Elisidepsin

We have previously reported the development of novel nanocapsules made of polyarginine (PArg) specifically designed for the delivery of small anticancer drugs into cells. Our goal, in this work, has been to investigate the potential of these nanocarriers for oral delivery of peptide anticancer drugs. To reach this objective, we chose the antitumoral peptide, elisidepsin, and evaluated the characteristics of the PArg nanocapsules in terms of drug loading capacity, stability in simulated intestinal fluids, and ability to interact with the intestinal epithelium both in vitro (Caco-2 model cell line) and in vivo. Our results suggest that elisidepsin can be effectively loaded into the nanocapsules by adjusting the formulation parameters, using a solvent displacement technique. The resulting nanocapsules were stable upon incubation in simulated intestinal fluids and had the ability to reduce, in a transient manner, the transepithelial electrical resistance of the Caco-2 cell monolayer. Confocal images also revealed that PArg nanocapsules were internalized by the monolayer without evident signs of cytotoxicity. Finally, the in vivo fluorescent imaging study illustrates the retention of the nanocapsules in the gastrointestinal tract upon oral administration. Overall, the results underline the potential interest of PArg nanocapsules as carriers for the oral administration of peptide drugs.

To determine the recommended dose and antitumor activity of single-agent elisidepsin as a 24-h intravenous (i.v.) infusion fortnightly [biweekly, d1 and 15 every 4 weeks (q4wk); Arm A, dose-intensity strategy] or as a 3-h i.v. infusion weekly (d1, 8, 15 and 22 q4wk; Arm B, dose-density strategy) in adult patients with unresectable, locally advanced or metastatic pretreated esophageal, gastroesophageal junction and gastric cancer.

Patients were randomized to one of two elisidepsin dosing schedules. Phase Ib starting doses were 8.0 mg flat dose (FD) in Arm A and 3.0 mg FD in Arm B. Phase II subsequently explored antitumor activity of both dosing schedules at the respective recommended doses.

Forty-four patients received elisidepsin: 12 in stage Ib and 32 in stage II. The recommended doses were defined as 10 mg FD (Arm A) and 3.75 mg FD (Arm B). Both schedules were well tolerated. Most adverse events were mild or moderate, reversible and predictable with no meaningful differences between schedules. The pharmacokinetic profiles of both schedules were similar to those reported previously in patients with solid tumors treated with a comparable dose. An interim analysis found tumor control in one patient receiving elisidepsin fortnightly, and in none given elisidepsin weekly; patient accrual was therefore discontinued due to lack of efficacy.

Both schedules at the recommended doses presented an acceptable safety profile, but lack of response means that we do not recommend further evaluation of single-agent elisidepsin as chemotherapy for unresectable, locally advanced or metastatic gastroesophageal cancer.