Britain’s Indivior is launching a new weapon to fight the U.S. opioid crisis this month. The company believes its long-lasting Sublocade injection, which is being launched in the United States in the week of Feb. 26, will become a blockbuster medicine, despite the fact initial sales are likely to be slow.

The FDA approved Sublocade (buprenorphine extended- release) injection for subcutaneous use last year. It is the first and only once-monthly injectable buprenorphine formulation for the treatment of moderate to severe opioid use disorder in patients who have initiated treatment with a transmucosal buprenorphine-containing product followed by dose adjustment for a minimum of seven days.

Sublocade is intended to be administered only by healthcare providers and should be used as part of a complete treatment program that includes counseling and psychosocial support.

“The net revenue potential of this product is well above $1 billion but we don’t want people to be unrealistic about what we will achieve in the first year,” the Indivior Chief Executive Shaun Thaxter said in an interview.

Sublocade represents a new approach to treating addiction. Instead of going to the pharmacy to pick up tablets or Indivior’s existing under-the-tongue film, the new injections will be delivered direct to doctors’ offices for administration.

Thaxter said it would take time for the new distribution model to bed down, adding: “We would expect to see some very noticeable sales growth by the last quarter (of 2018).”

Indivior has been treating addiction for more than two decades, initially selling tablets to help wean addicts off opioids including heroin and prescription painkillers. Now its big seller is Suboxone Film, which patients place under their tongue or inside their cheek once a day to suppress cravings.

Sublocade, which could be launched in Canada, Australia and Europe from late 2019, is the latest iteration and is designed to eliminate any risk that treatment could be diverted and misused by putting the product exclusively in the doctor’s office.

Competition is growing but Indivior has had some lucky breaks against rivals in recent months, with regulatory delays to both a rival long-lasting injection from Camurus and a generic version of its film from Dr. Reddy.

Ultimately, Indivior’s opioid addiction business could be in jeopardy if the epidemic of drug misuse is brought under control, but Thaxter said his researchers were widening their focus to other addictions, such as cocaine and alcohol.

“As we continue to expand the scope of our business beyond the opioid crisis to other addictions, there will continue to be sustainable business growth for shareholders as well,” he said.