Kolon TissueGene's osteoarthritis gene therapy TG-C, formerly known as Invossa-K in Korea, is approaching a significant milestone in its efforts to re-establish itself as a global pharmaceutical product. Kolon TissueGene is the subsidiary of Kolon Life Science.

The company announced the successful completion of patient dosing in its phase 3 clinical trial for TG-C in the U.S.

"This achievement comes 18 years after the initial FDA approval for phase 1 trials in 2006, a decade after the commencement of phase 3 trials in 2014, and four years after the FDA lifted the clinical hold on the trial in 2020," the company said.

The company stressed that this phase 3 trial is particularly significant as it marks the first instance of a Korean company conducting a trial involving over 1,000 patients in the U.S.

Approximately 1,000 eligible patients were selected from a pool of 6,800 applicants across 80 hospitals in the U.S., with dosing completed on July 10.

Kolon TissueGene will now monitor the treated patients for two years to track therapeutic outcomes, with results to be disclosed upon the conclusion of this observation period. Concurrently, the company plans to expedite preparations for FDA approval to bring TG-C to the U.S. market as soon as possible.

The company has also begun preparations for commercial production, collaborating with global contract development and manufacturing organizations (CDMOs) such as Switzerland's Lonza and Kolon Life Science's subsidiary Kolon Biotech.

"We expect the positive outcomes from the phase 2 trial in the U.S. will be replicated in the phase 3 study," Kolon TissueGene co-CEO Noh Moon-jong said. "We are committed to delivering meaningful results to our customers and shareholders who have trusted and waited for us."

Invossa, once hailed as the world's first gene therapy for osteoarthritis, received significant attention both domestically and internationally.

It completed Phase 3 trials for knee osteoarthritis involving 159 patients in Korea by 2016, leading to approval from the Ministry of Food and Drug Safety (MFDS) the following year. The treatment was subsequently administered to over 3,700 patients.

However, controversy arose in March 2019 during the U.S. phase 3 trials when it was discovered that one of Invossa's key ingredients was derived from kidney cells, not cartilage cells as originally claimed.

Kolon reported this to both the MFDS and the FDA. Consequently, the FDA imposed a clinical hold in May 2019, and the MFDS revoked Invossa's approval in July 2019.

Kolon contended that the misidentification of the cell origin did not affect the product's safety or efficacy, challenging the MFDS's decision in court.

The company has lost in both the first and second instances, with the courts upholding the cancellation of approval, and the case is currently pending before the Supreme Court.

In the U.S., the FDA accepted Kolon's explanation, lifting the clinical hold in April 2020 and allowing the resumption of phase 3 trials. The FDA also approved additional trials for TG-C in hip osteoarthritis (phase 2) and spinal patients (phase 1).