By Soyoung Kim and Jessica Toonkel
NEW YORK (Reuters) - Amgen Inc, the drugmaker in advanced discussions to buy Onyx Pharmaceuticals Inc, has asked Onyx for some of the data from an ongoing trial on the company's new blood cancer drug, two people familiar with the matter said on Thursday.
Amgen, the world's largest biotechnology company, has questions about Onyx's new blood cancer drug Kyprolis and wants access to some trial data to better evaluate the treatment, said the people, who wished to remain anonymous because the conversations are confidential.
The company is keen to acquire Onyx and does not believe sharing aspects of the trial data would negatively impact the success of the study, one of the people said.
Amgen wants to finalize the deal with Onyx in the near future and views the request for more information as a standard due diligence matter that is not uncommon in healthcare deals, that person said.
Onyx, however, does not want to access the data out of concern that doing so could negatively affect the study, the second source said.
Shares of Onyx Pharmaceuticals Inc were down 7.9 percent to $114.30 on Thursday after Bloomberg reported that the takeover talks had been held up by a dispute over access to Onyx's cancer drug data.
It could not be learned what kind of trial data Amgen asked to see. Drugmakers can obtain interim data indicating the overall progress of a trial, but not broken down by treatment regimens or specific details about patients.
For example, a drugmaker can access information on what percentage of patients in a trial had certain side effects, such as a heart issue.
Full data involving patient details are only available to the Data and Safety Monitoring Board that oversees trials.
Onyx does not have access to interim data from the Kyprolis trial, an Onyx spokeswoman said. She declined to comment further on the sales process. An Amgen spokesperson said it does not comment on speculation.
Reuters reported last week that Onyx was close to selling itself to Amgen for $130 per share, or $9.5 billion based on shares outstanding, and that a deal announcement could come very soon.
(Reporting by Soyoung Kim and Jessica Toonkel in New York, Additional reporting by Deena Beasley and Esha Dey in Bangalore; Editing by Joyjeet Das and Carol Bishopric)