Do a blood glucose level. And blood insulin.

In the primary stage it is possible.If the stage of cancer and the nature of drug is known, after that we can find the solution and analyse data.

Rob, I would suggest it is a modifier of metabolism. I founded already some animals study demonstrated that delta-9-THC and others may shift a appetite. Our novel drugs are different cmpds.

it is normal for animals to have a change in behaviour. Pls bear in that its unethical to keep them on the regime if there is a 20% weight loss.

I checked it already we do not have it even at high dosage.

Thank you, Rob! We did full panel of Agilent microarrays last spring.

Maybe some hormone was affected. For example, thyroid hormones elevated, like human being have hyperthyreosis.

Enhanced appetite is a common side effect of many drugs, especially those affecting the CNS (and I imagine to treat a glioblastoma, you've got to have a hearty drug to penetrate the blood brain barrier). Examples of drugs with the side effect of enhanced appetite are sodium valproate (epilepsy), vilazodone (antidepressant), risperidone (schisophrenia), hydroxyzine (depresses CNS and antihistamine) and Alprax (up to 30% of users have this side effect) and many hormones . The list goes on.

I suggest you try to quantify the incidence of the side effect by housing the subjects individually and feed ad libitum, but measure consumption ( and animal weight of course). If the animals are housed in groups, you can't tell whether all exhibit the effect, or only a certain percentage. Plus tests such as those suggested by Rob may put a more clinical edge on it; you might mimic the tests that were run for approval of other CNS drugs with this side effect, because ultimately that's what will be asked for.

Such a side effect isn't the end of the world; look at what prednisone does, yet users have to endure it for the good effects.

Thank you Kristine, we did it on group of mice. They gained weight (about 7.5%) probably due to high food consumption but loose it after a week of the drug withdrawn.

This suggest that it is a side effect of the drug.

Have you tried different doses and tested the effect?

Yes, we did.

Does the effect decease by lowering the dose?

Yes, it does.

It sounds that your data support that it is a side effect of your drug. Perhaps amelioration of the dose with a time course study and personnel genetic profiling would sort your problem. I also suggest to try different route of administration to avoid or mitigate this effect.