Subcutaneous ketamine infusion in palliative patients for major depressive disorder (SKIPMDD)—Phase II single-arm open-label feasibility study

Background Ketamine at subanaesthetic dosages (<0.5mg/kg) exhibits rapid onset (over hours to days) antidepressant effects against major depressive disorder in people who are otherwise well. However, its safety, tolerability and efficacy are not known for major depressive disorder in people with advanced life-limiting illnesses. Objective To determine the feasibility, safety, tolerability, acceptability and any antidepressant signal/ activity to justify and inform a fully powered study of subcutaneous ketamine infusions for major depressive disorder in the palliative setting. Methods This was a single arm, open-label, phase II feasibility study (Australian New Zealand Clinical Trial Registry Number—ACTRN12618001586202). We recruited adults (> 18-years-old) with advanced life-limiting illnesses referred to four palliative care services in Sydney, Australia, diagnosed with major depressive disorder from any care setting. Participants received weekly subcutaneous ketamine infusion (0.1–0.4mg/kg) over two hours using individual dose-titration design. Outcomes assessed were feasibility, safety, tolerability and antidepressant activity. Results Out of ninety-nine referrals, ten participants received ketamine and were analysed for responses. Accrual rate was 0.54 participants/month across sites with 50% of treated participants achieving > 50% reduction in baseline Montgomery-Åsberg Depression Rating Scale, meeting feasibility criteria set a priori. There were no clinically relevant harms encountered. Conclusions A future definitive trial exploring the effectiveness of subcutaneous infusion of ketamine for major depressive disorder in the palliative care setting may be feasible by addressing identified study barriers. Individual dose-titration of subcutaneous ketamine infusions over two hours from 0.1mg/kg can be well-tolerated and appears to produce transient antidepressant signals over hours to days.