Gilead Sciences (GILD -0.82%) is known for several things. It's a leader in developing HIV drugs such as Truvada and Genvoya. The company's drugs Sovaldi, Harvoni, and Epclusa have changed the landscape in treatment of hepatitis C. Gilead is now one of the biggest biotechs in the world.

But there's more to Gilead Sciences that you might realize. Here are seven things you probably didn't know about the big biotech.

A pile of Gilead Sciences' Truvada pills.

Image source: Getty Images.

1.The company is named after an ancient medication 

Gilead Sciences was originally named Oligogen when it was formed in 1987. However, its name was soon changed to Gilead Sciences, which does roll off the tongue much more easily than Oligogen. The name was inspired by the balm of Gilead, an ancient medicine referenced several times in the Bible.

2. The company tried (unsuccessfully) to woo Warren Buffett 

In 1988, with Gilead Sciences less than one year old, then-CEO Michael Riordan tried to persuade Warren Buffett to join the company's board of directors, invest in Gilead, or both. Buffett responded in a handwritten note that stated, "Sorry, but I would bring nothing special to the enterprise, except for my name." Riordan gave it one more shot, replying to Buffett by saying, "Mr. Buffett -- you are very modest." Buffett, of course, didn't join Gilead's board, nor did he invest in the biotech.

3. It took nine years before Gilead won its first drug approval

Gilead's first drug won regulatory approval in 1996, almost exactly nine years after the company was founded. That drug was Vistide, which was approved in the U.S. (and later in Europe) for treating cytomegalovirus retinitis in patients with AIDS. Gilead's initial sales force to promote Vistide consisted of 26 sales representatives and three regional directors.

4. One of Gilead's key early partners is now a major rival

Like many clinical-stage biotechs, in its early years Gilead Sciences sought out larger partners. One of those partners, Glaxo Wellcome, collaborated with Gilead in researching genetic code blockers. The two companies worked together for eight years before terminating the collaboration agreement. This early partner, now known as GlaxoSmithKline, is one Gilead's most significant rivals in the HIV market these days. Glaxo's HIV drugs Tivicay and Triumeq have been very successful, combining for sales of around $3.4 billion last year.

Money flowing into black hole

Image source: Getty Images.

5. Gilead was unprofitable for 14 years

Gilead didn't become profitable until 2001 -- 14 years after the company began operations. The company reported net income in 2001 of $52.3 million on total revenue of $233.8 million. Ambisome, an injectable fungal treatment that Gilead picked up with its 1999 acquisition of NeXstar Pharmaceuticals, contributed 70% of Gilead's revenue that year. The drug's sales last year were more than twice as high as they were in 2001, but Ambisome now makes up barely over 1% of Gilead's total revenue. 

6. It has the best cash flow of any biotech

Over the past 12 months, Gilead's levered free cash flow was $13.8 billion. That's better than any other biotech on the planet, including several that claim larger market caps than Gilead. While Johnson & Johnson narrowly edges Gilead in free cash flow, it's not an apples-to-apples comparison, since much of J&J's cash stems from its consumer and medical-device business segments.

7. Gilead stock is up more than 10,000% since its IPO 

Warren Buffett might regret not investing in Gilead Sciences when asked to do so back in 1988. Since Gilead held its initial public offering (IPO) in 1992, its stock is up more than 10,000%. If you had bought $10,000 of the biotech's shares back then and held on, you'd be sitting on a position worth around $1 million today. And it would have been much higher than that not too long ago. At its peak in early 2015, Gilead stock was up around 17,500% since its IPO.