TAK-285 is a novel dual HER2 and EGFR(HER1) inhibitor with IC50 of 17 nM and 23 nM, >10-fold selectivity for HER1/2 than HER4, less potent to MEK1/5, c-Met, Aurora B, Lck, CSK etc.
Among the 34 kinases tested, TAK-285 only significantly inhibits HER4 with IC50 of 260 nM, slightly inhibits MEK1, MEK5, c-Met, Aurora B, Lck, CSK, and Lyn B with IC50 of 1.1 μM, 5.7 μM, 4.2 μM, 1.7 μM, 2.4 μM, 4.7 μM, and 5.2 μM, respectively, and displays no activity against other kinases with IC50 of >10 μM. TAK-285 shows significant growth inhibitory activity against BT-474 cells (HER2-overexpressing human breast cancer cell line) with GI50 of 17 nM.Compared with SYR127063 a potent inhibitor of HER2, TAK-285 displays similar in vitro potency against HER2 and EGFR. Compared with the full cytoplasmic domains of the wild-type proteins, the mutations and shortened boundaries used for structure determination of HER2-KD and EGFR-KD do not significantly change the inhibitory activity (IC50) of TAK-285. TAK-285 binds to the inactive conformation of EGFR, and shows a similar binding mode with lapatinib in the active site.
The oral bioavailability of TAK-285 is 97.7% in rats and 72.2% in mice at a dose of 50 mg/kg. Oral administration of TAK-285 at 100 mg/kg twice daily for 14 days displays significant antitumor efficacy in the HER2-overexpressing BT-474 tumor xenograft mouse model with tumor/control (T/C) ratio of 29%, without affecting body weight. Similar to the BT-474 model, TAK-285 exhibits dose-dependent tumor growth inhibition of 4-1ST (HER2-overexpressing human gastric cancer tumor) xenografts in mice, with T/C of 44% and 11% at doses of 50 mg/kg and 100 mg/kg, twice daily, respectively, without significant body weight loss in mice. Furthermore, TAK-285 treatment induces dose-dependent growth inhibition of 4-1ST tumors in rats with T/C of 38% and 14% at doses of 6.25 mg/kg and 12.5 mg/kg, and, particularly noteworthy, tumor regression with T/C of -12% and -16% at doses of 25 mg/kg and 50 mg/kg, respectively. After oral administration of TAK-285, a significant amount of TAK-285 is present in the brain of rats in pharmacologically active, unbound form (approximately 20% of its free plasma level), indicating that TAK-285 has a potential in the therapy of CNS malignancies/metastases.
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