NEWPORT BEACH, CALIF. – It’s unclear how well deoxycholic acid (Kybella) will work in the clinic because doctors and patients are generally opting for fewer injections and fewer treatment sessions than were evaluated in phase III studies, according to Lawrence Bass, MD.
The fat cytolytic was approved in 2015 for shrinking double chins, with up to six 50-injection sessions. In trials, patients tended to get more than 40 shots in their first two sessions and more than 30 in subsequent sessions. At that dosing, 40.5% of patients in one trial and 46% in another lost at least 10% of their submental volume on MRI, according to Food and Drug Administration review documents.
Dr. Lawrence Bass
However, at the Summit in Aesthetic Medicine, Dr. Bass, a plastic surgeon in New York City, said that, in clinical practice, patients are typically being treated with 20 injections for two or three sessions – partly because of cost. “This product costs $300 for each 2 mL vial, which means in a typical 20-injection treatment, you use $600 of material,” he noted. An average treatment session in Manhattan costs patients about $1,500. In other parts of the country, sessions are probably around $1,200 each, he added.
Also, the necks of patients enrolled in trials “had to be pretty big, but the necks we are probably going to treat with this are the smaller and medium ones. The big ones are just going to do liposuction or something else,” he said. Given all the variables, “we don’t know how well the study experience is going to match clinical experience.”
Dr. Bass treated his first postapproval patient, a 52-year-old woman, with two 20-injection treatment sessions 2 months apart. “The fat definitely cleaned out” and her skin looked a bit tighter, but it’s tough to know if her skin truly tightened or simply draped flatter, he said.
FDA labeling notes that “the safe and effective use of Kybella for the treatment of subcutaneous fat outside the submental region has not been established and is not recommended,” but this advice is unlikely to keep doctors from trying it in off-label areas.
One issue is that “almost every other area is a whole lot bigger” than a double chin, Dr. Bass said. Treating a tummy with 50 injections six to eight times, for example, would cost patients $12,000-$15,000, which is “a whole lot more than lipo,” he added.
Also, administering more than 50 injections at a time for a larger area is not possible because of toxicity. Trying to get around that limit and cut costs by diluting deoxycholic acid or spacing the injections farther apart doesn’t seem to be an option, since phase II testing showed a loss of efficacy with that approach.
Dr. Bass tried deoxycholic acid on a woman with leftover tummy bulges following liposuction. After two 40-injection sessions, “there was still a little shape there, so I don’t think I’ll be doing that again,” he said at the meeting, which is held by Global Academy for Medical Education. Global Academy and this news organization are owned the same company.
Gynecomastia, meanwhile, would probably require too many shots, and the jowl, another potential target, is too close to the marginal mandibular branch of the facial nerve, “so you are not supposed to inject there,” Dr. Bass said. Diluted deoxycholic acid might be an option for bulging periorbital fat, “but I am going to let somebody who is braver than me try that for a while before I go there.”
Dr. Bass is an investigator and speaker for Cynosure, an investigator for Endo Pharmaceuticals and Neothetics, and an advisor to Merz. He participated in phase III testing of deoxycholic acid.
The indication approved for deoxycholic acid is “for improvement in the appearance of moderate to severe convexity or fullness associated with submental fat in adults.”