Forsøksdyr: Pilot study ERP

Godkjenningsdato 04.09.2018

The purpose of this pilot experiment is to assess the anti-tumour potency of the Ether-Oxyde Ricino Polyoxyethylenic in a xenograft model. We have shown in vitro that ERP exhibits a selective and high anti-tumour potency against several cancer cell line. In order to be able to progress in the pre-clinical evaluation of the ERP, we need to demonstrate its in vivo efficacy, as required by the Norwegian health authorities.
For this purpose, a small number of NOD/SCID mice (in order to establish xenograft tumor model) in a solid tumor model system will be treated with ERP as a pilot experiment. A colorectal luciferase-experssing tumor cell line will be inoculated subcutaneously (s.c.) or intraperitonally (i.p.). After tumor establishment, an escalating dose of ERP will be administrated intra-peritonally or intra-tumorally (i.t.). Tumor growth will be monitored weekly by IVIS performed under gas anesthesia. Upon test against control tissue, ERP exhibited a complete innocuity. We can then hypothesize that none of the described procedures are expected to cause more than moderate discomfort and distress to the animals. Tumor and ERP will be delivered by syringe. The health condition of the mice will be monitored daily and animals will be euthanized according to given criteria and tumor load.
We are expected ERP to be used as a potent anti cancerous small molecule designed specifically to adress the challenge of metastatic solid tumors. This treatment could be use in combination with chemotherapy for example to boost its effect.
We plan to do two series of pilot experiment: one to estimate the therapeutic dose of ERP and its prefferred injection strategy (total number of animals 20), the second to confirm ERP anti cancer efficiency using theraputic dose previously determined (total number of animal 80 : 20 per site of injection, repeated twice).
Replacement: Tox/efficacy studies in relevant immunodeficient mouse models with tumor xenograft are formally required to document proof of concept and lack of toxicity before submitting a clinical study protocol to the Norwegian regulatory authorities.
Reduction: By doing a dose-escalating study we limit number of animals needed to find the threshold for concentration ERP that are toxic for the mouse.
We use Tumor cell lines that are transformed so we can follow tumor growth with a significant smaller amount of animals using in vivo imaging system (IVIS). The Lymphocytes are also transformed with Gaussia luciferase giving us the opportunity to follow the homing of lymphocytes using the IVIS and minimizing the need of blood samples or harvesting of tumor/ organs.
The experiment is designed with a minimum number of animals to be able to draw reliable and statistically significant conclusions.
Refinment: Using dose-escalation, instead of giving fixed doses to different trial groups, we will find the dose-dependent tolerance with less distress to the animals because all animals will then be given doses that are marginally more toxic than previous doses (which will already be known not to cause distress). We will use gas anesthesia instead of systemically administered anesthesia during IVIS to minimize the discomfort.