Shares of Onyx Pharmaceuticals fell nearly 30% on Monday after data showed that its kidney cancer drug Nexavar did not work in patients with advanced skin cancer.
Onxy and its partner Bayer of Germany said a late-stage trial of the drug in combination with chemotherapy did not meet its main goal of improving progression-free survival, or the period in which a patient experiences no meaningful tumor growth.
"We are disappointed, first and foremost for the patients with refractory metastatic melanoma for whom treatment options are so limited," said Hollings Renton, the chief executive of Onyx, in a statement.
Renton said the companies will continue to test the drug in other cancers. A late stage trial of Nexavar is currently under way in liver cancer and a late-stage, or Phase III, trial of the drug in lung cancer was initiated earlier this year.
Nexavar, also known as sorafenib, is a tablet that blocks several kinases, or enzymes, that are involved in cell proliferation or in supplying blood to tumors, a process known as angiogenesis.
Last month Bayer said it expected sales of Nexavar to reach about $133 million this year and eventually to generate sales of at least $1 billion. The drug competes with Pfizer's Sutent.