Abstract
Keywords
Introduction
Schizophrenia is a chronic, severe and disabling illness1,2 affecting over 20 million people globally. 3 Antipsychotics are the cornerstone of pharmacological treatment for schizophrenia, 4 and maintenance treatment with oral antipsychotics can lead to improved outcomes such as symptom control and lower relapse rates.5–7 However, suboptimal adherence to daily oral antipsychotic medication is common and associated with more frequent relapse, hospitalization and a longer time to remission.8,9
Long-acting injectable antipsychotic treatments (LATs) offer advantages in schizophrenia treatment; for example, removing the burden of daily oral antipsychotic medication 10 may improve adherence. 11 Compared with daily oral antipsychotics, LAT use has been associated with fewer relapses and less carer burden as well as improvements in functioning, quality of life and mortality rates in patients with schizophrenia.12,13 A meta-analysis of 42 cohort studies reported that LATs are superior to oral medication with regard to the rate, but not risk, of hospitalization. 14 Second-generation LATs (SG-LATs) combine the improved tolerability of oral second-generation antipsychotics with the convenience and adherence of LATs. 15
Paliperidone palmitate 3-monthly (PP3M) is an SG-LAT indicated for the maintenance treatment of adult patients with schizophrenia who have been stabilized with paliperidone palmitate 1-monthly (PP1M).16,17 It is currently the only SG-LAT with a 3-monthly regimen.
18
Two randomized controlled trials (RCTs) demonstrated that PP3M has a favourable efficacy and safety profile in schizophrenia treatment. Berwaerts
REMISSIO was a 52-week, phase 3b study designed to complement RCTs by evaluating the efficacy and safety of transitioning patients with schizophrenia previously stabilized [Positive and Negative Syndrome Scale (PANSS) total score <70] with PP1M to PP3M in a naturalistic clinical setting. 22 The authors reported that 56.8% of patients achieved symptomatic remission [two-fold criteria as defined by the Remission in Schizophrenia Working Group: (1) symptom control based on PANSS eight core items, 23 (2) maintained for a minimum of 6 consecutive months], and 31.8% achieved both symptomatic and ‘functional remission’ [Personal and Social Performance (PSP) total score >70] at last observation carried forward (LOCF) endpoint. Patients who achieved symptomatic remission tended to be younger and had a shorter disease duration than those who did not achieve symptomatic remission. 22
Here we report results from exploratory
Methods
REMISSIO study design and PP3M treatment
REMISSIO (ClinicalTrials.gov: NCT02713282; EudraCT: 2015-004835-10) was a single-arm, open-label, 52-week, phase 3b study designed to evaluate the efficacy and safety of converting adult patients with schizophrenia stabilized with PP1M for ⩾4 months (the last two doses the same) to PP3M in a naturalistic clinical setting. Patients in the study had baseline PANSS total score <70 and were considered by the physician likely to benefit from switching. The study design (supplemental material Figure 1), patient eligibility criteria, and PP3M treatment and dosing were described in the primary publication. 22 The study protocol and amendments were reviewed by an independent ethics committee or institutional review board, as appropriate, for each study site. The study was conducted in compliance with the Declaration of Helsinki and was consistent with Good Clinical Practice and applicable regulatory requirements. Written informed consent was obtained from all patients before enrollment.
Efficacy and safety endpoints
The primary efficacy endpoint was the proportion of patients achieving symptomatic remission (according to the two-fold Andreasen criteria 23 ) at LOCF endpoint. 22 Secondary efficacy endpoints 22 included: symptomatic remission at Months 6, 9, 12; time to symptomatic remission; change from baseline in PANSS (total and subscales) and the five Marder factors, Clinical Global Impression-Severity (CGI-S) and Clinical Global Impression-Change (CGI-C) scores; PSP total and subscale scores; functional remission; patient satisfaction with medication; and health care resource utilization. Other secondary endpoints and safety evaluations are described more fully in the primary manuscript. 22
Statistical analysis
The modified intention-to-treat efficacy and safety analysis sets comprised all patients who provided written consent, received at least one dose of PP3M during the 52-week treatment period, and had at least one post-baseline efficacy or safety assessment, respectively. 22
Exploratory
Results
Patients
In total, 305 patients were included in the subgroup analysis: 123 in the younger (<35 years) group and 182 in the older (⩾35 years) group. Study completion rates were high in both age groups (younger: 95.9%; older: 95.1%) (Figure 1).

