The state-backed Riken research institute spent about ¥145 million from fiscal 2011 to 2014 on its failed study on STAP stem cells and a subsequent investigation into research misconduct, a government watchdog said Friday.

In its annual audit for fiscal 2014, the Board of Audit said the institute spent ¥53.2 million in relation to the study, led by former researcher Haruko Obokata and once touted as a potentially epoch-making breakthrough to create stimulus-triggered acquisition of pluripotency cells.

The expense included about ¥22.8 million for research goods and some ¥16.3 million for personnel costs.