A Novel Paclitaxel Conjugate with Higher Efficiency and Lower Toxicity: A New Drug Candidate for Cancer Treatment

Paclitaxel-lipoate (IDD-1040) is a conjugate formed by the chemical joining of the two compounds, by condensing a lipoic acid moiety to the C2′ of paclitaxel. IDD-1040 was evaluated for its anti-tumor activity and potential druggability, using an in vivo non-small-cell, lung cancer (NSCLC) xenograft mouse model. In the in vivo studies, IDD-1040 showed a maximum tolerated dose (MTD) of 250 mg/kg compared to paclitaxel (PTX), with an MTD of 20 mg/kg. Most interesting, IDD-1040 demonstrated higher anti-tumor activity, and its inhibitory activity on tumor volume (cell growth) was dose-dependent. That anti-tumor activity persisted for two weeks after cessation of IDD-1040 treatment, as opposed to PTX cessation, after which the tumor relapsed, confirming that IDD-1040 exhibits superior tumor inhibition. Similar to PTX treatment, no marked body weight decrease was observed during IDD-1040 treatment, indicating a low toxicity profile. The increase in animal body weight noted over time was due to the increasing weight of tumors, recorded in all the mouse test groups. The results also showed that mortality rate of mice was reduced by treatment with IDD-1040, more so than with PTX. Furthermore, in a preliminary study on the ex vivo distribution of IDD-1040, neutropenia was primarily concentrated in the liver 1 h after injection, and most of the drug was metabolized by the liver in 24 h. All of these results demonstrate IDD-1040’s great potential as a candidate drug for cancer treatment.