No drug has hit the market running like Gilead Sciences(NASDAQ:GILD) freshly approved oral hepatitis C drug Sovaldi. In a market that analysts estimate could be worth up to $20 billion, Sovaldi's made a huge impact in gaining regulatory approval first in the U.S. Some on Wall Street believe that Sovaldi could earn Gilead north of $8 billion in its first full year on the market alone, an astronomical sum that has blown out hype over this big biotech company's new star drug.

Yet investors have turned on Gilead recently, with much of the criticism coming over Sovaldi's hefty price tag. Enter its competitors in the oral hep C race, with big pharma's Merck (NYSE:MRK) looking to take its own bite out of this lucrative opportunity and aiming to knock Gilead and Sovaldi down a peg. Merck's combination hep C therapy of drugs MK-5172 and MK-8742 scored a 98% cure rate in a recent mid-stage trial, and the company's hoping for a victory in its currently underway phase 3 trial for the treatment as well.

Can Merck emerge as an under-the-radar contender to dominate the oral hepatitis C market and compete with Gilead for the billions of dollars at play? In the video below, Motley Fool contributor Dan Carroll takes you through what Merck's facing in its oral hep C combination therapy and whether you can believe in this stock as this hotly contested race heats up.

Dan Carroll has no position in any stocks mentioned. The Motley Fool recommends Gilead Sciences. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.