GC's Hunterase, a treatment for Hunter syndrome, has finally obtained full approval, 11 years after receiving conditional approval, the company said on Friday. 

After being designated as an orphan drug in September 2011, Hunterase, the world's second treatment for Hunter syndrome, received conditional approval on Jan. 9, 2012, contingent on conducting a phase 3 clinical trial.

Despit winning conditional approval, Hunterase faced delays in full approval due to challenges in patient recruitment and clinical design discussions, given the rare nature of the disease.

The phase 3 clinical trial plan was finally approved on November 18, 2016, and the trial evaluated the efficacy and safety of the enzyme replacement therapy in Hunter syndrome patients without prior treatment experience.

The phase 3 clinical trial results were completed in March of this year and submitted to the MFDS in May.

Following the review of the phase 3 results and completion of a Good Clinical Practice (GCP) inspection, the ministry amended the approval status to an official approval.

Notably, the phase 3 trial, which targeted Hunter syndrome patients over the age of five with no prior enzyme replacement therapy experience, demonstrated statistically significant superiority when comparing patients who received Hunterase intravenously once a week for 52 weeks to a placebo control group.

"The fact that Hunter syndrome is a serious and life-threatening rare disease, along with the high unmet medical demand and the practical difficulties in conducting confirmatory clinical trials, has led to the drug being supplied to patients under conditional approval," a GC official said. "The significance lies in completing the phase 3 trials, which has met the conditions to receive an official approval."

While the phase 3 clinical trial report took six years to obtain, the company was able to meet the conditional compliance criteria more than three years ahead of schedule initially discussed with the MFDS, he added.

Hunter syndrome, also known as mucopolysaccharidosis type II, is a rare disease that occurs at a rate of 1 in every 100,000 to 150,000 male births, characterized by skeletal abnormalities, cognitive impairment, and various other unpredictable symptoms, which can lead to death before the age of 15 in severe cases. There are approximately 70-80 patients in Korea.