In the past several weeks, the Food and Drug Administration (FDA) has approved two drugs to treat obesity—Qsymia (Vivus) and Belviq (Arena Pharmaceuticals)—as well as a drug that can drastically lower a person’s risk of getting the virus that causes AIDS—Truvada (Gilead).
The two obesity drug approvals are the first weight-loss drugs approved by FDA after 13 years of no approvals. Explaining why no new weight-loss drugs had been approved in over a decade, Eric Colman, M.D., deputy director of FDA’s Division of Metabolism and Endocrinology Products (DMEP), said that drug companies have been testing potential new weight loss drugs, but none had proven effective and safe for consumers until now. The agency was also much more risk adverse after the phen-phen incidents of the 1990s.
Both Truvada and Qsymia were approved with a Risk Evaluation and Mitigation Strategy (REMS), which underscores the need to educate healthcare providers about these drugs through continuing medical education (CME). For the two new weight-loss drugs, the first in over a decade, physicians will be uncertain about many of the aspects of prescribing, such as dosing, side effects, and adverse events. In fact, there is likely a whole generation of physicians in practice now who have little or no experience with weight-loss drugs and the risks that come with them. These factors demand CME.
The government, however, provides no direct source of funding for CME regarding these drugs. Instead, it will be up to the companies who manufacture these drugs to support independent, accredited, third-party CME programs, which will meet the REMS requirements and ensure that healthcare providers have evidence-based educational materials to enhance the positive outcomes these drugs may produce, while reducing the risk of harm.
Qsymia
Qsymia, formerly Qnexa, is a combination of the generic weight loss drug phentermine and the anti-seizure drug topiramate, can be used by obese or overweight adults who have high-blood pressure, diabetes or high cholesterol. The drug is approved for use in adults with a body mass index (BMI) of 30 or greater (obese) or adults with a BMI of 27 or greater (overweight) who have at least one weight-related condition such as high blood pressure (hypertension), type 2 diabetes, or high cholesterol (dyslipidemia). Belviq is approved for the same populations.
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 threatens the overall well being of patients and is a major public health concern,” Janet Woodcock, M.D., director of FDA’s Center for Drug Evaluation and Research (CDER) said in the release. “Qsymia, used responsibly in combination with a healthy lifestyle that includes a reduced-calorie diet and exercise, provides another treatment option for chronic weight management in Americans who are obese or are overweight and have at least one weight-related comorbid condition.”
Qsymia is a combination of two FDA-approved drugs, phentermine and topiramate, in an extended-release formulation. Phentermine is indicated for short-term weight loss in overweight or obese adults who are exercising and eating a reduced calorie diet. Topiramate is indicated to treat certain types of seizures in people who have epilepsy and to prevent migraine headaches.
Qsymia must not be used during pregnancy because it can cause harm to a fetus. Data show that a fetus exposed to topiramate, a component of Qsymia, in the first trimester of pregnancy has an increased risk of oral clefts (cleft lip with or without cleft palate). Females of reproductive potential must not be pregnant when starting Qsymia therapy or become pregnant while taking Qsymia. Females of reproductive potential should have a negative pregnancy test before starting Qsymia and every month while using the drug and should use effective contraception consistently while taking Qsymia.
The safety and efficacy of Qsymia were evaluated in two randomized, placebo-controlled trials that included approximately 3,700 obese and overweight patients with and without significant weight-related conditions treated for one year. All patients received lifestyle modification that consisted of a reduced calorie diet and regular physical activity.
The recommended daily dose of Qsymia contains 7.5 milligrams of phentermine and 46 mg of topiramate extended-release. Qsymia is also available at a higher dose (15 mg phentermine and 92 mg of topiramate extended-release) for select patients.
Results from the two trials show that after one year of treatment with the recommended and highest daily dose of Qsymia, patients had an average weight loss of 6.7 percent and 8.9 percent, respectively, over treatment with placebo. Approximately 62 percent and 69 percent of patients lost at least five percent of their body weight with the recommended dose and highest dose of Qsymia, respectively, compared with about 20 percent of patients treated with placebo.
Patients who did not lose at least three percent of their body weight by week 12 of treatment with Qsymia were unlikely to achieve and sustain weight loss with continued treatment at this dose. Therefore, response to therapy with the recommended daily dose of Qsymia should be evaluated by 12 weeks to determine, based on the amount of weight loss, whether to discontinue Qsymia or increase to the higher dose. If after 12 weeks on the higher dose of Qsymia, a patient does not lose at least five percent of body weight, then Qsymia should be discontinued, as these patients are unlikely to achieve clinically meaningful weight loss with continued treatment.
