A leading biochemist admitted Friday that she stole proprietary information potentially worth millions of dollars from a GlaxoSmithKline research facility in Montgomery County in hopes of launching a rival business in China with backing from that nation's government.

Yu Xue, 48, of Wayne, told a federal judge in Philadelphia that she pilfered promising therapies for cancer and other ailments, many of which she developed while working at the British pharmaceutical giant's Upper Merion location between 2006 and 2016.

The case is the latest in a string of recent prosecutions of Chinese American scientists accused of smuggling trade secrets stolen from U.S. companies to bolster China's competitive edge in science and technology fields.

"I'm very, very sorry for this mistake I made," Xue, a naturalized U.S. citizen, told U.S. District Judge Joel Slomsky. "At the very beginning I didn't have any intention of trying to steal anything."

But even as she was pleading guilty, Xue questioned the value and importance of the research she stole – auguring a debate over the seriousness of her crimes that is sure to dominate her sentencing in December.

"You can find all of the patents in the public domains, so I think the information I sent is not a trade secret," she told Slomsky. "A trade secret to me is not a publicly available [document]. The patents I sent to them is publicly available."

Assistant U.S. Attorney Robert J. Livermore disagreed.

"There are vast differences between the parties as to the value and importance of the information stolen," he said.

Still, Xue's guilty plea delivered a significant win to the U.S. Justice Department, which prior to her case had suffered a series of embarrassing setbacks in corporate espionage cases involving Chinese American scientists.

Both the Trump and Obama administrations have accused Chinese spy agencies of encouraging their nation's businesses to steal trade secrets from American corporations, and have made stanching that flow a priority. But recent high-profile blunders have prompted critics to accuse federal authorities of racial hysteria reminiscent of the Red Scares of the 1950s.

Prior to Friday's hearing, Xue's lawyer, Peter R. Zeidenberg, had likened her case to that of another scientist he represented — Temple University professor Xiaoxing Xi.

Authorities charged Xi with stealing sensitive U.S. technology in the field of superconductivity in May 2015, only to withdraw the case four months later after his legal team showed that agents had misunderstood the science, and that the information they had accused Xi of stealing had already been widely circulated in the public domain.

Yu Xue,  accompanied by her attorney, Peter Zeidenberg, attempts to block her face with her bag as they exit the federal courthouse in Philadelphia, Friday, Aug. 31, 2018. Xue, a cancer researcher, pleaded guilty to conspiring to steal biopharmaceutical trade secrets from GlaxoSmithKline.
Matt Rourke / AP
Yu Xue,  accompanied by her attorney, Peter Zeidenberg, attempts to block her face with her bag as they exit the federal courthouse in Philadelphia, Friday, Aug. 31, 2018. Xue, a cancer researcher, pleaded guilty to conspiring to steal biopharmaceutical trade secrets from GlaxoSmithKline.

In the 10 months preceding that decision, Justice Department lawyers also withdrew cases against four other Chinese American scientists across the country accused of passing along protected information, including allegations against two former senior biologists at GSK competitor Eli Lilly & Co.

Yet from the day FBI agents arrested Xue in late 2015, it was clear that they were confident that her case would not end in another public embarrassment.

The 45-count indictment against her and five co-defendants — including her twin sister, a brother, and another colleague at GSK's Upper Merion branch – contained long passages quoting the group's email exchanges, including several in which they appeared to acknowledge what they were doing was wrong and worried what would happen if they got caught.

When news of the trade secrets case against the Lilly scientists broke in 2013, Xue sent a brief email to one of the conspirators.

"So scary," she wrote, according to court filings. "Please do not send any doc containing GSK data out to others."

Nonetheless, prosecutors allege that between 2012 and 2015 Xue and a GSK colleague — Lucy Xi, 38, of Westlake Village, Calif. – continued to sneak dozens of confidential documents out of the company over email or by downloading them onto thumb drives. They shipped them to colleagues preparing to launch the rival firm, Renopharma, which they had established to exploit the research in China.

Xue, regarded as one of the top protein biochemists in the world, received a doctorate from the University of North Carolina before arriving at GSK, where she worked as a research scientist and senior-level manager.

She and her fellow conspirators were not directly charged with corporate espionage – an offense that would require prosecutors to prove involvement of a foreign government. Instead, she pleaded guilty Friday to one count of conspiracy to steal trade secrets, an offense punishable by up to 10 years in prison.

Still, prosecutors suspect there was at least some level of involvement by Chinese government officials in setting up and backing Xue's company.

U.S. economic officials have accused China of setting up government-backed funds aimed at luring Chinese American scientists back to their native country and encouraging them to bring privileged technology and science research with them.

In one August 2012 message cited in the indictment, Xue identified two key Chinese officials whom she felt confident she could persuade to invest in Renopharma through a "special government fund," and laid out plans to give them "expensive gifts" to cement their support.

Renopharma's own financial records from March 2014 list the equivalent of about $300,000 the company received from various government-backed funds in China that year.

Zeidenberg, however, has insisted there was nothing nefarious about those payments and likened them to economic development grants routinely doled out by state and local governments in the United States.

He declined to comment after Friday's hearing, but suggested in court that investigators also had misunderstood his client's intent and the significance of the information she stole. He cast her decision to plead guilty as an effort to move past questions about what she did to ones about what it all meant.

"We are now litigating what's truly at issue in this case," he said. "As opposed to what actually happened, we've ended up where we were going to end up anyway: What was the significance of that?"

One of Xue's codefendants is expected to plead guilty in September. Three others are scheduled for trial in October.