Patient disposition (mITT analysis set) when analysed by (a) age; and (b) disease duration.
There were 72 patients in the ⩽3 years disease duration and 233 in the >3 years group. The mean (standard deviation; SD) disease duration in each group was 1.7 (1.1) years and 11.6 (6.8) years, respectively.
Baseline demographics and clinical characteristics
The mean (SD) age of the younger group was 28.5 (3.8) years
Demographic and baseline clinical characteristics (mITT analysis set).
Values are mean (standard deviation) unless otherwise stated.
To baseline visit.
BMI, body mass index; mITT, modified intention-to-treat; PP1M, paliperidone palmitate 1-month.
Baseline demographics and clinical characteristics for the two disease duration groups are presented in Table 1. When comparing age groups, the rate of prior hospitalization and suicide attempts are similar, but there were fewer suicide attempts in those with a shorter than a longer duration of disease (2.8%
PP3M exposure and dose
The mean duration of PP3M exposure, mean dose of PP3M and distribution of PP3M dose categories were similar in the two age (Table 2) and the two disease duration groups. The proportion of patients who required dose modification was low overall: 12.2% (⩾1 dose decrease/increase: 7.3%/4.9%)
PP3M exposure and dosing (mITT analysis set).
Values are mean (standard deviation) unless otherwise stated.
Time between the first and last PP3M administration.
eq., equivalent; mITT, modified intention-to-treat; PP3M, paliperidone palmitate 3-monthly.
Concomitant medication
The proportions of patients requiring concomitant medication at baseline and during PP3M treatment were similar in the two age groups. At baseline, 43.1% of younger
For those with disease duration of >3 years, 44.6% continued to use at least one psychotropic medication initiated prior to starting PP3M and 27.9% initiated treatment with a new psychotropic medication after starting PP3M.
Primary efficacy endpoint
At LOCF endpoint, 60.7% (95% CI: 51.4%, 69.4%) of younger patients and 54.1% of older patients (95% CI: 46.6%, 61.6%) achieved symptomatic remission (Figure 2a).

Symptomatic remission during follow-up and at LOCF endpoint (mITT efficacy set) by (a) patient age; and (b) disease duration.
When analysed by shorter or longer disease duration, similar proportions (95% CI) of patients achieved symptomatic remission at LOCF endpoint: 57.8% (45.4%, 69.4%)
Secondary efficacy endpoints
The Kaplan–Meier estimate of median (95% CI) time to symptomatic remission was numerically, though non-significantly shorter for younger patients, 189 (184, 262) days
PANSS total and subscales
At baseline, mean (95% CI) PANSS total scores were similar: 51.2 (49.1, 53.2)

Mean PANSS total score: from baseline to LOCF endpoint (mITT efficacy set) by (a) patient age; and (b) disease duration.
PANSS subscale scores: change from baseline to LOCF endpoint (mITT efficacy set).
Data are mean (95% CI). Only patients with baseline and ⩾1 post-baseline assessments were included in the analysis.
CI, confidence interval; LOCF, last observation carried forward; mITT, modified intention-to-treat; PANSS, Positive and Negative Syndrome Scale.
Mean (95% CI) PANSS total scores were similar in patients with disease duration of ⩽3 years [52.5 (49.9, 55.1)] and of >3 years [52.4 (51.1, 53.8)] at baseline, and indicated mild/moderate disease severity. Mean (95% CI) PANSS total score change from baseline to LOCF endpoint was −2.8 (−4.9, −0.7) and −3.2 (−4.3, −2.0) for the ⩽3 year and >3 year groups, respectively (Figure 3b).
