Kolon TissueGene’s TG-C failed to demonstrate statistically significant efficacy over placebo in a U.S. Phase 3 knee osteoarthritis trial, while 104-week data showed no new safety signals.
Written By: Anamika Koshti, Pharm D
Reviewed By: Pharmacally Editorial Team
Kolon TissueGene has reported topline results from the TGC-15302 Phase 3 study (NCT03291470) evaluating TG-C in patients with knee osteoarthritis. The investigational cell and gene therapy failed to demonstrate statistically significant efficacy over placebo on the trial’s co-primary endpoints at 12 months, although the 104-week safety analysis did not identify new safety signals or unexpected adverse events.
Evaluating a Cell and Gene Therapy for Knee Osteoarthritis
TG-C is an investigational allogeneic cell and gene therapy developed for knee osteoarthritis and administered as a single intra-articular injection. The randomized, double-blind, placebo controlled Phase 3 trial enrolled 531 patients with knee osteoarthritis. Patients were followed for 24 months to assess efficacy and safety. The study evaluated changes from baseline in the Visual Analog Scale (VAS) pain score and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) total score as co-primary efficacy endpoints at 12 months.
Primary Efficacy Endpoints Fail to Reach Statistical Significance
The VAS pain score decreased by 38.7 points from baseline in the TG-C group compared with 39.2 points in the placebo group. The between-group difference was 0.5 points, with a 95% confidence interval of -4.3 to 5.3 and a p-value of 0.8322. WOMAC total scores decreased by 27.61 points with TG-C and 26.54 points with placebo. The between-group difference was -1.07 points, with a 95% confidence interval of -4.75 to 2.62 and a p-value of 0.5701. With both p values above 0.05, TG-C did not demonstrate a statistically significant treatment benefit over placebo on either co-primary endpoint. The topline results therefore failed to establish the efficacy objective of the TGC-15302 study.
Long-Term Safety Findings Remain Consistent
The 104-week safety analysis showed broadly similar treatment-emergent adverse event rates between the two groups. Events were reported in 83.9% of patients receiving TG-C and 78.1% of those receiving placebo. Severe adverse events occurred in 14.8% and 11.9% of patients, respectively, while serious adverse events were reported in 10.3% and 8.6%. Most reported adverse events were Grade 1 or 2. Kolon TissueGene said the long-term analysis identified no clinically significant new safety concerns or unexpected safety signals. The rate of total knee replacement was 0.6% in the TG-C group compared with 5.3% in the placebo group.
Company Plans Further FDA Discussions
Kolon TissueGene plans to assess the TGC-15302 findings together with results from a separate U.S. Phase 3 study of TG-C (NCT03203330) as part of future discussions with the U.S. Food and Drug Administration. The company has indicated that the high placebo response observed in the TGC-15302 trial will be considered in its ongoing analysis. The additional Phase 3 study, NCT03203330, is evaluating TG-C in patients with knee osteoarthritis and remains part of the company’s broader U.S. development program.
What This Means for Patients?
TG-C maintained a broadly consistent long-term safety profile in the TGC-15302 trial but failed to demonstrate statistically significant efficacy over placebo on its co-primary pain and function endpoints. Results from the additional Phase 3 study and subsequent FDA discussions will help determine the next development path for the investigational therapy.
Reference
Kolon TissueGene misses efficacy in US phase 3, pursues FDA talks – CHOSUNBIZ
About the Writer
Anamika Koshti (LinkedIn) is a PharmD professional and healthcare writer with interests in clinical research, pharmacovigilance, and evidence-based medicine. She has authored peer-reviewed publications on Alzheimer’s disease and PCOS, presented research at national conferences, and gained hands-on experience in medical content development and clinical data interpretation. She is committed to translating complex medical research into accurate, accessible content for healthcare professionals and patients.