Kolon TissueGene's gene-therapy knee treatment TG-C, formerly sold in Korea as Invossa, missed its primary goal in a US Phase 3 trial. Topline results released July 20 showed patients who got TG-C saw their pain score (VAS) drop 38.6 points and function score (WOMAC) drop 26.34 points over two years. Patients who got a saline placebo injection did slightly better, dropping 39.1 and 27.57 points respectively. There is one twist. Only 2 of 310 TG-C patients (0.6 percent) needed total knee replacement surgery during the trial, versus 8 of 151 placebo patients (5.3 percent). That gap hints TG-C may have slowed the underlying joint damage even though it did not beat placebo on subjective pain scores. Kolon TissueGene ran two near-identical Phase 3 trials about five months apart, and the second one, trial 12301, reads out in October. The US Food and Drug Administration typically wants two independent pivotal trials to show consistent results before approving a drug, so a second miss would make approval even less likely. TG-C is the same drug that triggered a scandal in 2019, when regulators discovered one of its two injected components was not the cartilage cell it was labeled as. The stock has been drifting lower since May, well before this readout.
Why it matters · The pain endpoint failed but the surgery-avoidance signal favors TG-C, making October's second trial the swing factor for FDA approval odds.
Worth asking · TG-C missed its main goal but beat placebo on surgery avoidance. Does the real verdict wait for October's second trial, or is the answer already in?