long before pass FDA approval. In many cases, once the it passed phase one, it is signed up with a big pharma already as co-development. If the phase II data is good, the big pharma will invest further by buy part of the equity of the company. A targeted $500 MM sales drug could cost more than $100 milion in phase III. Not to mention it might fail.
Even a very small biotech could be very expensive to most chinese companies to buy. As the development process goes further, the price tag goes higher. To invest in biotechs, you need to buy a portfolio of biotechs to ensure there some of them will succeed eventually. There is not many Chinese companies could afford to do that. Not many chinese companies have the vision to do that either.