AstraZeneca - what a wild ride

I bought AZN first back in Feb 2012, and topped up (tripled) my position in July 2013; purely based on fundamentals. And now the stock is “in play” because of talks of being acquired by Pfizer (PFE) or GlaxSmithKline (GSK).

Not sure if I should hold on or sell right now. I am sitting on about 65% gain, 70+% if you don’t count reinvested dividends.

Any insights?