Five vials of a live vaccine virus used to inoculate against smallpox were seized by the U.S. Marshals from stem cell treatment centers in California that had been used to treat cancer patients.

The “potentially dangerous and unproven treatment” combined a live version of the Vaccinia virus vaccine and stem cells that originated in body fat, and injected them directly into patients’ tumors, according to the U.S. Food and Drug Administration.

The treatments were apparently not approved by the regulatory agency.

“The FDA will not allow deceitful actors to take advantage of vulnerable patients by purporting to have treatments or cures for serious diseases without any proof that they actually work,” said Scott Gottlieb, the FDA Commissioner.

The Vaccinia virus vaccine was instrumental in eradicating smallpox in the 20th century – though it does not contain smallpox itself. Currently doses are reserved for people at risk for smallpox, including members of the military who may have to face a bioterrorism event.

The U.S. Marshals seized five vials of the vaccine on Friday. Each of the containers held approximately 100 doses of the vaccine. Four were recovered intact – but the fifth had been partly used.

StemImmune touts stem-cell-based immunotherapies capable of “unleashing a stealth attack on cancer” on its website. The company, which was founded in 2014, also contends it is working with the FDA on an investigational new drug application to allow a Phase I and Phase II clinical trial of its leading product candidate.

In a statement released to Laboratory Equipment, StemImmune said safety of patients is paramount.

"StemImmune... is fully cooperating with the FDA about the development and use of its stem cell-based investigational cancer therapy," the company said. "Our primary concern has and continues to be the safety and well-being of patients in clinical trials and compassionate use programs. At this time, we are working to understand and address the questions raised by the FDA about the use of our therapy for cancer patients in individual compassionate use programs in clinics. As more information becomes available to us, we will update this statement."

The contested treatments were administered to cancer patients at two California Stem Cell Treatment Centers, one in Rancho Mirage and the other in Beverly Hills.

The patients could have had compromised immune systems – and may have been at risk for adverse effects like heart inflammation, the FDA contends.

The people who were in contact with the patients may have been at risk additionally for becoming infected with the live virus used in the vaccine. The health effects could have included inflammation and swelling for at-risk unvaccinated people, including those who were pregnant, who had heart or immune system problems, or skin problems like eczema and psoriasis or other conditions, they FDA said.

“I especially won’t allow cases such as this one to go unchallenged, where we have good medical reasons to believe these purported treatments can actually harm patients and make their conditions worse,” added Gottlieb.

Smallpox has been considered eradicated since the last case was reported in Kenya in 1977 – although some advocate stockpiling the Vaccinia vaccines in case of a biological weapons terror attack.