Kolon TissueGene finally broke silence amid a growing suspicion that it might have pretended to be unaware of the mislabeling of the drug ingredient of Invossa-K although it had known it two years ago.

Last Friday, the company said in a public filing it was aware in March 2017 that the cell ingredient of the second fluid of Invossa was not cartilage-derived but kidney-derived cells (GP2-293 cells).

Kolon TissueGene, a U.S.-based subsidiary of Kolon Life Science, initially developed the gene therapy for osteoarthritis.

The company has all the data about Invossa development and the master cell bank. The firm has the key to finding out why and how the second cell ingredient of Invossa was changed from cartilage-derived cells to kidney-derived ones. (Related article: Why is TissueGene CEO silent about Invossa mislabeling?)

After TissueGene’s disclosure on Friday and growing suspicion on an intentional cover-up of the mislabeling, the company released another statement on its homepage on Wednesday.

“The U.S. Food and Drug Administration’s letter stated that we should submit cell characteristics data for a resumption of the clinical trial. The FDA did not specify oncological clinical data or the reason why the company determined that the cells were not tumorigenic as the reason for the suspension of the clinical trial,” Kolon TissueGene said. “These were within the range of our expectations. Thus, we will do our best to submit data as soon as possible and get approval for a resumption of the clinical study.”

As for the reason why it did not disclose that it had received a test result from a manufacturing firm Lonza about 293 cells, which was four months before getting local approval, the company merely said, “We will make sure that all suspicions can be cleared through the inspection of the Ministry of Food and Drug Safety (MFDS) scheduled this month.”

Industry watchers said the company did not clarify whether it hid the mislabeling but only emphasized that it would resume the clinical trial in the U.S. Some critics said the company was excessively complacent about handling the issue.

“Normally, an FDA’s decision affects the local business significantly. The company seems to think that a resumption of the study in the U.S. will resolve the local issue altogether,” a biotech industry official said. “However, Invossa was already an authorized drug in Korea, whereas it was in the clinical stage in the U.S. The two are very different, but the company seems to be too naïve about the local problem.”

Another expert said Kolon TissueGene was too optimistic about the possibility of a trial resumption in the U.S.

Kim Byung-soo, a professor at the Catholic University of Korea, said the FDA could choose not to lift the trial suspension if it considered submitted data was not convincing enough.

“The company’s pinning hope on resuming the trial just because the FDA did not specify the reason for stopping the trial shows that the company is not judging the situation properly,” he said.

The data that the FDA demanded is not something the company can prepare in a short amount of time, he noted. “The company might have to write up a paper or conduct a trial all over again. However, it is saying as if it could shortly resume the trial,” Kim said, criticizing Kolon TissueGene.

Shareholders of Kolon Life Science and Kolon TissueGene have begun to lose trust in the companies. Some minority shareholders are joining the class-action lawsuit against the two firms, with a law firm and a civic group. Minority shareholders account for 56 percent of the stake in Kolon Life Science, and 38 percent in Kolon TissueGene.

The prosecution has started investigations on Kolon and the MFDS over the mislabeling of the Invossa’s ingredient.

On April 30, a civic group filed a complaint with the prosecution against Kolon Life Science and CEO Lee Woo-sok for violating the Pharmaceutical Affairs Act, and the MFDS and Food and Drug Safety Minister Lee Eui-kyung on charges of dereliction of duty in authorizing and managing drugs.

The Seoul Central District Prosecutors’ Office assigned the case to the Detective Two Division, led by senior prosecutor Kwon Soon-jeong. Specialized in medical crime, the team dealt with the humidifier disinfectant scandal.