May 22 (Reuters) - Amgen Inc said it will terminate a collaboration with AstraZeneca Plc to develop an inflammation drug after it observed suicidal thoughts in subjects of a trial.

AstraZeneca could decide on the development and marketing of the drug for all territories, except for Japan and certain Asian territories, where Kyowa Hakko Kirin has the rights to it, Amgen said.

Amgen said such safety concerns would likely result in a restrictive label, potentially limiting the number of patients using the drug.

(Reporting by Amrutha Penumudi in Bengaluru; Editing by Don Sebastian)