Kolon TissueGene has encountered a setback in its Phase 3 clinical trial of the osteoarthritis gene therapy TG-C (formerly Inboza). The company plans to analyze the unexpectedly high placebo response before finalizing its development schedule and regulatory strategy.
On July 21, Kolon TissueGene held a press conference at the Kolon One & Only Tower in Gangseo-gu, Seoul, where it presented a summary of the top-line results from the first Phase 3 trial in the United States and its subsequent development plans.
Previously, Kolon TissueGene announced that while pain relief and joint function improvement were confirmed at the 12-month primary endpoints of the trial, statistical significance compared to the placebo group was not achieved.
In the first U.S. Phase 3 trial, TGC-15302, the change in Visual Analog Scale (VAS) scores was -38.7 for the TG-C group and -39.2 for the placebo group. The total change in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores was -27.61 for TG-C and -26.54 for the placebo.
These results are similar to or exceed data from previous U.S. Phase 2 and Korean Phase 3 trials. While the efficacy of TG-C was replicated compared to past clinical results, the company noted a significant placebo response.
Jeon Seung-ho, co-CEO of Kolon TissueGene, stated, "Our goal was to demonstrate a difference from the placebo group, but the placebo response was greater than expected. Commercialization is likely to be delayed beyond our initial timeline, and we plan to revise our development schedule once we analyze the causes of this response."
The company suggested that ethical considerations in osteoarthritis trials, such as the use of co-administered pain relievers, may have influenced the high placebo response.
Concerns regarding the safety of TG-C were not substantiated. The rate of patients who required knee joint replacement surgery due to worsening osteoarthritis was 0.6% in the TG-C group (2 out of 310) compared to 5.3% in the placebo group (8 out of 151).
The anticipated timeline for submitting a Biologics License Application (BLA) to the U.S. Food and Drug Administration (FDA) in the first quarter of next year and commercialization in 2028 is now more uncertain. Jeon emphasized, "Our goals remain clear, and we will define our direction based on the analysis results."
Kolon TissueGene is set to announce the results of its second Phase 3 trial in the U.S. in October. Although both trials followed the same protocol, they were conducted independently at different clinical trial sites with different evaluators and patient groups.
Meanwhile, as of 3 p.m. on July 21, Kolon TissueGene's stock price had dropped by 29.9%, hitting the lower limit. Jeon remarked, "This is not the end, and we hope you consider that there is still a journey ahead. We will continue to communicate transparently with the market."
* This article has been translated by AI.
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