Addyi approved to treat premenopausal women
The US Food and Drug Administration (US FDA) approved Addyi (flibanserin) to treat acquired, generalised hypoactive sexual desire disorder (HSDD) in premenopausal women. Prior to Addyi’s approval, there were no FDA-approved treatments for sexual desire disorders in men or women.
HSDD is characterised by low sexual desire that causes marked distress or interpersonal difficulty and is not due to a co-existing medical or psychiatric condition, problems within the relationship, or the effects of a medication or other drug substance. HSDD is acquired when it develops in a patient who previously had no problems with sexual desire. HSDD is generalised when it occurs regardless of the type of sexual activity, the situation or the sexual partner.
Addyi can cause severely low blood pressure (hypotension) and loss of consciousness (syncope). These risks are increased and more severe when patients drink alcohol or take Addyi with certain medicines (known as moderate or strong CYP3A4 inhibitors) that interfere with the breakdown of Addyi in the body. Because of the alcohol interaction, the use of alcohol is contraindicated while taking Addyi. Health care professionals must assess the likelihood of the patient reliably abstaining from alcohol before prescribing Addyi.
Addyi is being approved with a risk evaluation and mitigation strategy (REMS), which includes elements to assure safe use (ETASU). The FDA is requiring this REMS because of the increased risk of severe hypotension and syncope due to the interaction between Addyi and alcohol. The REMS requires that prescribers be certified with the REMS programme by enrolling and completing training. Certified prescribers must counsel patients using a Patient-Provider Agreement Form about the increased risk of severe hypotension and syncope and about the importance of not drinking alcohol during treatment with Addyi. Additionally, pharmacies must be certified with the REMS programme by enrolling and completing training. Certified pharmacies must only dispense Addyi to patients with a prescription from a certified prescriber. Additionally, pharmacists must counsel patients prior to dispensing not to drink alcohol during treatment with Addyi.
Addyi is also being approved with a Boxed Warning to highlight the risks of severe hypotension and syncope in patients who drink alcohol during treatment with Addyi, in those who also use moderate or strong CYP3A4 inhibitors, and in those who have liver impairment. Addyi is contraindicated in these patients. In addition, the FDA is requiring the company that owns Addyi to conduct three well-designed studies in women to better understand the known serious risks of the interaction between Addyi and alcohol.
Addyi is a serotonin 1A receptor agonist and a serotonin 2A receptor antagonist, but the mechanism by which the drug improves sexual desire and related distress is not known. Addyi is taken once daily. It is dosed at bedtime to help decrease the risk of adverse events occurring due to possible hypotension, syncope and central nervous system depression (such as sleepiness and sedation). Patients should discontinue treatment after eight weeks if they do not report an improvement in sexual desire and associated distress.
The effectiveness of the 100 mg bedtime dose of Addyi was evaluated in three 24-week randomized, double-blind, placebo-controlled trials in about 2,400 premenopausal women with acquired, generalised HSDD. The average age of the trial participants was 36 years, with an average duration of HSDD of approximately five years. In these trials, women counted the number of satisfying sexual events, reported sexual desire over the preceding four weeks (scored on a range of 1.2 to 6.0) and reported distress related to low sexual desire (on a range of 0 to 4). On average, treatment with Addyi increased the number of satisfying sexual events by 0.5 to one additional event per month over placebo increased the sexual desire score by 0.3 to 0.4 over placebo, and decreased the distress score related to sexual desire by 0.3 to 0.4 over placebo.
Additional analyses explored whether the improvements with Addyi were meaningful to patients, taking into account the effects of treatment seen among those patients who reported feeling much improved or very much improved overall. Across the three trials, about 10 per cent more Addyi-treated patients than placebo-treated patients reported meaningful improvements in satisfying sexual events, sexual desire or distress. Addyi has not been shown to enhance sexual performance.
The 100 mg bedtime dose of Addyi has been administered to about 3,000 generally healthy premenopausal women with acquired, generalised HSDD in clinical trials, of whom about 1,700 received treatment for at least six months and 850 received treatment for at least one year.
The most common adverse reactions associated with the use of Addyi are dizziness, somnolence (sleepiness), nausea, fatigue, insomnia and dry mouth.