Listen to this story.
Cat face
Photo courtesy of Salem Valley Veterinary Clinic
This cat is among the estimated 30% of patients with feline chronic gingivostomatitis whose condition doesn't improve after having their teeth removed. The poor coat quality with scurf and crusts around the mouth and eyes are signs of the inflammatory oral disease, according to the cat's veterinarian, Dr. Jordan Peters. Some owners of stricken cats have begun treating their pets on their own with an unproven imported product sold online.
A foreign business that produces an effective, if unauthorized, drug for a deadly cat disease is now selling a black-market compound to treat another difficult condition in cats. This time, doctors have strong doubts about the product, not the least because its full contents are a mystery.
Marketed under the name Mutoral, the compound is being promoted as a treatment for feline chronic gingivostomatitis by Mutian Sciences, a biotechnology company founded in China in 2018, according to its website.
The syndrome, known as FCGS or stomatitis for short, is characterized by ongoing inflammation in the mouth that can result in painful ulcers. Its cause isn't entirely understood, and there is no cure. The invasive act of extracting a cat's teeth can help ease the condition in many, but not all, cases.
Mutian is known to many U.S. veterinarians and cat owners as a purveyor of an illegal antiviral medication for feline infectious peritonitis (FIP), a devastating and usually lethal condition for which there has effectively been no legal treatment until recently.
For more than five years, some owners of cats diagnosed with FIP have been using Facebook to learn how to buy and administer the black-market treatment. While there have been many different unlicensed brands available, Mutian's was the main source for cat owners who responded to a 2020 survey about their use of the antiviral compound. That survey, conducted by a North American research team, found survival rates of 80% or better in treated cats, judging from owner reports.
Veterinarians, who couldn't legally be involved with the treatment, faced difficult decisions about how to safely and ethically support clients who had no treatment alternatives. A recent announcement that a compounded FIP tablet will be available as of June 1 might resolve that conundrum.
Like the treatment for FIP, the product for stomatitis — a pill obtainable online — is promoted in a private Facebook group, where members share their experiences, questions and frequently, testimonials.
There is, however, a crucial difference between Mutian's remedies for stomatitis and for FIP. The active ingredient in the FIP drug is a known antiviral compound that has been shown in multiple clinical trials to reverse the disease. By contrast, one of two active ingredients in the stomatitis product is a mystery.
The active ingredients in Mutoral are listed as moxifloxacin hydrochloride, an antibiotic used to treat bacterial infections, and something called MT-2071 (according to the package label) or MT-2073 (according to product information on the website). VIN News could find no information identifying the "MT" agent or any published or posted research on the efficacy or safety of Mutoral.
Researchers who study FCGS at veterinary schools at Cornell University; the University of California, Davis; the University of Pennsylvania; and the University of Wisconsin told VIN News they had no information about Mutoral.
"If somebody tells me what this is, how it works and why ... I'll start to be less skeptical about it," said Dr. Santiago Peralta, an associate professor in veterinary dentistry and oral surgery at Cornell, adding, "As far as I know, there is absolutely no scientific literature that would support its use."
Mutian did not respond to multiple queries sent by VIN News over the course of two months to email addresses associated with the company.
'A super-mysterious illness'
If the composition of Mutoral is a puzzler, so, too, is the condition it purportedly relieves. Peralta described stomatitis as a "super-mysterious illness." For starters, no one knows how many cats are affected. Estimates range from fewer than 1% to 12%; Peralta believes the lower estimate is more accurate.
Furthermore, no one knows its exact cause or causes.
A 2023 research review led by Dr. Maria Soltero-Rivera, who runs a stomatitis clinic at UC Davis, found that the disease likely is related to an aberrant immune response and probably is associated with feline calicivirus, a common pathogen in cats.
Affected cats typically develop inflammatory lesions throughout the mouth that can be moderately to severely painful. Other signs include decreased grooming or failure to groom, bad breath, being underweight and being withdrawn.
Surgical removal of all, or nearly all, teeth is the mainstay treatment, although exactly why extracting teeth can be beneficial is not fully understood.
Extraction cures about 30% of cats with stomatitis, substantially improves 40% and does not help 30%, according to Dr. Boaz Arzi, a UC Davis professor of veterinary dentistry and oral surgery. He calls those results "all over the place."
"If extractions were curing stomatitis," Arzi said, "we should [see an] 80%, 90% [or] at least 70% cure rate."
He suspects at least two disease processes could be at play: periodontal disease and stomatitis. For some lucky cats, removing the teeth might enable the periodontal disease to clear, taking pressure off the immune system, enabling it to successfully fight the stomatitis.
In cats that do not improve after extractions, medical management includes immunosuppressive or immunomodulation therapies such as steroids or cyclosporin; pain medication; and sometimes antibiotics.
"But some cats simply do not respond to any form of therapy," Peralta said. "And sometimes, the clients can't either provide proper care or support or they are just exhausted." In those cases, he said, euthanasia is a last resort.
A playbook from FIP experience
Dr. Jordan Peters, a resident in veterinary dentistry and maxillofacial surgery in Connecticut, first heard about the black-market stomatitis pill through a Facebook group devoted to FIP.
"Every now and then, somebody in that group will make a post about stomatitis because, you know, it's long been thought the disease may involve a viral component, and they're a bunch of people that have some experience with viral diseases in cats, so they share," Peters explained. In a post, he saw a link to a separate private group dedicated to stomatitis. The group was established by Mutian in December. Peters clicked through and was allowed to join.
Cat mouth
Photo courtesy of Salem Valley Veterinary Clinic
This view inside the cat's mouth shows severe, continued inflammation and erosion of the mucosa with secondary infections. If the patient had been cured by tooth extraction, all of its oral tissues would be the same light-pink color as the palate.
