What it means for a patient
- ATX-101 is approved in the United States and Canada to reduce fat under the chin.
- Most treated subjects improved by at least 1 grade. A 2-grade improvement was less common (13.4%).
- More treatments gave more responders in this trial: 55% after 2 treatments, 75% after 4.
- Temporary weakness of the nerve that moves the lower lip was reported at a rate of 4.3% among treated subjects. It was mostly mild and resolved.
- Most other side effects were at the injection site, mild or moderate and short-lived.
Why this paper matters
It reported phase 3 results for ATX-101 with an MRI measure of fat volume and a count of nerve side effects. The authors describe ATX-101 as a safe and effective first-in-class injectable drug for submental fat.
Overview
ATX-101, an injectable form of deoxycholic acid, is approved in the United States and Canada for reducing submental fat. REFINE-1 was a multicenter, randomized, double-blind, placebo-controlled phase 3 trial. Subjects dissatisfied with their moderate or severe submental fat received ATX-101 (2 mg/cm²) or placebo. The main outcomes were composite 1-grade and 2-grade improvements on clinician and subject scales 12 weeks after the last treatment. MRI gave an objective measure of volume.
Findings
- 256 subjects received ATX-101 and 250 received placebo.
- Composite response of 1 grade or more: 70.0% with ATX-101 vs 18.6% with placebo (p < .001).
- Composite response of 2 grades or more: 13.4% vs 0% (p < .001).
- MRI responders: 46.3% vs 5.3% (p < .001), more than 8 times higher with ATX-101.
- Treated subjects reported improvement in the psychological impact of submental fat and satisfaction with treatment (p < .001 for all vs placebo).
- Clinician-rated 1-grade improvement among ATX-101 subjects: 55% after 2 treatments, 75% after 4.
- Adverse events were mostly mild or moderate, transient and located at the injection site.
- Marginal mandibular nerve paresis was reported at a rate of 4.3% among ATX-101 subjects (1.0% across all ATX-101 treatment sessions).
- The nerve paresis was mostly mild and transient and resolved without lasting effects.
Terms
- Submental fat (SMF): fat under the chin.
- ATX-101 (deoxycholic acid): an injectable form of a bile acid that destroys fat cells.
- Composite response: improvement on both the clinician scale and the subject scale.
- MRI (magnetic resonance imaging): a scan used here to measure the volume of fat under the chin.
- Marginal mandibular nerve: the branch of the facial nerve that moves the lower lip.
- Paresis: partial weakness of a muscle caused by nerve injury.
- Placebo: an inactive injection used for comparison.
- Double-blind: neither subjects nor investigators know who received the drug.
- Sequelae: lasting after-effects.