Arkansas bankruptcy filings.

It’s been called a “silent epidemic” that’s slowly wasting away the livers of millions of Americans while doctors have a paltry understanding of the disease and no approved treatments.

Nonalcoholic steatohepatitis is now in the sights of more than a dozen drugmakers. Allergan Plc became the latest, announcing last week two deals to acquire treatments for the disease. It’s racing companies from startup Intercept Pharmaceuticals Inc. to giants including Gilead Sciences Inc. and Pfizer Inc. to reach an untapped market that could be worth $5 billion to $10 billion a year, according to a May estimate by RBC Capital Markets Corp. analyst Michael Yee.

Drugmakers are still working to determine how different components of the disease — inflammation, scarring and metabolic changes — interact and are experimenting with a variety of treatment mechanisms.

Nonalcoholic steatohepatitis occurs when fat accumulates in the liver along with inflammation and damage, and as much as a quarter of the U.S. population may have a precursor condition called nonalcoholic fatty liver disease. The ailment develops slowly, and patients often don’t show symptoms until their livers are heavily damaged.

While doctors need to perform a biopsy to diagnose nonalcoholic steatohepatitis, between 6 and 15 million people in the U.S. alone are estimated to have the condition, and about 20 percent of them will go on to develop life-threatening cirrhosis. It will be the leading cause of liver transplants by 2020, according to Allergan. Drugs that treat it will likely command high prices, said Elizabeth Krutoholow, an analyst at Bloomberg Intelligence.

At the head of the race are Intercept and French biotech firm Genfit, with large trials underway. Tobira Therapeutics Inc., which Allergan agreed to buy last week for as much as $1.7 billion, is preparing to recruit patients for a final-stage study. Investors are also watching for results from two of Gilead’s midstage trials that are expected to be presented this year.

Intercept is testing Ocaliva, a drug already approved to treat a rare liver disease called primary biliary cirrhosis, against nonalcoholic steatohepatitis. CEO Mark Pruzanski said in an interview that he hopes Ocaliva will become a backbone treatment, used in combination with other drugs.

Genfit is developing elafibranor, a once-a-day-treatment that raises fat metabolism and fights inflammation, to “treat the underlying cause of fibrosis,” Dean Hum, Genfit’s chief scientific officer, said in an interview.

While elafibranor failed to meet a primary goal in a midstage trial last year, it showed promise in a subset of patients with moderate and severe forms of the disease.

Merck said it will pay as much as $450 million for its partnership with NGM. Gilead, maker of the blockbuster hepatitis C drugs Sovaldi and Harvoni, bought a drug from Nimbus Therapeutics LLC for $1.2 billion, including milestone payments. Before that, Gilead also bought a drug from Phenex Pharmaceuticals AG for as much as $470 million.

Gilead now has four candidates in its portfolio and will have data from two later this year. The drugs target different aspects of the disease and will be developed individually, but may be used in potent cocktails. Allergan’s Tobira Therapeutics is the biggest deal so far, and last week the company also announced a $50 million purchase of Akarna Therapeutics Ltd.

Pfizer, one of the nation’s largest drugmakers, may be a future acquirer. It has a drug in trials and two more to be tested in humans by the end of the year.

“Data is starting to come out of studies, and a lot of confidence will be built and lost,” said Jay Luly, chief executive officer of Enanta Pharmaceuticals Inc., which will begin testing an experimental treatment in patients this year. “The same, I expect, will happen with money.”