Stattic is a small molecule inhibitor of STAT3 with IC50 values of 2.562 ± 0.409 μM, 3.481 ± 0.953 μM, 2.282 ± 0.423 μM and 2.648 ± 0.542 μM, respectively, in UM-SCC-17B, OSC-19, Cal33 and UM-SCC-22B cell lines [1].

Stattic is reported to selectively inhibit dimerization, activation and nuclear translocation of STAT3. It can also induce the apoptosis of STAT3-dependent breast cancer cell lines [2].

The inhibition of STAT3 by Stattic results in decreased STAT3-mediated HIF-1 expression and subsequent radiosensitization of HNSCC cells. Inhibiting the STAT3 signaling pathway may represent an effective strategy in the treatment of HNSCC. The evidence of Stattic activity in vivo has also been found. Stattic pre-treatment sensitizes orthotopic xenograft HNSCC tumors to radiation, wich results in signi?cantly reduced tumor growth, although this effect was not as dramatic as anticipated by the in vitro studies [1].