Clinical Global Impression
Mean (95% CI) CGI-S scores at baseline and LOCF were similar in both age groups. The proportion of patients with CGI-C scores indicating improvements at LOCF endpoint were slightly higher in the younger group: 70.4%

CGI-C: frequency distribution score categories at LOCF endpoint (mITT efficacy set) by (a) patient age; and (b) disease duration.
Personal and Social Performance
There was a trend suggesting that more patients in the younger age group achieved functional remission, PSP score 71–100 (95% CI) both at baseline [43.7% (34.6, 53.1)

PSP frequency distribution score categories* from baseline to LOCF endpoint (mITT efficacy set) by (a) patient age; and (b) disease duration.

Composite symptomatic and functional remission* during follow-up and at LOCF endpoint (mITT efficacy set)† by (a) patient age; and (b) disease duration.
Satisfaction with medication
Patient satisfaction with medication was high in both age groups at baseline and LOCF endpoint. The proportion of younger/older patients who were very or extremely satisfied was 57.5%/61.1% at baseline and 63.4%/60.4% at LOCF endpoint, respectively. The proportion of physicians reporting that they were very or extremely satisfied with the medication given to younger/older patients was 64.7%/69.0% at baseline and 78.2%/73.6% at LOCF endpoint, respectively.
The proportion of recently diagnosed/chronic patients who were very or extremely satisfied was 58.6%/60.0% at baseline and 60.0%/62.1% at LOCF endpoint, respectively. The proportions of physicians who reported being very or extremely satisfied with the medication given to recently diagnosed/chronic patients was 65.6%/67.7% at baseline and 71.6%/76.6% at LOCF endpoint, respectively.
Carer burden
The overall carer burden, as assessed by mean (95% CI) Involvement Evaluation Questionnaire (IEQ) total score, decreased from 22.0 (19.7, 24.4) at baseline to 19.5 (17.2, 21.8) at LOCF endpoint in younger patients and from 25.1 (22.1, 28.1) to 20.0 (17.5, 22.5) in older patients, equating to changes from baseline of −2.6 (−4.9, −0.2) and −5.1 (−8.0, −2.3), respectively. There were similar reductions in the IEQ total score in patients with both shorter and longer duration of disease.
Healthcare resource utilization
The proportion of patients requiring hospitalization for psychiatric reasons in the younger group was 16.4% in the 12 months prior to baseline and 4.9% during the PP3M treatment period. Corresponding rates in the older group were 9.4% and 1.1%, respectively (Figure 7a). Mean (SD) total number of days spent in hospital for psychiatric reasons were 33.6 (22.9) in the 12 months prior to baseline and 13.8 (10.3) during the PP3M treatment period in younger patients, and 32.7 (22.6) and 16.1 (11.7) in older patients, respectively. When analysed by duration of disease, the proportion of patients requiring hospitalization for psychiatric reasons in the shorter disease duration group was 23.9% in the 12 months before PP3M initiation and 4.2% during PP3M treatment. In the more chronic group, the proportions were 8.6% and 2.2%, respectively (Figure 7b).

Hospitalizations for psychiatric reasons: prior to PP3M initiation and during follow-up (mITT efficacy set) by (a) patient age; and (b) disease duration.
Relationship between disease duration and patient age
To investigate the influence of patient age, the disease duration groups were stratified according to age (<35 years and ⩾35 years). As expected, psychiatric history was most extensive in older patients with chronic disease (duration >3 years, age ⩾35 years).
Selected efficacy endpoints for this analysis are presented in Supplemental Table 1. Symptomatic remission rates at LOCF endpoint improved by a comparable amount across all four groups. Generally, patients in the older group and those with more chronic disease tended to achieve lower effectiveness responses among the four groups.
