OncoMed hits the brakes on cancer studies after troubling safety signs

OncoMed CEO Paul Hastings

Cancer biotech OncoMed Pharmaceuticals ($OMED) voluntarily halted dosing and enrollment in two early studies after patients experienced bone damage, sending its shares down roughly 20%.

The Redwood City, CA, company is pausing Phase I trials of vantictumab and Fzd8-Fc, two Bayer-partnered therapies that target cancer stem cells, planning to retool their protocols to ensure patient safety. The biotech said 13% of subjects taking vantictumab and 5% of those on Fzd8-Fc reported mild to moderate bone-related adverse events, leading it to halt the studies as "a precautionary measure."

Analyzing the data, OncoMed is now working to amend the studies' design, reducing dosage, altering safety monitoring and changing the patient enrollment criteria. The biotech plans to send its new protocols to the FDA and resume development of vantictumab and Fzd8-Fc if and when the agency signs off.

"With patient safety as our first priority, we aim to fully understand these events, continue to conduct a thorough analysis of data in hand, and work closely with the investigators and the FDA to determine the best path forward," CEO Paul Hastings said in a statement.

Bayer partnered with OncoMed in 2010, handing over $40 million up front for the right to buy up to 5 candidates that inhibit cancer stem cells' Wnt signaling pathway, agreeing to pay as much as $387.5 million for each. Vantictumab and Fzd8-Fc are the two most advanced candidates under that deal.

The setback marred OncoMed's share price in early trading Friday, but the safety issues don't cast a shadow over demcizumab, the biotech's lead prospect. Late last year, Celgene ($CELG) stepped in with a deal worth up to $3.3 billion to get its hands on the Phase II cancer therapy and 5 more preclinical assets that use the same cancer stem cell technology.

Before Celgene came calling, OncoMed pulled off an above-the-range IPO in July 2013, raising $82 million. The biotech is trading about 18% above its debut price.

- read the statement

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