 2007. GSK has an option to license the drug through the end of proof-of-concept Phase 2 trials.

CEO Paul Hastings said in a statement that the company will now unblind the trial, assess the results, and figure out what the next steps for the study should be. Investors aren’t waiting around, however—shares of OncoMed fell over 43 percent in pre-market trading on Monday.

OncoMed is holding a conference call this morning to discuss the data.

Just days ago, OncoMed reported data from an early pancreatic cancer study of another drug, demcizumab, which is part of a separate collaboration with Celgene. The results of that test were positive, but then again tarextumab had also generated good numbers in an early stage study—a reminder of how hard it can be to translate the results from a small, single arm study in a larger, placebo controlled randomized trial. Leerink Partners analyst Paul Matteis called the demcizumab data “encouraging,” but wrote also that “single arm data need to be taken with a grain of salt.” A Phase 2 trial of demcizumab is underway, and should produce results next year.

OncoMed develops antibody drugs that target proteins on cancer stem cells—a subset of tumor cells that can renew themselves and cause tumors to regrow despite treatment. Tarextumab and demcizumab are two of the first drugs to come from that work. Tarextumab is also being tested in a mid-stage trial in lung cancer.