Following Kybella’s recent FDA approval for treating submental fat, Aesthetics investigates the drug’s efficacy and how it should be used in practice
Double chins have long been associated with a displeasing aesthetic appearance, with many consumers resorting to surgery to remove unwanted submental fat. Now, however, a non-surgical alternative is expected to cause a stir in the US aesthetic market.1 In 2014, the American Society for Dermatologic Surgery (ASDS) reported that 68% of consumers are bothered by submental fullness.2 This notably high statistic is unsurprising says Dr Heidi Waldorf, director of laser and cosmetic dermatology at Mount Sinai Medical Center in New York and a lead clinical investigator in the Kybella study. “Many of my patients, both women and men, are looking for non-surgical options to help treat their double chin,” she explains, adding, “the statistic is almost as much as those who say they are bothered by the lines and wrinkles around their eyes [71%2].”
Yet there seems to have been a distinct lack of non-surgical options for treating this ‘problem’ area – until now. Kybella, manufactured by US-based company Kythera Biopharmaceuticals, is expected to become available to US-based practitioners who have completed training in its administration this summer. As of yet, however, no filings have been submitted for the product to launch in Europe. Despite this, the Food and Drug Administration (FDA) approval of the drug has generated global news headlines. The Telegraph reported that Kythera’s shares jumped by almost 8% following the announcement,3 whilst business analysts have suggested that Kybella could bring in more than $300 million a year.1
Also know as ATX-101, Kybella is identical to the deoxycholic acid that is produced in the body, which works to help the body absorb fat.5 The FDA explains that Kybella is a cytolytic drug, which aims to destroy fat cells when injected into submental fat. Kythera claims that once destroyed, those cells cannot store or accumulate fat.4 Kybella is administered by injection into the fat under the chin, which can be tailored to individual patient requirements. Patients can receive up to 50 injections in a single treatment, with up to six single treatments administered no less than one month apart. Dr Waldorf says, “Personally, I’m excited about the opportunity to offer my patients a clinically-proven, non-surgical option that I can customise to the patient and their treatment goals.”
Research into the efficacy of Kybella was supported by a global development programme, which included more than 20 clinical trials and 2,600 participants worldwide. More than 1,600 participants were treated with the drug, of which 68.2% responded to Kybella in the final phase III trials, compared to just 20.5% who were treated with the placebo drug.6 Significantly, patients noted not only an improvement in the amount of fat under their chin, but also an improvement in the emotional impact of receiving treatment. For Dr Waldorf, this was very satisfying to hear; “As a cosmetic dermatologist, I want my patients to feel better about themselves both physically and emotionally,” she explains.
The FDA enrolled 1,022 adult participants with moderate or severe submental fat in its two clinical trials into the safety and efficacy of Kybella. Participants underwent treatment with either Kybella or a placebo for up to six treatments and results indicated that a reduction in the fat was observed more frequently in those who were treated with Kybella.5 Each treatment takes approximately 15 to 20 minutes and, according to Kythera, patients experience visible results after two to four treatments.4 Up to six treatments may be administered and once aesthetic response is achieved, re-treatment is not expected.4
The drug does, however, come with reported side effects. In the clinical trials, 72% of subjects treated with Kybella experienced injection site hematoma/bruising, and cases of marginal mandibular nerve injury were reported.4 These manifested as an asymmetric smile or facial muscle weakness and resolved spontaneously from 1-298 days, with a median of 44 days.4 In addition, dysphagia (difficulty swallowing) occurred in patients during the trials, with subjects experiencing pain, swelling, and induration of the submental area. Again, cases of dysphagia resolved spontaneously, ranging from 1-81 days, with a median of three days.4 Kythera advises practitioners to avoid injecting into or in close proximity to the marginal mandibular branch of the facial nerve, avoid using Kybella in patients with a current or prior history of dysphagia, and take caution when treating patients with bleeding abnormalities, or those who are currently being treated with antiplatelet or anticoagulant therapy.4
The company also notes that in order to avoid potential tissue damage, Kybella should not be injected into or in close proximity (1-1.5cm) to salivary glands, lymph nodes or muscles.4 It is further advised that the drug should not be injected outside the submental area or in the presence of infection at the injection site.7
Upon reflection of the research discussed, it seems likely that Kybella will have a substantial impact on the way in which aesthetic practitioners approach submental fat treatment in the future. And whilst there may be no plans to launch the drug in the UK in the near future, UK-based practitioners can take this as an opportunity to follow Kybella’s overseas’ development and learn more from our US-based colleagues administering the treatment.