Pharmaceutical companies across the United States are racing to develop the first treatments for nonalcoholic steatohepatitis (NASH), a slow, silent, obesity-related disease that is destroying the livers of millions of Americans.

Allergan Plc recently joined drug-making heavyweights Pfizer Inc., Gilead Sciences and Intercept Pharmaceuticals in the race to break into the market, making a series of deals worth nearly $1.7 billion aimed toward developing new NASH treatments, Bloomberg reports.

Industry analysts say the thus-far untapped market for NASH treatment could be worth between $5 billion and $10 billion a year. The disease occurs when fat accumulates in the liver, along with inflammation and scarring. Nearly one quarter of the U.S. population has a precursor to the condition called non-alcoholic fatty liver disease, or NAFLD, which like other liver diseases, develops slowly and without symptoms until irreversible liver damage occurs.

There are currently no approved treatments for NAFLD or NASH, but people can prevent the condition through diet changes and weight loss. Right now, drugmakers are looking to determine how different components of the disease, such as inflammation, metabolic changes and liver scarring, interact and are experimenting with a number of treatment mechanisms.

At the head of the race at the moment are New York City–based Intercept and French biotech firm Genfit, both of which have large clinical trials under way. Tobira, one of the companies Allergan acquired in its $1.7 billion bid for NASH treatment, is preparing to recruit patients for a final-stage study. Gilead is also in the midst of conducting two mid-stage trials, the results of which are to be presented later this year. Pfizer, the largest U.S. drugmaker, has one NASH drug currently in trials and is expected to acquire treatments in the future.

However, achieving a NASH treatment won’t be easy. Already, past trials at Genfit and Tobira have failed. Earlier this year, Raptor Pharmaceutical Corp. ended its NASH program. However, with about 6 million to 15 million people in the U.S. alone estimated to have the condition, it’s bound to be a profitable market for those who develop effective therapies.