American biopharmaceutical company Titan Pharmaceuticals has submitted a New Drug Application (NDA) to the US Food and Drug Administration (FDA) for Probuphine, designed to treat adult patients with opioid dependence.

Probuphine, which is the subcutaneous implant formulation of buprenorphine hydrochloride, is claimed to deliver six months of medication following a single treatment.

Commenting on the submission, Titan Pharmaceuticals president Sunil Bhonsle said; "Not only does this key milestone mark a significant step forward for Titan and our shareholders but, most importantly, we believe that Probuphine, if approved, will provide an important treatment option for patients and physicians."

Titan also sought a priority review of Probuphine based on the pre-NDA meeting outcome and by referring to the approved sublingual tablet formulations of buprenorphine.

"We are extremely pleased to submit this NDA, including our request for a priority review of Probuphine, following the successful manufacture of the first commercial scale batch in the new production facility," added Bhonsle.

All priority-designated submissions will be reviewed by the FDA at a target date of six months, as per the prescription drug user fee act (PDUFA), while it is 10 months for standard review submissions, said the company.

As part of its clinical trials to study the effectiveness and safety levels of Probuphine, Titan performed a 24-week placebo-controlled study on 163 patients that revealed significant treatment benefits.

A 287-patient confirmatory study resulted in improved efficacy over placebo alongside demonstrating non-inferiority with the currently available daily dosed sublingual formulation of buprenorphine, which according to the company posted US sales of about $1.3bn in 2011.

Two open-label safety studies were also conducted, which offered six more months of Probuphine treatment for all the patients who finished the controlled study.

The company’s potential partner, who announced an investment of $4.25m in Titan during September, has offered further support in commercialising the formulation and extended the option to execute the proposed licensing agreement to 31 December 2012.

There are about 6 million people in the world with opioid dependence, out of which nearly 50% are addicted to illicit opioids such as heroin, while the remaining people are addicted to prescription drugs such as oxycontin, methadone, and codeine, Titan said.

Probuphine, which was well-tolerated in all clinical studies, is the company’s second product, with the first being Fanapt (iloperidone), an atypical antipsychotic drug.