WH-word

[Gomery]

Scientist have broken new ground in the search for an Alzheimer's cure, discovering a new potential cause of the disease, which it may be possible to target with drug treatments.

Subject : Scientist
Verb : have broken
Object : new ground in the search for an Alzheimer's cure
noun phases : discovering a new potential cause of the disease

I don't understand "Which" and "it" is refer to what?
Would someone can explain these words?

 

[probus]

Both "which" and "it may be possible to target " refer to "disease".

 

[Raymott]

I reckon they refer to "cause".
It's the new potential cause that may be possible to target with drug treatments.