Hypericin-Mediated Intraperitoneal Photodynamic Diagnostics and Therapy in Peritoneal Metastases of Gastric Cancer (Hypericin-PDT; EudraCT-Number 2015-005277-21; NCT-02840331)
13. August 2018 (online)
In peritoneal metastases (PM), cytoreductive surgery and HIPEC may provide long-term survival. However, detection of PM by radiological diagnostics is demanding.
Moreover, even laparoscopy often fails in differentiation between tumor and scar tissue. Hypericin, St. John's Wort, has been shown to accumulate in tumor cells. Because of its autofluorescent und photocytotoxic properties, hypericin might be a good candidate for photodynamic diagnostics and therapy in peritoneal metastases.
Materials and methods:
Patients suffering form locallyadvanced gastric cancer receive a single oral dose of 900 mg Hypericin (Laif 900®) 2 – 4h prior to routine staging-laparoscopy. In addition to standard-whitelight-laparoscopy (WL), fluorescence-laparoscopy (FL) is performed using Storz OPAL1 technology with long-wave UV range. In case of macroscopic PM in WL, which is also positive in FL, photodynamic therapy is performed by exposing one representative nodule to ultraviolet light for 15 minutes.
Primary endpoint of the study is the detection of PM by FL with respect to size, number, and location compared with WL. The concentration of hypericin in peritoneum and serum as well as the histological proof of apoptosis as a result of photodynamic therapy serve as secondary endpoints.
The study is performed in a two-step setting. In step 1, patients are enrolled irrespective of whether or not the staging-CT shows PM. Step 1 is completed, when either 8 CT-positive patients (CT showing PM) or a minimum of 20 patients are included in total. The study proceeds to step 2, if FL was feasible in at least 75% of all patients (meaning 15 feasible FL in 20 patients) and if in at least 4 of 8 CT-positive patients PM could be confirmed by FL. Within step 2, only CT-negative patients are enrolled up to a total amount of 50 patients.
Study initiation as investigator-initiated trial (IIT) has been performed in May 2017. The study is supported by a AKF-Grant (341 – 1-0) of the University of Tübingen and a grant by Storz, Tuttlingen. Preliminary results show the feasibility of the system.