The Effect of a Six Week Intensified Pharmacological Treatment for Major Depressive Disorder Compared to Treatment as Usual in Subjects Who Had a First-time Treatment Failure on Their First-line Treatment.

Over 28 million people suffer from current depressive disorder in the European Union. Major depressive disorder (MDD) is one of the most common psychiatric illnesses. The symptoms cause clinically significant distress or impairment in social, occupational, and other important areas of functioning. To treat MDD, there are several antidepressants available and prescribing medication is a process of trial-and-error. Guidelines do not explicitly advise on the order in which antidepressant medication should be prescribed. The choice of antidepressant should be tailored to the patient, while involving the patient in the decision-making process. In general, the choice for the first- and second-line treatment will be a second-generation antidepressant. Recently, esketamine nasal spray (intranasal (IN) administration) was approved for patients with treatment-resistant MDD (TRD). A patient is diagnosed with TRD when having used two antidepressants in sufficient duration and adequate dose without sufficient effect. TRD is associated with a negative impact on quality of life, higher risk for hospitalisations and suicide, comorbidities, poorer social and occupational functioning and a high carer burden. The efficacy of intranasal use of esketamine has been demonstrated in MDD subjects with treatment-resistant symptoms but also in subjects with non-treatment resistant depression, and is approved by the FDA and EMA as a third-line treatment. Besides the registered esketamine nasal spray, which is not available in all countries to all patients because of the high costs, off-label utilization of (es)ketamine infusions (IV) is growing extensively over time to treat TRD. Research conducted so far indicates an unequivocal initial substantial response to (es)ketamine IV in MDD populations, regardless of whether or not patients suffer from treatment resistant MDD. However, until now, there has not been a study investigating this in a sufficiently large population. This may be a unique opportunity to potentially prevent patients progressing into a treatment resistant illness stage. The potential implications of the results of the current study are the prevention of unnecessary trials of ineffective treatments, reducing subject burden substantially, as well as a reduction of healthcare and societal costs.