[throwup238]

This is the correct answer. Biotech VCs invest very large amounts based on early scientific results and the vast majority of biotech companies go public before they even have revenue because they can't legally charge a penny until regulatory approval. This is how the pharmaceutical has been offloading their increasing R&D expenses onto the public since the patent cliff picked up speed in the 1990s.

A major PR push exposes them to as many investors as fast as possible both at the VC and public level. When the science is particularly solid, this process can happen fast and involve ridiculous amounts of money (i.e Sofosbuvir discovered 2007, first tested 2010, bought for $11 billion in 2011, approved 2013).