In his practice, Peters said, he and his mentor see an average of two to six cats with the condition every week. "When I see a refractory stomatitis appointment on my schedule, I grimace because I know it's gonna be a long, hard talk," he said, referring to cases in which tooth extraction didn't help. "And most of it is going to be explaining that there isn't going to be a cure and that the best that we can hope for is to manage it."
Peters has been monitoring the Facebook group because he's hopeful that Mutoral could help a lot of cats in the same way that the underground treatment for FIP has done.
"Most of the things I'm seeing are positive responses [to Mutoral] and questions," Peters said, noting that that group has grown markedly since he joined in January — from 300 members to more than 800 in early May.
Screenshots from the group reviewed by VIN News include owner posts showing their cats before and after treatment. "Before" images feature skinny felines with unkempt coats and stained, drool-covered muzzles. "After" images show cats with well-tended coats and clean faces. Some owners post pictures of their cats' mouths and gums that exhibit decreasing redness with treatment.
Peters said he can't be sure that these reports are a representative sample of Mutoral users' experiences, since comments are moderated. Once, he submitted a message asking pet owners with good or bad results to direct-message him about their experiences. His request was never posted.
Occasionally, some members of the group say the drug is not working or not working as well as they'd hoped.
The site administrators write that Mutoral is not effective in every case, and they dispense advice on whether to stick with treatment. They discourage use of the compound to treat other conditions or in lieu of having a cat's teeth removed.
VIN News attempted to contact the group administrators and received no response.
What's in Mutoral?
Mutian's website describes one active ingredient in Mutoral, MT-2073, as a JAK inhibitor. Short for "Janus kinase," JAK is a family of enzymes whose activity can induce inflammation, itching and pain.
A variety of JAK inhibitors have been approved by the FDA to treat medical conditions in humans, including rheumatoid arthritis, Covid-19 and certain blood cancers. Oclacitinib maleate is another approved JAK inhibitor. Sold under the brand name Apoquel, it is used by veterinarians to control atopic dermatitis and pruritus associated with allergic dermatitis. Neither MT-2071 nor MT-2073 is approved by the FDA, according to agency spokesperson Siobhan DeLancey.
Mutian claims on its website that results from a "15-week pivotal study" using MT-2073 to treat cats with stomatitis "show that the drug met co-primary endpoints and key secondary endpoints related to stomatitis symptom reduction and oral damage repair." The study itself is not provided.
Mutian
VIN News Service photo
A VIN News Service reporter ordered two versions of Mutoral from a Mutian website in March. A debit card used for the initial payment didn't go through, and the bank put a hold on the card. A second attempt with a credit card was successful. The treatments, which are intended to be given in stages, arrived a few weeks later from “Shipping 7170000000 Department” in Quentin, Pennsylvania. The order's cost of $168 would conceivably cover about one-sixth of the 12-week recommended treatment for a 5 kg cat.
Asked for his interpretation of Mutian's claim, Dr. Steven Valeika, a veterinarian in North Carolina with a doctorate in epidemiology, replied by email, "It's indecipherable."
He elaborated: "What were these primary and secondary endpoints? How were they measured? How many cats were in the study? What kind of study design did they use? Was it a randomized trial with a placebo group? Instead of actual data, they've put out a science-y sounding blurb."
Based on owners' positive reports on Facebook and many more anecdotal reports of the Mutian product saving many cats with its FIP product, Peters doesn't think Mutoral is "snake oil" or the equivalent of a sugar pill. He suspects that it really is a JAK inhibitor, and he'd like to see researchers in the U.S. find a way to study it.
UC Davis's Arzi and Cornell's Peralta say, that theoretically, a JAK inhibitor might be effective in treating stomatitis. "But theoretical doesn't necessarily mean 'efficacy,' " Peralta said.
Meanwhile, they are deep in their own efforts to find a cure. Peralta's team is working to better characterize the abnormal immune response. "If we are able to identify what kind of pathways are dysregulated in these cats, there may be a way to inhibit those pathways," he said.
His team also is trying to identify genetic risk in hopes of answering the question: "Why, in an environment with 10 to 20 cats, do only one or two develop the disease?"
Arzi and collaborators at UC Davis are focused on developing a treatment using stem cells.
"We went with the assumption that the immune system is struggling," he explained. "That is why we give stem cells, to essentially jumpstart the immune system or modulate the response." This differs from the current medical management approach, which uses steroids to suppress the immune response.
Based on the work, UC Davis has licensed a stem cell treatment to a veterinary regenerative medicine company called Gallant, which is running a clinical study for pet cats with stomatitis.
Back on Facebook, Peters, the practitioner in Connecticut, has mixed feelings about the unconventional group effort. He's heartened by the reports of good outcomes but worries that pet owners using social media to procure advice and unapproved drugs — drugs that veterinarians can't legally advise them about even if they wanted to — could undermine faith in veterinary medicine.
Moreover, he's concerned that unfettered use of the antibiotic in Mutoral, moxifloxacin, could promote development of drug-resistant pathogens. It is classified by the World Health Organization among the "highest priority critically important antimicrobials." Moxifloxacin is used to treat a variety of bacterial infections, including multidrug resistant tuberculosis.
Another Facebook user, Peter Cohen, is likewise wary. A cat lover in Southern California, Cohen was once a supporter of Mutian, having referred many people to a Facebook group called FIP Warriors that helped members buy underground treatments for FIP. But with the advent of Mutoral, he's disenchanted.
"This new drug from Mutian has no basis in research that I have been able to find, no scientific mechanism that would explain how it could possibly work and is NOT being recommended by FIP Warriors," he wrote in an email to VIN News. "It is garbage and could even be dangerous to cats. Please tell all who will listen to stay away from it."