BioWorld International Correspondent

PARIS - Diatos SA successfully completed a Phase I clinical trial of its anti-cancer compound DTS-201, a novel doxorubicin prodrug developed for the targeted treatment of several solid cancers, including chemo-resistant tumors.

DTS-201 uses the Tumor Selective Prodrug (TSP) technology platform developed by Paris-based Diatos, which causes the product to be activated by enzymes specifically expressed by the tumor while ignoring healthy cells. The clinical data yielded by this trial provide the first proof of concept in man for the TSP platform.

The main conclusions drawn from the trial are that DTS-201 was well tolerated and brought measurable clinical benefit to 40 percent of the 25 patients enrolled, since nine patients with chemo-resistant tumors showed disease stabilization through at least four treatment cycles.

Diatos has decided that this outcome "warrants further assessment of the product in multiple clinical Phase II studies," which are due to get under way in the near future, according to the company's President and CEO, John Tchelingerian.

Shortly before reporting the results of the DTS-201 trial, Diatos announced the start of a regulatory toxicology program for DTS-108, a prodrug of SN38, the active metabolite of irinotecan that is used for the treatment of colon and lung cancer. DTS-108 embodies Diatos' Vectocell peptide-based intracellular delivery system, and a Phase I trial of the product is scheduled for the first half of 2008.

Preclinical data show that DTS-108 improves anti-tumoral efficacy and safety compared to irinotecan as a result of an efficient and non-hepatic mode of activation. This results in significantly higher volumes of the active metabolite circulating in the organism, while reducing gastrointestinal toxicity.

Pointing out that "DTS-108 is the first drug utilizing our Vectocell technology platform to reach the clinic," Tchelingerian said this was "an important validation of our technology platform If these encouraging preclinical observations are reproduced in the clinic, then we will have a second-generation irinotecan that will provide a significantly improved patient treatment option in the areas of colon and lung cancer. In addition, clinical studies may indicate other potential novel indications where DTS-108 can be effective and where irinotecan cannot be used."

Diatos has one other product in clinical development and that is DTS-301, a polymer gel formulation of paclitaxel depot, which has completed a Phase IIa trial in esophageal cancer and is about to enter a Phase IIb/III trial. In July this year, the company completed a Series D private funding round in which it raised €9.4 million.