Fig. 2.

Structural comparison of commonly used mTOR inhibitors. Structure of the first discovered, naturally occurring, and prototype drug of the mTOR inhibitors, rapamycin. Shown in comparison are two commonly used rapalogs possessing improved pharmacokinetic profiles and FDA approved indications including refractory renal cell carcinoma and in combination therapies for other solid tumors. CCI-779: cell cycle Inhibitor 779.