Complex sentence: Human clinical trials of Teixobactin were estimated to be at least two years away, and one of the co-discoverers of the antibiotic estimated it would cost "in the low 100 millions" of dollars to develop a teixobactin drug over five or six years.
Split into simpler sentences: Human clinical trials of Teixobactin were estimated to be at least two years away. One of the co-discoverers of the antibiotic estimated it would cost "in the low 100 millions" of dollars to develop a teixobactin drug over five or six years.