Long-Term, Open-Label, Safety Study of Edivoxetine 12 to 18 mg Once Daily as Adjunctive Treatment for Patients With Major Depressive Disorder Who Are Partial Responders to Selective Serotonin Reuptake Inhibitor Treatment

Investigational Drugs for the Treatment of Depression (Part 1): Monoaminergic, Orexinergic, GABA-Ergic, and Anti-Inflammatory Agents

Therapeutic management of depression has currently important limitations, and its low efficacy is reflected in high rates of non-response even after multiple trials of antidepressants. Almost two-thirds of the patients diagnosed with major depression who received a 4–6 weeks trial of antidepressant could not reach remission, and more than 30% of these patients are considered treatment-resistant. In bipolar depression, the situation is also discouraging if we analyze the high suicide rate, the risk for the treatment-emergent affective switch when antidepressants are added, the high rate of treatment resistance (up to 25%), and the severe functional impairments associated with these episodes. Therefore, new therapeutic agents are needed, as well as new pathogenetic models for depression. The vast majority of the currently approved antidepressants are based on the monoamine hypothesis, although new drugs exploiting different neurotransmitter pathways have been recently approved by FDA. Brexanolone, an allopregnanolone analog, is an example of such new antidepressants, and its approval for post-partum depression inspired the search for a new generation of neurosteroids and GABA-ergic modulators, with an easier way of administration and superior tolerability profile. Orexin receptors antagonists are also extensively studied for different psychiatric disorders, depression included, in phase II trials. Antiinflammatory drugs, both cyclo-oxygenase 2 inhibitors and biological therapy, are investigated in patients with depressive disorders based on the proven correlation between inflammation and mood disorders in preclinical and clinical studies. Also, a new generation of monoamine-based investigational drugs is explored, ranging from triple reuptake inhibitors to atypical antipsychotics, in patients with major depression. In conclusion, there is hope for new treatments in uni- and bipolar depression, as it became clear, after almost seven decades, that new pathogenetic pathways should be targeted to increase these patients’ response rate.

A randomised, placebo-controlled 24-week study evaluating adjunctive brexpiprazole in patients with major depressive disorder

OBJECTIVE

To evaluate brexpiprazole adjunctive to antidepressant therapies (ADTs) as maintenance treatment in patients with major depressive disorder with inadequate response to ADT, utilising a novel study design.

METHODS

The study comprised an 8-week prospective treatment period with open-label ADT with double-blind placebo treatment and a 24-week randomised treatment period. Investigators and patients were blinded to treatment periods, randomisation criteria, and timing of randomisation. Patients with early response to open-label ADT were withdrawn at Week 6. Patients fulfilling criteria for inadequate response were randomised to ADT+brexpiprazole 1-3 mg/day, or ADT+placebo. The primary endpoint was full remission: Montgomery-Åsberg Depression Rating Scale (MADRS) total score ≤10 and ≥50% decrease from randomisation (i.e. baseline) in MADRS total score for at least 8 consecutive weeks.

RESULTS

The primary efficacy analysis failed to show a statistically significant difference between the proportions of patients on ADT+brexpiprazole (21.4%) and ADT+placebo (24.9%) achieving full remission; odds ratio: 0.83; p=0.2641. The secondary endpoint of change from baseline to Week 6 in MADRS total score showed no difference between ADT+brexpiprazole and ADT+placebo (-0.4; p=0.3259). The most frequent treatment-emergent adverse event (TEAE) in patients receiving ADT+brexpiprazole was weight increased (9.5% vs. 5.0% in ADT+placebo). The incidence of TEAEs leading to withdrawal in the randomised treatment period was 6.3% in the ADT+brexpiprazole group and 3.4% in the ADT+placebo group.

CONCLUSION

Adjunctive brexpiprazole did not differentiate from ADT+placebo on the primary endpoint of full remission. A number of design elements in this previously untried study design may have contributed to the study result. Brexpiprazole was well tolerated.

Long-Term, Open-Label, Safety Study of Edivoxetine Monotherapy in Children and Adolescents with Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

The purpose of this study was to assess the long-term safety and tolerability of edivoxetine, a selective norepinephrine reuptake inhibitor, which was being developed as monotherapy in pediatric attention-deficit/hyperactivity disorder (ADHD).

METHODS

This was an open-label study of edivoxetine once daily dosing (0.1-0.3 mg/kg) as treatment for ADHD in children (6-11 years) and adolescents (12-17 years) to assess safety for up to 5 years. The safety assessments included the incidence of adverse events, vital signs, electrocardiograms, laboratory tests, percentile changes in weight, height, and body mass index, and Tanner staging. Efficacy of treatment with edivoxetine was also assessed using the Attention-Deficit/Hyperactivity Disorder Rating Scale-Version IV-Parent Reported: Investigator Scored (ADHDRS-IV) and Clinical Global Impressions-ADHD-Severity (CGI-ADHD-S).

RESULTS

A total of 267 children and adolescents were enrolled and 20 completed the 5-year study. Most of the participants were male (70.4%) and white (67.4%), and the mean age was 11.6 years. Two hundred three participants (76.9%; N = 264) experienced at least one adverse event. Treatment-emergent adverse events reported in >10% of participants were headache, vomiting, nausea, and upper respiratory tract infection. Serious adverse events (SAEs) were reported by seven participants (2.7%) during study treatment periods, and one participant was diagnosed with suspect epilepsy during the follow-up period after discontinuation of edivoxetine.

CONCLUSION

Long-term open-label treatment with edivoxetine as monotherapy in children and adolescents with ADHD revealed a safety profile that was consistent with its pharmacological effects on norepinephrine transmission and with that reported in short-term studies of edivoxetine. The study was terminated early due to slow enrollment and the very low number of 5-year completers. Lilly is not proceeding with further development of edivoxetine, as announced in 2013.

Safety and tolerability of edivoxetine as adjunctive treatment to selective serotonin reuptake inhibitor antidepressants for patients with major depressive disorder

Objective:

The aim of this analysis was to assess the safety profile of edivoxetine as adjunctive treatment to selective serotonin reuptake inhibitor (SSRI) antidepressants.

Methods:

A pooled analysis was conducted on data obtained from the integrated safety database of edivoxetine as adjunctive treatment to SSRIs. Safety and tolerability assessments included discontinuation rates, spontaneously reported treatment-emergent adverse events (TEAEs), clinical laboratory tests, blood pressure (BP) and pulse, and electrocardiograms (ECGs).

Results:

The analysis included 1260 patients treated with adjunctive edivoxetine and 806 treated with adjunctive placebo. Study completion rates were 85.2% and 84.5% (p=0.994), respectively. Discontinuations due to adverse events were 4.9% and 3.5% (p=0.07), respectively. Significantly more patients in the adjunctive edivoxetine group compared with adjunctive placebo group reported at least one TEAE (56.8 vs 43.7%, p<0.001). The most common TEAEs (occurred ≥5% frequency) were hyperhidrosis, nausea, and tachycardia. Mean changes in sitting BP and pulse at the last visit were increased significantly in patients treated with adjunctive edivoxetine compared with adjunctive placebo (SBP: 2.7 vs 0.5 mm Hg, p<0.001; DBP: 4.1 vs 0.8 mm Hg, p<0.001; pulse: 8.8 vs −1.3 bpm, p<0.001). There were no clinically significant changes in laboratory measures.

Conclusions:

The tolerability and safety profile of edivoxetine as adjunctive treatment to SSRI antidepressants was consistent with its norepinephrine reuptake inhibitor mechanism of action, and was comparable with edivoxetine monotherapy treatment in patients with major depressive disorder.