Gilead Sciences Inc.'s Sovaldi was a real breakthrough in the fight against the chronic liver disease hepatitis C (HCV). The condition may show no symptoms for years after initial infection but can slowly become debilitating.
Hepatitis C affects as many as 200 million people worldwide, and before Sovaldi, the approved drug regimen could treat only about 50% of cases and could cause serious side effects. Treatment was generally long - 24 to 48 weeks - and arduous.
Sovaldi, on the other hand, could cure more than 90% of cases in a matter of weeks at a cost, in the United States, of around $94,000. The pricing caused controversy, but the drug proved transformative for HCV patients, their families, and doctors.
Sovaldi also proved a huge windfall for investors when it received FDA approval in 2013 and entered the pharmaceutical marketplace the following year.
So far, Gilead shareholders have seen a 2:1 split, several dividend payouts, and gains of more than 155% since 2013. Sales of Sovaldi and Gilead's other HCV drug, Harvoni, topped $12.5 billion in 2015 alone.
In the pharmaceutical industry, a "blockbuster" is any drug that brings in $1 billion or more in revenue per year.
It's the prize that every biotech hopes to win - and every biotech investor hopes to cash in on.
So how do you spot one in the making? If the market suspects a drug candidate has blockbuster potential, catalysts (events like positive clinical study results and regulatory milestones) will give its manufacturer's share price a big, big boost.
There is no crystal ball that's 100% accurate when experimental drugs are concerned, but here are some telling questions that can narrow your search...
Last week's $45.2 billion Time Warner-Comcast deal pushed the global deal tally to $336 billion so far this year - the most since 2007 - and another blockbuster deal announced this week will push that figure even higher.
On Tuesday Irish drugmaker Actavis PLC (NYSE: ACT), producer of generic and specialty urology and women's health products, agreed to buy New York-based Forest Laboratories Inc. (NYSE: FRX) for $25 billion.