AstraZeneca Shares Plummet 16% On Late-stage Trial Failure; Bristol-Myers Shares Fall 6% And Merck Shares Rise 5%

AstraZeneca PLC shares plummeted as much as 16% in premarket trade Thursday after the company said its cancer drug combination failed to meet its primary endpoint in a late-stage clinical trial. In the AstraZeneca late-stage trial, the combination of the drugs Imfinzi and tremelimumab -- intended for previously-untreated patients with metastatic first-line non-small cell lung cancer -- did not improve progression-free survival compared to the standard of care. The results could have implications for Bristol-Myers Squibb Co.'s cancer drug combination, and the company's shares dropped 6.2% in premarket trade. Meanwhile, shares of cancer drug rival Merck & Co. -- which has a key position in the first-line lung cancer market with cancer drug Keytruda -- rose 5% in premarket trade. For AstraZeneca, "this is a clear disappointment given the large market opportunity," said Leerink Research analyst Seamus Fernandez. "The read-through is an obvious negative read-through for BMY's combo of Opdivo and Yervoy in the ongoing CheckMate-227 trial... While there are several key differences in trial design between MYSTIC and CM-227, they are unlikely to result in meaningfully different outcomes." However, EvercoreISI analyst Umer Raffat was slightly more optimistic, noting that the AstraZeneca trial isn't over yet and also has overall survival as a primary endpoint, with results expected in the first half of next year. "It will be unreasonable to pretend as if nothing has changed on MYSTIC... but I also acknowledge that we shouldn't forget about several [immuno-oncology] trials which have delivered [overall survival] benefit despite not having any [progression-free survival] benefit," Raffat said. AstraZeneca shares have surged 10% over the last three months, Bristol-Myers shares have lifted 0.6% and Merck shares have dropped 1.3%, compared with a 3.7% rise in the S&P 500 .