Qsymia must not be used in patients with glaucoma or hyperthyroidism. Qsymia can increase heart rate; this drug’s effect on heart rate in patients at high risk for heart attack or stroke is not known. Therefore, the use of Qsymia in patients with recent (within the last six months) or unstable heart disease or stroke is not recommended. Regular monitoring of heart rate is recommended for all patients taking Qsymia, especially when starting Qsymia or increasing the dose.
The FDA approved Qsymia with a REMS, which consists of a Medication Guide advising patients about important safety information and elements to assure safe use that include prescriber training and pharmacy certification. The purpose of the REMS is to educate prescribers and their patients about the increased risk of birth defects associated with first trimester exposure to Qsymia, the need for pregnancy prevention, and the need to discontinue therapy if pregnancy occurs. Qsymia will only be dispensed through specially certified pharmacies.
Belviq
Belviq works by activating the serotonin 2C receptor in the brain. Activation of this receptor may help a person eat less and feel full after eating smaller amounts of food.
The safety and efficacy of Belviq were evaluated in three randomized, placebo-controlled trials that included nearly 8,000 obese and overweight patients, with and without type 2 diabetes, treated for 52 to 104 weeks. All participants received lifestyle modification that consisted of a reduced calorie diet and exercise counseling. Compared with placebo, treatment with Belviq for up to one year was associated with average weight loss ranging from 3 percent to 3.7 percent.
About 47 percent of patients without type 2 diabetes lost at least 5 percent of their body weight compared with about 23 percent of patients treated with placebo. In people with type 2 diabetes, about 38 percent of patients treated with Belviq and 16 percent treated with placebo lost at least 5 percent of their body weight. Belviq treatment was associated with favorable changes in glycemic control in those with type 2 diabetes. The approved labeling for Belviq recommends that the drug be discontinued in patients who fail to lose 5 percent of their body weight after 12 weeks of treatment, as these patients are unlikely to achieve clinically meaningful weight loss with continued treatment.
Belviq should not be used during pregnancy. Treatment with Belviq may cause serious side effects, including serotonin syndrome, particularly when taken with certain medicines that increase serotonin levels or activate serotonin receptors. These include, but are not limited to, drugs commonly used to treat depression and migraine. Belviq may also cause disturbances in attention or memory.
In 1997, the weight-loss drugs fenfluramine and dexfenfluramine were withdrawn from the market after evidence emerged that they caused heart valve damage. This effect is assumed to be related to activation of the serotonin 2B receptor on heart tissue. When used at the approved dose of 10 milligrams twice a day, Belviq does not appear to activate the serotonin 2B receptor.
Heart valve function was assessed by echocardiography in nearly 8,000 patients in the Belviq development program. There was no statistically significant difference in the development of FDA-defined valve abnormalities between Belviq and placebo-treated patients. Because preliminary data suggest that the number of serotonin 2B receptors may be increased in patients with congestive heart failure, Belviq should be used with caution in patients with this condition. Belviq has not been studied in patients with serious valvular heart disease.
The drug’s manufacturer will be required to conduct six postmarketing studies, including a long-term cardiovascular outcomes trial to assess the effect of Belviq on the risk for major adverse cardiac events such as heart attack and stroke. The most common side effects of Belviq in non-diabetic patients are headache, dizziness, fatigue, nausea, dry mouth, and constipation, and in diabetic patients are low blood sugar (hypoglycemia), headache, back pain, cough, and fatigue.
HIV Drug
Truvada (emtricitabine/tenofovir disoproxil fumarate) is the first drug approved to reduce the risk of HIV infection in uninfected individuals who are at high risk of HIV infection and who may engage in sexual activity with HIV-infected partners. Truvada, taken daily, is to be used for pre-exposure prophylaxis (PrEP) in combination with safer sex practices to reduce the risk of sexually-acquired HIV infection in adults at high risk. The FDA previously approved Truvada to be used in combination with other antiretroviral agents for the treatment of HIV-infected adults and children 12 years or older.
As part of PrEP, HIV-uninfected individuals who are at high risk will take Truvada daily to lower their chances of becoming infected with HIV should they be exposed to the virus. A PrEP indication means Truvada is approved for use as part of a comprehensive HIV prevention strategy that includes other prevention methods, such as safe sex practices, risk reduction counseling, and regular HIV testing.
“Today’s approval marks an important milestone in our fight against HIV,” said FDA Commissioner Margaret A. Hamburg, M.D. “Every year, about 50,000 U.S. adults and adolescents are diagnosed with HIV infection, despite the availability of prevention methods and strategies to educate, test, and care for people living with the disease. New treatments as well as prevention methods are needed to fight the HIV epidemic in this country.”