Safety
Overall, the safety data were similar in the two age groups and in those with disease of shorter and longer disease duration, with a possible indication of more frequent adverse effects in those with a shorter disease duration compared with a longer duration (Table 4). The proportions of younger
Summary of TEAEs (mITT safety set).
Events occurring >1% in either group shown.
AE, adverse event; mITT, modified intention-to-treat; TEAE, treatment-emergent adverse event.
The proportion of TEAEs leading to study discontinuation was low and similar in both age groups (1.6%
There was a slightly higher proportion of younger patients with possible/probable/very likely drug-related TEAEs (32.8%
The most common drug-related TEAEs were injection site pain (6.6%
Discussion
This
The early phase of psychosis is a critical window for treatment – the aggressive nature of schizophrenia, the intensity of symptoms and functional deterioration occur in the first years after diagnosis.25,26 Earlier LAT use is associated with favourable clinical outcomes, and LATs are increasingly recognized as an earlier treatment option for younger adult patients.13,27
Several factors determined the age cut-off point of 35 years. Firstly, various psychosis early-intervention programmes set the upper limit of age entry as 35 years.24,28 Secondly, studies often define the upper age limit for younger patients at 35–40 years.29–31 Lastly, results of a recent multinational incidence study reported that most patients – 68% of men and 51% of women – present to mental health services before 35 years of age. 32
The duration cut-off at 3 years is based on the ‘critical period hypothesis’. This suggests that the psychosocial function of patients with schizophreniform illnesses declines within the first 3 years after onset and then tends to level out. The authors suggested that intensive treatment, including antipsychotic medication, in the first 3 years of illness could improve long-term outcomes.25,26
Achieving and maintaining symptomatic remission is an important treatment goal associated with significant functioning and quality of life, and may reduce healthcare resource utilization.33,34 Despite such improvements, patients may not attain the same level of functioning that they had before the episode/relapse, and symptom remission should be considered ‘a necessary, but not sufficient step towards recovery’. 23
The most important finding in this
Patient age is, of course, correlated with disease duration, and in the current analysis, mean disease duration in the younger group was less than half that of the older group. It is possible that disease duration rather than age
As a complement to symptomatic remission, functional remission is a valuable goal for patients with schizophrenia. It is associated with real-world outcomes, such as ability to work and live independently.38–41 The functional remission data in this analysis indicated that younger patients had higher baseline functioning, and this was maintained to LOCF endpoint. This is supportive evidence for use of LATs in younger patients in early disease, and is consistent with a retrospective review of medical records of adult patients with newly diagnosed schizophrenia which found improvements in functional remission in young patients (mean age: 24.1 years) receiving treatment with PP1M for ⩾12 months in a naturalistic clinical setting. 41
In the present analysis, somewhat higher proportions of younger than older patients and shorter than longer disease duration achieved both symptomatic and functional remission (although CIs overlapped, indicating a non-significant trend). This is in line with an observational study of a cohort of young patients with schizophrenia (<35 years) treated with LATs, which found that clinical remission correlated strongly with functional remission. The authors proposed that clinical remission ‘facilitated’ functional remission, particularly during the early phase of the illness. 42
PANSS total and subscale scores indicated a reduction in disease severity during the 1-year follow-up period in both age groups. Improvements were seen in both negative symptoms and other non-psychotic symptoms. The improvement in disease severity indicated by PANSS scores was corroborated by the high proportion of patients with CGI-C improvements in both age groups. Various studies have demonstrated improvements in PANSS in patients with early schizophrenia treated with LATs.
