Why is it drugs targeting the ischaemic cascade* have been unsuccessful in trials?

Cris Cerebrale – CNS Diseases Case Study

Why is it drugs targeting the ischaemic cascade* have been
unsuccessful in trials?

You should cite a specific example of a target and drug that have
been trialled in humans, together with the outcome in animals and
humans (150-200words) followed by a general discussion of the
problems that have been encountered when targeting the
ischaemic cascade therapeutically and translating outcomes in
animals to humans (250-350 words).

Make sure to include a diagram of the ischemic cascade and
where/how drug interacts with the pathway.

* – your drug must act on a target within the ischaemic cascade
and be neuroprotective this means NO thrombolytics