As a part of this action, the FDA is strengthening Truvada’s Boxed Warning to alert health care professionals and uninfected individuals that Truvada for PrEP must only be used by individuals who are confirmed to be HIV-negative prior to prescribing the drug and at least every three months during use. The drug is contraindicated for PrEP in individuals with unknown or positive HIV status. The FDA strongly recommends against such use.
Truvada for PrEP is being approved with a Risk Evaluation and Mitigation Strategy (REMS) to minimize the risk to uninfected individuals of acquiring HIV infection and to reduce the risk of development of resistant HIV-1 variants. The central component of this REMS is a training and education program to assist prescribers in counseling individuals who are taking or considering Truvada for PrEP. The training and education program will not restrict distribution of Truvada but will provide information about the importance of adhering to the recommended dosing regimen and understanding the serious risks of becoming infected with HIV while taking Truvada for the PrEP indication.
“The REMS for Truvada for the PrEP indication is aimed at educating health care professionals and uninfected individuals to help ensure its safe use for this indication without placing an unnecessary burden on health care professionals and patients,” said Janet Woodcock, M.D. The REMS for Truvada for PrEP includes:
- A Medication Guide to support the education of uninfected individuals taking Truvada for PrEP about the serious risk of becoming infected with HIV and the development of drug-resistant variants if they continue taking Truvada after becoming infected with HIV.
- Prescriber training and education targets likely prescribers of Truvada for PrEP.
This program includes:
- A training guide for health care professionals that emphasizes the importance of screening patients for sexually transmitted infections (STIs), the need for uninfected individuals to have a negative HIV-1 test result before taking Truvada for PrEP, the importance of patients strictly adhering to the recommended dosing regimen, and the use of Truvada for PrEP as part of a comprehensive prevention strategy that includes safe sex practices and regular HIV testing.
- A safety brochure for prescribers outlining key serious risk information about Truvada for the PrEP indication, the importance of comprehensive management with regular monitoring of uninfected individuals’ HIV-infection status and the importance of uninfected individuals adhering to the recommended dosing regimen.
- A safety brochure for uninfected individuals outlining key serious risk information about Truvada for PrEP, recommended screening tests before starting Truvada for PrEP, the importance of regular testing for HIV status while taking Truvada for PrEP and key information to tell one’s health care provider.
- An education slide deck for face-to-face meetings between the drug maker and prescribers.
- A checklist for prescribers indicating they have taken the necessary steps to ensure the drug will be used appropriately, to be placed in the uninfected individual’s medical record.
- An Agreement Form for Initiating Truvada for PrEP to be signed by both the prescriber and uninfected individual and placed in the individual’s medical record.
Vivus Inc. will be required to conduct 10 postmarketing requirements, including a long-term cardiovascular outcomes trial to assess the effect of Qsymia on the risk for major adverse cardiac events such as heart attack and stroke. The most common side effects of Qsymia are tingling of hands and feet (paresthesia), dizziness, altered taste sensation, insomnia, constipation, and dry mouth.
Truvada’s safety and efficacy for PrEP were demonstrated in two large, randomized, double-blind, placebo-controlled clinical trials. The iPrEx trial evaluated Truvada in 2,499 HIV-negative men or transgender women who have sex with men and with evidence of high risk behavior for HIV infection, such as inconsistent or no condom use during sex with a partner of positive or unknown HIV status, a high number of sex partners, and exchange of sex for commodities. Results showed Truvada was effective in reducing the risk of HIV infection by 42 percent compared with placebo in this population. Efficacy was strongly correlated with drug adherence in this trial.
The Partners PrEP trial was conducted in 4,758 heterosexual couples where one partner was HIV-infected and the other was not (serodiscordant couples). The trial evaluated the efficacy and safety of Truvada and tenofovir versus placebo in preventing HIV infection in the uninfected male or female partner. Results showed Truvada reduced the risk of becoming infected by 75 percent compared with placebo.
No new side effects were identified in the clinical trials evaluating Truvada for the PrEP indication. The most common side effects reported with Truvada included diarrhea, nausea, abdominal pain, headache, and weight loss. Serious adverse events in general, as well as those specifically related to kidney or bone toxicity, were uncommon.
As a condition of approval, Truvada’s manufacturer, Gilead Sciences, Inc., is required to collect viral isolates from individuals who acquire HIV while taking Truvada and to evaluate these isolates for the presence of resistance. Additionally, the company is required to collect data on pregnancy outcomes for women who become pregnant while taking Truvada for PrEP and to conduct a trial to evaluate drug adherence and its relationship to adverse events, risk of seroconversion, and resistance development in seroconverters.
Gilead has committed to provide national drug utilization data in order to better characterize individuals who utilize Truvada for a PrEP indication and to develop an adherence questionnaire that will assist prescribers in identifying individuals at risk for low compliance.