13
For example, in an open-label trial of 382 patients who had been diagnosed with schizophrenia for a mean of 1.5 years and who had received a LAT for 6 months, significant (
The rates and number of days of hospitalizations for psychiatric reasons decreased during the year after PP3M initiation in both age groups. This is consistent with both the primary REMISSIO study and other studies that have demonstrated a reduction in rehospitalization rates for patients treated with LATs.19,22,45 For example, an electronic healthcare database study involving veterans with schizophrenia who were transitioned from PP1M to PP3M demonstrated a significant reduction in mean total healthcare costs (from $27,745 to $23,772). 46 A cost-effectiveness analysis in the Netherlands reported that PP3M performed better than PP1M, risperidone LAT, haloperidol LAT and oral olanzapine in relation to hospitalization rates (0.11, 0.46, 0.40, 0.56 and 0.57, respectively). 45 A separate analysis in Spain found patients treated with PP3M to have a lower hospitalization rate than those treated with PP1M (0.034 and 0.065, respectively). 47
As in the primary study,
22
patient and physician satisfaction with PP3M therapy was high, in line with the high study completion rates (>95% in both age groups). Mean PP3M dose and duration of exposure were similar for both age groups. Overall low frequency of dose changes (which were permitted after first PP3M administration) during the study confirms the real-world pragmatic applicability of the dose-switching regimen in the prescribing information.16,17 Frequency of dose adjustments, albeit low, was about twice that in the younger (12.2%) than the older age group (6.0%). While this could suggest that a proportion of younger patients – possibly those with the lowest duration of disease – may not have been adequately stabilized on PP1M prior to switching to PP3M, there are several other reasons why such dose adjustments may have occurred. For example, high levels of patient functioning, weight gain and problematic alcohol use have been shown to be predictors of dose modification or discontinuation in patients with schizophrenia.
35
Ringen
PP3M generally exhibited a favourable safety profile and was well tolerated in both age and duration groups. The proportion of patients with possible/probable or very likely drug-related TEAEs was slightly higher in the younger
The primary limitations of this analysis are those inherent to
Conclusion
The results from this exploratory
Supplemental Material
sj-pdf-1-tpp-10.1177_2045125320981500 – Supplemental material for Stable patients with schizophrenia switched to paliperidone palmitate 3-monthly formulation in a naturalistic setting: impact of patient age and disease duration on outcomes
Supplemental material, sj-pdf-1-tpp-10.1177_2045125320981500 for Stable patients with schizophrenia switched to paliperidone palmitate 3-monthly formulation in a naturalistic setting: impact of patient age and disease duration on outcomes by Katalin Pungor, Vasilis P. Bozikas, Robin Emsley, Pierre-Michel Llorca, Srihari Gopal, Maju Mathews, Annette Wooller and Paul Bergmans in Therapeutic Advances in Psychopharmacology
Supplemental Material
sj-pdf-2-tpp-10.1177_2045125320981500 – Supplemental material for Stable patients with schizophrenia switched to paliperidone palmitate 3-monthly formulation in a naturalistic setting: impact of patient age and disease duration on outcomes
Supplemental material, sj-pdf-2-tpp-10.1177_2045125320981500 for Stable patients with schizophrenia switched to paliperidone palmitate 3-monthly formulation in a naturalistic setting: impact of patient age and disease duration on outcomes by Katalin Pungor, Vasilis P. Bozikas, Robin Emsley, Pierre-Michel Llorca, Srihari Gopal, Maju Mathews, Annette Wooller and Paul Bergmans in Therapeutic Advances in Psychopharmacology
Supplemental Material
sj-pdf-3-tpp-10.1177_2045125320981500 – Supplemental material for Stable patients with schizophrenia switched to paliperidone palmitate 3-monthly formulation in a naturalistic setting: impact of patient age and disease duration on outcomes
Supplemental material, sj-pdf-3-tpp-10.1177_2045125320981500 for Stable patients with schizophrenia switched to paliperidone palmitate 3-monthly formulation in a naturalistic setting: impact of patient age and disease duration on outcomes by Katalin Pungor, Vasilis P. Bozikas, Robin Emsley, Pierre-Michel Llorca, Srihari Gopal, Maju Mathews, Annette Wooller and Paul Bergmans in Therapeutic Advances in Psychopharmacology
Footnotes
Conflict of interest statement
Funding
Data sharing statement
Supplemental material
References
Supplementary Material
Please find the following supplemental material available below.
For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.
For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.
