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The drug is approved for use in adults with a body mass index (BMI) of 30 or greater (obesity) or adults with a BMI of 27 or greater (overweight) who have at least one weight-related condition such as hypertension, type 2 diabetes, or high cholesterol (dyslipidemia).
BMI, which measures body fat based on an individual’s weight and height, is used to define the obesity and overweight categories. According to the Centers for Disease Control and Prevention, more than one-third of adults in the United States are obese. Obesity is a public health concern and threatens the overall well-being of patients,” said James Smith, M.D., M.S., acting deputy director of the Division of Metabolism and Endocrinology Products in FDA’s Center for Drug Evaluation and Research. “Saxenda, used responsibly in combination with a healthy lifestyle that includes a reduced-calorie diet and exercise, provides an additional treatment option for chronic weight management for people who are obese or are overweight and have at least one weight-related comorbid condition.
Saxenda is a glucagon-like peptide-1 (GLP-1) receptor agonist and should not be used in combination with any other drug belonging to this class, including Victoza, a treatment for type 2 diabetes. Saxenda and Victoza contain the same active ingredient (liraglutide) at different doses (3 mg and 1.8 mg, respectively). However, Saxenda is not indicated for the treatment of type 2 diabetes, as the safety and efficacy of Saxenda for the treatment of diabetes has not been established.
The safety and effectiveness of Saxenda were evaluated in three clinical trials that included approximately 4,800 obese and overweight patients with and without significant weight-related conditions. All patients received counseling regarding lifestyle modifications that consisted of a reduced-calorie diet and regular physical activity.
Results from a clinical trial that enrolled patients without diabetes showed that patients had an average weight loss of 4.5 percent from baseline compared to treatment with a placebo (inactive pill) at one year. In this trial, 62 percent of patients treated with Saxenda lost at least 5 percent of their body weight compared with 34 percent of patients treated with placebo. Results from another clinical trial that enrolled patients with type 2 diabetes showed that patients had an average weight loss of 3.7 percent from baseline compared to treatment with placebo at one year. In this trial, 49 percent of patients treated with Saxenda lost at least 5 percent of their body weight compared with 16 percent of patients treated with placebo.
Patients using Saxenda should be evaluated after 16 weeks to determine if the treatment is working. If a patient has not lost at least 4 percent of baseline body weight, Saxenda should be discontinued, as it is unlikely that the patient will achieve and sustain clinically meaningful weight loss with continued treatment.
Saxenda has a boxed warning stating that tumors of the thyroid gland (thyroid C-cell tumors) have been observed in rodent studies with Saxenda but that it is unknown whether Saxenda causes thyroid C-cell tumors, including a type of thyroid cancer called medullary thyroid carcinoma (MTC), in humans. Saxenda should not be used in patients with a personal or family history of MTC or in patients with multiple endocrine neoplasia syndrome type 2 (a disease in which patients have tumors in more than one gland in their body, which predisposes them to MTC).
Serious side effects reported in patients treated with Saxenda include pancreatitis, gallbladder disease, renal impairment, and suicidal thoughts. Saxenda can also raise heart rate and should be discontinued in patients who experience a sustained increase in resting heart rate.
In clinical trials, the most common side effects observed in patients treated with Saxenda were nausea, diarrhea, constipation, vomiting, low blood sugar (hypoglycemia), and decreased appetite.
The FDA is requiring the following post-marketing studies for Saxenda:
- clinical trials to evaluate dosing, safety, and efficacy in pediatric patients;
- a study to assess potential effects on growth, sexual maturation, and central nervous system development and function in immature rats;
- an MTC case registry of at least 15 years duration to identify any increase in MTC incidence related to Saxenda; and
- an evaluation of the potential risk of breast cancer with Saxenda in ongoing clinical trials.
In addition, the cardiovascular safety of liraglutide is being investigated in an ongoing cardiovascular outcomes trial.
The FDA approved Saxenda with a Risk Evaluation and Mitigation Strategy (REMS), which consists of a communication plan to inform health care professionals about the serious risks associated with Saxenda.