In this June 2017 file photo, Barry Cadden, president of the New England Compounding Center, followed by members of his legal team, arrives at the federal courthouse for his sentencing in Boston.
CNN  — 

Barry Cadden, the former owner of a Massachusetts compounding pharmacy linked to a deadly 2012 multistate fungal meningitis outbreak, pleaded no contest Monday to 11 counts of involuntary manslaughter relating to the Michigan residents who died from contaminated drugs, prosecutors said.

More than 100 people died across the US, federal prosecutors have said. Among them, at least 11 Michigan residents who received injection treatments that were compounded and produced at the New England Compounding Center (NECC), which Cadden owned, according to a news release from the Michigan Department of Attorney General Dana Nessel.

The drug those residents were injected with was contaminated, the attorney general’s office said.

“Cadden ran his pharmaceutical lab with a shocking and abhorrent disregard for basic safety rules and practices, and in doing so he tragically killed eleven Michigan patients,” Nessel said in a statement. “Patients must be able to trust their medications are safe, and doctors must be assured they aren’t administering deadly poison.”

Cadden will have to serve between 10 to 15 years in prison, which will run concurrently with a federal sentence he’s already serving in connection with the outbreak, the release said. CNN was not able to reach an attorney for Cadden. His sentencing is scheduled for April 18.

Nearly 800 people in 20 states were diagnosed with a fungal infection in 2012 after receiving injections from contaminated vials of medicine manufactured by the NECC, the US Attorney’s Office for the District of Massachusetts has said.

The outbreak became the “largest public health crisis ever caused by a contaminated pharmaceutical drug,” the US attorney’s office said.

Bruce Singal, an attorney for Cadden, told CNN in 2017 their “thoughts and prayers” were with the outbreak victims and added he had “nothing more to say.”

Compounding pharmacists customize medications to fit an individual’s needs, and compounding pharmacies usually make only a couple of doses for a specific patient, which can lower the cost of production, CNN has previously reported.

The Michigan attorney general said Cadden “disregarded sterility procedures … and ran his business in an egregiously unsafe manner, endorsing laboratory directives wherein cleaning records and scientific testing results were regularly forced and fabricated.”

Cadden directed and authorized shipments of contaminated methylprednisolone acetate, a preservative-free steroid, to customers across the US, Massachusetts prosecutors said in 2021. He authorized the drug shipments before they were confirmed to be sterile, did not notify customers when they were not sterile, and compounded drugs with expired ingredients, the US Attorney’s Office in Massachusetts said.

“Cadden also repeatedly took steps to shield NECC’s operations from regulatory oversight by the FDA by claiming to be a pharmacy dispensing drugs pursuant to valid, patient-specific prescriptions,” the office said in their 2021 release. “NECC routinely dispensed drugs in bulk without valid prescriptions. NECC even used fictional and celebrity names on fake prescriptions to dispense drugs, such as ‘Michael Jackson,’ ‘Freddie Mae’ and ‘Diana Ross.’”

In 2017, Cadden was sentenced to nine years in prison after he was convicted in federal court of more than 50 charges – including racketeering and racketeering conspiracy. He was resentenced in 2021 to 14.5 years in prison and ordered to pay forfeiture of $1.4 million and restitution of $82 million, according to a news release from the US Attorney’s Office for the District of Massachusetts.

More than a dozen people linked to the compounding pharmacy have been convicted in connection with the outbreak, CNN has reported.

Among them, a former co-owner, vice president and general manager of the compounding pharmacy, who was convicted in 2018 of conspiring to defraud the United States and sentenced to one year in prison and one year of supervised release, CNN has reported.

A former supervisory pharmacist was also resentenced in 2021 to 10.5 years in prison and three years of supervised release and ordered to pay more than $470,000 forfeiture and $82 million restitution after he was convicted of more than 70 federal charges, including racketeering and racketeering conspiracy, according to the US Attorney’s Office for the District of Massachusetts.

The NECC and several affiliated companies reached a $200 million settlement in 2015 with the victims and their families across the US – and $10.5 million was designated for the Michigan victims and their families, according to the news release from Nessel’s office.