A sentence adverbial is simply an adverb (modifies a verb telling when, where, how, or to what extent). In this case, the adverb begins the sentence and refers to the sentence's content.
As for the content, I think this means that the strategy is designed to increase immunity in order to fight cancer cells, but, it just doesn't always work or it cannot be replicated, but, strikingly, the strategy (using the patented stem cell procedure) helps increase Vitamin C, thus leading to dominant antioxidant power--that in turn increases immunity which helps destroy cancer cells.
This. Is. Huge!!!!!!!!!!!!!
See you guys at a penny tomorrow.
All in my humble opinion.