Mechanism of Action

Kybella (deoxycholic acid) is a non-human and non-animal formulation of deoxycholic acid, a naturally-occurring molecule in the body that aids in the breakdown and absorption of dietary fat. When injected into subcutaneous fat, Kybella causes the destruction of fat cells. Once destroyed, those cells cannot store or accumulate fat. The preference for fat cells leaves surrounding tissue largely unaffected.

Side Effects

Adverse effects associated with the use of Kybella may include, but are not limited to, the following:

Injection site edema/swelling

Hematoma

Pain

Numbness

Erythema

Induration

Dosing/Administration

Kybella is supplied as an injection for subcutaneous administration. Kybella is injected using an area-adjusted dose of 2 mg/cm2. A single treatment consists of up to a maximum of 50 injections, 0.2 mL each (up to a total of 10 mL), spaced 1-cm apart. Up to six single treatments may be administered at intervals no less than one month apart.

Clinical Trial Results

FDA approval of Kybella was based on two identical randomized, multi-center, double-blind, placebo-controlled trials in healthy adults (ages 19 to 65, BMI ≤ 40 kg/m2) with moderate or severe convexity or fullness associated with submental fat. Subjects received up to six treatments with Kybella (N=514, combined trials) or placebo (N=508, combined trials) at no less than one month intervals. Use of ice/cold packs, topical and/or injectable local anesthesia was allowed during the clinical trials. Injection volume was 0.2 mL per injection site, spaced 1 cm apart into the submental fat tissue, which is also expressed in dose per area as 2 mg/cm2. For each treatment session a maximum of 100 mg (10 mL) was permitted over the entire treatment area. Subjects were administered an average of 6.4 mL at the first treatment session, and subjects who received all six treatments were administered an average of 4.4 mL at the sixth treatment session. Fifty-nine percent of subjects received all six treatments. The co-primary efficacy assessments were based on at least two-grade and at least one-grade improvements in submental convexity or fullness on the composite of clinician-reported and patient-reported ratings of submental fat 12 weeks after final treatment. Reductions in submental fat volume were observed more frequently in the Kybella group compared to the placebo group. 68.2 percent of subjects responded to Kybella based on a composite of validated physician and patient measurements. Subjects treated with Kybella reported an improvement in the amount of fat in the area under the chin. Subjects also reported improvement in the emotional impact of submental fat when asked how happy, bothered, self-conscious, embarrassed, old or overweight they felt following treatment in relation to the amount of their submental fat.