The probability of response after each subcutaneous injection of esketamine in treatment-resistant depression.

INTRODUCTION: The administration of multiple esketamine doses has shown efficacy for unipolar and bipolar treatment-resistant depression (TRD). Nevertheless, the probability of responding or not after each dose in the real-world remains unknown. This study aimed to estimate it throughout four doses of esketamine, administrated via subcutaneous (SC). MATERIAL AND METHODS: We conducted a retrospective analysis of a case series of 70 patients with TRD who received treatment from the esketamine assistance program at Federal University of Sao Paulo, between April 2017 and December 2018. The SC injections were administrated weekly at a dose of 0.5-1.0mg/kg, in conjunction with patients' psychotropic drugs. Response was defined as a decrease of at least 50% in the Montgomery-Åsberg Depression Rating Scale between baseline and 24h after dose. We used hidden Markov modeling in order to estimate de probability of response after each esketamine injection. RESULTS: The probability of a patient that was a "non-responder" to become a "responder" following a SC injection of esketamine was 17.30% and the probability that this patient remains a "non-responder" was 82.70%. The probability of a patient that was a "responder" to remain as a "responder" was 95%. CONCLUSIONS: Patients with TRD who had not responded after the first dose of esketamine, still had a chance of responding after the subsequent dose administrated via SC.

Repeated subcutaneous esketamine for treatment-resistant depression: Impact of the degree of treatment resistance and anxiety comorbidity.

BACKGROUND: A large number of studies indicate that subanesthetic doses of ketamine induce a fast antidepressant effect. Limited studies have investigated the subcutaneous (SC) route, and it remains unclear for whom this treatment is most suitable. AIMS: The aim of this study was to examine the effect on depressive symptoms of repeated subanesthetic doses of SC esketamine in unipolar and bipolar treatment-resistant depression (TRD) and clinical predictors of response. METHODS: A retrospective analysis of 70 patients who received six SC esketamine doses weekly as an adjunctive treatment was carried out. Doses started at 0.5 mg/kg and it could be titrated up to 1 mg/kg, according to response. The primary outcome was reduction in depressive symptoms. Statistical analysis to investigate clinical predictors of effectiveness included logistic regression analysis using a dependent variable of a 50% reduction in rating scale scores at the end of treatment. Comparisons between groups were made through analysis of variance and treatment effects. RESULTS: At baseline, our sample presented with severe treatment resistance in 65.7%, as assessed by the Maudsley Staging Method (MSM), and 47.1% had anxiety disorder comorbidity. The response rate was 50%. A better outcome was predicted by mild and moderate MSM scores (OR = 3.162, p = 0.041) and anxiety disorder comorbidity (OR = 3.149, p = 0.028). CONCLUSIONS: Our results suggest that higher levels of treatment resistance may be associated with a poor response to SC esketamine. Unlike traditional pharmacotherapies, it might benefit those with poor prognosis such as patients with depression and comorbid anxiety. Therefore, future research could investigate whether esketamine should receive a more prominent place in the treatment algorithm for TRD.

The probability of response after each subcutaneous injection of esketamine in treatment-resistant depression.

INTRODUCTION: The administration of multiple esketamine doses has shown efficacy for unipolar and bipolar treatment-resistant depression (TRD). Nevertheless, the probability of responding or not after each dose in the real-world remains unknown. This study aimed to estimate it throughout four doses of esketamine, administrated via subcutaneous (SC). MATERIAL AND METHODS: We conducted a retrospective analysis of a case series of 70 patients with TRD who received treatment from the esketamine assistance program at Federal University of Sao Paulo, between April 2017 and December 2018. The SC injections were administrated weekly at a dose of 0.5-1.0mg/kg, in conjunction with patients' psychotropic drugs. Response was defined as a decrease of at least 50% in the Montgomery-Åsberg Depression Rating Scale between baseline and 24h after dose. We used hidden Markov modeling in order to estimate de probability of response after each esketamine injection. RESULTS: The probability of a patient that was a "non-responder" to become a "responder" following a SC injection of esketamine was 17.30% and the probability that this patient remains a "non-responder" was 82.70%. The probability of a patient that was a "responder" to remain as a "responder" was 95%. CONCLUSIONS: Patients with TRD who had not responded after the first dose of esketamine, still had a chance of responding after the subsequent dose administrated via SC.

Effects of subcutaneous esketamine on blood pressure and heart rate in treatment-resistant depression.

INTRODUCTION AND OBJECTIVES: The impact of multiple subcutaneous (s.c.) esketamine injections on the blood pressure (BP) and heart rate (HR) of patients with unipolar and bipolar treatment-resistant depression (TRD) is poorly understood. This study aimed to assess the cardiovascular safety of multiple s.c. doses of esketamine in patients with TRD. METHODS: Seventy TRD patients received 394 weekly s.c. esketamine injections in conjunction with oral antidepressant therapy for up to six weeks. Weekly esketamine doses were 0.5, 0.75 or 1.0 mg/kg according to each patient's response to treatment. Participants were monitored before each treatment and every 15 minutes thereafter for 120 minutes. We assessed systolic blood pressure (SBP), diastolic blood pressure (DBP), and HR measurements for the entire treatment course. RESULTS: BP increased after the first s.c. esketamine injection, reaching maximum mean SBP/DBP levels of 4.87/5.54 mmHg within 30-45 minutes. At the end of monitoring, 120 minutes post dose, vital signs returned to pretreatment levels. We did not detect significant differences in BP between doses of 0.5, 0.75, and 1 mg/kg esketamine. Mean HR did not differ significantly between doses or before and after s.c. esketamine injection. CONCLUSIONS: The BP changes observed with repeated s.c. esketamine injections were mild and well tolerated for doses up to 1 mg/kg. The s.c. route is a simple and safe method of esketamine administration, even for patients with clinical comorbidities, including obesity, hypertension, diabetes, and dyslipidemia. However, 14/70 patients experienced treatment-emergent transient hypertension (SBP >180 mmHg and/or a DBP >110 mmHg). Therefore, we strongly recommend monitoring BP for 90 minutes after esketamine dosing. Since s.c. esketamine is cheap, requires less frequent dosing (once a week), and is a simpler procedure compared to intravenous infusions, it might have an impact on public health.