Clinical-stage biotechnology company Oncothyreon Inc. said Tuesday its partner Merck Serono temporarily suspended all clinical trials of the drug candidate Stimuvax because of potential safety issues.
Stimuvax is Oncothyreon's lead drug candidate and the company does not have a product on the market.
Shares of Oncothyreon fell $1.29, or 27 percent, to $3.49 in morning trading. Shares have traded between $1.18 and $7.77 over the last 52 weeks.
The company said the suspension was a result of a "suspected unexpected serious adverse reaction" in a multiple myeloma patient. Specifically, the patient in a small exploratory study receiving an intensive regimen of the drug developed an inflammation of the brain.
The drug is currently being studied separately in two larger, Phase III, studies focusing on breast and lung cancer. Those studies are suspended because of the potential safety issue.