unprecedented

precede : 先立つ、〜の前に来る、〜より上位にある
　be preceded by ~ : 先に〜から始まる
precedent: 前例、先行する
　precedent-breaking : 先例を破る
precedented : 先例のある
unprecedented : 前例のない、未曾有の
「Aging research has experienced an unprecedented advance over recent years, particularly with the discovery that the rate of aging is controlled, at least to some extent, by genetic pathways and biochemical processes conserved in evolution.」