The first-ever implant to fight addiction to opioids, a class of drugs that includes prescription painkillers and heroin, was approved by the U.S. Food and Drug Administration on Thursday (5/26).

The matchstick-sized implant, developed by Titan Pharmaceuticals Inc. and privately owned Braeburn Pharmaceuticals, is by design less susceptible to abuse or the illicit resale that plagues existing oral therapies.

Currently, two drugs are predominantly used to treat opioid addiction – methadone, which is dispensed only in government-endorsed clinics, and the less-addictive buprenorphine, which exists as a pill or strip of film.

The implant administers buprenorphine for up to six months after users have been stabilized on the oral form of the drug.

“I intend to make this the most successful implant that’s ever been marketed … and I think it’s absolutely possible given the unmet need,” Braeburn Chief Executive Behshad Sheldon said in an interview ahead of the FDA decision.

Fewer than half of the estimated 2.2 million Americans who need treatment for opioid abuse are receiving help, according to the U.S. Centers for Human and Health Services (HHS). Braeburn declined to forecast the potential size of the market for its implant, Probuphine.

The company estimated the U.S. market for opioid addiction treatments at about $2 billion, excluding methadone and Vivitrol, Alkermes Plc’s treatment for the prevention of relapse after opioid detoxification.

The market for long-acting therapies such as Probuphine could be even larger if attempts to raise the limit on the number of opioid addicts a doctor can treat are successful.

Under the current law, a doctor can treat only 30 opioid addicts within a year of obtaining a waiver, rising to a maximum 100 after procurement of a second waiver. The Congress and the HHS are working toward increasing this limit.

Of particular interest to Braeburn and Titan is a proposal that exempts from the patient cap any treatment directly administered by a physician, such as an implant or injection.

Probuphine’s path to approval has not been smooth. In 2013, the FDA rejected the implant, saying it needed additional data. After the submission of new trial data, FDA staff in January raised reservations about possible complications from the insertion and removal of the implant. Data also showed that some users continued to need oral buprenorphine. Despite these concerns, an independent panel of experts to the FDA voted largely in favor of the treatment.

Braeburn, in collaboration with Sweden’s Camurus AB, also has a weekly and monthly injectable buprenorphine formulation in late-stage development.

Britain’s Indivior Plc, which is also evaluating a long-acting injectable in a late-stage study, received the U.S. FDA’s fast-track status on Thursday (5/26) for the treatment.