A Clinical Trial of Add-on Oral Slow-release Ketamine Treatment in Major Depression

Inclusion Criteria: * The subject has given their written consent to participate in the trial. * BMI ≥ 18 and ≤ 35 kg/m2. * Primary diagnosis of MDD meeting DSM-5-TR criteria and one of the following episode characteristics: (a)MDD, single episode, moderate (ICD-10-CM: F32.1); (b) MDD, single episode, severe, without psychotic features (ICD-10-CM: F32.2); (c) MDD, recurrent, moderate (ICD-10-CM: F33.1); (d) MDD, recurrent, severe, without psychotic features (ICD-10-CM: F33.2) * Duration of current depressive episode no longer than 12 months prior to screening. * MADRS score ≥ 22 at screening * Willingness to start a new, conventional antidepressant treatment which is chosen by the treating physician with regards to side effect profile and previous treatments, together with KET01, dosed according to the prescribed schedule. * Willingness to terminate any ongoing antidepressant treatment if deemed ineffective by study physician in accordance with clinical practice (tapering or immediate stop), followed by a wash-out phase of at least 7 days without medication before treatment with the new antidepressant is initiated together with KET01. * For females of childbearing potential: Must be willing to undergo pregnancy tests and will be required to use highly effective contraceptive measures from the time of informed consent until 28 days after last IMP intake. Methods that can achieve a failure rate of less than 1% per year when used consistently and correctly are considered as hig…