Every-6-month dosing of the long-acting injectable paliperidone palmitate (Invega Hafyera) for schizophrenia was effective and safe up to 3 years, researchers reported during a poster presentation at the recent Psych Congress 2023.

In this exclusive MedPage Today video, lead author Christoph Correll, MD, of the Feinstein Institutes for Medical Research at Northwell Health in Manhasset, New York, explains the study design, results, and conclusions.

Following is a transcript of his remarks:

Hi everyone, I’m going to talk about a poster where we looked at the outcomes when transitioning to Paliperidone Palmitate 6-months from paliperidone palmitate 1-month versus paliperidone palmitate 3-months [PP3M].

So in this study that was funded by Janssen Scientific Affairs, clinically stable patients with schizophrenia who wish to transition to paliperidone palmitate once-every-6-months (or PP6M) can do so while they’ve either been adequately treated with paliperidone palmitate once-monthly (or PP1M) for at least 4 months, to paliperidone palmitate once-monthly every 3 months, or paliperidone palmitate 3-months directly for at least one injection cycle.

Results from that double-blind, randomized, active-controlled, parallel group, noninferiority trial demonstrated that the efficacy of a twice-yearly dosing regimen of paliperidone palmitate 6-monthly was noninferior to that of paliperidone 3-monthly, preventing relapse in patients with schizophrenia adequately treated with either previously PP1M or PP3M.

The relapse rates were 7.5% for the 6-monthly formulation and 4.9% for the 3-monthly formulation. So the differences in relapse rates for the patients transitioning from PP1M to PP6M or PP3M to PP6M had not been assessed previously and that was the objective of this poster.

In terms of the design, these were patients 18 to 70 years of age. They had a DSM5 diagnosis of schizophrenia and a PANSS [Positive and Negative Syndrome Scale] total score of at least 70. The primary efficacy endpoint was relapse during the double-blind phase, and a Kaplan-Meier method — that’s a survival method of analysis — was used to estimate the 12-month cumulative estimate rates of people remaining relapse free. And then there was a noninferiority margin that shouldn’t exceed 10% difference.

Secondary endpoints included change from baseline during the double-blind phase and PANSS total and subscores, CGI [clinical global impression] severity scale scores, and the PSP — or the personal and social performance scale — that looks at functioning. And then there were also safety assessments that are the usual.

In terms of results, there were 231 patients in the PP1M-to-PP6M group, 247 patients in the PP3M-to-PP6M group, and 224 patients in the comparator PP3M group. Baseline demographic and disease characteristics were very similar. In terms of Kaplan-Meier estimates of the relapse, basically the transition from PP1M to PP6M after 4 months of PP1M or PP3M to PP6M were basically very similar with a -2.7 for the PP1M-to-PP6M and a -2.9 from the PP3M-to-PP6M. Relapse occurred in 7.8% of patients in the PP1M-to-PP6M group and 7.3% — only 0.5% difference — in the PP3M-to-PP6M group. And the median time to relapse was not estimable in any group because there were so few people who relapsed, less than 90% or 93% basically.

Basically in terms of PANSS total and subscale scores, PSP, and CGI scores, they were also further improving somewhat, and they were similar between the groups.

In terms of adverse effects, a total of 61% and 63.2% of patients in the PP1M-to-PP6M and PP3M-to-PP6M groups experienced a treatment emergent adverse event. So there was no difference whether you went from a 4-month at least 1-monthly formulation to 6-month, or at least one cycle of the 3-months.

One limitation is that the initial PP1M or PP3M treatment was not randomized, that was clinically determined. But then there was randomization, whether people went into the PP3M or PP6M arm.

So in conclusion, adults with schizophrenia who transitioned to PP6M from either PP1M or PP3M experience similarly low relapse rates. That supports generalizability of the noninferiority findings, whether you go from the 1-month or 3-month formulation to the 6-month formulation, and it’s noninferior also to the 3-month formulation.